Source file src/reflect/all_test.go

Documentation: reflect

     1  // Copyright 2009 The Go Authors. All rights reserved.
     2  // Use of this source code is governed by a BSD-style
     3  // license that can be found in the LICENSE file.
     4  
     5  package reflect_test
     6  
     7  import (
     8  	"bytes"
     9  	"encoding/base64"
    10  	"flag"
    11  	"fmt"
    12  	"go/token"
    13  	"io"
    14  	"math"
    15  	"math/rand"
    16  	"os"
    17  	. "reflect"
    18  	"runtime"
    19  	"sort"
    20  	"strconv"
    21  	"strings"
    22  	"sync"
    23  	"sync/atomic"
    24  	"testing"
    25  	"time"
    26  	"unsafe"
    27  )
    28  
    29  var sink interface{}
    30  
    31  func TestBool(t *testing.T) {
    32  	v := ValueOf(true)
    33  	if v.Bool() != true {
    34  		t.Fatal("ValueOf(true).Bool() = false")
    35  	}
    36  }
    37  
    38  type integer int
    39  type T struct {
    40  	a int
    41  	b float64
    42  	c string
    43  	d *int
    44  }
    45  
    46  type pair struct {
    47  	i interface{}
    48  	s string
    49  }
    50  
    51  func assert(t *testing.T, s, want string) {
    52  	if s != want {
    53  		t.Errorf("have %#q want %#q", s, want)
    54  	}
    55  }
    56  
    57  var typeTests = []pair{
    58  	{struct{ x int }{}, "int"},
    59  	{struct{ x int8 }{}, "int8"},
    60  	{struct{ x int16 }{}, "int16"},
    61  	{struct{ x int32 }{}, "int32"},
    62  	{struct{ x int64 }{}, "int64"},
    63  	{struct{ x uint }{}, "uint"},
    64  	{struct{ x uint8 }{}, "uint8"},
    65  	{struct{ x uint16 }{}, "uint16"},
    66  	{struct{ x uint32 }{}, "uint32"},
    67  	{struct{ x uint64 }{}, "uint64"},
    68  	{struct{ x float32 }{}, "float32"},
    69  	{struct{ x float64 }{}, "float64"},
    70  	{struct{ x int8 }{}, "int8"},
    71  	{struct{ x (**int8) }{}, "**int8"},
    72  	{struct{ x (**integer) }{}, "**reflect_test.integer"},
    73  	{struct{ x ([32]int32) }{}, "[32]int32"},
    74  	{struct{ x ([]int8) }{}, "[]int8"},
    75  	{struct{ x (map[string]int32) }{}, "map[string]int32"},
    76  	{struct{ x (chan<- string) }{}, "chan<- string"},
    77  	{struct {
    78  		x struct {
    79  			c chan *int32
    80  			d float32
    81  		}
    82  	}{},
    83  		"struct { c chan *int32; d float32 }",
    84  	},
    85  	{struct{ x (func(a int8, b int32)) }{}, "func(int8, int32)"},
    86  	{struct {
    87  		x struct {
    88  			c func(chan *integer, *int8)
    89  		}
    90  	}{},
    91  		"struct { c func(chan *reflect_test.integer, *int8) }",
    92  	},
    93  	{struct {
    94  		x struct {
    95  			a int8
    96  			b int32
    97  		}
    98  	}{},
    99  		"struct { a int8; b int32 }",
   100  	},
   101  	{struct {
   102  		x struct {
   103  			a int8
   104  			b int8
   105  			c int32
   106  		}
   107  	}{},
   108  		"struct { a int8; b int8; c int32 }",
   109  	},
   110  	{struct {
   111  		x struct {
   112  			a int8
   113  			b int8
   114  			c int8
   115  			d int32
   116  		}
   117  	}{},
   118  		"struct { a int8; b int8; c int8; d int32 }",
   119  	},
   120  	{struct {
   121  		x struct {
   122  			a int8
   123  			b int8
   124  			c int8
   125  			d int8
   126  			e int32
   127  		}
   128  	}{},
   129  		"struct { a int8; b int8; c int8; d int8; e int32 }",
   130  	},
   131  	{struct {
   132  		x struct {
   133  			a int8
   134  			b int8
   135  			c int8
   136  			d int8
   137  			e int8
   138  			f int32
   139  		}
   140  	}{},
   141  		"struct { a int8; b int8; c int8; d int8; e int8; f int32 }",
   142  	},
   143  	{struct {
   144  		x struct {
   145  			a int8 `reflect:"hi there"`
   146  		}
   147  	}{},
   148  		`struct { a int8 "reflect:\"hi there\"" }`,
   149  	},
   150  	{struct {
   151  		x struct {
   152  			a int8 `reflect:"hi \x00there\t\n\"\\"`
   153  		}
   154  	}{},
   155  		`struct { a int8 "reflect:\"hi \\x00there\\t\\n\\\"\\\\\"" }`,
   156  	},
   157  	{struct {
   158  		x struct {
   159  			f func(args ...int)
   160  		}
   161  	}{},
   162  		"struct { f func(...int) }",
   163  	},
   164  	{struct {
   165  		x (interface {
   166  			a(func(func(int) int) func(func(int)) int)
   167  			b()
   168  		})
   169  	}{},
   170  		"interface { reflect_test.a(func(func(int) int) func(func(int)) int); reflect_test.b() }",
   171  	},
   172  	{struct {
   173  		x struct {
   174  			int32
   175  			int64
   176  		}
   177  	}{},
   178  		"struct { int32; int64 }",
   179  	},
   180  }
   181  
   182  var valueTests = []pair{
   183  	{new(int), "132"},
   184  	{new(int8), "8"},
   185  	{new(int16), "16"},
   186  	{new(int32), "32"},
   187  	{new(int64), "64"},
   188  	{new(uint), "132"},
   189  	{new(uint8), "8"},
   190  	{new(uint16), "16"},
   191  	{new(uint32), "32"},
   192  	{new(uint64), "64"},
   193  	{new(float32), "256.25"},
   194  	{new(float64), "512.125"},
   195  	{new(complex64), "532.125+10i"},
   196  	{new(complex128), "564.25+1i"},
   197  	{new(string), "stringy cheese"},
   198  	{new(bool), "true"},
   199  	{new(*int8), "*int8(0)"},
   200  	{new(**int8), "**int8(0)"},
   201  	{new([5]int32), "[5]int32{0, 0, 0, 0, 0}"},
   202  	{new(**integer), "**reflect_test.integer(0)"},
   203  	{new(map[string]int32), "map[string]int32{<can't iterate on maps>}"},
   204  	{new(chan<- string), "chan<- string"},
   205  	{new(func(a int8, b int32)), "func(int8, int32)(0)"},
   206  	{new(struct {
   207  		c chan *int32
   208  		d float32
   209  	}),
   210  		"struct { c chan *int32; d float32 }{chan *int32, 0}",
   211  	},
   212  	{new(struct{ c func(chan *integer, *int8) }),
   213  		"struct { c func(chan *reflect_test.integer, *int8) }{func(chan *reflect_test.integer, *int8)(0)}",
   214  	},
   215  	{new(struct {
   216  		a int8
   217  		b int32
   218  	}),
   219  		"struct { a int8; b int32 }{0, 0}",
   220  	},
   221  	{new(struct {
   222  		a int8
   223  		b int8
   224  		c int32
   225  	}),
   226  		"struct { a int8; b int8; c int32 }{0, 0, 0}",
   227  	},
   228  }
   229  
   230  func testType(t *testing.T, i int, typ Type, want string) {
   231  	s := typ.String()
   232  	if s != want {
   233  		t.Errorf("#%d: have %#q, want %#q", i, s, want)
   234  	}
   235  }
   236  
   237  func TestTypes(t *testing.T) {
   238  	for i, tt := range typeTests {
   239  		testType(t, i, ValueOf(tt.i).Field(0).Type(), tt.s)
   240  	}
   241  }
   242  
   243  func TestSet(t *testing.T) {
   244  	for i, tt := range valueTests {
   245  		v := ValueOf(tt.i)
   246  		v = v.Elem()
   247  		switch v.Kind() {
   248  		case Int:
   249  			v.SetInt(132)
   250  		case Int8:
   251  			v.SetInt(8)
   252  		case Int16:
   253  			v.SetInt(16)
   254  		case Int32:
   255  			v.SetInt(32)
   256  		case Int64:
   257  			v.SetInt(64)
   258  		case Uint:
   259  			v.SetUint(132)
   260  		case Uint8:
   261  			v.SetUint(8)
   262  		case Uint16:
   263  			v.SetUint(16)
   264  		case Uint32:
   265  			v.SetUint(32)
   266  		case Uint64:
   267  			v.SetUint(64)
   268  		case Float32:
   269  			v.SetFloat(256.25)
   270  		case Float64:
   271  			v.SetFloat(512.125)
   272  		case Complex64:
   273  			v.SetComplex(532.125 + 10i)
   274  		case Complex128:
   275  			v.SetComplex(564.25 + 1i)
   276  		case String:
   277  			v.SetString("stringy cheese")
   278  		case Bool:
   279  			v.SetBool(true)
   280  		}
   281  		s := valueToString(v)
   282  		if s != tt.s {
   283  			t.Errorf("#%d: have %#q, want %#q", i, s, tt.s)
   284  		}
   285  	}
   286  }
   287  
   288  func TestSetValue(t *testing.T) {
   289  	for i, tt := range valueTests {
   290  		v := ValueOf(tt.i).Elem()
   291  		switch v.Kind() {
   292  		case Int:
   293  			v.Set(ValueOf(int(132)))
   294  		case Int8:
   295  			v.Set(ValueOf(int8(8)))
   296  		case Int16:
   297  			v.Set(ValueOf(int16(16)))
   298  		case Int32:
   299  			v.Set(ValueOf(int32(32)))
   300  		case Int64:
   301  			v.Set(ValueOf(int64(64)))
   302  		case Uint:
   303  			v.Set(ValueOf(uint(132)))
   304  		case Uint8:
   305  			v.Set(ValueOf(uint8(8)))
   306  		case Uint16:
   307  			v.Set(ValueOf(uint16(16)))
   308  		case Uint32:
   309  			v.Set(ValueOf(uint32(32)))
   310  		case Uint64:
   311  			v.Set(ValueOf(uint64(64)))
   312  		case Float32:
   313  			v.Set(ValueOf(float32(256.25)))
   314  		case Float64:
   315  			v.Set(ValueOf(512.125))
   316  		case Complex64:
   317  			v.Set(ValueOf(complex64(532.125 + 10i)))
   318  		case Complex128:
   319  			v.Set(ValueOf(complex128(564.25 + 1i)))
   320  		case String:
   321  			v.Set(ValueOf("stringy cheese"))
   322  		case Bool:
   323  			v.Set(ValueOf(true))
   324  		}
   325  		s := valueToString(v)
   326  		if s != tt.s {
   327  			t.Errorf("#%d: have %#q, want %#q", i, s, tt.s)
   328  		}
   329  	}
   330  }
   331  
   332  func TestCanSetField(t *testing.T) {
   333  	type embed struct{ x, X int }
   334  	type Embed struct{ x, X int }
   335  	type S1 struct {
   336  		embed
   337  		x, X int
   338  	}
   339  	type S2 struct {
   340  		*embed
   341  		x, X int
   342  	}
   343  	type S3 struct {
   344  		Embed
   345  		x, X int
   346  	}
   347  	type S4 struct {
   348  		*Embed
   349  		x, X int
   350  	}
   351  
   352  	type testCase struct {
   353  		index  []int
   354  		canSet bool
   355  	}
   356  	tests := []struct {
   357  		val   Value
   358  		cases []testCase
   359  	}{{
   360  		val: ValueOf(&S1{}),
   361  		cases: []testCase{
   362  			{[]int{0}, false},
   363  			{[]int{0, 0}, false},
   364  			{[]int{0, 1}, true},
   365  			{[]int{1}, false},
   366  			{[]int{2}, true},
   367  		},
   368  	}, {
   369  		val: ValueOf(&S2{embed: &embed{}}),
   370  		cases: []testCase{
   371  			{[]int{0}, false},
   372  			{[]int{0, 0}, false},
   373  			{[]int{0, 1}, true},
   374  			{[]int{1}, false},
   375  			{[]int{2}, true},
   376  		},
   377  	}, {
   378  		val: ValueOf(&S3{}),
   379  		cases: []testCase{
   380  			{[]int{0}, true},
   381  			{[]int{0, 0}, false},
   382  			{[]int{0, 1}, true},
   383  			{[]int{1}, false},
   384  			{[]int{2}, true},
   385  		},
   386  	}, {
   387  		val: ValueOf(&S4{Embed: &Embed{}}),
   388  		cases: []testCase{
   389  			{[]int{0}, true},
   390  			{[]int{0, 0}, false},
   391  			{[]int{0, 1}, true},
   392  			{[]int{1}, false},
   393  			{[]int{2}, true},
   394  		},
   395  	}}
   396  
   397  	for _, tt := range tests {
   398  		t.Run(tt.val.Type().Name(), func(t *testing.T) {
   399  			for _, tc := range tt.cases {
   400  				f := tt.val
   401  				for _, i := range tc.index {
   402  					if f.Kind() == Ptr {
   403  						f = f.Elem()
   404  					}
   405  					f = f.Field(i)
   406  				}
   407  				if got := f.CanSet(); got != tc.canSet {
   408  					t.Errorf("CanSet() = %v, want %v", got, tc.canSet)
   409  				}
   410  			}
   411  		})
   412  	}
   413  }
   414  
   415  var _i = 7
   416  
   417  var valueToStringTests = []pair{
   418  	{123, "123"},
   419  	{123.5, "123.5"},
   420  	{byte(123), "123"},
   421  	{"abc", "abc"},
   422  	{T{123, 456.75, "hello", &_i}, "reflect_test.T{123, 456.75, hello, *int(&7)}"},
   423  	{new(chan *T), "*chan *reflect_test.T(&chan *reflect_test.T)"},
   424  	{[10]int{1, 2, 3, 4, 5, 6, 7, 8, 9, 10}, "[10]int{1, 2, 3, 4, 5, 6, 7, 8, 9, 10}"},
   425  	{&[10]int{1, 2, 3, 4, 5, 6, 7, 8, 9, 10}, "*[10]int(&[10]int{1, 2, 3, 4, 5, 6, 7, 8, 9, 10})"},
   426  	{[]int{1, 2, 3, 4, 5, 6, 7, 8, 9, 10}, "[]int{1, 2, 3, 4, 5, 6, 7, 8, 9, 10}"},
   427  	{&[]int{1, 2, 3, 4, 5, 6, 7, 8, 9, 10}, "*[]int(&[]int{1, 2, 3, 4, 5, 6, 7, 8, 9, 10})"},
   428  }
   429  
   430  func TestValueToString(t *testing.T) {
   431  	for i, test := range valueToStringTests {
   432  		s := valueToString(ValueOf(test.i))
   433  		if s != test.s {
   434  			t.Errorf("#%d: have %#q, want %#q", i, s, test.s)
   435  		}
   436  	}
   437  }
   438  
   439  func TestArrayElemSet(t *testing.T) {
   440  	v := ValueOf(&[10]int{1, 2, 3, 4, 5, 6, 7, 8, 9, 10}).Elem()
   441  	v.Index(4).SetInt(123)
   442  	s := valueToString(v)
   443  	const want = "[10]int{1, 2, 3, 4, 123, 6, 7, 8, 9, 10}"
   444  	if s != want {
   445  		t.Errorf("[10]int: have %#q want %#q", s, want)
   446  	}
   447  
   448  	v = ValueOf([]int{1, 2, 3, 4, 5, 6, 7, 8, 9, 10})
   449  	v.Index(4).SetInt(123)
   450  	s = valueToString(v)
   451  	const want1 = "[]int{1, 2, 3, 4, 123, 6, 7, 8, 9, 10}"
   452  	if s != want1 {
   453  		t.Errorf("[]int: have %#q want %#q", s, want1)
   454  	}
   455  }
   456  
   457  func TestPtrPointTo(t *testing.T) {
   458  	var ip *int32
   459  	var i int32 = 1234
   460  	vip := ValueOf(&ip)
   461  	vi := ValueOf(&i).Elem()
   462  	vip.Elem().Set(vi.Addr())
   463  	if *ip != 1234 {
   464  		t.Errorf("got %d, want 1234", *ip)
   465  	}
   466  
   467  	ip = nil
   468  	vp := ValueOf(&ip).Elem()
   469  	vp.Set(Zero(vp.Type()))
   470  	if ip != nil {
   471  		t.Errorf("got non-nil (%p), want nil", ip)
   472  	}
   473  }
   474  
   475  func TestPtrSetNil(t *testing.T) {
   476  	var i int32 = 1234
   477  	ip := &i
   478  	vip := ValueOf(&ip)
   479  	vip.Elem().Set(Zero(vip.Elem().Type()))
   480  	if ip != nil {
   481  		t.Errorf("got non-nil (%d), want nil", *ip)
   482  	}
   483  }
   484  
   485  func TestMapSetNil(t *testing.T) {
   486  	m := make(map[string]int)
   487  	vm := ValueOf(&m)
   488  	vm.Elem().Set(Zero(vm.Elem().Type()))
   489  	if m != nil {
   490  		t.Errorf("got non-nil (%p), want nil", m)
   491  	}
   492  }
   493  
   494  func TestAll(t *testing.T) {
   495  	testType(t, 1, TypeOf((int8)(0)), "int8")
   496  	testType(t, 2, TypeOf((*int8)(nil)).Elem(), "int8")
   497  
   498  	typ := TypeOf((*struct {
   499  		c chan *int32
   500  		d float32
   501  	})(nil))
   502  	testType(t, 3, typ, "*struct { c chan *int32; d float32 }")
   503  	etyp := typ.Elem()
   504  	testType(t, 4, etyp, "struct { c chan *int32; d float32 }")
   505  	styp := etyp
   506  	f := styp.Field(0)
   507  	testType(t, 5, f.Type, "chan *int32")
   508  
   509  	f, present := styp.FieldByName("d")
   510  	if !present {
   511  		t.Errorf("FieldByName says present field is absent")
   512  	}
   513  	testType(t, 6, f.Type, "float32")
   514  
   515  	f, present = styp.FieldByName("absent")
   516  	if present {
   517  		t.Errorf("FieldByName says absent field is present")
   518  	}
   519  
   520  	typ = TypeOf([32]int32{})
   521  	testType(t, 7, typ, "[32]int32")
   522  	testType(t, 8, typ.Elem(), "int32")
   523  
   524  	typ = TypeOf((map[string]*int32)(nil))
   525  	testType(t, 9, typ, "map[string]*int32")
   526  	mtyp := typ
   527  	testType(t, 10, mtyp.Key(), "string")
   528  	testType(t, 11, mtyp.Elem(), "*int32")
   529  
   530  	typ = TypeOf((chan<- string)(nil))
   531  	testType(t, 12, typ, "chan<- string")
   532  	testType(t, 13, typ.Elem(), "string")
   533  
   534  	// make sure tag strings are not part of element type
   535  	typ = TypeOf(struct {
   536  		d []uint32 `reflect:"TAG"`
   537  	}{}).Field(0).Type
   538  	testType(t, 14, typ, "[]uint32")
   539  }
   540  
   541  func TestInterfaceGet(t *testing.T) {
   542  	var inter struct {
   543  		E interface{}
   544  	}
   545  	inter.E = 123.456
   546  	v1 := ValueOf(&inter)
   547  	v2 := v1.Elem().Field(0)
   548  	assert(t, v2.Type().String(), "interface {}")
   549  	i2 := v2.Interface()
   550  	v3 := ValueOf(i2)
   551  	assert(t, v3.Type().String(), "float64")
   552  }
   553  
   554  func TestInterfaceValue(t *testing.T) {
   555  	var inter struct {
   556  		E interface{}
   557  	}
   558  	inter.E = 123.456
   559  	v1 := ValueOf(&inter)
   560  	v2 := v1.Elem().Field(0)
   561  	assert(t, v2.Type().String(), "interface {}")
   562  	v3 := v2.Elem()
   563  	assert(t, v3.Type().String(), "float64")
   564  
   565  	i3 := v2.Interface()
   566  	if _, ok := i3.(float64); !ok {
   567  		t.Error("v2.Interface() did not return float64, got ", TypeOf(i3))
   568  	}
   569  }
   570  
   571  func TestFunctionValue(t *testing.T) {
   572  	var x interface{} = func() {}
   573  	v := ValueOf(x)
   574  	if fmt.Sprint(v.Interface()) != fmt.Sprint(x) {
   575  		t.Fatalf("TestFunction returned wrong pointer")
   576  	}
   577  	assert(t, v.Type().String(), "func()")
   578  }
   579  
   580  var appendTests = []struct {
   581  	orig, extra []int
   582  }{
   583  	{make([]int, 2, 4), []int{22}},
   584  	{make([]int, 2, 4), []int{22, 33, 44}},
   585  }
   586  
   587  func sameInts(x, y []int) bool {
   588  	if len(x) != len(y) {
   589  		return false
   590  	}
   591  	for i, xx := range x {
   592  		if xx != y[i] {
   593  			return false
   594  		}
   595  	}
   596  	return true
   597  }
   598  
   599  func TestAppend(t *testing.T) {
   600  	for i, test := range appendTests {
   601  		origLen, extraLen := len(test.orig), len(test.extra)
   602  		want := append(test.orig, test.extra...)
   603  		// Convert extra from []int to []Value.
   604  		e0 := make([]Value, len(test.extra))
   605  		for j, e := range test.extra {
   606  			e0[j] = ValueOf(e)
   607  		}
   608  		// Convert extra from []int to *SliceValue.
   609  		e1 := ValueOf(test.extra)
   610  		// Test Append.
   611  		a0 := ValueOf(test.orig)
   612  		have0 := Append(a0, e0...).Interface().([]int)
   613  		if !sameInts(have0, want) {
   614  			t.Errorf("Append #%d: have %v, want %v (%p %p)", i, have0, want, test.orig, have0)
   615  		}
   616  		// Check that the orig and extra slices were not modified.
   617  		if len(test.orig) != origLen {
   618  			t.Errorf("Append #%d origLen: have %v, want %v", i, len(test.orig), origLen)
   619  		}
   620  		if len(test.extra) != extraLen {
   621  			t.Errorf("Append #%d extraLen: have %v, want %v", i, len(test.extra), extraLen)
   622  		}
   623  		// Test AppendSlice.
   624  		a1 := ValueOf(test.orig)
   625  		have1 := AppendSlice(a1, e1).Interface().([]int)
   626  		if !sameInts(have1, want) {
   627  			t.Errorf("AppendSlice #%d: have %v, want %v", i, have1, want)
   628  		}
   629  		// Check that the orig and extra slices were not modified.
   630  		if len(test.orig) != origLen {
   631  			t.Errorf("AppendSlice #%d origLen: have %v, want %v", i, len(test.orig), origLen)
   632  		}
   633  		if len(test.extra) != extraLen {
   634  			t.Errorf("AppendSlice #%d extraLen: have %v, want %v", i, len(test.extra), extraLen)
   635  		}
   636  	}
   637  }
   638  
   639  func TestCopy(t *testing.T) {
   640  	a := []int{1, 2, 3, 4, 10, 9, 8, 7}
   641  	b := []int{11, 22, 33, 44, 1010, 99, 88, 77, 66, 55, 44}
   642  	c := []int{11, 22, 33, 44, 1010, 99, 88, 77, 66, 55, 44}
   643  	for i := 0; i < len(b); i++ {
   644  		if b[i] != c[i] {
   645  			t.Fatalf("b != c before test")
   646  		}
   647  	}
   648  	a1 := a
   649  	b1 := b
   650  	aa := ValueOf(&a1).Elem()
   651  	ab := ValueOf(&b1).Elem()
   652  	for tocopy := 1; tocopy <= 7; tocopy++ {
   653  		aa.SetLen(tocopy)
   654  		Copy(ab, aa)
   655  		aa.SetLen(8)
   656  		for i := 0; i < tocopy; i++ {
   657  			if a[i] != b[i] {
   658  				t.Errorf("(i) tocopy=%d a[%d]=%d, b[%d]=%d",
   659  					tocopy, i, a[i], i, b[i])
   660  			}
   661  		}
   662  		for i := tocopy; i < len(b); i++ {
   663  			if b[i] != c[i] {
   664  				if i < len(a) {
   665  					t.Errorf("(ii) tocopy=%d a[%d]=%d, b[%d]=%d, c[%d]=%d",
   666  						tocopy, i, a[i], i, b[i], i, c[i])
   667  				} else {
   668  					t.Errorf("(iii) tocopy=%d b[%d]=%d, c[%d]=%d",
   669  						tocopy, i, b[i], i, c[i])
   670  				}
   671  			} else {
   672  				t.Logf("tocopy=%d elem %d is okay\n", tocopy, i)
   673  			}
   674  		}
   675  	}
   676  }
   677  
   678  func TestCopyString(t *testing.T) {
   679  	t.Run("Slice", func(t *testing.T) {
   680  		s := bytes.Repeat([]byte{'_'}, 8)
   681  		val := ValueOf(s)
   682  
   683  		n := Copy(val, ValueOf(""))
   684  		if expecting := []byte("________"); n != 0 || !bytes.Equal(s, expecting) {
   685  			t.Errorf("got n = %d, s = %s, expecting n = 0, s = %s", n, s, expecting)
   686  		}
   687  
   688  		n = Copy(val, ValueOf("hello"))
   689  		if expecting := []byte("hello___"); n != 5 || !bytes.Equal(s, expecting) {
   690  			t.Errorf("got n = %d, s = %s, expecting n = 5, s = %s", n, s, expecting)
   691  		}
   692  
   693  		n = Copy(val, ValueOf("helloworld"))
   694  		if expecting := []byte("hellowor"); n != 8 || !bytes.Equal(s, expecting) {
   695  			t.Errorf("got n = %d, s = %s, expecting n = 8, s = %s", n, s, expecting)
   696  		}
   697  	})
   698  	t.Run("Array", func(t *testing.T) {
   699  		s := [...]byte{'_', '_', '_', '_', '_', '_', '_', '_'}
   700  		val := ValueOf(&s).Elem()
   701  
   702  		n := Copy(val, ValueOf(""))
   703  		if expecting := []byte("________"); n != 0 || !bytes.Equal(s[:], expecting) {
   704  			t.Errorf("got n = %d, s = %s, expecting n = 0, s = %s", n, s[:], expecting)
   705  		}
   706  
   707  		n = Copy(val, ValueOf("hello"))
   708  		if expecting := []byte("hello___"); n != 5 || !bytes.Equal(s[:], expecting) {
   709  			t.Errorf("got n = %d, s = %s, expecting n = 5, s = %s", n, s[:], expecting)
   710  		}
   711  
   712  		n = Copy(val, ValueOf("helloworld"))
   713  		if expecting := []byte("hellowor"); n != 8 || !bytes.Equal(s[:], expecting) {
   714  			t.Errorf("got n = %d, s = %s, expecting n = 8, s = %s", n, s[:], expecting)
   715  		}
   716  	})
   717  }
   718  
   719  func TestCopyArray(t *testing.T) {
   720  	a := [8]int{1, 2, 3, 4, 10, 9, 8, 7}
   721  	b := [11]int{11, 22, 33, 44, 1010, 99, 88, 77, 66, 55, 44}
   722  	c := b
   723  	aa := ValueOf(&a).Elem()
   724  	ab := ValueOf(&b).Elem()
   725  	Copy(ab, aa)
   726  	for i := 0; i < len(a); i++ {
   727  		if a[i] != b[i] {
   728  			t.Errorf("(i) a[%d]=%d, b[%d]=%d", i, a[i], i, b[i])
   729  		}
   730  	}
   731  	for i := len(a); i < len(b); i++ {
   732  		if b[i] != c[i] {
   733  			t.Errorf("(ii) b[%d]=%d, c[%d]=%d", i, b[i], i, c[i])
   734  		} else {
   735  			t.Logf("elem %d is okay\n", i)
   736  		}
   737  	}
   738  }
   739  
   740  func TestBigUnnamedStruct(t *testing.T) {
   741  	b := struct{ a, b, c, d int64 }{1, 2, 3, 4}
   742  	v := ValueOf(b)
   743  	b1 := v.Interface().(struct {
   744  		a, b, c, d int64
   745  	})
   746  	if b1.a != b.a || b1.b != b.b || b1.c != b.c || b1.d != b.d {
   747  		t.Errorf("ValueOf(%v).Interface().(*Big) = %v", b, b1)
   748  	}
   749  }
   750  
   751  type big struct {
   752  	a, b, c, d, e int64
   753  }
   754  
   755  func TestBigStruct(t *testing.T) {
   756  	b := big{1, 2, 3, 4, 5}
   757  	v := ValueOf(b)
   758  	b1 := v.Interface().(big)
   759  	if b1.a != b.a || b1.b != b.b || b1.c != b.c || b1.d != b.d || b1.e != b.e {
   760  		t.Errorf("ValueOf(%v).Interface().(big) = %v", b, b1)
   761  	}
   762  }
   763  
   764  type Basic struct {
   765  	x int
   766  	y float32
   767  }
   768  
   769  type NotBasic Basic
   770  
   771  type DeepEqualTest struct {
   772  	a, b interface{}
   773  	eq   bool
   774  }
   775  
   776  // Simple functions for DeepEqual tests.
   777  var (
   778  	fn1 func()             // nil.
   779  	fn2 func()             // nil.
   780  	fn3 = func() { fn1() } // Not nil.
   781  )
   782  
   783  type self struct{}
   784  
   785  type Loop *Loop
   786  type Loopy interface{}
   787  
   788  var loop1, loop2 Loop
   789  var loopy1, loopy2 Loopy
   790  var cycleMap1, cycleMap2, cycleMap3 map[string]interface{}
   791  
   792  func init() {
   793  	loop1 = &loop2
   794  	loop2 = &loop1
   795  
   796  	loopy1 = &loopy2
   797  	loopy2 = &loopy1
   798  
   799  	cycleMap1 = map[string]interface{}{}
   800  	cycleMap1["cycle"] = cycleMap1
   801  	cycleMap2 = map[string]interface{}{}
   802  	cycleMap2["cycle"] = cycleMap2
   803  	cycleMap3 = map[string]interface{}{}
   804  	cycleMap3["different"] = cycleMap3
   805  }
   806  
   807  var deepEqualTests = []DeepEqualTest{
   808  	// Equalities
   809  	{nil, nil, true},
   810  	{1, 1, true},
   811  	{int32(1), int32(1), true},
   812  	{0.5, 0.5, true},
   813  	{float32(0.5), float32(0.5), true},
   814  	{"hello", "hello", true},
   815  	{make([]int, 10), make([]int, 10), true},
   816  	{&[3]int{1, 2, 3}, &[3]int{1, 2, 3}, true},
   817  	{Basic{1, 0.5}, Basic{1, 0.5}, true},
   818  	{error(nil), error(nil), true},
   819  	{map[int]string{1: "one", 2: "two"}, map[int]string{2: "two", 1: "one"}, true},
   820  	{fn1, fn2, true},
   821  
   822  	// Inequalities
   823  	{1, 2, false},
   824  	{int32(1), int32(2), false},
   825  	{0.5, 0.6, false},
   826  	{float32(0.5), float32(0.6), false},
   827  	{"hello", "hey", false},
   828  	{make([]int, 10), make([]int, 11), false},
   829  	{&[3]int{1, 2, 3}, &[3]int{1, 2, 4}, false},
   830  	{Basic{1, 0.5}, Basic{1, 0.6}, false},
   831  	{Basic{1, 0}, Basic{2, 0}, false},
   832  	{map[int]string{1: "one", 3: "two"}, map[int]string{2: "two", 1: "one"}, false},
   833  	{map[int]string{1: "one", 2: "txo"}, map[int]string{2: "two", 1: "one"}, false},
   834  	{map[int]string{1: "one"}, map[int]string{2: "two", 1: "one"}, false},
   835  	{map[int]string{2: "two", 1: "one"}, map[int]string{1: "one"}, false},
   836  	{nil, 1, false},
   837  	{1, nil, false},
   838  	{fn1, fn3, false},
   839  	{fn3, fn3, false},
   840  	{[][]int{{1}}, [][]int{{2}}, false},
   841  	{math.NaN(), math.NaN(), false},
   842  	{&[1]float64{math.NaN()}, &[1]float64{math.NaN()}, false},
   843  	{&[1]float64{math.NaN()}, self{}, true},
   844  	{[]float64{math.NaN()}, []float64{math.NaN()}, false},
   845  	{[]float64{math.NaN()}, self{}, true},
   846  	{map[float64]float64{math.NaN(): 1}, map[float64]float64{1: 2}, false},
   847  	{map[float64]float64{math.NaN(): 1}, self{}, true},
   848  
   849  	// Nil vs empty: not the same.
   850  	{[]int{}, []int(nil), false},
   851  	{[]int{}, []int{}, true},
   852  	{[]int(nil), []int(nil), true},
   853  	{map[int]int{}, map[int]int(nil), false},
   854  	{map[int]int{}, map[int]int{}, true},
   855  	{map[int]int(nil), map[int]int(nil), true},
   856  
   857  	// Mismatched types
   858  	{1, 1.0, false},
   859  	{int32(1), int64(1), false},
   860  	{0.5, "hello", false},
   861  	{[]int{1, 2, 3}, [3]int{1, 2, 3}, false},
   862  	{&[3]interface{}{1, 2, 4}, &[3]interface{}{1, 2, "s"}, false},
   863  	{Basic{1, 0.5}, NotBasic{1, 0.5}, false},
   864  	{map[uint]string{1: "one", 2: "two"}, map[int]string{2: "two", 1: "one"}, false},
   865  
   866  	// Possible loops.
   867  	{&loop1, &loop1, true},
   868  	{&loop1, &loop2, true},
   869  	{&loopy1, &loopy1, true},
   870  	{&loopy1, &loopy2, true},
   871  	{&cycleMap1, &cycleMap2, true},
   872  	{&cycleMap1, &cycleMap3, false},
   873  }
   874  
   875  func TestDeepEqual(t *testing.T) {
   876  	for _, test := range deepEqualTests {
   877  		if test.b == (self{}) {
   878  			test.b = test.a
   879  		}
   880  		if r := DeepEqual(test.a, test.b); r != test.eq {
   881  			t.Errorf("DeepEqual(%#v, %#v) = %v, want %v", test.a, test.b, r, test.eq)
   882  		}
   883  	}
   884  }
   885  
   886  func TestTypeOf(t *testing.T) {
   887  	// Special case for nil
   888  	if typ := TypeOf(nil); typ != nil {
   889  		t.Errorf("expected nil type for nil value; got %v", typ)
   890  	}
   891  	for _, test := range deepEqualTests {
   892  		v := ValueOf(test.a)
   893  		if !v.IsValid() {
   894  			continue
   895  		}
   896  		typ := TypeOf(test.a)
   897  		if typ != v.Type() {
   898  			t.Errorf("TypeOf(%v) = %v, but ValueOf(%v).Type() = %v", test.a, typ, test.a, v.Type())
   899  		}
   900  	}
   901  }
   902  
   903  type Recursive struct {
   904  	x int
   905  	r *Recursive
   906  }
   907  
   908  func TestDeepEqualRecursiveStruct(t *testing.T) {
   909  	a, b := new(Recursive), new(Recursive)
   910  	*a = Recursive{12, a}
   911  	*b = Recursive{12, b}
   912  	if !DeepEqual(a, b) {
   913  		t.Error("DeepEqual(recursive same) = false, want true")
   914  	}
   915  }
   916  
   917  type _Complex struct {
   918  	a int
   919  	b [3]*_Complex
   920  	c *string
   921  	d map[float64]float64
   922  }
   923  
   924  func TestDeepEqualComplexStruct(t *testing.T) {
   925  	m := make(map[float64]float64)
   926  	stra, strb := "hello", "hello"
   927  	a, b := new(_Complex), new(_Complex)
   928  	*a = _Complex{5, [3]*_Complex{a, b, a}, &stra, m}
   929  	*b = _Complex{5, [3]*_Complex{b, a, a}, &strb, m}
   930  	if !DeepEqual(a, b) {
   931  		t.Error("DeepEqual(complex same) = false, want true")
   932  	}
   933  }
   934  
   935  func TestDeepEqualComplexStructInequality(t *testing.T) {
   936  	m := make(map[float64]float64)
   937  	stra, strb := "hello", "helloo" // Difference is here
   938  	a, b := new(_Complex), new(_Complex)
   939  	*a = _Complex{5, [3]*_Complex{a, b, a}, &stra, m}
   940  	*b = _Complex{5, [3]*_Complex{b, a, a}, &strb, m}
   941  	if DeepEqual(a, b) {
   942  		t.Error("DeepEqual(complex different) = true, want false")
   943  	}
   944  }
   945  
   946  type UnexpT struct {
   947  	m map[int]int
   948  }
   949  
   950  func TestDeepEqualUnexportedMap(t *testing.T) {
   951  	// Check that DeepEqual can look at unexported fields.
   952  	x1 := UnexpT{map[int]int{1: 2}}
   953  	x2 := UnexpT{map[int]int{1: 2}}
   954  	if !DeepEqual(&x1, &x2) {
   955  		t.Error("DeepEqual(x1, x2) = false, want true")
   956  	}
   957  
   958  	y1 := UnexpT{map[int]int{2: 3}}
   959  	if DeepEqual(&x1, &y1) {
   960  		t.Error("DeepEqual(x1, y1) = true, want false")
   961  	}
   962  }
   963  
   964  func check2ndField(x interface{}, offs uintptr, t *testing.T) {
   965  	s := ValueOf(x)
   966  	f := s.Type().Field(1)
   967  	if f.Offset != offs {
   968  		t.Error("mismatched offsets in structure alignment:", f.Offset, offs)
   969  	}
   970  }
   971  
   972  // Check that structure alignment & offsets viewed through reflect agree with those
   973  // from the compiler itself.
   974  func TestAlignment(t *testing.T) {
   975  	type T1inner struct {
   976  		a int
   977  	}
   978  	type T1 struct {
   979  		T1inner
   980  		f int
   981  	}
   982  	type T2inner struct {
   983  		a, b int
   984  	}
   985  	type T2 struct {
   986  		T2inner
   987  		f int
   988  	}
   989  
   990  	x := T1{T1inner{2}, 17}
   991  	check2ndField(x, uintptr(unsafe.Pointer(&x.f))-uintptr(unsafe.Pointer(&x)), t)
   992  
   993  	x1 := T2{T2inner{2, 3}, 17}
   994  	check2ndField(x1, uintptr(unsafe.Pointer(&x1.f))-uintptr(unsafe.Pointer(&x1)), t)
   995  }
   996  
   997  func Nil(a interface{}, t *testing.T) {
   998  	n := ValueOf(a).Field(0)
   999  	if !n.IsNil() {
  1000  		t.Errorf("%v should be nil", a)
  1001  	}
  1002  }
  1003  
  1004  func NotNil(a interface{}, t *testing.T) {
  1005  	n := ValueOf(a).Field(0)
  1006  	if n.IsNil() {
  1007  		t.Errorf("value of type %v should not be nil", ValueOf(a).Type().String())
  1008  	}
  1009  }
  1010  
  1011  func TestIsNil(t *testing.T) {
  1012  	// These implement IsNil.
  1013  	// Wrap in extra struct to hide interface type.
  1014  	doNil := []interface{}{
  1015  		struct{ x *int }{},
  1016  		struct{ x interface{} }{},
  1017  		struct{ x map[string]int }{},
  1018  		struct{ x func() bool }{},
  1019  		struct{ x chan int }{},
  1020  		struct{ x []string }{},
  1021  		struct{ x unsafe.Pointer }{},
  1022  	}
  1023  	for _, ts := range doNil {
  1024  		ty := TypeOf(ts).Field(0).Type
  1025  		v := Zero(ty)
  1026  		v.IsNil() // panics if not okay to call
  1027  	}
  1028  
  1029  	// Check the implementations
  1030  	var pi struct {
  1031  		x *int
  1032  	}
  1033  	Nil(pi, t)
  1034  	pi.x = new(int)
  1035  	NotNil(pi, t)
  1036  
  1037  	var si struct {
  1038  		x []int
  1039  	}
  1040  	Nil(si, t)
  1041  	si.x = make([]int, 10)
  1042  	NotNil(si, t)
  1043  
  1044  	var ci struct {
  1045  		x chan int
  1046  	}
  1047  	Nil(ci, t)
  1048  	ci.x = make(chan int)
  1049  	NotNil(ci, t)
  1050  
  1051  	var mi struct {
  1052  		x map[int]int
  1053  	}
  1054  	Nil(mi, t)
  1055  	mi.x = make(map[int]int)
  1056  	NotNil(mi, t)
  1057  
  1058  	var ii struct {
  1059  		x interface{}
  1060  	}
  1061  	Nil(ii, t)
  1062  	ii.x = 2
  1063  	NotNil(ii, t)
  1064  
  1065  	var fi struct {
  1066  		x func(t *testing.T)
  1067  	}
  1068  	Nil(fi, t)
  1069  	fi.x = TestIsNil
  1070  	NotNil(fi, t)
  1071  }
  1072  
  1073  func TestIsZero(t *testing.T) {
  1074  	for i, tt := range []struct {
  1075  		x    interface{}
  1076  		want bool
  1077  	}{
  1078  		// Booleans
  1079  		{true, false},
  1080  		{false, true},
  1081  		// Numeric types
  1082  		{int(0), true},
  1083  		{int(1), false},
  1084  		{int8(0), true},
  1085  		{int8(1), false},
  1086  		{int16(0), true},
  1087  		{int16(1), false},
  1088  		{int32(0), true},
  1089  		{int32(1), false},
  1090  		{int64(0), true},
  1091  		{int64(1), false},
  1092  		{uint(0), true},
  1093  		{uint(1), false},
  1094  		{uint8(0), true},
  1095  		{uint8(1), false},
  1096  		{uint16(0), true},
  1097  		{uint16(1), false},
  1098  		{uint32(0), true},
  1099  		{uint32(1), false},
  1100  		{uint64(0), true},
  1101  		{uint64(1), false},
  1102  		{float32(0), true},
  1103  		{float32(1.2), false},
  1104  		{float64(0), true},
  1105  		{float64(1.2), false},
  1106  		{math.Copysign(0, -1), false},
  1107  		{complex64(0), true},
  1108  		{complex64(1.2), false},
  1109  		{complex128(0), true},
  1110  		{complex128(1.2), false},
  1111  		{complex(math.Copysign(0, -1), 0), false},
  1112  		{complex(0, math.Copysign(0, -1)), false},
  1113  		{complex(math.Copysign(0, -1), math.Copysign(0, -1)), false},
  1114  		{uintptr(0), true},
  1115  		{uintptr(128), false},
  1116  		// Array
  1117  		{Zero(TypeOf([5]string{})).Interface(), true},
  1118  		{[5]string{"", "", "", "", ""}, true},
  1119  		{[5]string{}, true},
  1120  		{[5]string{"", "", "", "a", ""}, false},
  1121  		// Chan
  1122  		{(chan string)(nil), true},
  1123  		{make(chan string), false},
  1124  		{time.After(1), false},
  1125  		// Func
  1126  		{(func())(nil), true},
  1127  		{New, false},
  1128  		// Interface
  1129  		{New(TypeOf(new(error)).Elem()).Elem(), true},
  1130  		{(io.Reader)(strings.NewReader("")), false},
  1131  		// Map
  1132  		{(map[string]string)(nil), true},
  1133  		{map[string]string{}, false},
  1134  		{make(map[string]string), false},
  1135  		// Ptr
  1136  		{(*func())(nil), true},
  1137  		{(*int)(nil), true},
  1138  		{new(int), false},
  1139  		// Slice
  1140  		{[]string{}, false},
  1141  		{([]string)(nil), true},
  1142  		{make([]string, 0), false},
  1143  		// Strings
  1144  		{"", true},
  1145  		{"not-zero", false},
  1146  		// Structs
  1147  		{T{}, true},
  1148  		{T{123, 456.75, "hello", &_i}, false},
  1149  		// UnsafePointer
  1150  		{(unsafe.Pointer)(nil), true},
  1151  		{(unsafe.Pointer)(new(int)), false},
  1152  	} {
  1153  		var x Value
  1154  		if v, ok := tt.x.(Value); ok {
  1155  			x = v
  1156  		} else {
  1157  			x = ValueOf(tt.x)
  1158  		}
  1159  
  1160  		b := x.IsZero()
  1161  		if b != tt.want {
  1162  			t.Errorf("%d: IsZero((%s)(%+v)) = %t, want %t", i, x.Kind(), tt.x, b, tt.want)
  1163  		}
  1164  
  1165  		if !Zero(TypeOf(tt.x)).IsZero() {
  1166  			t.Errorf("%d: IsZero(Zero(TypeOf((%s)(%+v)))) is false", i, x.Kind(), tt.x)
  1167  		}
  1168  	}
  1169  
  1170  	func() {
  1171  		defer func() {
  1172  			if r := recover(); r == nil {
  1173  				t.Error("should panic for invalid value")
  1174  			}
  1175  		}()
  1176  		(Value{}).IsZero()
  1177  	}()
  1178  }
  1179  
  1180  func TestInterfaceExtraction(t *testing.T) {
  1181  	var s struct {
  1182  		W io.Writer
  1183  	}
  1184  
  1185  	s.W = os.Stdout
  1186  	v := Indirect(ValueOf(&s)).Field(0).Interface()
  1187  	if v != s.W.(interface{}) {
  1188  		t.Error("Interface() on interface: ", v, s.W)
  1189  	}
  1190  }
  1191  
  1192  func TestNilPtrValueSub(t *testing.T) {
  1193  	var pi *int
  1194  	if pv := ValueOf(pi); pv.Elem().IsValid() {
  1195  		t.Error("ValueOf((*int)(nil)).Elem().IsValid()")
  1196  	}
  1197  }
  1198  
  1199  func TestMap(t *testing.T) {
  1200  	m := map[string]int{"a": 1, "b": 2}
  1201  	mv := ValueOf(m)
  1202  	if n := mv.Len(); n != len(m) {
  1203  		t.Errorf("Len = %d, want %d", n, len(m))
  1204  	}
  1205  	keys := mv.MapKeys()
  1206  	newmap := MakeMap(mv.Type())
  1207  	for k, v := range m {
  1208  		// Check that returned Keys match keys in range.
  1209  		// These aren't required to be in the same order.
  1210  		seen := false
  1211  		for _, kv := range keys {
  1212  			if kv.String() == k {
  1213  				seen = true
  1214  				break
  1215  			}
  1216  		}
  1217  		if !seen {
  1218  			t.Errorf("Missing key %q", k)
  1219  		}
  1220  
  1221  		// Check that value lookup is correct.
  1222  		vv := mv.MapIndex(ValueOf(k))
  1223  		if vi := vv.Int(); vi != int64(v) {
  1224  			t.Errorf("Key %q: have value %d, want %d", k, vi, v)
  1225  		}
  1226  
  1227  		// Copy into new map.
  1228  		newmap.SetMapIndex(ValueOf(k), ValueOf(v))
  1229  	}
  1230  	vv := mv.MapIndex(ValueOf("not-present"))
  1231  	if vv.IsValid() {
  1232  		t.Errorf("Invalid key: got non-nil value %s", valueToString(vv))
  1233  	}
  1234  
  1235  	newm := newmap.Interface().(map[string]int)
  1236  	if len(newm) != len(m) {
  1237  		t.Errorf("length after copy: newm=%d, m=%d", len(newm), len(m))
  1238  	}
  1239  
  1240  	for k, v := range newm {
  1241  		mv, ok := m[k]
  1242  		if mv != v {
  1243  			t.Errorf("newm[%q] = %d, but m[%q] = %d, %v", k, v, k, mv, ok)
  1244  		}
  1245  	}
  1246  
  1247  	newmap.SetMapIndex(ValueOf("a"), Value{})
  1248  	v, ok := newm["a"]
  1249  	if ok {
  1250  		t.Errorf("newm[\"a\"] = %d after delete", v)
  1251  	}
  1252  
  1253  	mv = ValueOf(&m).Elem()
  1254  	mv.Set(Zero(mv.Type()))
  1255  	if m != nil {
  1256  		t.Errorf("mv.Set(nil) failed")
  1257  	}
  1258  }
  1259  
  1260  func TestNilMap(t *testing.T) {
  1261  	var m map[string]int
  1262  	mv := ValueOf(m)
  1263  	keys := mv.MapKeys()
  1264  	if len(keys) != 0 {
  1265  		t.Errorf(">0 keys for nil map: %v", keys)
  1266  	}
  1267  
  1268  	// Check that value for missing key is zero.
  1269  	x := mv.MapIndex(ValueOf("hello"))
  1270  	if x.Kind() != Invalid {
  1271  		t.Errorf("m.MapIndex(\"hello\") for nil map = %v, want Invalid Value", x)
  1272  	}
  1273  
  1274  	// Check big value too.
  1275  	var mbig map[string][10 << 20]byte
  1276  	x = ValueOf(mbig).MapIndex(ValueOf("hello"))
  1277  	if x.Kind() != Invalid {
  1278  		t.Errorf("mbig.MapIndex(\"hello\") for nil map = %v, want Invalid Value", x)
  1279  	}
  1280  
  1281  	// Test that deletes from a nil map succeed.
  1282  	mv.SetMapIndex(ValueOf("hi"), Value{})
  1283  }
  1284  
  1285  func TestChan(t *testing.T) {
  1286  	for loop := 0; loop < 2; loop++ {
  1287  		var c chan int
  1288  		var cv Value
  1289  
  1290  		// check both ways to allocate channels
  1291  		switch loop {
  1292  		case 1:
  1293  			c = make(chan int, 1)
  1294  			cv = ValueOf(c)
  1295  		case 0:
  1296  			cv = MakeChan(TypeOf(c), 1)
  1297  			c = cv.Interface().(chan int)
  1298  		}
  1299  
  1300  		// Send
  1301  		cv.Send(ValueOf(2))
  1302  		if i := <-c; i != 2 {
  1303  			t.Errorf("reflect Send 2, native recv %d", i)
  1304  		}
  1305  
  1306  		// Recv
  1307  		c <- 3
  1308  		if i, ok := cv.Recv(); i.Int() != 3 || !ok {
  1309  			t.Errorf("native send 3, reflect Recv %d, %t", i.Int(), ok)
  1310  		}
  1311  
  1312  		// TryRecv fail
  1313  		val, ok := cv.TryRecv()
  1314  		if val.IsValid() || ok {
  1315  			t.Errorf("TryRecv on empty chan: %s, %t", valueToString(val), ok)
  1316  		}
  1317  
  1318  		// TryRecv success
  1319  		c <- 4
  1320  		val, ok = cv.TryRecv()
  1321  		if !val.IsValid() {
  1322  			t.Errorf("TryRecv on ready chan got nil")
  1323  		} else if i := val.Int(); i != 4 || !ok {
  1324  			t.Errorf("native send 4, TryRecv %d, %t", i, ok)
  1325  		}
  1326  
  1327  		// TrySend fail
  1328  		c <- 100
  1329  		ok = cv.TrySend(ValueOf(5))
  1330  		i := <-c
  1331  		if ok {
  1332  			t.Errorf("TrySend on full chan succeeded: value %d", i)
  1333  		}
  1334  
  1335  		// TrySend success
  1336  		ok = cv.TrySend(ValueOf(6))
  1337  		if !ok {
  1338  			t.Errorf("TrySend on empty chan failed")
  1339  			select {
  1340  			case x := <-c:
  1341  				t.Errorf("TrySend failed but it did send %d", x)
  1342  			default:
  1343  			}
  1344  		} else {
  1345  			if i = <-c; i != 6 {
  1346  				t.Errorf("TrySend 6, recv %d", i)
  1347  			}
  1348  		}
  1349  
  1350  		// Close
  1351  		c <- 123
  1352  		cv.Close()
  1353  		if i, ok := cv.Recv(); i.Int() != 123 || !ok {
  1354  			t.Errorf("send 123 then close; Recv %d, %t", i.Int(), ok)
  1355  		}
  1356  		if i, ok := cv.Recv(); i.Int() != 0 || ok {
  1357  			t.Errorf("after close Recv %d, %t", i.Int(), ok)
  1358  		}
  1359  	}
  1360  
  1361  	// check creation of unbuffered channel
  1362  	var c chan int
  1363  	cv := MakeChan(TypeOf(c), 0)
  1364  	c = cv.Interface().(chan int)
  1365  	if cv.TrySend(ValueOf(7)) {
  1366  		t.Errorf("TrySend on sync chan succeeded")
  1367  	}
  1368  	if v, ok := cv.TryRecv(); v.IsValid() || ok {
  1369  		t.Errorf("TryRecv on sync chan succeeded: isvalid=%v ok=%v", v.IsValid(), ok)
  1370  	}
  1371  
  1372  	// len/cap
  1373  	cv = MakeChan(TypeOf(c), 10)
  1374  	c = cv.Interface().(chan int)
  1375  	for i := 0; i < 3; i++ {
  1376  		c <- i
  1377  	}
  1378  	if l, m := cv.Len(), cv.Cap(); l != len(c) || m != cap(c) {
  1379  		t.Errorf("Len/Cap = %d/%d want %d/%d", l, m, len(c), cap(c))
  1380  	}
  1381  }
  1382  
  1383  // caseInfo describes a single case in a select test.
  1384  type caseInfo struct {
  1385  	desc      string
  1386  	canSelect bool
  1387  	recv      Value
  1388  	closed    bool
  1389  	helper    func()
  1390  	panic     bool
  1391  }
  1392  
  1393  var allselect = flag.Bool("allselect", false, "exhaustive select test")
  1394  
  1395  func TestSelect(t *testing.T) {
  1396  	selectWatch.once.Do(func() { go selectWatcher() })
  1397  
  1398  	var x exhaustive
  1399  	nch := 0
  1400  	newop := func(n int, cap int) (ch, val Value) {
  1401  		nch++
  1402  		if nch%101%2 == 1 {
  1403  			c := make(chan int, cap)
  1404  			ch = ValueOf(c)
  1405  			val = ValueOf(n)
  1406  		} else {
  1407  			c := make(chan string, cap)
  1408  			ch = ValueOf(c)
  1409  			val = ValueOf(fmt.Sprint(n))
  1410  		}
  1411  		return
  1412  	}
  1413  
  1414  	for n := 0; x.Next(); n++ {
  1415  		if testing.Short() && n >= 1000 {
  1416  			break
  1417  		}
  1418  		if n >= 100000 && !*allselect {
  1419  			break
  1420  		}
  1421  		if n%100000 == 0 && testing.Verbose() {
  1422  			println("TestSelect", n)
  1423  		}
  1424  		var cases []SelectCase
  1425  		var info []caseInfo
  1426  
  1427  		// Ready send.
  1428  		if x.Maybe() {
  1429  			ch, val := newop(len(cases), 1)
  1430  			cases = append(cases, SelectCase{
  1431  				Dir:  SelectSend,
  1432  				Chan: ch,
  1433  				Send: val,
  1434  			})
  1435  			info = append(info, caseInfo{desc: "ready send", canSelect: true})
  1436  		}
  1437  
  1438  		// Ready recv.
  1439  		if x.Maybe() {
  1440  			ch, val := newop(len(cases), 1)
  1441  			ch.Send(val)
  1442  			cases = append(cases, SelectCase{
  1443  				Dir:  SelectRecv,
  1444  				Chan: ch,
  1445  			})
  1446  			info = append(info, caseInfo{desc: "ready recv", canSelect: true, recv: val})
  1447  		}
  1448  
  1449  		// Blocking send.
  1450  		if x.Maybe() {
  1451  			ch, val := newop(len(cases), 0)
  1452  			cases = append(cases, SelectCase{
  1453  				Dir:  SelectSend,
  1454  				Chan: ch,
  1455  				Send: val,
  1456  			})
  1457  			// Let it execute?
  1458  			if x.Maybe() {
  1459  				f := func() { ch.Recv() }
  1460  				info = append(info, caseInfo{desc: "blocking send", helper: f})
  1461  			} else {
  1462  				info = append(info, caseInfo{desc: "blocking send"})
  1463  			}
  1464  		}
  1465  
  1466  		// Blocking recv.
  1467  		if x.Maybe() {
  1468  			ch, val := newop(len(cases), 0)
  1469  			cases = append(cases, SelectCase{
  1470  				Dir:  SelectRecv,
  1471  				Chan: ch,
  1472  			})
  1473  			// Let it execute?
  1474  			if x.Maybe() {
  1475  				f := func() { ch.Send(val) }
  1476  				info = append(info, caseInfo{desc: "blocking recv", recv: val, helper: f})
  1477  			} else {
  1478  				info = append(info, caseInfo{desc: "blocking recv"})
  1479  			}
  1480  		}
  1481  
  1482  		// Zero Chan send.
  1483  		if x.Maybe() {
  1484  			// Maybe include value to send.
  1485  			var val Value
  1486  			if x.Maybe() {
  1487  				val = ValueOf(100)
  1488  			}
  1489  			cases = append(cases, SelectCase{
  1490  				Dir:  SelectSend,
  1491  				Send: val,
  1492  			})
  1493  			info = append(info, caseInfo{desc: "zero Chan send"})
  1494  		}
  1495  
  1496  		// Zero Chan receive.
  1497  		if x.Maybe() {
  1498  			cases = append(cases, SelectCase{
  1499  				Dir: SelectRecv,
  1500  			})
  1501  			info = append(info, caseInfo{desc: "zero Chan recv"})
  1502  		}
  1503  
  1504  		// nil Chan send.
  1505  		if x.Maybe() {
  1506  			cases = append(cases, SelectCase{
  1507  				Dir:  SelectSend,
  1508  				Chan: ValueOf((chan int)(nil)),
  1509  				Send: ValueOf(101),
  1510  			})
  1511  			info = append(info, caseInfo{desc: "nil Chan send"})
  1512  		}
  1513  
  1514  		// nil Chan recv.
  1515  		if x.Maybe() {
  1516  			cases = append(cases, SelectCase{
  1517  				Dir:  SelectRecv,
  1518  				Chan: ValueOf((chan int)(nil)),
  1519  			})
  1520  			info = append(info, caseInfo{desc: "nil Chan recv"})
  1521  		}
  1522  
  1523  		// closed Chan send.
  1524  		if x.Maybe() {
  1525  			ch := make(chan int)
  1526  			close(ch)
  1527  			cases = append(cases, SelectCase{
  1528  				Dir:  SelectSend,
  1529  				Chan: ValueOf(ch),
  1530  				Send: ValueOf(101),
  1531  			})
  1532  			info = append(info, caseInfo{desc: "closed Chan send", canSelect: true, panic: true})
  1533  		}
  1534  
  1535  		// closed Chan recv.
  1536  		if x.Maybe() {
  1537  			ch, val := newop(len(cases), 0)
  1538  			ch.Close()
  1539  			val = Zero(val.Type())
  1540  			cases = append(cases, SelectCase{
  1541  				Dir:  SelectRecv,
  1542  				Chan: ch,
  1543  			})
  1544  			info = append(info, caseInfo{desc: "closed Chan recv", canSelect: true, closed: true, recv: val})
  1545  		}
  1546  
  1547  		var helper func() // goroutine to help the select complete
  1548  
  1549  		// Add default? Must be last case here, but will permute.
  1550  		// Add the default if the select would otherwise
  1551  		// block forever, and maybe add it anyway.
  1552  		numCanSelect := 0
  1553  		canProceed := false
  1554  		canBlock := true
  1555  		canPanic := false
  1556  		helpers := []int{}
  1557  		for i, c := range info {
  1558  			if c.canSelect {
  1559  				canProceed = true
  1560  				canBlock = false
  1561  				numCanSelect++
  1562  				if c.panic {
  1563  					canPanic = true
  1564  				}
  1565  			} else if c.helper != nil {
  1566  				canProceed = true
  1567  				helpers = append(helpers, i)
  1568  			}
  1569  		}
  1570  		if !canProceed || x.Maybe() {
  1571  			cases = append(cases, SelectCase{
  1572  				Dir: SelectDefault,
  1573  			})
  1574  			info = append(info, caseInfo{desc: "default", canSelect: canBlock})
  1575  			numCanSelect++
  1576  		} else if canBlock {
  1577  			// Select needs to communicate with another goroutine.
  1578  			cas := &info[helpers[x.Choose(len(helpers))]]
  1579  			helper = cas.helper
  1580  			cas.canSelect = true
  1581  			numCanSelect++
  1582  		}
  1583  
  1584  		// Permute cases and case info.
  1585  		// Doing too much here makes the exhaustive loop
  1586  		// too exhausting, so just do two swaps.
  1587  		for loop := 0; loop < 2; loop++ {
  1588  			i := x.Choose(len(cases))
  1589  			j := x.Choose(len(cases))
  1590  			cases[i], cases[j] = cases[j], cases[i]
  1591  			info[i], info[j] = info[j], info[i]
  1592  		}
  1593  
  1594  		if helper != nil {
  1595  			// We wait before kicking off a goroutine to satisfy a blocked select.
  1596  			// The pause needs to be big enough to let the select block before
  1597  			// we run the helper, but if we lose that race once in a while it's okay: the
  1598  			// select will just proceed immediately. Not a big deal.
  1599  			// For short tests we can grow [sic] the timeout a bit without fear of taking too long
  1600  			pause := 10 * time.Microsecond
  1601  			if testing.Short() {
  1602  				pause = 100 * time.Microsecond
  1603  			}
  1604  			time.AfterFunc(pause, helper)
  1605  		}
  1606  
  1607  		// Run select.
  1608  		i, recv, recvOK, panicErr := runSelect(cases, info)
  1609  		if panicErr != nil && !canPanic {
  1610  			t.Fatalf("%s\npanicked unexpectedly: %v", fmtSelect(info), panicErr)
  1611  		}
  1612  		if panicErr == nil && canPanic && numCanSelect == 1 {
  1613  			t.Fatalf("%s\nselected #%d incorrectly (should panic)", fmtSelect(info), i)
  1614  		}
  1615  		if panicErr != nil {
  1616  			continue
  1617  		}
  1618  
  1619  		cas := info[i]
  1620  		if !cas.canSelect {
  1621  			recvStr := ""
  1622  			if recv.IsValid() {
  1623  				recvStr = fmt.Sprintf(", received %v, %v", recv.Interface(), recvOK)
  1624  			}
  1625  			t.Fatalf("%s\nselected #%d incorrectly%s", fmtSelect(info), i, recvStr)
  1626  			continue
  1627  		}
  1628  		if cas.panic {
  1629  			t.Fatalf("%s\nselected #%d incorrectly (case should panic)", fmtSelect(info), i)
  1630  			continue
  1631  		}
  1632  
  1633  		if cases[i].Dir == SelectRecv {
  1634  			if !recv.IsValid() {
  1635  				t.Fatalf("%s\nselected #%d but got %v, %v, want %v, %v", fmtSelect(info), i, recv, recvOK, cas.recv.Interface(), !cas.closed)
  1636  			}
  1637  			if !cas.recv.IsValid() {
  1638  				t.Fatalf("%s\nselected #%d but internal error: missing recv value", fmtSelect(info), i)
  1639  			}
  1640  			if recv.Interface() != cas.recv.Interface() || recvOK != !cas.closed {
  1641  				if recv.Interface() == cas.recv.Interface() && recvOK == !cas.closed {
  1642  					t.Fatalf("%s\nselected #%d, got %#v, %v, and DeepEqual is broken on %T", fmtSelect(info), i, recv.Interface(), recvOK, recv.Interface())
  1643  				}
  1644  				t.Fatalf("%s\nselected #%d but got %#v, %v, want %#v, %v", fmtSelect(info), i, recv.Interface(), recvOK, cas.recv.Interface(), !cas.closed)
  1645  			}
  1646  		} else {
  1647  			if recv.IsValid() || recvOK {
  1648  				t.Fatalf("%s\nselected #%d but got %v, %v, want %v, %v", fmtSelect(info), i, recv, recvOK, Value{}, false)
  1649  			}
  1650  		}
  1651  	}
  1652  }
  1653  
  1654  // selectWatch and the selectWatcher are a watchdog mechanism for running Select.
  1655  // If the selectWatcher notices that the select has been blocked for >1 second, it prints
  1656  // an error describing the select and panics the entire test binary.
  1657  var selectWatch struct {
  1658  	sync.Mutex
  1659  	once sync.Once
  1660  	now  time.Time
  1661  	info []caseInfo
  1662  }
  1663  
  1664  func selectWatcher() {
  1665  	for {
  1666  		time.Sleep(1 * time.Second)
  1667  		selectWatch.Lock()
  1668  		if selectWatch.info != nil && time.Since(selectWatch.now) > 10*time.Second {
  1669  			fmt.Fprintf(os.Stderr, "TestSelect:\n%s blocked indefinitely\n", fmtSelect(selectWatch.info))
  1670  			panic("select stuck")
  1671  		}
  1672  		selectWatch.Unlock()
  1673  	}
  1674  }
  1675  
  1676  // runSelect runs a single select test.
  1677  // It returns the values returned by Select but also returns
  1678  // a panic value if the Select panics.
  1679  func runSelect(cases []SelectCase, info []caseInfo) (chosen int, recv Value, recvOK bool, panicErr interface{}) {
  1680  	defer func() {
  1681  		panicErr = recover()
  1682  
  1683  		selectWatch.Lock()
  1684  		selectWatch.info = nil
  1685  		selectWatch.Unlock()
  1686  	}()
  1687  
  1688  	selectWatch.Lock()
  1689  	selectWatch.now = time.Now()
  1690  	selectWatch.info = info
  1691  	selectWatch.Unlock()
  1692  
  1693  	chosen, recv, recvOK = Select(cases)
  1694  	return
  1695  }
  1696  
  1697  // fmtSelect formats the information about a single select test.
  1698  func fmtSelect(info []caseInfo) string {
  1699  	var buf bytes.Buffer
  1700  	fmt.Fprintf(&buf, "\nselect {\n")
  1701  	for i, cas := range info {
  1702  		fmt.Fprintf(&buf, "%d: %s", i, cas.desc)
  1703  		if cas.recv.IsValid() {
  1704  			fmt.Fprintf(&buf, " val=%#v", cas.recv.Interface())
  1705  		}
  1706  		if cas.canSelect {
  1707  			fmt.Fprintf(&buf, " canselect")
  1708  		}
  1709  		if cas.panic {
  1710  			fmt.Fprintf(&buf, " panic")
  1711  		}
  1712  		fmt.Fprintf(&buf, "\n")
  1713  	}
  1714  	fmt.Fprintf(&buf, "}")
  1715  	return buf.String()
  1716  }
  1717  
  1718  type two [2]uintptr
  1719  
  1720  // Difficult test for function call because of
  1721  // implicit padding between arguments.
  1722  func dummy(b byte, c int, d byte, e two, f byte, g float32, h byte) (i byte, j int, k byte, l two, m byte, n float32, o byte) {
  1723  	return b, c, d, e, f, g, h
  1724  }
  1725  
  1726  func TestFunc(t *testing.T) {
  1727  	ret := ValueOf(dummy).Call([]Value{
  1728  		ValueOf(byte(10)),
  1729  		ValueOf(20),
  1730  		ValueOf(byte(30)),
  1731  		ValueOf(two{40, 50}),
  1732  		ValueOf(byte(60)),
  1733  		ValueOf(float32(70)),
  1734  		ValueOf(byte(80)),
  1735  	})
  1736  	if len(ret) != 7 {
  1737  		t.Fatalf("Call returned %d values, want 7", len(ret))
  1738  	}
  1739  
  1740  	i := byte(ret[0].Uint())
  1741  	j := int(ret[1].Int())
  1742  	k := byte(ret[2].Uint())
  1743  	l := ret[3].Interface().(two)
  1744  	m := byte(ret[4].Uint())
  1745  	n := float32(ret[5].Float())
  1746  	o := byte(ret[6].Uint())
  1747  
  1748  	if i != 10 || j != 20 || k != 30 || l != (two{40, 50}) || m != 60 || n != 70 || o != 80 {
  1749  		t.Errorf("Call returned %d, %d, %d, %v, %d, %g, %d; want 10, 20, 30, [40, 50], 60, 70, 80", i, j, k, l, m, n, o)
  1750  	}
  1751  
  1752  	for i, v := range ret {
  1753  		if v.CanAddr() {
  1754  			t.Errorf("result %d is addressable", i)
  1755  		}
  1756  	}
  1757  }
  1758  
  1759  func TestCallConvert(t *testing.T) {
  1760  	v := ValueOf(new(io.ReadWriter)).Elem()
  1761  	f := ValueOf(func(r io.Reader) io.Reader { return r })
  1762  	out := f.Call([]Value{v})
  1763  	if len(out) != 1 || out[0].Type() != TypeOf(new(io.Reader)).Elem() || !out[0].IsNil() {
  1764  		t.Errorf("expected [nil], got %v", out)
  1765  	}
  1766  }
  1767  
  1768  type emptyStruct struct{}
  1769  
  1770  type nonEmptyStruct struct {
  1771  	member int
  1772  }
  1773  
  1774  func returnEmpty() emptyStruct {
  1775  	return emptyStruct{}
  1776  }
  1777  
  1778  func takesEmpty(e emptyStruct) {
  1779  }
  1780  
  1781  func returnNonEmpty(i int) nonEmptyStruct {
  1782  	return nonEmptyStruct{member: i}
  1783  }
  1784  
  1785  func takesNonEmpty(n nonEmptyStruct) int {
  1786  	return n.member
  1787  }
  1788  
  1789  func TestCallWithStruct(t *testing.T) {
  1790  	r := ValueOf(returnEmpty).Call(nil)
  1791  	if len(r) != 1 || r[0].Type() != TypeOf(emptyStruct{}) {
  1792  		t.Errorf("returning empty struct returned %#v instead", r)
  1793  	}
  1794  	r = ValueOf(takesEmpty).Call([]Value{ValueOf(emptyStruct{})})
  1795  	if len(r) != 0 {
  1796  		t.Errorf("takesEmpty returned values: %#v", r)
  1797  	}
  1798  	r = ValueOf(returnNonEmpty).Call([]Value{ValueOf(42)})
  1799  	if len(r) != 1 || r[0].Type() != TypeOf(nonEmptyStruct{}) || r[0].Field(0).Int() != 42 {
  1800  		t.Errorf("returnNonEmpty returned %#v", r)
  1801  	}
  1802  	r = ValueOf(takesNonEmpty).Call([]Value{ValueOf(nonEmptyStruct{member: 42})})
  1803  	if len(r) != 1 || r[0].Type() != TypeOf(1) || r[0].Int() != 42 {
  1804  		t.Errorf("takesNonEmpty returned %#v", r)
  1805  	}
  1806  }
  1807  
  1808  func TestCallReturnsEmpty(t *testing.T) {
  1809  	// Issue 21717: past-the-end pointer write in Call with
  1810  	// nonzero-sized frame and zero-sized return value.
  1811  	runtime.GC()
  1812  	var finalized uint32
  1813  	f := func() (emptyStruct, *[2]int64) {
  1814  		i := new([2]int64) // big enough to not be tinyalloc'd, so finalizer always runs when i dies
  1815  		runtime.SetFinalizer(i, func(*[2]int64) { atomic.StoreUint32(&finalized, 1) })
  1816  		return emptyStruct{}, i
  1817  	}
  1818  	v := ValueOf(f).Call(nil)[0] // out[0] should not alias out[1]'s memory, so the finalizer should run.
  1819  	timeout := time.After(5 * time.Second)
  1820  	for atomic.LoadUint32(&finalized) == 0 {
  1821  		select {
  1822  		case <-timeout:
  1823  			t.Fatal("finalizer did not run")
  1824  		default:
  1825  		}
  1826  		runtime.Gosched()
  1827  		runtime.GC()
  1828  	}
  1829  	runtime.KeepAlive(v)
  1830  }
  1831  
  1832  func BenchmarkCall(b *testing.B) {
  1833  	fv := ValueOf(func(a, b string) {})
  1834  	b.ReportAllocs()
  1835  	b.RunParallel(func(pb *testing.PB) {
  1836  		args := []Value{ValueOf("a"), ValueOf("b")}
  1837  		for pb.Next() {
  1838  			fv.Call(args)
  1839  		}
  1840  	})
  1841  }
  1842  
  1843  func BenchmarkCallArgCopy(b *testing.B) {
  1844  	byteArray := func(n int) Value {
  1845  		return Zero(ArrayOf(n, TypeOf(byte(0))))
  1846  	}
  1847  	sizes := [...]struct {
  1848  		fv  Value
  1849  		arg Value
  1850  	}{
  1851  		{ValueOf(func(a [128]byte) {}), byteArray(128)},
  1852  		{ValueOf(func(a [256]byte) {}), byteArray(256)},
  1853  		{ValueOf(func(a [1024]byte) {}), byteArray(1024)},
  1854  		{ValueOf(func(a [4096]byte) {}), byteArray(4096)},
  1855  		{ValueOf(func(a [65536]byte) {}), byteArray(65536)},
  1856  	}
  1857  	for _, size := range sizes {
  1858  		bench := func(b *testing.B) {
  1859  			args := []Value{size.arg}
  1860  			b.SetBytes(int64(size.arg.Len()))
  1861  			b.ResetTimer()
  1862  			b.RunParallel(func(pb *testing.PB) {
  1863  				for pb.Next() {
  1864  					size.fv.Call(args)
  1865  				}
  1866  			})
  1867  		}
  1868  		name := fmt.Sprintf("size=%v", size.arg.Len())
  1869  		b.Run(name, bench)
  1870  	}
  1871  }
  1872  
  1873  func TestMakeFunc(t *testing.T) {
  1874  	f := dummy
  1875  	fv := MakeFunc(TypeOf(f), func(in []Value) []Value { return in })
  1876  	ValueOf(&f).Elem().Set(fv)
  1877  
  1878  	// Call g with small arguments so that there is
  1879  	// something predictable (and different from the
  1880  	// correct results) in those positions on the stack.
  1881  	g := dummy
  1882  	g(1, 2, 3, two{4, 5}, 6, 7, 8)
  1883  
  1884  	// Call constructed function f.
  1885  	i, j, k, l, m, n, o := f(10, 20, 30, two{40, 50}, 60, 70, 80)
  1886  	if i != 10 || j != 20 || k != 30 || l != (two{40, 50}) || m != 60 || n != 70 || o != 80 {
  1887  		t.Errorf("Call returned %d, %d, %d, %v, %d, %g, %d; want 10, 20, 30, [40, 50], 60, 70, 80", i, j, k, l, m, n, o)
  1888  	}
  1889  }
  1890  
  1891  func TestMakeFuncInterface(t *testing.T) {
  1892  	fn := func(i int) int { return i }
  1893  	incr := func(in []Value) []Value {
  1894  		return []Value{ValueOf(int(in[0].Int() + 1))}
  1895  	}
  1896  	fv := MakeFunc(TypeOf(fn), incr)
  1897  	ValueOf(&fn).Elem().Set(fv)
  1898  	if r := fn(2); r != 3 {
  1899  		t.Errorf("Call returned %d, want 3", r)
  1900  	}
  1901  	if r := fv.Call([]Value{ValueOf(14)})[0].Int(); r != 15 {
  1902  		t.Errorf("Call returned %d, want 15", r)
  1903  	}
  1904  	if r := fv.Interface().(func(int) int)(26); r != 27 {
  1905  		t.Errorf("Call returned %d, want 27", r)
  1906  	}
  1907  }
  1908  
  1909  func TestMakeFuncVariadic(t *testing.T) {
  1910  	// Test that variadic arguments are packed into a slice and passed as last arg
  1911  	fn := func(_ int, is ...int) []int { return nil }
  1912  	fv := MakeFunc(TypeOf(fn), func(in []Value) []Value { return in[1:2] })
  1913  	ValueOf(&fn).Elem().Set(fv)
  1914  
  1915  	r := fn(1, 2, 3)
  1916  	if r[0] != 2 || r[1] != 3 {
  1917  		t.Errorf("Call returned [%v, %v]; want 2, 3", r[0], r[1])
  1918  	}
  1919  
  1920  	r = fn(1, []int{2, 3}...)
  1921  	if r[0] != 2 || r[1] != 3 {
  1922  		t.Errorf("Call returned [%v, %v]; want 2, 3", r[0], r[1])
  1923  	}
  1924  
  1925  	r = fv.Call([]Value{ValueOf(1), ValueOf(2), ValueOf(3)})[0].Interface().([]int)
  1926  	if r[0] != 2 || r[1] != 3 {
  1927  		t.Errorf("Call returned [%v, %v]; want 2, 3", r[0], r[1])
  1928  	}
  1929  
  1930  	r = fv.CallSlice([]Value{ValueOf(1), ValueOf([]int{2, 3})})[0].Interface().([]int)
  1931  	if r[0] != 2 || r[1] != 3 {
  1932  		t.Errorf("Call returned [%v, %v]; want 2, 3", r[0], r[1])
  1933  	}
  1934  
  1935  	f := fv.Interface().(func(int, ...int) []int)
  1936  
  1937  	r = f(1, 2, 3)
  1938  	if r[0] != 2 || r[1] != 3 {
  1939  		t.Errorf("Call returned [%v, %v]; want 2, 3", r[0], r[1])
  1940  	}
  1941  	r = f(1, []int{2, 3}...)
  1942  	if r[0] != 2 || r[1] != 3 {
  1943  		t.Errorf("Call returned [%v, %v]; want 2, 3", r[0], r[1])
  1944  	}
  1945  }
  1946  
  1947  // Dummy type that implements io.WriteCloser
  1948  type WC struct {
  1949  }
  1950  
  1951  func (w *WC) Write(p []byte) (n int, err error) {
  1952  	return 0, nil
  1953  }
  1954  func (w *WC) Close() error {
  1955  	return nil
  1956  }
  1957  
  1958  func TestMakeFuncValidReturnAssignments(t *testing.T) {
  1959  	// reflect.Values returned from the wrapped function should be assignment-converted
  1960  	// to the types returned by the result of MakeFunc.
  1961  
  1962  	// Concrete types should be promotable to interfaces they implement.
  1963  	var f func() error
  1964  	f = MakeFunc(TypeOf(f), func([]Value) []Value {
  1965  		return []Value{ValueOf(io.EOF)}
  1966  	}).Interface().(func() error)
  1967  	f()
  1968  
  1969  	// Super-interfaces should be promotable to simpler interfaces.
  1970  	var g func() io.Writer
  1971  	g = MakeFunc(TypeOf(g), func([]Value) []Value {
  1972  		var w io.WriteCloser = &WC{}
  1973  		return []Value{ValueOf(&w).Elem()}
  1974  	}).Interface().(func() io.Writer)
  1975  	g()
  1976  
  1977  	// Channels should be promotable to directional channels.
  1978  	var h func() <-chan int
  1979  	h = MakeFunc(TypeOf(h), func([]Value) []Value {
  1980  		return []Value{ValueOf(make(chan int))}
  1981  	}).Interface().(func() <-chan int)
  1982  	h()
  1983  
  1984  	// Unnamed types should be promotable to named types.
  1985  	type T struct{ a, b, c int }
  1986  	var i func() T
  1987  	i = MakeFunc(TypeOf(i), func([]Value) []Value {
  1988  		return []Value{ValueOf(struct{ a, b, c int }{a: 1, b: 2, c: 3})}
  1989  	}).Interface().(func() T)
  1990  	i()
  1991  }
  1992  
  1993  func TestMakeFuncInvalidReturnAssignments(t *testing.T) {
  1994  	// Type doesn't implement the required interface.
  1995  	shouldPanic(func() {
  1996  		var f func() error
  1997  		f = MakeFunc(TypeOf(f), func([]Value) []Value {
  1998  			return []Value{ValueOf(int(7))}
  1999  		}).Interface().(func() error)
  2000  		f()
  2001  	})
  2002  	// Assigning to an interface with additional methods.
  2003  	shouldPanic(func() {
  2004  		var f func() io.ReadWriteCloser
  2005  		f = MakeFunc(TypeOf(f), func([]Value) []Value {
  2006  			var w io.WriteCloser = &WC{}
  2007  			return []Value{ValueOf(&w).Elem()}
  2008  		}).Interface().(func() io.ReadWriteCloser)
  2009  		f()
  2010  	})
  2011  	// Directional channels can't be assigned to bidirectional ones.
  2012  	shouldPanic(func() {
  2013  		var f func() chan int
  2014  		f = MakeFunc(TypeOf(f), func([]Value) []Value {
  2015  			var c <-chan int = make(chan int)
  2016  			return []Value{ValueOf(c)}
  2017  		}).Interface().(func() chan int)
  2018  		f()
  2019  	})
  2020  	// Two named types which are otherwise identical.
  2021  	shouldPanic(func() {
  2022  		type T struct{ a, b, c int }
  2023  		type U struct{ a, b, c int }
  2024  		var f func() T
  2025  		f = MakeFunc(TypeOf(f), func([]Value) []Value {
  2026  			return []Value{ValueOf(U{a: 1, b: 2, c: 3})}
  2027  		}).Interface().(func() T)
  2028  		f()
  2029  	})
  2030  }
  2031  
  2032  type Point struct {
  2033  	x, y int
  2034  }
  2035  
  2036  // This will be index 0.
  2037  func (p Point) AnotherMethod(scale int) int {
  2038  	return -1
  2039  }
  2040  
  2041  // This will be index 1.
  2042  func (p Point) Dist(scale int) int {
  2043  	//println("Point.Dist", p.x, p.y, scale)
  2044  	return p.x*p.x*scale + p.y*p.y*scale
  2045  }
  2046  
  2047  // This will be index 2.
  2048  func (p Point) GCMethod(k int) int {
  2049  	runtime.GC()
  2050  	return k + p.x
  2051  }
  2052  
  2053  // This will be index 3.
  2054  func (p Point) NoArgs() {
  2055  	// Exercise no-argument/no-result paths.
  2056  }
  2057  
  2058  // This will be index 4.
  2059  func (p Point) TotalDist(points ...Point) int {
  2060  	tot := 0
  2061  	for _, q := range points {
  2062  		dx := q.x - p.x
  2063  		dy := q.y - p.y
  2064  		tot += dx*dx + dy*dy // Should call Sqrt, but it's just a test.
  2065  
  2066  	}
  2067  	return tot
  2068  }
  2069  
  2070  // This will be index 5.
  2071  func (p *Point) Int64Method(x int64) int64 {
  2072  	return x
  2073  }
  2074  
  2075  // This will be index 6.
  2076  func (p *Point) Int32Method(x int32) int32 {
  2077  	return x
  2078  }
  2079  
  2080  func TestMethod(t *testing.T) {
  2081  	// Non-curried method of type.
  2082  	p := Point{3, 4}
  2083  	i := TypeOf(p).Method(1).Func.Call([]Value{ValueOf(p), ValueOf(10)})[0].Int()
  2084  	if i != 250 {
  2085  		t.Errorf("Type Method returned %d; want 250", i)
  2086  	}
  2087  
  2088  	m, ok := TypeOf(p).MethodByName("Dist")
  2089  	if !ok {
  2090  		t.Fatalf("method by name failed")
  2091  	}
  2092  	i = m.Func.Call([]Value{ValueOf(p), ValueOf(11)})[0].Int()
  2093  	if i != 275 {
  2094  		t.Errorf("Type MethodByName returned %d; want 275", i)
  2095  	}
  2096  
  2097  	m, ok = TypeOf(p).MethodByName("NoArgs")
  2098  	if !ok {
  2099  		t.Fatalf("method by name failed")
  2100  	}
  2101  	n := len(m.Func.Call([]Value{ValueOf(p)}))
  2102  	if n != 0 {
  2103  		t.Errorf("NoArgs returned %d values; want 0", n)
  2104  	}
  2105  
  2106  	i = TypeOf(&p).Method(1).Func.Call([]Value{ValueOf(&p), ValueOf(12)})[0].Int()
  2107  	if i != 300 {
  2108  		t.Errorf("Pointer Type Method returned %d; want 300", i)
  2109  	}
  2110  
  2111  	m, ok = TypeOf(&p).MethodByName("Dist")
  2112  	if !ok {
  2113  		t.Fatalf("ptr method by name failed")
  2114  	}
  2115  	i = m.Func.Call([]Value{ValueOf(&p), ValueOf(13)})[0].Int()
  2116  	if i != 325 {
  2117  		t.Errorf("Pointer Type MethodByName returned %d; want 325", i)
  2118  	}
  2119  
  2120  	m, ok = TypeOf(&p).MethodByName("NoArgs")
  2121  	if !ok {
  2122  		t.Fatalf("method by name failed")
  2123  	}
  2124  	n = len(m.Func.Call([]Value{ValueOf(&p)}))
  2125  	if n != 0 {
  2126  		t.Errorf("NoArgs returned %d values; want 0", n)
  2127  	}
  2128  
  2129  	// Curried method of value.
  2130  	tfunc := TypeOf((func(int) int)(nil))
  2131  	v := ValueOf(p).Method(1)
  2132  	if tt := v.Type(); tt != tfunc {
  2133  		t.Errorf("Value Method Type is %s; want %s", tt, tfunc)
  2134  	}
  2135  	i = v.Call([]Value{ValueOf(14)})[0].Int()
  2136  	if i != 350 {
  2137  		t.Errorf("Value Method returned %d; want 350", i)
  2138  	}
  2139  	v = ValueOf(p).MethodByName("Dist")
  2140  	if tt := v.Type(); tt != tfunc {
  2141  		t.Errorf("Value MethodByName Type is %s; want %s", tt, tfunc)
  2142  	}
  2143  	i = v.Call([]Value{ValueOf(15)})[0].Int()
  2144  	if i != 375 {
  2145  		t.Errorf("Value MethodByName returned %d; want 375", i)
  2146  	}
  2147  	v = ValueOf(p).MethodByName("NoArgs")
  2148  	v.Call(nil)
  2149  
  2150  	// Curried method of pointer.
  2151  	v = ValueOf(&p).Method(1)
  2152  	if tt := v.Type(); tt != tfunc {
  2153  		t.Errorf("Pointer Value Method Type is %s; want %s", tt, tfunc)
  2154  	}
  2155  	i = v.Call([]Value{ValueOf(16)})[0].Int()
  2156  	if i != 400 {
  2157  		t.Errorf("Pointer Value Method returned %d; want 400", i)
  2158  	}
  2159  	v = ValueOf(&p).MethodByName("Dist")
  2160  	if tt := v.Type(); tt != tfunc {
  2161  		t.Errorf("Pointer Value MethodByName Type is %s; want %s", tt, tfunc)
  2162  	}
  2163  	i = v.Call([]Value{ValueOf(17)})[0].Int()
  2164  	if i != 425 {
  2165  		t.Errorf("Pointer Value MethodByName returned %d; want 425", i)
  2166  	}
  2167  	v = ValueOf(&p).MethodByName("NoArgs")
  2168  	v.Call(nil)
  2169  
  2170  	// Curried method of interface value.
  2171  	// Have to wrap interface value in a struct to get at it.
  2172  	// Passing it to ValueOf directly would
  2173  	// access the underlying Point, not the interface.
  2174  	var x interface {
  2175  		Dist(int) int
  2176  	} = p
  2177  	pv := ValueOf(&x).Elem()
  2178  	v = pv.Method(0)
  2179  	if tt := v.Type(); tt != tfunc {
  2180  		t.Errorf("Interface Method Type is %s; want %s", tt, tfunc)
  2181  	}
  2182  	i = v.Call([]Value{ValueOf(18)})[0].Int()
  2183  	if i != 450 {
  2184  		t.Errorf("Interface Method returned %d; want 450", i)
  2185  	}
  2186  	v = pv.MethodByName("Dist")
  2187  	if tt := v.Type(); tt != tfunc {
  2188  		t.Errorf("Interface MethodByName Type is %s; want %s", tt, tfunc)
  2189  	}
  2190  	i = v.Call([]Value{ValueOf(19)})[0].Int()
  2191  	if i != 475 {
  2192  		t.Errorf("Interface MethodByName returned %d; want 475", i)
  2193  	}
  2194  }
  2195  
  2196  func TestMethodValue(t *testing.T) {
  2197  	p := Point{3, 4}
  2198  	var i int64
  2199  
  2200  	// Curried method of value.
  2201  	tfunc := TypeOf((func(int) int)(nil))
  2202  	v := ValueOf(p).Method(1)
  2203  	if tt := v.Type(); tt != tfunc {
  2204  		t.Errorf("Value Method Type is %s; want %s", tt, tfunc)
  2205  	}
  2206  	i = ValueOf(v.Interface()).Call([]Value{ValueOf(10)})[0].Int()
  2207  	if i != 250 {
  2208  		t.Errorf("Value Method returned %d; want 250", i)
  2209  	}
  2210  	v = ValueOf(p).MethodByName("Dist")
  2211  	if tt := v.Type(); tt != tfunc {
  2212  		t.Errorf("Value MethodByName Type is %s; want %s", tt, tfunc)
  2213  	}
  2214  	i = ValueOf(v.Interface()).Call([]Value{ValueOf(11)})[0].Int()
  2215  	if i != 275 {
  2216  		t.Errorf("Value MethodByName returned %d; want 275", i)
  2217  	}
  2218  	v = ValueOf(p).MethodByName("NoArgs")
  2219  	ValueOf(v.Interface()).Call(nil)
  2220  	v.Interface().(func())()
  2221  
  2222  	// Curried method of pointer.
  2223  	v = ValueOf(&p).Method(1)
  2224  	if tt := v.Type(); tt != tfunc {
  2225  		t.Errorf("Pointer Value Method Type is %s; want %s", tt, tfunc)
  2226  	}
  2227  	i = ValueOf(v.Interface()).Call([]Value{ValueOf(12)})[0].Int()
  2228  	if i != 300 {
  2229  		t.Errorf("Pointer Value Method returned %d; want 300", i)
  2230  	}
  2231  	v = ValueOf(&p).MethodByName("Dist")
  2232  	if tt := v.Type(); tt != tfunc {
  2233  		t.Errorf("Pointer Value MethodByName Type is %s; want %s", tt, tfunc)
  2234  	}
  2235  	i = ValueOf(v.Interface()).Call([]Value{ValueOf(13)})[0].Int()
  2236  	if i != 325 {
  2237  		t.Errorf("Pointer Value MethodByName returned %d; want 325", i)
  2238  	}
  2239  	v = ValueOf(&p).MethodByName("NoArgs")
  2240  	ValueOf(v.Interface()).Call(nil)
  2241  	v.Interface().(func())()
  2242  
  2243  	// Curried method of pointer to pointer.
  2244  	pp := &p
  2245  	v = ValueOf(&pp).Elem().Method(1)
  2246  	if tt := v.Type(); tt != tfunc {
  2247  		t.Errorf("Pointer Pointer Value Method Type is %s; want %s", tt, tfunc)
  2248  	}
  2249  	i = ValueOf(v.Interface()).Call([]Value{ValueOf(14)})[0].Int()
  2250  	if i != 350 {
  2251  		t.Errorf("Pointer Pointer Value Method returned %d; want 350", i)
  2252  	}
  2253  	v = ValueOf(&pp).Elem().MethodByName("Dist")
  2254  	if tt := v.Type(); tt != tfunc {
  2255  		t.Errorf("Pointer Pointer Value MethodByName Type is %s; want %s", tt, tfunc)
  2256  	}
  2257  	i = ValueOf(v.Interface()).Call([]Value{ValueOf(15)})[0].Int()
  2258  	if i != 375 {
  2259  		t.Errorf("Pointer Pointer Value MethodByName returned %d; want 375", i)
  2260  	}
  2261  
  2262  	// Curried method of interface value.
  2263  	// Have to wrap interface value in a struct to get at it.
  2264  	// Passing it to ValueOf directly would
  2265  	// access the underlying Point, not the interface.
  2266  	var s = struct {
  2267  		X interface {
  2268  			Dist(int) int
  2269  		}
  2270  	}{p}
  2271  	pv := ValueOf(s).Field(0)
  2272  	v = pv.Method(0)
  2273  	if tt := v.Type(); tt != tfunc {
  2274  		t.Errorf("Interface Method Type is %s; want %s", tt, tfunc)
  2275  	}
  2276  	i = ValueOf(v.Interface()).Call([]Value{ValueOf(16)})[0].Int()
  2277  	if i != 400 {
  2278  		t.Errorf("Interface Method returned %d; want 400", i)
  2279  	}
  2280  	v = pv.MethodByName("Dist")
  2281  	if tt := v.Type(); tt != tfunc {
  2282  		t.Errorf("Interface MethodByName Type is %s; want %s", tt, tfunc)
  2283  	}
  2284  	i = ValueOf(v.Interface()).Call([]Value{ValueOf(17)})[0].Int()
  2285  	if i != 425 {
  2286  		t.Errorf("Interface MethodByName returned %d; want 425", i)
  2287  	}
  2288  
  2289  	// For issue #33628: method args are not stored at the right offset
  2290  	// on amd64p32.
  2291  	m64 := ValueOf(&p).MethodByName("Int64Method").Interface().(func(int64) int64)
  2292  	if x := m64(123); x != 123 {
  2293  		t.Errorf("Int64Method returned %d; want 123", x)
  2294  	}
  2295  	m32 := ValueOf(&p).MethodByName("Int32Method").Interface().(func(int32) int32)
  2296  	if x := m32(456); x != 456 {
  2297  		t.Errorf("Int32Method returned %d; want 456", x)
  2298  	}
  2299  }
  2300  
  2301  func TestVariadicMethodValue(t *testing.T) {
  2302  	p := Point{3, 4}
  2303  	points := []Point{{20, 21}, {22, 23}, {24, 25}}
  2304  	want := int64(p.TotalDist(points[0], points[1], points[2]))
  2305  
  2306  	// Curried method of value.
  2307  	tfunc := TypeOf((func(...Point) int)(nil))
  2308  	v := ValueOf(p).Method(4)
  2309  	if tt := v.Type(); tt != tfunc {
  2310  		t.Errorf("Variadic Method Type is %s; want %s", tt, tfunc)
  2311  	}
  2312  	i := ValueOf(v.Interface()).Call([]Value{ValueOf(points[0]), ValueOf(points[1]), ValueOf(points[2])})[0].Int()
  2313  	if i != want {
  2314  		t.Errorf("Variadic Method returned %d; want %d", i, want)
  2315  	}
  2316  	i = ValueOf(v.Interface()).CallSlice([]Value{ValueOf(points)})[0].Int()
  2317  	if i != want {
  2318  		t.Errorf("Variadic Method CallSlice returned %d; want %d", i, want)
  2319  	}
  2320  
  2321  	f := v.Interface().(func(...Point) int)
  2322  	i = int64(f(points[0], points[1], points[2]))
  2323  	if i != want {
  2324  		t.Errorf("Variadic Method Interface returned %d; want %d", i, want)
  2325  	}
  2326  	i = int64(f(points...))
  2327  	if i != want {
  2328  		t.Errorf("Variadic Method Interface Slice returned %d; want %d", i, want)
  2329  	}
  2330  }
  2331  
  2332  type DirectIfaceT struct {
  2333  	p *int
  2334  }
  2335  
  2336  func (d DirectIfaceT) M() int { return *d.p }
  2337  
  2338  func TestDirectIfaceMethod(t *testing.T) {
  2339  	x := 42
  2340  	v := DirectIfaceT{&x}
  2341  	typ := TypeOf(v)
  2342  	m, ok := typ.MethodByName("M")
  2343  	if !ok {
  2344  		t.Fatalf("cannot find method M")
  2345  	}
  2346  	in := []Value{ValueOf(v)}
  2347  	out := m.Func.Call(in)
  2348  	if got := out[0].Int(); got != 42 {
  2349  		t.Errorf("Call with value receiver got %d, want 42", got)
  2350  	}
  2351  
  2352  	pv := &v
  2353  	typ = TypeOf(pv)
  2354  	m, ok = typ.MethodByName("M")
  2355  	if !ok {
  2356  		t.Fatalf("cannot find method M")
  2357  	}
  2358  	in = []Value{ValueOf(pv)}
  2359  	out = m.Func.Call(in)
  2360  	if got := out[0].Int(); got != 42 {
  2361  		t.Errorf("Call with pointer receiver got %d, want 42", got)
  2362  	}
  2363  }
  2364  
  2365  // Reflect version of $GOROOT/test/method5.go
  2366  
  2367  // Concrete types implementing M method.
  2368  // Smaller than a word, word-sized, larger than a word.
  2369  // Value and pointer receivers.
  2370  
  2371  type Tinter interface {
  2372  	M(int, byte) (byte, int)
  2373  }
  2374  
  2375  type Tsmallv byte
  2376  
  2377  func (v Tsmallv) M(x int, b byte) (byte, int) { return b, x + int(v) }
  2378  
  2379  type Tsmallp byte
  2380  
  2381  func (p *Tsmallp) M(x int, b byte) (byte, int) { return b, x + int(*p) }
  2382  
  2383  type Twordv uintptr
  2384  
  2385  func (v Twordv) M(x int, b byte) (byte, int) { return b, x + int(v) }
  2386  
  2387  type Twordp uintptr
  2388  
  2389  func (p *Twordp) M(x int, b byte) (byte, int) { return b, x + int(*p) }
  2390  
  2391  type Tbigv [2]uintptr
  2392  
  2393  func (v Tbigv) M(x int, b byte) (byte, int) { return b, x + int(v[0]) + int(v[1]) }
  2394  
  2395  type Tbigp [2]uintptr
  2396  
  2397  func (p *Tbigp) M(x int, b byte) (byte, int) { return b, x + int(p[0]) + int(p[1]) }
  2398  
  2399  type tinter interface {
  2400  	m(int, byte) (byte, int)
  2401  }
  2402  
  2403  // Embedding via pointer.
  2404  
  2405  type Tm1 struct {
  2406  	Tm2
  2407  }
  2408  
  2409  type Tm2 struct {
  2410  	*Tm3
  2411  }
  2412  
  2413  type Tm3 struct {
  2414  	*Tm4
  2415  }
  2416  
  2417  type Tm4 struct {
  2418  }
  2419  
  2420  func (t4 Tm4) M(x int, b byte) (byte, int) { return b, x + 40 }
  2421  
  2422  func TestMethod5(t *testing.T) {
  2423  	CheckF := func(name string, f func(int, byte) (byte, int), inc int) {
  2424  		b, x := f(1000, 99)
  2425  		if b != 99 || x != 1000+inc {
  2426  			t.Errorf("%s(1000, 99) = %v, %v, want 99, %v", name, b, x, 1000+inc)
  2427  		}
  2428  	}
  2429  
  2430  	CheckV := func(name string, i Value, inc int) {
  2431  		bx := i.Method(0).Call([]Value{ValueOf(1000), ValueOf(byte(99))})
  2432  		b := bx[0].Interface()
  2433  		x := bx[1].Interface()
  2434  		if b != byte(99) || x != 1000+inc {
  2435  			t.Errorf("direct %s.M(1000, 99) = %v, %v, want 99, %v", name, b, x, 1000+inc)
  2436  		}
  2437  
  2438  		CheckF(name+".M", i.Method(0).Interface().(func(int, byte) (byte, int)), inc)
  2439  	}
  2440  
  2441  	var TinterType = TypeOf(new(Tinter)).Elem()
  2442  
  2443  	CheckI := func(name string, i interface{}, inc int) {
  2444  		v := ValueOf(i)
  2445  		CheckV(name, v, inc)
  2446  		CheckV("(i="+name+")", v.Convert(TinterType), inc)
  2447  	}
  2448  
  2449  	sv := Tsmallv(1)
  2450  	CheckI("sv", sv, 1)
  2451  	CheckI("&sv", &sv, 1)
  2452  
  2453  	sp := Tsmallp(2)
  2454  	CheckI("&sp", &sp, 2)
  2455  
  2456  	wv := Twordv(3)
  2457  	CheckI("wv", wv, 3)
  2458  	CheckI("&wv", &wv, 3)
  2459  
  2460  	wp := Twordp(4)
  2461  	CheckI("&wp", &wp, 4)
  2462  
  2463  	bv := Tbigv([2]uintptr{5, 6})
  2464  	CheckI("bv", bv, 11)
  2465  	CheckI("&bv", &bv, 11)
  2466  
  2467  	bp := Tbigp([2]uintptr{7, 8})
  2468  	CheckI("&bp", &bp, 15)
  2469  
  2470  	t4 := Tm4{}
  2471  	t3 := Tm3{&t4}
  2472  	t2 := Tm2{&t3}
  2473  	t1 := Tm1{t2}
  2474  	CheckI("t4", t4, 40)
  2475  	CheckI("&t4", &t4, 40)
  2476  	CheckI("t3", t3, 40)
  2477  	CheckI("&t3", &t3, 40)
  2478  	CheckI("t2", t2, 40)
  2479  	CheckI("&t2", &t2, 40)
  2480  	CheckI("t1", t1, 40)
  2481  	CheckI("&t1", &t1, 40)
  2482  
  2483  	var tnil Tinter
  2484  	vnil := ValueOf(&tnil).Elem()
  2485  	shouldPanic(func() { vnil.Method(0) })
  2486  }
  2487  
  2488  func TestInterfaceSet(t *testing.T) {
  2489  	p := &Point{3, 4}
  2490  
  2491  	var s struct {
  2492  		I interface{}
  2493  		P interface {
  2494  			Dist(int) int
  2495  		}
  2496  	}
  2497  	sv := ValueOf(&s).Elem()
  2498  	sv.Field(0).Set(ValueOf(p))
  2499  	if q := s.I.(*Point); q != p {
  2500  		t.Errorf("i: have %p want %p", q, p)
  2501  	}
  2502  
  2503  	pv := sv.Field(1)
  2504  	pv.Set(ValueOf(p))
  2505  	if q := s.P.(*Point); q != p {
  2506  		t.Errorf("i: have %p want %p", q, p)
  2507  	}
  2508  
  2509  	i := pv.Method(0).Call([]Value{ValueOf(10)})[0].Int()
  2510  	if i != 250 {
  2511  		t.Errorf("Interface Method returned %d; want 250", i)
  2512  	}
  2513  }
  2514  
  2515  type T1 struct {
  2516  	a string
  2517  	int
  2518  }
  2519  
  2520  func TestAnonymousFields(t *testing.T) {
  2521  	var field StructField
  2522  	var ok bool
  2523  	var t1 T1
  2524  	type1 := TypeOf(t1)
  2525  	if field, ok = type1.FieldByName("int"); !ok {
  2526  		t.Fatal("no field 'int'")
  2527  	}
  2528  	if field.Index[0] != 1 {
  2529  		t.Error("field index should be 1; is", field.Index)
  2530  	}
  2531  }
  2532  
  2533  type FTest struct {
  2534  	s     interface{}
  2535  	name  string
  2536  	index []int
  2537  	value int
  2538  }
  2539  
  2540  type D1 struct {
  2541  	d int
  2542  }
  2543  type D2 struct {
  2544  	d int
  2545  }
  2546  
  2547  type S0 struct {
  2548  	A, B, C int
  2549  	D1
  2550  	D2
  2551  }
  2552  
  2553  type S1 struct {
  2554  	B int
  2555  	S0
  2556  }
  2557  
  2558  type S2 struct {
  2559  	A int
  2560  	*S1
  2561  }
  2562  
  2563  type S1x struct {
  2564  	S1
  2565  }
  2566  
  2567  type S1y struct {
  2568  	S1
  2569  }
  2570  
  2571  type S3 struct {
  2572  	S1x
  2573  	S2
  2574  	D, E int
  2575  	*S1y
  2576  }
  2577  
  2578  type S4 struct {
  2579  	*S4
  2580  	A int
  2581  }
  2582  
  2583  // The X in S6 and S7 annihilate, but they also block the X in S8.S9.
  2584  type S5 struct {
  2585  	S6
  2586  	S7
  2587  	S8
  2588  }
  2589  
  2590  type S6 struct {
  2591  	X int
  2592  }
  2593  
  2594  type S7 S6
  2595  
  2596  type S8 struct {
  2597  	S9
  2598  }
  2599  
  2600  type S9 struct {
  2601  	X int
  2602  	Y int
  2603  }
  2604  
  2605  // The X in S11.S6 and S12.S6 annihilate, but they also block the X in S13.S8.S9.
  2606  type S10 struct {
  2607  	S11
  2608  	S12
  2609  	S13
  2610  }
  2611  
  2612  type S11 struct {
  2613  	S6
  2614  }
  2615  
  2616  type S12 struct {
  2617  	S6
  2618  }
  2619  
  2620  type S13 struct {
  2621  	S8
  2622  }
  2623  
  2624  // The X in S15.S11.S1 and S16.S11.S1 annihilate.
  2625  type S14 struct {
  2626  	S15
  2627  	S16
  2628  }
  2629  
  2630  type S15 struct {
  2631  	S11
  2632  }
  2633  
  2634  type S16 struct {
  2635  	S11
  2636  }
  2637  
  2638  var fieldTests = []FTest{
  2639  	{struct{}{}, "", nil, 0},
  2640  	{struct{}{}, "Foo", nil, 0},
  2641  	{S0{A: 'a'}, "A", []int{0}, 'a'},
  2642  	{S0{}, "D", nil, 0},
  2643  	{S1{S0: S0{A: 'a'}}, "A", []int{1, 0}, 'a'},
  2644  	{S1{B: 'b'}, "B", []int{0}, 'b'},
  2645  	{S1{}, "S0", []int{1}, 0},
  2646  	{S1{S0: S0{C: 'c'}}, "C", []int{1, 2}, 'c'},
  2647  	{S2{A: 'a'}, "A", []int{0}, 'a'},
  2648  	{S2{}, "S1", []int{1}, 0},
  2649  	{S2{S1: &S1{B: 'b'}}, "B", []int{1, 0}, 'b'},
  2650  	{S2{S1: &S1{S0: S0{C: 'c'}}}, "C", []int{1, 1, 2}, 'c'},
  2651  	{S2{}, "D", nil, 0},
  2652  	{S3{}, "S1", nil, 0},
  2653  	{S3{S2: S2{A: 'a'}}, "A", []int{1, 0}, 'a'},
  2654  	{S3{}, "B", nil, 0},
  2655  	{S3{D: 'd'}, "D", []int{2}, 0},
  2656  	{S3{E: 'e'}, "E", []int{3}, 'e'},
  2657  	{S4{A: 'a'}, "A", []int{1}, 'a'},
  2658  	{S4{}, "B", nil, 0},
  2659  	{S5{}, "X", nil, 0},
  2660  	{S5{}, "Y", []int{2, 0, 1}, 0},
  2661  	{S10{}, "X", nil, 0},
  2662  	{S10{}, "Y", []int{2, 0, 0, 1}, 0},
  2663  	{S14{}, "X", nil, 0},
  2664  }
  2665  
  2666  func TestFieldByIndex(t *testing.T) {
  2667  	for _, test := range fieldTests {
  2668  		s := TypeOf(test.s)
  2669  		f := s.FieldByIndex(test.index)
  2670  		if f.Name != "" {
  2671  			if test.index != nil {
  2672  				if f.Name != test.name {
  2673  					t.Errorf("%s.%s found; want %s", s.Name(), f.Name, test.name)
  2674  				}
  2675  			} else {
  2676  				t.Errorf("%s.%s found", s.Name(), f.Name)
  2677  			}
  2678  		} else if len(test.index) > 0 {
  2679  			t.Errorf("%s.%s not found", s.Name(), test.name)
  2680  		}
  2681  
  2682  		if test.value != 0 {
  2683  			v := ValueOf(test.s).FieldByIndex(test.index)
  2684  			if v.IsValid() {
  2685  				if x, ok := v.Interface().(int); ok {
  2686  					if x != test.value {
  2687  						t.Errorf("%s%v is %d; want %d", s.Name(), test.index, x, test.value)
  2688  					}
  2689  				} else {
  2690  					t.Errorf("%s%v value not an int", s.Name(), test.index)
  2691  				}
  2692  			} else {
  2693  				t.Errorf("%s%v value not found", s.Name(), test.index)
  2694  			}
  2695  		}
  2696  	}
  2697  }
  2698  
  2699  func TestFieldByName(t *testing.T) {
  2700  	for _, test := range fieldTests {
  2701  		s := TypeOf(test.s)
  2702  		f, found := s.FieldByName(test.name)
  2703  		if found {
  2704  			if test.index != nil {
  2705  				// Verify field depth and index.
  2706  				if len(f.Index) != len(test.index) {
  2707  					t.Errorf("%s.%s depth %d; want %d: %v vs %v", s.Name(), test.name, len(f.Index), len(test.index), f.Index, test.index)
  2708  				} else {
  2709  					for i, x := range f.Index {
  2710  						if x != test.index[i] {
  2711  							t.Errorf("%s.%s.Index[%d] is %d; want %d", s.Name(), test.name, i, x, test.index[i])
  2712  						}
  2713  					}
  2714  				}
  2715  			} else {
  2716  				t.Errorf("%s.%s found", s.Name(), f.Name)
  2717  			}
  2718  		} else if len(test.index) > 0 {
  2719  			t.Errorf("%s.%s not found", s.Name(), test.name)
  2720  		}
  2721  
  2722  		if test.value != 0 {
  2723  			v := ValueOf(test.s).FieldByName(test.name)
  2724  			if v.IsValid() {
  2725  				if x, ok := v.Interface().(int); ok {
  2726  					if x != test.value {
  2727  						t.Errorf("%s.%s is %d; want %d", s.Name(), test.name, x, test.value)
  2728  					}
  2729  				} else {
  2730  					t.Errorf("%s.%s value not an int", s.Name(), test.name)
  2731  				}
  2732  			} else {
  2733  				t.Errorf("%s.%s value not found", s.Name(), test.name)
  2734  			}
  2735  		}
  2736  	}
  2737  }
  2738  
  2739  func TestImportPath(t *testing.T) {
  2740  	tests := []struct {
  2741  		t    Type
  2742  		path string
  2743  	}{
  2744  		{TypeOf(&base64.Encoding{}).Elem(), "encoding/base64"},
  2745  		{TypeOf(int(0)), ""},
  2746  		{TypeOf(int8(0)), ""},
  2747  		{TypeOf(int16(0)), ""},
  2748  		{TypeOf(int32(0)), ""},
  2749  		{TypeOf(int64(0)), ""},
  2750  		{TypeOf(uint(0)), ""},
  2751  		{TypeOf(uint8(0)), ""},
  2752  		{TypeOf(uint16(0)), ""},
  2753  		{TypeOf(uint32(0)), ""},
  2754  		{TypeOf(uint64(0)), ""},
  2755  		{TypeOf(uintptr(0)), ""},
  2756  		{TypeOf(float32(0)), ""},
  2757  		{TypeOf(float64(0)), ""},
  2758  		{TypeOf(complex64(0)), ""},
  2759  		{TypeOf(complex128(0)), ""},
  2760  		{TypeOf(byte(0)), ""},
  2761  		{TypeOf(rune(0)), ""},
  2762  		{TypeOf([]byte(nil)), ""},
  2763  		{TypeOf([]rune(nil)), ""},
  2764  		{TypeOf(string("")), ""},
  2765  		{TypeOf((*interface{})(nil)).Elem(), ""},
  2766  		{TypeOf((*byte)(nil)), ""},
  2767  		{TypeOf((*rune)(nil)), ""},
  2768  		{TypeOf((*int64)(nil)), ""},
  2769  		{TypeOf(map[string]int{}), ""},
  2770  		{TypeOf((*error)(nil)).Elem(), ""},
  2771  		{TypeOf((*Point)(nil)), ""},
  2772  		{TypeOf((*Point)(nil)).Elem(), "reflect_test"},
  2773  	}
  2774  	for _, test := range tests {
  2775  		if path := test.t.PkgPath(); path != test.path {
  2776  			t.Errorf("%v.PkgPath() = %q, want %q", test.t, path, test.path)
  2777  		}
  2778  	}
  2779  }
  2780  
  2781  func TestFieldPkgPath(t *testing.T) {
  2782  	type x int
  2783  	typ := TypeOf(struct {
  2784  		Exported   string
  2785  		unexported string
  2786  		OtherPkgFields
  2787  		int // issue 21702
  2788  		*x  // issue 21122
  2789  	}{})
  2790  
  2791  	type pkgpathTest struct {
  2792  		index    []int
  2793  		pkgPath  string
  2794  		embedded bool
  2795  	}
  2796  
  2797  	checkPkgPath := func(name string, s []pkgpathTest) {
  2798  		for _, test := range s {
  2799  			f := typ.FieldByIndex(test.index)
  2800  			if got, want := f.PkgPath, test.pkgPath; got != want {
  2801  				t.Errorf("%s: Field(%d).PkgPath = %q, want %q", name, test.index, got, want)
  2802  			}
  2803  			if got, want := f.Anonymous, test.embedded; got != want {
  2804  				t.Errorf("%s: Field(%d).Anonymous = %v, want %v", name, test.index, got, want)
  2805  			}
  2806  		}
  2807  	}
  2808  
  2809  	checkPkgPath("testStruct", []pkgpathTest{
  2810  		{[]int{0}, "", false},             // Exported
  2811  		{[]int{1}, "reflect_test", false}, // unexported
  2812  		{[]int{2}, "", true},              // OtherPkgFields
  2813  		{[]int{2, 0}, "", false},          // OtherExported
  2814  		{[]int{2, 1}, "reflect", false},   // otherUnexported
  2815  		{[]int{3}, "reflect_test", true},  // int
  2816  		{[]int{4}, "reflect_test", true},  // *x
  2817  	})
  2818  
  2819  	type localOtherPkgFields OtherPkgFields
  2820  	typ = TypeOf(localOtherPkgFields{})
  2821  	checkPkgPath("localOtherPkgFields", []pkgpathTest{
  2822  		{[]int{0}, "", false},        // OtherExported
  2823  		{[]int{1}, "reflect", false}, // otherUnexported
  2824  	})
  2825  }
  2826  
  2827  func TestVariadicType(t *testing.T) {
  2828  	// Test example from Type documentation.
  2829  	var f func(x int, y ...float64)
  2830  	typ := TypeOf(f)
  2831  	if typ.NumIn() == 2 && typ.In(0) == TypeOf(int(0)) {
  2832  		sl := typ.In(1)
  2833  		if sl.Kind() == Slice {
  2834  			if sl.Elem() == TypeOf(0.0) {
  2835  				// ok
  2836  				return
  2837  			}
  2838  		}
  2839  	}
  2840  
  2841  	// Failed
  2842  	t.Errorf("want NumIn() = 2, In(0) = int, In(1) = []float64")
  2843  	s := fmt.Sprintf("have NumIn() = %d", typ.NumIn())
  2844  	for i := 0; i < typ.NumIn(); i++ {
  2845  		s += fmt.Sprintf(", In(%d) = %s", i, typ.In(i))
  2846  	}
  2847  	t.Error(s)
  2848  }
  2849  
  2850  type inner struct {
  2851  	x int
  2852  }
  2853  
  2854  type outer struct {
  2855  	y int
  2856  	inner
  2857  }
  2858  
  2859  func (*inner) M() {}
  2860  func (*outer) M() {}
  2861  
  2862  func TestNestedMethods(t *testing.T) {
  2863  	typ := TypeOf((*outer)(nil))
  2864  	if typ.NumMethod() != 1 || typ.Method(0).Func.Pointer() != ValueOf((*outer).M).Pointer() {
  2865  		t.Errorf("Wrong method table for outer: (M=%p)", (*outer).M)
  2866  		for i := 0; i < typ.NumMethod(); i++ {
  2867  			m := typ.Method(i)
  2868  			t.Errorf("\t%d: %s %#x\n", i, m.Name, m.Func.Pointer())
  2869  		}
  2870  	}
  2871  }
  2872  
  2873  type unexp struct{}
  2874  
  2875  func (*unexp) f() (int32, int8) { return 7, 7 }
  2876  func (*unexp) g() (int64, int8) { return 8, 8 }
  2877  
  2878  type unexpI interface {
  2879  	f() (int32, int8)
  2880  }
  2881  
  2882  var unexpi unexpI = new(unexp)
  2883  
  2884  func TestUnexportedMethods(t *testing.T) {
  2885  	typ := TypeOf(unexpi)
  2886  
  2887  	if got := typ.NumMethod(); got != 0 {
  2888  		t.Errorf("NumMethod=%d, want 0 satisfied methods", got)
  2889  	}
  2890  }
  2891  
  2892  type InnerInt struct {
  2893  	X int
  2894  }
  2895  
  2896  type OuterInt struct {
  2897  	Y int
  2898  	InnerInt
  2899  }
  2900  
  2901  func (i *InnerInt) M() int {
  2902  	return i.X
  2903  }
  2904  
  2905  func TestEmbeddedMethods(t *testing.T) {
  2906  	typ := TypeOf((*OuterInt)(nil))
  2907  	if typ.NumMethod() != 1 || typ.Method(0).Func.Pointer() != ValueOf((*OuterInt).M).Pointer() {
  2908  		t.Errorf("Wrong method table for OuterInt: (m=%p)", (*OuterInt).M)
  2909  		for i := 0; i < typ.NumMethod(); i++ {
  2910  			m := typ.Method(i)
  2911  			t.Errorf("\t%d: %s %#x\n", i, m.Name, m.Func.Pointer())
  2912  		}
  2913  	}
  2914  
  2915  	i := &InnerInt{3}
  2916  	if v := ValueOf(i).Method(0).Call(nil)[0].Int(); v != 3 {
  2917  		t.Errorf("i.M() = %d, want 3", v)
  2918  	}
  2919  
  2920  	o := &OuterInt{1, InnerInt{2}}
  2921  	if v := ValueOf(o).Method(0).Call(nil)[0].Int(); v != 2 {
  2922  		t.Errorf("i.M() = %d, want 2", v)
  2923  	}
  2924  
  2925  	f := (*OuterInt).M
  2926  	if v := f(o); v != 2 {
  2927  		t.Errorf("f(o) = %d, want 2", v)
  2928  	}
  2929  }
  2930  
  2931  type FuncDDD func(...interface{}) error
  2932  
  2933  func (f FuncDDD) M() {}
  2934  
  2935  func TestNumMethodOnDDD(t *testing.T) {
  2936  	rv := ValueOf((FuncDDD)(nil))
  2937  	if n := rv.NumMethod(); n != 1 {
  2938  		t.Fatalf("NumMethod()=%d, want 1", n)
  2939  	}
  2940  }
  2941  
  2942  func TestPtrTo(t *testing.T) {
  2943  	// This block of code means that the ptrToThis field of the
  2944  	// reflect data for *unsafe.Pointer is non zero, see
  2945  	// https://golang.org/issue/19003
  2946  	var x unsafe.Pointer
  2947  	var y = &x
  2948  	var z = &y
  2949  
  2950  	var i int
  2951  
  2952  	typ := TypeOf(z)
  2953  	for i = 0; i < 100; i++ {
  2954  		typ = PtrTo(typ)
  2955  	}
  2956  	for i = 0; i < 100; i++ {
  2957  		typ = typ.Elem()
  2958  	}
  2959  	if typ != TypeOf(z) {
  2960  		t.Errorf("after 100 PtrTo and Elem, have %s, want %s", typ, TypeOf(z))
  2961  	}
  2962  }
  2963  
  2964  func TestPtrToGC(t *testing.T) {
  2965  	type T *uintptr
  2966  	tt := TypeOf(T(nil))
  2967  	pt := PtrTo(tt)
  2968  	const n = 100
  2969  	var x []interface{}
  2970  	for i := 0; i < n; i++ {
  2971  		v := New(pt)
  2972  		p := new(*uintptr)
  2973  		*p = new(uintptr)
  2974  		**p = uintptr(i)
  2975  		v.Elem().Set(ValueOf(p).Convert(pt))
  2976  		x = append(x, v.Interface())
  2977  	}
  2978  	runtime.GC()
  2979  
  2980  	for i, xi := range x {
  2981  		k := ValueOf(xi).Elem().Elem().Elem().Interface().(uintptr)
  2982  		if k != uintptr(i) {
  2983  			t.Errorf("lost x[%d] = %d, want %d", i, k, i)
  2984  		}
  2985  	}
  2986  }
  2987  
  2988  func BenchmarkPtrTo(b *testing.B) {
  2989  	// Construct a type with a zero ptrToThis.
  2990  	type T struct{ int }
  2991  	t := SliceOf(TypeOf(T{}))
  2992  	ptrToThis := ValueOf(t).Elem().FieldByName("ptrToThis")
  2993  	if !ptrToThis.IsValid() {
  2994  		b.Fatalf("%v has no ptrToThis field; was it removed from rtype?", t)
  2995  	}
  2996  	if ptrToThis.Int() != 0 {
  2997  		b.Fatalf("%v.ptrToThis unexpectedly nonzero", t)
  2998  	}
  2999  	b.ResetTimer()
  3000  
  3001  	// Now benchmark calling PtrTo on it: we'll have to hit the ptrMap cache on
  3002  	// every call.
  3003  	b.RunParallel(func(pb *testing.PB) {
  3004  		for pb.Next() {
  3005  			PtrTo(t)
  3006  		}
  3007  	})
  3008  }
  3009  
  3010  func TestAddr(t *testing.T) {
  3011  	var p struct {
  3012  		X, Y int
  3013  	}
  3014  
  3015  	v := ValueOf(&p)
  3016  	v = v.Elem()
  3017  	v = v.Addr()
  3018  	v = v.Elem()
  3019  	v = v.Field(0)
  3020  	v.SetInt(2)
  3021  	if p.X != 2 {
  3022  		t.Errorf("Addr.Elem.Set failed to set value")
  3023  	}
  3024  
  3025  	// Again but take address of the ValueOf value.
  3026  	// Exercises generation of PtrTypes not present in the binary.
  3027  	q := &p
  3028  	v = ValueOf(&q).Elem()
  3029  	v = v.Addr()
  3030  	v = v.Elem()
  3031  	v = v.Elem()
  3032  	v = v.Addr()
  3033  	v = v.Elem()
  3034  	v = v.Field(0)
  3035  	v.SetInt(3)
  3036  	if p.X != 3 {
  3037  		t.Errorf("Addr.Elem.Set failed to set value")
  3038  	}
  3039  
  3040  	// Starting without pointer we should get changed value
  3041  	// in interface.
  3042  	qq := p
  3043  	v = ValueOf(&qq).Elem()
  3044  	v0 := v
  3045  	v = v.Addr()
  3046  	v = v.Elem()
  3047  	v = v.Field(0)
  3048  	v.SetInt(4)
  3049  	if p.X != 3 { // should be unchanged from last time
  3050  		t.Errorf("somehow value Set changed original p")
  3051  	}
  3052  	p = v0.Interface().(struct {
  3053  		X, Y int
  3054  	})
  3055  	if p.X != 4 {
  3056  		t.Errorf("Addr.Elem.Set valued to set value in top value")
  3057  	}
  3058  
  3059  	// Verify that taking the address of a type gives us a pointer
  3060  	// which we can convert back using the usual interface
  3061  	// notation.
  3062  	var s struct {
  3063  		B *bool
  3064  	}
  3065  	ps := ValueOf(&s).Elem().Field(0).Addr().Interface()
  3066  	*(ps.(**bool)) = new(bool)
  3067  	if s.B == nil {
  3068  		t.Errorf("Addr.Interface direct assignment failed")
  3069  	}
  3070  }
  3071  
  3072  func noAlloc(t *testing.T, n int, f func(int)) {
  3073  	if testing.Short() {
  3074  		t.Skip("skipping malloc count in short mode")
  3075  	}
  3076  	if runtime.GOMAXPROCS(0) > 1 {
  3077  		t.Skip("skipping; GOMAXPROCS>1")
  3078  	}
  3079  	i := -1
  3080  	allocs := testing.AllocsPerRun(n, func() {
  3081  		f(i)
  3082  		i++
  3083  	})
  3084  	if allocs > 0 {
  3085  		t.Errorf("%d iterations: got %v mallocs, want 0", n, allocs)
  3086  	}
  3087  }
  3088  
  3089  func TestAllocations(t *testing.T) {
  3090  	noAlloc(t, 100, func(j int) {
  3091  		var i interface{}
  3092  		var v Value
  3093  
  3094  		// We can uncomment this when compiler escape analysis
  3095  		// is good enough to see that the integer assigned to i
  3096  		// does not escape and therefore need not be allocated.
  3097  		//
  3098  		// i = 42 + j
  3099  		// v = ValueOf(i)
  3100  		// if int(v.Int()) != 42+j {
  3101  		// 	panic("wrong int")
  3102  		// }
  3103  
  3104  		i = func(j int) int { return j }
  3105  		v = ValueOf(i)
  3106  		if v.Interface().(func(int) int)(j) != j {
  3107  			panic("wrong result")
  3108  		}
  3109  	})
  3110  }
  3111  
  3112  func TestSmallNegativeInt(t *testing.T) {
  3113  	i := int16(-1)
  3114  	v := ValueOf(i)
  3115  	if v.Int() != -1 {
  3116  		t.Errorf("int16(-1).Int() returned %v", v.Int())
  3117  	}
  3118  }
  3119  
  3120  func TestIndex(t *testing.T) {
  3121  	xs := []byte{1, 2, 3, 4, 5, 6, 7, 8}
  3122  	v := ValueOf(xs).Index(3).Interface().(byte)
  3123  	if v != xs[3] {
  3124  		t.Errorf("xs.Index(3) = %v; expected %v", v, xs[3])
  3125  	}
  3126  	xa := [8]byte{10, 20, 30, 40, 50, 60, 70, 80}
  3127  	v = ValueOf(xa).Index(2).Interface().(byte)
  3128  	if v != xa[2] {
  3129  		t.Errorf("xa.Index(2) = %v; expected %v", v, xa[2])
  3130  	}
  3131  	s := "0123456789"
  3132  	v = ValueOf(s).Index(3).Interface().(byte)
  3133  	if v != s[3] {
  3134  		t.Errorf("s.Index(3) = %v; expected %v", v, s[3])
  3135  	}
  3136  }
  3137  
  3138  func TestSlice(t *testing.T) {
  3139  	xs := []int{1, 2, 3, 4, 5, 6, 7, 8}
  3140  	v := ValueOf(xs).Slice(3, 5).Interface().([]int)
  3141  	if len(v) != 2 {
  3142  		t.Errorf("len(xs.Slice(3, 5)) = %d", len(v))
  3143  	}
  3144  	if cap(v) != 5 {
  3145  		t.Errorf("cap(xs.Slice(3, 5)) = %d", cap(v))
  3146  	}
  3147  	if !DeepEqual(v[0:5], xs[3:]) {
  3148  		t.Errorf("xs.Slice(3, 5)[0:5] = %v", v[0:5])
  3149  	}
  3150  	xa := [8]int{10, 20, 30, 40, 50, 60, 70, 80}
  3151  	v = ValueOf(&xa).Elem().Slice(2, 5).Interface().([]int)
  3152  	if len(v) != 3 {
  3153  		t.Errorf("len(xa.Slice(2, 5)) = %d", len(v))
  3154  	}
  3155  	if cap(v) != 6 {
  3156  		t.Errorf("cap(xa.Slice(2, 5)) = %d", cap(v))
  3157  	}
  3158  	if !DeepEqual(v[0:6], xa[2:]) {
  3159  		t.Errorf("xs.Slice(2, 5)[0:6] = %v", v[0:6])
  3160  	}
  3161  	s := "0123456789"
  3162  	vs := ValueOf(s).Slice(3, 5).Interface().(string)
  3163  	if vs != s[3:5] {
  3164  		t.Errorf("s.Slice(3, 5) = %q; expected %q", vs, s[3:5])
  3165  	}
  3166  
  3167  	rv := ValueOf(&xs).Elem()
  3168  	rv = rv.Slice(3, 4)
  3169  	ptr2 := rv.Pointer()
  3170  	rv = rv.Slice(5, 5)
  3171  	ptr3 := rv.Pointer()
  3172  	if ptr3 != ptr2 {
  3173  		t.Errorf("xs.Slice(3,4).Slice3(5,5).Pointer() = %#x, want %#x", ptr3, ptr2)
  3174  	}
  3175  }
  3176  
  3177  func TestSlice3(t *testing.T) {
  3178  	xs := []int{1, 2, 3, 4, 5, 6, 7, 8}
  3179  	v := ValueOf(xs).Slice3(3, 5, 7).Interface().([]int)
  3180  	if len(v) != 2 {
  3181  		t.Errorf("len(xs.Slice3(3, 5, 7)) = %d", len(v))
  3182  	}
  3183  	if cap(v) != 4 {
  3184  		t.Errorf("cap(xs.Slice3(3, 5, 7)) = %d", cap(v))
  3185  	}
  3186  	if !DeepEqual(v[0:4], xs[3:7:7]) {
  3187  		t.Errorf("xs.Slice3(3, 5, 7)[0:4] = %v", v[0:4])
  3188  	}
  3189  	rv := ValueOf(&xs).Elem()
  3190  	shouldPanic(func() { rv.Slice3(1, 2, 1) })
  3191  	shouldPanic(func() { rv.Slice3(1, 1, 11) })
  3192  	shouldPanic(func() { rv.Slice3(2, 2, 1) })
  3193  
  3194  	xa := [8]int{10, 20, 30, 40, 50, 60, 70, 80}
  3195  	v = ValueOf(&xa).Elem().Slice3(2, 5, 6).Interface().([]int)
  3196  	if len(v) != 3 {
  3197  		t.Errorf("len(xa.Slice(2, 5, 6)) = %d", len(v))
  3198  	}
  3199  	if cap(v) != 4 {
  3200  		t.Errorf("cap(xa.Slice(2, 5, 6)) = %d", cap(v))
  3201  	}
  3202  	if !DeepEqual(v[0:4], xa[2:6:6]) {
  3203  		t.Errorf("xs.Slice(2, 5, 6)[0:4] = %v", v[0:4])
  3204  	}
  3205  	rv = ValueOf(&xa).Elem()
  3206  	shouldPanic(func() { rv.Slice3(1, 2, 1) })
  3207  	shouldPanic(func() { rv.Slice3(1, 1, 11) })
  3208  	shouldPanic(func() { rv.Slice3(2, 2, 1) })
  3209  
  3210  	s := "hello world"
  3211  	rv = ValueOf(&s).Elem()
  3212  	shouldPanic(func() { rv.Slice3(1, 2, 3) })
  3213  
  3214  	rv = ValueOf(&xs).Elem()
  3215  	rv = rv.Slice3(3, 5, 7)
  3216  	ptr2 := rv.Pointer()
  3217  	rv = rv.Slice3(4, 4, 4)
  3218  	ptr3 := rv.Pointer()
  3219  	if ptr3 != ptr2 {
  3220  		t.Errorf("xs.Slice3(3,5,7).Slice3(4,4,4).Pointer() = %#x, want %#x", ptr3, ptr2)
  3221  	}
  3222  }
  3223  
  3224  func TestSetLenCap(t *testing.T) {
  3225  	xs := []int{1, 2, 3, 4, 5, 6, 7, 8}
  3226  	xa := [8]int{10, 20, 30, 40, 50, 60, 70, 80}
  3227  
  3228  	vs := ValueOf(&xs).Elem()
  3229  	shouldPanic(func() { vs.SetLen(10) })
  3230  	shouldPanic(func() { vs.SetCap(10) })
  3231  	shouldPanic(func() { vs.SetLen(-1) })
  3232  	shouldPanic(func() { vs.SetCap(-1) })
  3233  	shouldPanic(func() { vs.SetCap(6) }) // smaller than len
  3234  	vs.SetLen(5)
  3235  	if len(xs) != 5 || cap(xs) != 8 {
  3236  		t.Errorf("after SetLen(5), len, cap = %d, %d, want 5, 8", len(xs), cap(xs))
  3237  	}
  3238  	vs.SetCap(6)
  3239  	if len(xs) != 5 || cap(xs) != 6 {
  3240  		t.Errorf("after SetCap(6), len, cap = %d, %d, want 5, 6", len(xs), cap(xs))
  3241  	}
  3242  	vs.SetCap(5)
  3243  	if len(xs) != 5 || cap(xs) != 5 {
  3244  		t.Errorf("after SetCap(5), len, cap = %d, %d, want 5, 5", len(xs), cap(xs))
  3245  	}
  3246  	shouldPanic(func() { vs.SetCap(4) }) // smaller than len
  3247  	shouldPanic(func() { vs.SetLen(6) }) // bigger than cap
  3248  
  3249  	va := ValueOf(&xa).Elem()
  3250  	shouldPanic(func() { va.SetLen(8) })
  3251  	shouldPanic(func() { va.SetCap(8) })
  3252  }
  3253  
  3254  func TestVariadic(t *testing.T) {
  3255  	var b bytes.Buffer
  3256  	V := ValueOf
  3257  
  3258  	b.Reset()
  3259  	V(fmt.Fprintf).Call([]Value{V(&b), V("%s, %d world"), V("hello"), V(42)})
  3260  	if b.String() != "hello, 42 world" {
  3261  		t.Errorf("after Fprintf Call: %q != %q", b.String(), "hello 42 world")
  3262  	}
  3263  
  3264  	b.Reset()
  3265  	V(fmt.Fprintf).CallSlice([]Value{V(&b), V("%s, %d world"), V([]interface{}{"hello", 42})})
  3266  	if b.String() != "hello, 42 world" {
  3267  		t.Errorf("after Fprintf CallSlice: %q != %q", b.String(), "hello 42 world")
  3268  	}
  3269  }
  3270  
  3271  func TestFuncArg(t *testing.T) {
  3272  	f1 := func(i int, f func(int) int) int { return f(i) }
  3273  	f2 := func(i int) int { return i + 1 }
  3274  	r := ValueOf(f1).Call([]Value{ValueOf(100), ValueOf(f2)})
  3275  	if r[0].Int() != 101 {
  3276  		t.Errorf("function returned %d, want 101", r[0].Int())
  3277  	}
  3278  }
  3279  
  3280  func TestStructArg(t *testing.T) {
  3281  	type padded struct {
  3282  		B string
  3283  		C int32
  3284  	}
  3285  	var (
  3286  		gotA  padded
  3287  		gotB  uint32
  3288  		wantA = padded{"3", 4}
  3289  		wantB = uint32(5)
  3290  	)
  3291  	f := func(a padded, b uint32) {
  3292  		gotA, gotB = a, b
  3293  	}
  3294  	ValueOf(f).Call([]Value{ValueOf(wantA), ValueOf(wantB)})
  3295  	if gotA != wantA || gotB != wantB {
  3296  		t.Errorf("function called with (%v, %v), want (%v, %v)", gotA, gotB, wantA, wantB)
  3297  	}
  3298  }
  3299  
  3300  var tagGetTests = []struct {
  3301  	Tag   StructTag
  3302  	Key   string
  3303  	Value string
  3304  }{
  3305  	{`protobuf:"PB(1,2)"`, `protobuf`, `PB(1,2)`},
  3306  	{`protobuf:"PB(1,2)"`, `foo`, ``},
  3307  	{`protobuf:"PB(1,2)"`, `rotobuf`, ``},
  3308  	{`protobuf:"PB(1,2)" json:"name"`, `json`, `name`},
  3309  	{`protobuf:"PB(1,2)" json:"name"`, `protobuf`, `PB(1,2)`},
  3310  	{`k0:"values contain spaces" k1:"and\ttabs"`, "k0", "values contain spaces"},
  3311  	{`k0:"values contain spaces" k1:"and\ttabs"`, "k1", "and\ttabs"},
  3312  }
  3313  
  3314  func TestTagGet(t *testing.T) {
  3315  	for _, tt := range tagGetTests {
  3316  		if v := tt.Tag.Get(tt.Key); v != tt.Value {
  3317  			t.Errorf("StructTag(%#q).Get(%#q) = %#q, want %#q", tt.Tag, tt.Key, v, tt.Value)
  3318  		}
  3319  	}
  3320  }
  3321  
  3322  func TestBytes(t *testing.T) {
  3323  	type B []byte
  3324  	x := B{1, 2, 3, 4}
  3325  	y := ValueOf(x).Bytes()
  3326  	if !bytes.Equal(x, y) {
  3327  		t.Fatalf("ValueOf(%v).Bytes() = %v", x, y)
  3328  	}
  3329  	if &x[0] != &y[0] {
  3330  		t.Errorf("ValueOf(%p).Bytes() = %p", &x[0], &y[0])
  3331  	}
  3332  }
  3333  
  3334  func TestSetBytes(t *testing.T) {
  3335  	type B []byte
  3336  	var x B
  3337  	y := []byte{1, 2, 3, 4}
  3338  	ValueOf(&x).Elem().SetBytes(y)
  3339  	if !bytes.Equal(x, y) {
  3340  		t.Fatalf("ValueOf(%v).Bytes() = %v", x, y)
  3341  	}
  3342  	if &x[0] != &y[0] {
  3343  		t.Errorf("ValueOf(%p).Bytes() = %p", &x[0], &y[0])
  3344  	}
  3345  }
  3346  
  3347  type Private struct {
  3348  	x int
  3349  	y **int
  3350  	Z int
  3351  }
  3352  
  3353  func (p *Private) m() {
  3354  }
  3355  
  3356  type private struct {
  3357  	Z int
  3358  	z int
  3359  	S string
  3360  	A [1]Private
  3361  	T []Private
  3362  }
  3363  
  3364  func (p *private) P() {
  3365  }
  3366  
  3367  type Public struct {
  3368  	X int
  3369  	Y **int
  3370  	private
  3371  }
  3372  
  3373  func (p *Public) M() {
  3374  }
  3375  
  3376  func TestUnexported(t *testing.T) {
  3377  	var pub Public
  3378  	pub.S = "S"
  3379  	pub.T = pub.A[:]
  3380  	v := ValueOf(&pub)
  3381  	isValid(v.Elem().Field(0))
  3382  	isValid(v.Elem().Field(1))
  3383  	isValid(v.Elem().Field(2))
  3384  	isValid(v.Elem().FieldByName("X"))
  3385  	isValid(v.Elem().FieldByName("Y"))
  3386  	isValid(v.Elem().FieldByName("Z"))
  3387  	isValid(v.Type().Method(0).Func)
  3388  	m, _ := v.Type().MethodByName("M")
  3389  	isValid(m.Func)
  3390  	m, _ = v.Type().MethodByName("P")
  3391  	isValid(m.Func)
  3392  	isNonNil(v.Elem().Field(0).Interface())
  3393  	isNonNil(v.Elem().Field(1).Interface())
  3394  	isNonNil(v.Elem().Field(2).Field(2).Index(0))
  3395  	isNonNil(v.Elem().FieldByName("X").Interface())
  3396  	isNonNil(v.Elem().FieldByName("Y").Interface())
  3397  	isNonNil(v.Elem().FieldByName("Z").Interface())
  3398  	isNonNil(v.Elem().FieldByName("S").Index(0).Interface())
  3399  	isNonNil(v.Type().Method(0).Func.Interface())
  3400  	m, _ = v.Type().MethodByName("P")
  3401  	isNonNil(m.Func.Interface())
  3402  
  3403  	var priv Private
  3404  	v = ValueOf(&priv)
  3405  	isValid(v.Elem().Field(0))
  3406  	isValid(v.Elem().Field(1))
  3407  	isValid(v.Elem().FieldByName("x"))
  3408  	isValid(v.Elem().FieldByName("y"))
  3409  	shouldPanic(func() { v.Elem().Field(0).Interface() })
  3410  	shouldPanic(func() { v.Elem().Field(1).Interface() })
  3411  	shouldPanic(func() { v.Elem().FieldByName("x").Interface() })
  3412  	shouldPanic(func() { v.Elem().FieldByName("y").Interface() })
  3413  	shouldPanic(func() { v.Type().Method(0) })
  3414  }
  3415  
  3416  func TestSetPanic(t *testing.T) {
  3417  	ok := func(f func()) { f() }
  3418  	bad := shouldPanic
  3419  	clear := func(v Value) { v.Set(Zero(v.Type())) }
  3420  
  3421  	type t0 struct {
  3422  		W int
  3423  	}
  3424  
  3425  	type t1 struct {
  3426  		Y int
  3427  		t0
  3428  	}
  3429  
  3430  	type T2 struct {
  3431  		Z       int
  3432  		namedT0 t0
  3433  	}
  3434  
  3435  	type T struct {
  3436  		X int
  3437  		t1
  3438  		T2
  3439  		NamedT1 t1
  3440  		NamedT2 T2
  3441  		namedT1 t1
  3442  		namedT2 T2
  3443  	}
  3444  
  3445  	// not addressable
  3446  	v := ValueOf(T{})
  3447  	bad(func() { clear(v.Field(0)) })                   // .X
  3448  	bad(func() { clear(v.Field(1)) })                   // .t1
  3449  	bad(func() { clear(v.Field(1).Field(0)) })          // .t1.Y
  3450  	bad(func() { clear(v.Field(1).Field(1)) })          // .t1.t0
  3451  	bad(func() { clear(v.Field(1).Field(1).Field(0)) }) // .t1.t0.W
  3452  	bad(func() { clear(v.Field(2)) })                   // .T2
  3453  	bad(func() { clear(v.Field(2).Field(0)) })          // .T2.Z
  3454  	bad(func() { clear(v.Field(2).Field(1)) })          // .T2.namedT0
  3455  	bad(func() { clear(v.Field(2).Field(1).Field(0)) }) // .T2.namedT0.W
  3456  	bad(func() { clear(v.Field(3)) })                   // .NamedT1
  3457  	bad(func() { clear(v.Field(3).Field(0)) })          // .NamedT1.Y
  3458  	bad(func() { clear(v.Field(3).Field(1)) })          // .NamedT1.t0
  3459  	bad(func() { clear(v.Field(3).Field(1).Field(0)) }) // .NamedT1.t0.W
  3460  	bad(func() { clear(v.Field(4)) })                   // .NamedT2
  3461  	bad(func() { clear(v.Field(4).Field(0)) })          // .NamedT2.Z
  3462  	bad(func() { clear(v.Field(4).Field(1)) })          // .NamedT2.namedT0
  3463  	bad(func() { clear(v.Field(4).Field(1).Field(0)) }) // .NamedT2.namedT0.W
  3464  	bad(func() { clear(v.Field(5)) })                   // .namedT1
  3465  	bad(func() { clear(v.Field(5).Field(0)) })          // .namedT1.Y
  3466  	bad(func() { clear(v.Field(5).Field(1)) })          // .namedT1.t0
  3467  	bad(func() { clear(v.Field(5).Field(1).Field(0)) }) // .namedT1.t0.W
  3468  	bad(func() { clear(v.Field(6)) })                   // .namedT2
  3469  	bad(func() { clear(v.Field(6).Field(0)) })          // .namedT2.Z
  3470  	bad(func() { clear(v.Field(6).Field(1)) })          // .namedT2.namedT0
  3471  	bad(func() { clear(v.Field(6).Field(1).Field(0)) }) // .namedT2.namedT0.W
  3472  
  3473  	// addressable
  3474  	v = ValueOf(&T{}).Elem()
  3475  	ok(func() { clear(v.Field(0)) })                    // .X
  3476  	bad(func() { clear(v.Field(1)) })                   // .t1
  3477  	ok(func() { clear(v.Field(1).Field(0)) })           // .t1.Y
  3478  	bad(func() { clear(v.Field(1).Field(1)) })          // .t1.t0
  3479  	ok(func() { clear(v.Field(1).Field(1).Field(0)) })  // .t1.t0.W
  3480  	ok(func() { clear(v.Field(2)) })                    // .T2
  3481  	ok(func() { clear(v.Field(2).Field(0)) })           // .T2.Z
  3482  	bad(func() { clear(v.Field(2).Field(1)) })          // .T2.namedT0
  3483  	bad(func() { clear(v.Field(2).Field(1).Field(0)) }) // .T2.namedT0.W
  3484  	ok(func() { clear(v.Field(3)) })                    // .NamedT1
  3485  	ok(func() { clear(v.Field(3).Field(0)) })           // .NamedT1.Y
  3486  	bad(func() { clear(v.Field(3).Field(1)) })          // .NamedT1.t0
  3487  	ok(func() { clear(v.Field(3).Field(1).Field(0)) })  // .NamedT1.t0.W
  3488  	ok(func() { clear(v.Field(4)) })                    // .NamedT2
  3489  	ok(func() { clear(v.Field(4).Field(0)) })           // .NamedT2.Z
  3490  	bad(func() { clear(v.Field(4).Field(1)) })          // .NamedT2.namedT0
  3491  	bad(func() { clear(v.Field(4).Field(1).Field(0)) }) // .NamedT2.namedT0.W
  3492  	bad(func() { clear(v.Field(5)) })                   // .namedT1
  3493  	bad(func() { clear(v.Field(5).Field(0)) })          // .namedT1.Y
  3494  	bad(func() { clear(v.Field(5).Field(1)) })          // .namedT1.t0
  3495  	bad(func() { clear(v.Field(5).Field(1).Field(0)) }) // .namedT1.t0.W
  3496  	bad(func() { clear(v.Field(6)) })                   // .namedT2
  3497  	bad(func() { clear(v.Field(6).Field(0)) })          // .namedT2.Z
  3498  	bad(func() { clear(v.Field(6).Field(1)) })          // .namedT2.namedT0
  3499  	bad(func() { clear(v.Field(6).Field(1).Field(0)) }) // .namedT2.namedT0.W
  3500  }
  3501  
  3502  type timp int
  3503  
  3504  func (t timp) W() {}
  3505  func (t timp) Y() {}
  3506  func (t timp) w() {}
  3507  func (t timp) y() {}
  3508  
  3509  func TestCallPanic(t *testing.T) {
  3510  	type t0 interface {
  3511  		W()
  3512  		w()
  3513  	}
  3514  	type T1 interface {
  3515  		Y()
  3516  		y()
  3517  	}
  3518  	type T2 struct {
  3519  		T1
  3520  		t0
  3521  	}
  3522  	type T struct {
  3523  		t0 // 0
  3524  		T1 // 1
  3525  
  3526  		NamedT0 t0 // 2
  3527  		NamedT1 T1 // 3
  3528  		NamedT2 T2 // 4
  3529  
  3530  		namedT0 t0 // 5
  3531  		namedT1 T1 // 6
  3532  		namedT2 T2 // 7
  3533  	}
  3534  	ok := func(f func()) { f() }
  3535  	bad := shouldPanic
  3536  	call := func(v Value) { v.Call(nil) }
  3537  
  3538  	i := timp(0)
  3539  	v := ValueOf(T{i, i, i, i, T2{i, i}, i, i, T2{i, i}})
  3540  	ok(func() { call(v.Field(0).Method(0)) })         // .t0.W
  3541  	bad(func() { call(v.Field(0).Elem().Method(0)) }) // .t0.W
  3542  	bad(func() { call(v.Field(0).Method(1)) })        // .t0.w
  3543  	bad(func() { call(v.Field(0).Elem().Method(2)) }) // .t0.w
  3544  	ok(func() { call(v.Field(1).Method(0)) })         // .T1.Y
  3545  	ok(func() { call(v.Field(1).Elem().Method(0)) })  // .T1.Y
  3546  	bad(func() { call(v.Field(1).Method(1)) })        // .T1.y
  3547  	bad(func() { call(v.Field(1).Elem().Method(2)) }) // .T1.y
  3548  
  3549  	ok(func() { call(v.Field(2).Method(0)) })         // .NamedT0.W
  3550  	ok(func() { call(v.Field(2).Elem().Method(0)) })  // .NamedT0.W
  3551  	bad(func() { call(v.Field(2).Method(1)) })        // .NamedT0.w
  3552  	bad(func() { call(v.Field(2).Elem().Method(2)) }) // .NamedT0.w
  3553  
  3554  	ok(func() { call(v.Field(3).Method(0)) })         // .NamedT1.Y
  3555  	ok(func() { call(v.Field(3).Elem().Method(0)) })  // .NamedT1.Y
  3556  	bad(func() { call(v.Field(3).Method(1)) })        // .NamedT1.y
  3557  	bad(func() { call(v.Field(3).Elem().Method(3)) }) // .NamedT1.y
  3558  
  3559  	ok(func() { call(v.Field(4).Field(0).Method(0)) })         // .NamedT2.T1.Y
  3560  	ok(func() { call(v.Field(4).Field(0).Elem().Method(0)) })  // .NamedT2.T1.W
  3561  	ok(func() { call(v.Field(4).Field(1).Method(0)) })         // .NamedT2.t0.W
  3562  	bad(func() { call(v.Field(4).Field(1).Elem().Method(0)) }) // .NamedT2.t0.W
  3563  
  3564  	bad(func() { call(v.Field(5).Method(0)) })        // .namedT0.W
  3565  	bad(func() { call(v.Field(5).Elem().Method(0)) }) // .namedT0.W
  3566  	bad(func() { call(v.Field(5).Method(1)) })        // .namedT0.w
  3567  	bad(func() { call(v.Field(5).Elem().Method(2)) }) // .namedT0.w
  3568  
  3569  	bad(func() { call(v.Field(6).Method(0)) })        // .namedT1.Y
  3570  	bad(func() { call(v.Field(6).Elem().Method(0)) }) // .namedT1.Y
  3571  	bad(func() { call(v.Field(6).Method(0)) })        // .namedT1.y
  3572  	bad(func() { call(v.Field(6).Elem().Method(0)) }) // .namedT1.y
  3573  
  3574  	bad(func() { call(v.Field(7).Field(0).Method(0)) })        // .namedT2.T1.Y
  3575  	bad(func() { call(v.Field(7).Field(0).Elem().Method(0)) }) // .namedT2.T1.W
  3576  	bad(func() { call(v.Field(7).Field(1).Method(0)) })        // .namedT2.t0.W
  3577  	bad(func() { call(v.Field(7).Field(1).Elem().Method(0)) }) // .namedT2.t0.W
  3578  }
  3579  
  3580  func shouldPanic(f func()) {
  3581  	defer func() {
  3582  		if recover() == nil {
  3583  			panic("did not panic")
  3584  		}
  3585  	}()
  3586  	f()
  3587  }
  3588  
  3589  func isNonNil(x interface{}) {
  3590  	if x == nil {
  3591  		panic("nil interface")
  3592  	}
  3593  }
  3594  
  3595  func isValid(v Value) {
  3596  	if !v.IsValid() {
  3597  		panic("zero Value")
  3598  	}
  3599  }
  3600  
  3601  func TestAlias(t *testing.T) {
  3602  	x := string("hello")
  3603  	v := ValueOf(&x).Elem()
  3604  	oldvalue := v.Interface()
  3605  	v.SetString("world")
  3606  	newvalue := v.Interface()
  3607  
  3608  	if oldvalue != "hello" || newvalue != "world" {
  3609  		t.Errorf("aliasing: old=%q new=%q, want hello, world", oldvalue, newvalue)
  3610  	}
  3611  }
  3612  
  3613  var V = ValueOf
  3614  
  3615  func EmptyInterfaceV(x interface{}) Value {
  3616  	return ValueOf(&x).Elem()
  3617  }
  3618  
  3619  func ReaderV(x io.Reader) Value {
  3620  	return ValueOf(&x).Elem()
  3621  }
  3622  
  3623  func ReadWriterV(x io.ReadWriter) Value {
  3624  	return ValueOf(&x).Elem()
  3625  }
  3626  
  3627  type Empty struct{}
  3628  type MyStruct struct {
  3629  	x int `some:"tag"`
  3630  }
  3631  type MyString string
  3632  type MyBytes []byte
  3633  type MyRunes []int32
  3634  type MyFunc func()
  3635  type MyByte byte
  3636  
  3637  type IntChan chan int
  3638  type IntChanRecv <-chan int
  3639  type IntChanSend chan<- int
  3640  type BytesChan chan []byte
  3641  type BytesChanRecv <-chan []byte
  3642  type BytesChanSend chan<- []byte
  3643  
  3644  var convertTests = []struct {
  3645  	in  Value
  3646  	out Value
  3647  }{
  3648  	// numbers
  3649  	/*
  3650  		Edit .+1,/\*\//-1>cat >/tmp/x.go && go run /tmp/x.go
  3651  
  3652  		package main
  3653  
  3654  		import "fmt"
  3655  
  3656  		var numbers = []string{
  3657  			"int8", "uint8", "int16", "uint16",
  3658  			"int32", "uint32", "int64", "uint64",
  3659  			"int", "uint", "uintptr",
  3660  			"float32", "float64",
  3661  		}
  3662  
  3663  		func main() {
  3664  			// all pairs but in an unusual order,
  3665  			// to emit all the int8, uint8 cases
  3666  			// before n grows too big.
  3667  			n := 1
  3668  			for i, f := range numbers {
  3669  				for _, g := range numbers[i:] {
  3670  					fmt.Printf("\t{V(%s(%d)), V(%s(%d))},\n", f, n, g, n)
  3671  					n++
  3672  					if f != g {
  3673  						fmt.Printf("\t{V(%s(%d)), V(%s(%d))},\n", g, n, f, n)
  3674  						n++
  3675  					}
  3676  				}
  3677  			}
  3678  		}
  3679  	*/
  3680  	{V(int8(1)), V(int8(1))},
  3681  	{V(int8(2)), V(uint8(2))},
  3682  	{V(uint8(3)), V(int8(3))},
  3683  	{V(int8(4)), V(int16(4))},
  3684  	{V(int16(5)), V(int8(5))},
  3685  	{V(int8(6)), V(uint16(6))},
  3686  	{V(uint16(7)), V(int8(7))},
  3687  	{V(int8(8)), V(int32(8))},
  3688  	{V(int32(9)), V(int8(9))},
  3689  	{V(int8(10)), V(uint32(10))},
  3690  	{V(uint32(11)), V(int8(11))},
  3691  	{V(int8(12)), V(int64(12))},
  3692  	{V(int64(13)), V(int8(13))},
  3693  	{V(int8(14)), V(uint64(14))},
  3694  	{V(uint64(15)), V(int8(15))},
  3695  	{V(int8(16)), V(int(16))},
  3696  	{V(int(17)), V(int8(17))},
  3697  	{V(int8(18)), V(uint(18))},
  3698  	{V(uint(19)), V(int8(19))},
  3699  	{V(int8(20)), V(uintptr(20))},
  3700  	{V(uintptr(21)), V(int8(21))},
  3701  	{V(int8(22)), V(float32(22))},
  3702  	{V(float32(23)), V(int8(23))},
  3703  	{V(int8(24)), V(float64(24))},
  3704  	{V(float64(25)), V(int8(25))},
  3705  	{V(uint8(26)), V(uint8(26))},
  3706  	{V(uint8(27)), V(int16(27))},
  3707  	{V(int16(28)), V(uint8(28))},
  3708  	{V(uint8(29)), V(uint16(29))},
  3709  	{V(uint16(30)), V(uint8(30))},
  3710  	{V(uint8(31)), V(int32(31))},
  3711  	{V(int32(32)), V(uint8(32))},
  3712  	{V(uint8(33)), V(uint32(33))},
  3713  	{V(uint32(34)), V(uint8(34))},
  3714  	{V(uint8(35)), V(int64(35))},
  3715  	{V(int64(36)), V(uint8(36))},
  3716  	{V(uint8(37)), V(uint64(37))},
  3717  	{V(uint64(38)), V(uint8(38))},
  3718  	{V(uint8(39)), V(int(39))},
  3719  	{V(int(40)), V(uint8(40))},
  3720  	{V(uint8(41)), V(uint(41))},
  3721  	{V(uint(42)), V(uint8(42))},
  3722  	{V(uint8(43)), V(uintptr(43))},
  3723  	{V(uintptr(44)), V(uint8(44))},
  3724  	{V(uint8(45)), V(float32(45))},
  3725  	{V(float32(46)), V(uint8(46))},
  3726  	{V(uint8(47)), V(float64(47))},
  3727  	{V(float64(48)), V(uint8(48))},
  3728  	{V(int16(49)), V(int16(49))},
  3729  	{V(int16(50)), V(uint16(50))},
  3730  	{V(uint16(51)), V(int16(51))},
  3731  	{V(int16(52)), V(int32(52))},
  3732  	{V(int32(53)), V(int16(53))},
  3733  	{V(int16(54)), V(uint32(54))},
  3734  	{V(uint32(55)), V(int16(55))},
  3735  	{V(int16(56)), V(int64(56))},
  3736  	{V(int64(57)), V(int16(57))},
  3737  	{V(int16(58)), V(uint64(58))},
  3738  	{V(uint64(59)), V(int16(59))},
  3739  	{V(int16(60)), V(int(60))},
  3740  	{V(int(61)), V(int16(61))},
  3741  	{V(int16(62)), V(uint(62))},
  3742  	{V(uint(63)), V(int16(63))},
  3743  	{V(int16(64)), V(uintptr(64))},
  3744  	{V(uintptr(65)), V(int16(65))},
  3745  	{V(int16(66)), V(float32(66))},
  3746  	{V(float32(67)), V(int16(67))},
  3747  	{V(int16(68)), V(float64(68))},
  3748  	{V(float64(69)), V(int16(69))},
  3749  	{V(uint16(70)), V(uint16(70))},
  3750  	{V(uint16(71)), V(int32(71))},
  3751  	{V(int32(72)), V(uint16(72))},
  3752  	{V(uint16(73)), V(uint32(73))},
  3753  	{V(uint32(74)), V(uint16(74))},
  3754  	{V(uint16(75)), V(int64(75))},
  3755  	{V(int64(76)), V(uint16(76))},
  3756  	{V(uint16(77)), V(uint64(77))},
  3757  	{V(uint64(78)), V(uint16(78))},
  3758  	{V(uint16(79)), V(int(79))},
  3759  	{V(int(80)), V(uint16(80))},
  3760  	{V(uint16(81)), V(uint(81))},
  3761  	{V(uint(82)), V(uint16(82))},
  3762  	{V(uint16(83)), V(uintptr(83))},
  3763  	{V(uintptr(84)), V(uint16(84))},
  3764  	{V(uint16(85)), V(float32(85))},
  3765  	{V(float32(86)), V(uint16(86))},
  3766  	{V(uint16(87)), V(float64(87))},
  3767  	{V(float64(88)), V(uint16(88))},
  3768  	{V(int32(89)), V(int32(89))},
  3769  	{V(int32(90)), V(uint32(90))},
  3770  	{V(uint32(91)), V(int32(91))},
  3771  	{V(int32(92)), V(int64(92))},
  3772  	{V(int64(93)), V(int32(93))},
  3773  	{V(int32(94)), V(uint64(94))},
  3774  	{V(uint64(95)), V(int32(95))},
  3775  	{V(int32(96)), V(int(96))},
  3776  	{V(int(97)), V(int32(97))},
  3777  	{V(int32(98)), V(uint(98))},
  3778  	{V(uint(99)), V(int32(99))},
  3779  	{V(int32(100)), V(uintptr(100))},
  3780  	{V(uintptr(101)), V(int32(101))},
  3781  	{V(int32(102)), V(float32(102))},
  3782  	{V(float32(103)), V(int32(103))},
  3783  	{V(int32(104)), V(float64(104))},
  3784  	{V(float64(105)), V(int32(105))},
  3785  	{V(uint32(106)), V(uint32(106))},
  3786  	{V(uint32(107)), V(int64(107))},
  3787  	{V(int64(108)), V(uint32(108))},
  3788  	{V(uint32(109)), V(uint64(109))},
  3789  	{V(uint64(110)), V(uint32(110))},
  3790  	{V(uint32(111)), V(int(111))},
  3791  	{V(int(112)), V(uint32(112))},
  3792  	{V(uint32(113)), V(uint(113))},
  3793  	{V(uint(114)), V(uint32(114))},
  3794  	{V(uint32(115)), V(uintptr(115))},
  3795  	{V(uintptr(116)), V(uint32(116))},
  3796  	{V(uint32(117)), V(float32(117))},
  3797  	{V(float32(118)), V(uint32(118))},
  3798  	{V(uint32(119)), V(float64(119))},
  3799  	{V(float64(120)), V(uint32(120))},
  3800  	{V(int64(121)), V(int64(121))},
  3801  	{V(int64(122)), V(uint64(122))},
  3802  	{V(uint64(123)), V(int64(123))},
  3803  	{V(int64(124)), V(int(124))},
  3804  	{V(int(125)), V(int64(125))},
  3805  	{V(int64(126)), V(uint(126))},
  3806  	{V(uint(127)), V(int64(127))},
  3807  	{V(int64(128)), V(uintptr(128))},
  3808  	{V(uintptr(129)), V(int64(129))},
  3809  	{V(int64(130)), V(float32(130))},
  3810  	{V(float32(131)), V(int64(131))},
  3811  	{V(int64(132)), V(float64(132))},
  3812  	{V(float64(133)), V(int64(133))},
  3813  	{V(uint64(134)), V(uint64(134))},
  3814  	{V(uint64(135)), V(int(135))},
  3815  	{V(int(136)), V(uint64(136))},
  3816  	{V(uint64(137)), V(uint(137))},
  3817  	{V(uint(138)), V(uint64(138))},
  3818  	{V(uint64(139)), V(uintptr(139))},
  3819  	{V(uintptr(140)), V(uint64(140))},
  3820  	{V(uint64(141)), V(float32(141))},
  3821  	{V(float32(142)), V(uint64(142))},
  3822  	{V(uint64(143)), V(float64(143))},
  3823  	{V(float64(144)), V(uint64(144))},
  3824  	{V(int(145)), V(int(145))},
  3825  	{V(int(146)), V(uint(146))},
  3826  	{V(uint(147)), V(int(147))},
  3827  	{V(int(148)), V(uintptr(148))},
  3828  	{V(uintptr(149)), V(int(149))},
  3829  	{V(int(150)), V(float32(150))},
  3830  	{V(float32(151)), V(int(151))},
  3831  	{V(int(152)), V(float64(152))},
  3832  	{V(float64(153)), V(int(153))},
  3833  	{V(uint(154)), V(uint(154))},
  3834  	{V(uint(155)), V(uintptr(155))},
  3835  	{V(uintptr(156)), V(uint(156))},
  3836  	{V(uint(157)), V(float32(157))},
  3837  	{V(float32(158)), V(uint(158))},
  3838  	{V(uint(159)), V(float64(159))},
  3839  	{V(float64(160)), V(uint(160))},
  3840  	{V(uintptr(161)), V(uintptr(161))},
  3841  	{V(uintptr(162)), V(float32(162))},
  3842  	{V(float32(163)), V(uintptr(163))},
  3843  	{V(uintptr(164)), V(float64(164))},
  3844  	{V(float64(165)), V(uintptr(165))},
  3845  	{V(float32(166)), V(float32(166))},
  3846  	{V(float32(167)), V(float64(167))},
  3847  	{V(float64(168)), V(float32(168))},
  3848  	{V(float64(169)), V(float64(169))},
  3849  
  3850  	// truncation
  3851  	{V(float64(1.5)), V(int(1))},
  3852  
  3853  	// complex
  3854  	{V(complex64(1i)), V(complex64(1i))},
  3855  	{V(complex64(2i)), V(complex128(2i))},
  3856  	{V(complex128(3i)), V(complex64(3i))},
  3857  	{V(complex128(4i)), V(complex128(4i))},
  3858  
  3859  	// string
  3860  	{V(string("hello")), V(string("hello"))},
  3861  	{V(string("bytes1")), V([]byte("bytes1"))},
  3862  	{V([]byte("bytes2")), V(string("bytes2"))},
  3863  	{V([]byte("bytes3")), V([]byte("bytes3"))},
  3864  	{V(string("runes♝")), V([]rune("runes♝"))},
  3865  	{V([]rune("runes♕")), V(string("runes♕"))},
  3866  	{V([]rune("runes🙈🙉🙊")), V([]rune("runes🙈🙉🙊"))},
  3867  	{V(int('a')), V(string("a"))},
  3868  	{V(int8('a')), V(string("a"))},
  3869  	{V(int16('a')), V(string("a"))},
  3870  	{V(int32('a')), V(string("a"))},
  3871  	{V(int64('a')), V(string("a"))},
  3872  	{V(uint('a')), V(string("a"))},
  3873  	{V(uint8('a')), V(string("a"))},
  3874  	{V(uint16('a')), V(string("a"))},
  3875  	{V(uint32('a')), V(string("a"))},
  3876  	{V(uint64('a')), V(string("a"))},
  3877  	{V(uintptr('a')), V(string("a"))},
  3878  	{V(int(-1)), V(string("\uFFFD"))},
  3879  	{V(int8(-2)), V(string("\uFFFD"))},
  3880  	{V(int16(-3)), V(string("\uFFFD"))},
  3881  	{V(int32(-4)), V(string("\uFFFD"))},
  3882  	{V(int64(-5)), V(string("\uFFFD"))},
  3883  	{V(uint(0x110001)), V(string("\uFFFD"))},
  3884  	{V(uint32(0x110002)), V(string("\uFFFD"))},
  3885  	{V(uint64(0x110003)), V(string("\uFFFD"))},
  3886  	{V(uintptr(0x110004)), V(string("\uFFFD"))},
  3887  
  3888  	// named string
  3889  	{V(MyString("hello")), V(string("hello"))},
  3890  	{V(string("hello")), V(MyString("hello"))},
  3891  	{V(string("hello")), V(string("hello"))},
  3892  	{V(MyString("hello")), V(MyString("hello"))},
  3893  	{V(MyString("bytes1")), V([]byte("bytes1"))},
  3894  	{V([]byte("bytes2")), V(MyString("bytes2"))},
  3895  	{V([]byte("bytes3")), V([]byte("bytes3"))},
  3896  	{V(MyString("runes♝")), V([]rune("runes♝"))},
  3897  	{V([]rune("runes♕")), V(MyString("runes♕"))},
  3898  	{V([]rune("runes🙈🙉🙊")), V([]rune("runes🙈🙉🙊"))},
  3899  	{V([]rune("runes🙈🙉🙊")), V(MyRunes("runes🙈🙉🙊"))},
  3900  	{V(MyRunes("runes🙈🙉🙊")), V([]rune("runes🙈🙉🙊"))},
  3901  	{V(int('a')), V(MyString("a"))},
  3902  	{V(int8('a')), V(MyString("a"))},
  3903  	{V(int16('a')), V(MyString("a"))},
  3904  	{V(int32('a')), V(MyString("a"))},
  3905  	{V(int64('a')), V(MyString("a"))},
  3906  	{V(uint('a')), V(MyString("a"))},
  3907  	{V(uint8('a')), V(MyString("a"))},
  3908  	{V(uint16('a')), V(MyString("a"))},
  3909  	{V(uint32('a')), V(MyString("a"))},
  3910  	{V(uint64('a')), V(MyString("a"))},
  3911  	{V(uintptr('a')), V(MyString("a"))},
  3912  	{V(int(-1)), V(MyString("\uFFFD"))},
  3913  	{V(int8(-2)), V(MyString("\uFFFD"))},
  3914  	{V(int16(-3)), V(MyString("\uFFFD"))},
  3915  	{V(int32(-4)), V(MyString("\uFFFD"))},
  3916  	{V(int64(-5)), V(MyString("\uFFFD"))},
  3917  	{V(uint(0x110001)), V(MyString("\uFFFD"))},
  3918  	{V(uint32(0x110002)), V(MyString("\uFFFD"))},
  3919  	{V(uint64(0x110003)), V(MyString("\uFFFD"))},
  3920  	{V(uintptr(0x110004)), V(MyString("\uFFFD"))},
  3921  
  3922  	// named []byte
  3923  	{V(string("bytes1")), V(MyBytes("bytes1"))},
  3924  	{V(MyBytes("bytes2")), V(string("bytes2"))},
  3925  	{V(MyBytes("bytes3")), V(MyBytes("bytes3"))},
  3926  	{V(MyString("bytes1")), V(MyBytes("bytes1"))},
  3927  	{V(MyBytes("bytes2")), V(MyString("bytes2"))},
  3928  
  3929  	// named []rune
  3930  	{V(string("runes♝")), V(MyRunes("runes♝"))},
  3931  	{V(MyRunes("runes♕")), V(string("runes♕"))},
  3932  	{V(MyRunes("runes🙈🙉🙊")), V(MyRunes("runes🙈🙉🙊"))},
  3933  	{V(MyString("runes♝")), V(MyRunes("runes♝"))},
  3934  	{V(MyRunes("runes♕")), V(MyString("runes♕"))},
  3935  
  3936  	// named types and equal underlying types
  3937  	{V(new(int)), V(new(integer))},
  3938  	{V(new(integer)), V(new(int))},
  3939  	{V(Empty{}), V(struct{}{})},
  3940  	{V(new(Empty)), V(new(struct{}))},
  3941  	{V(struct{}{}), V(Empty{})},
  3942  	{V(new(struct{})), V(new(Empty))},
  3943  	{V(Empty{}), V(Empty{})},
  3944  	{V(MyBytes{}), V([]byte{})},
  3945  	{V([]byte{}), V(MyBytes{})},
  3946  	{V((func())(nil)), V(MyFunc(nil))},
  3947  	{V((MyFunc)(nil)), V((func())(nil))},
  3948  
  3949  	// structs with different tags
  3950  	{V(struct {
  3951  		x int `some:"foo"`
  3952  	}{}), V(struct {
  3953  		x int `some:"bar"`
  3954  	}{})},
  3955  
  3956  	{V(struct {
  3957  		x int `some:"bar"`
  3958  	}{}), V(struct {
  3959  		x int `some:"foo"`
  3960  	}{})},
  3961  
  3962  	{V(MyStruct{}), V(struct {
  3963  		x int `some:"foo"`
  3964  	}{})},
  3965  
  3966  	{V(struct {
  3967  		x int `some:"foo"`
  3968  	}{}), V(MyStruct{})},
  3969  
  3970  	{V(MyStruct{}), V(struct {
  3971  		x int `some:"bar"`
  3972  	}{})},
  3973  
  3974  	{V(struct {
  3975  		x int `some:"bar"`
  3976  	}{}), V(MyStruct{})},
  3977  
  3978  	// can convert *byte and *MyByte
  3979  	{V((*byte)(nil)), V((*MyByte)(nil))},
  3980  	{V((*MyByte)(nil)), V((*byte)(nil))},
  3981  
  3982  	// cannot convert mismatched array sizes
  3983  	{V([2]byte{}), V([2]byte{})},
  3984  	{V([3]byte{}), V([3]byte{})},
  3985  
  3986  	// cannot convert other instances
  3987  	{V((**byte)(nil)), V((**byte)(nil))},
  3988  	{V((**MyByte)(nil)), V((**MyByte)(nil))},
  3989  	{V((chan byte)(nil)), V((chan byte)(nil))},
  3990  	{V((chan MyByte)(nil)), V((chan MyByte)(nil))},
  3991  	{V(([]byte)(nil)), V(([]byte)(nil))},
  3992  	{V(([]MyByte)(nil)), V(([]MyByte)(nil))},
  3993  	{V((map[int]byte)(nil)), V((map[int]byte)(nil))},
  3994  	{V((map[int]MyByte)(nil)), V((map[int]MyByte)(nil))},
  3995  	{V((map[byte]int)(nil)), V((map[byte]int)(nil))},
  3996  	{V((map[MyByte]int)(nil)), V((map[MyByte]int)(nil))},
  3997  	{V([2]byte{}), V([2]byte{})},
  3998  	{V([2]MyByte{}), V([2]MyByte{})},
  3999  
  4000  	// other
  4001  	{V((***int)(nil)), V((***int)(nil))},
  4002  	{V((***byte)(nil)), V((***byte)(nil))},
  4003  	{V((***int32)(nil)), V((***int32)(nil))},
  4004  	{V((***int64)(nil)), V((***int64)(nil))},
  4005  	{V((chan byte)(nil)), V((chan byte)(nil))},
  4006  	{V((chan MyByte)(nil)), V((chan MyByte)(nil))},
  4007  	{V((map[int]bool)(nil)), V((map[int]bool)(nil))},
  4008  	{V((map[int]byte)(nil)), V((map[int]byte)(nil))},
  4009  	{V((map[uint]bool)(nil)), V((map[uint]bool)(nil))},
  4010  	{V([]uint(nil)), V([]uint(nil))},
  4011  	{V([]int(nil)), V([]int(nil))},
  4012  	{V(new(interface{})), V(new(interface{}))},
  4013  	{V(new(io.Reader)), V(new(io.Reader))},
  4014  	{V(new(io.Writer)), V(new(io.Writer))},
  4015  
  4016  	// channels
  4017  	{V(IntChan(nil)), V((chan<- int)(nil))},
  4018  	{V(IntChan(nil)), V((<-chan int)(nil))},
  4019  	{V((chan int)(nil)), V(IntChanRecv(nil))},
  4020  	{V((chan int)(nil)), V(IntChanSend(nil))},
  4021  	{V(IntChanRecv(nil)), V((<-chan int)(nil))},
  4022  	{V((<-chan int)(nil)), V(IntChanRecv(nil))},
  4023  	{V(IntChanSend(nil)), V((chan<- int)(nil))},
  4024  	{V((chan<- int)(nil)), V(IntChanSend(nil))},
  4025  	{V(IntChan(nil)), V((chan int)(nil))},
  4026  	{V((chan int)(nil)), V(IntChan(nil))},
  4027  	{V((chan int)(nil)), V((<-chan int)(nil))},
  4028  	{V((chan int)(nil)), V((chan<- int)(nil))},
  4029  	{V(BytesChan(nil)), V((chan<- []byte)(nil))},
  4030  	{V(BytesChan(nil)), V((<-chan []byte)(nil))},
  4031  	{V((chan []byte)(nil)), V(BytesChanRecv(nil))},
  4032  	{V((chan []byte)(nil)), V(BytesChanSend(nil))},
  4033  	{V(BytesChanRecv(nil)), V((<-chan []byte)(nil))},
  4034  	{V((<-chan []byte)(nil)), V(BytesChanRecv(nil))},
  4035  	{V(BytesChanSend(nil)), V((chan<- []byte)(nil))},
  4036  	{V((chan<- []byte)(nil)), V(BytesChanSend(nil))},
  4037  	{V(BytesChan(nil)), V((chan []byte)(nil))},
  4038  	{V((chan []byte)(nil)), V(BytesChan(nil))},
  4039  	{V((chan []byte)(nil)), V((<-chan []byte)(nil))},
  4040  	{V((chan []byte)(nil)), V((chan<- []byte)(nil))},
  4041  
  4042  	// cannot convert other instances (channels)
  4043  	{V(IntChan(nil)), V(IntChan(nil))},
  4044  	{V(IntChanRecv(nil)), V(IntChanRecv(nil))},
  4045  	{V(IntChanSend(nil)), V(IntChanSend(nil))},
  4046  	{V(BytesChan(nil)), V(BytesChan(nil))},
  4047  	{V(BytesChanRecv(nil)), V(BytesChanRecv(nil))},
  4048  	{V(BytesChanSend(nil)), V(BytesChanSend(nil))},
  4049  
  4050  	// interfaces
  4051  	{V(int(1)), EmptyInterfaceV(int(1))},
  4052  	{V(string("hello")), EmptyInterfaceV(string("hello"))},
  4053  	{V(new(bytes.Buffer)), ReaderV(new(bytes.Buffer))},
  4054  	{ReadWriterV(new(bytes.Buffer)), ReaderV(new(bytes.Buffer))},
  4055  	{V(new(bytes.Buffer)), ReadWriterV(new(bytes.Buffer))},
  4056  }
  4057  
  4058  func TestConvert(t *testing.T) {
  4059  	canConvert := map[[2]Type]bool{}
  4060  	all := map[Type]bool{}
  4061  
  4062  	for _, tt := range convertTests {
  4063  		t1 := tt.in.Type()
  4064  		if !t1.ConvertibleTo(t1) {
  4065  			t.Errorf("(%s).ConvertibleTo(%s) = false, want true", t1, t1)
  4066  			continue
  4067  		}
  4068  
  4069  		t2 := tt.out.Type()
  4070  		if !t1.ConvertibleTo(t2) {
  4071  			t.Errorf("(%s).ConvertibleTo(%s) = false, want true", t1, t2)
  4072  			continue
  4073  		}
  4074  
  4075  		all[t1] = true
  4076  		all[t2] = true
  4077  		canConvert[[2]Type{t1, t2}] = true
  4078  
  4079  		// vout1 represents the in value converted to the in type.
  4080  		v1 := tt.in
  4081  		vout1 := v1.Convert(t1)
  4082  		out1 := vout1.Interface()
  4083  		if vout1.Type() != tt.in.Type() || !DeepEqual(out1, tt.in.Interface()) {
  4084  			t.Errorf("ValueOf(%T(%[1]v)).Convert(%s) = %T(%[3]v), want %T(%[4]v)", tt.in.Interface(), t1, out1, tt.in.Interface())
  4085  		}
  4086  
  4087  		// vout2 represents the in value converted to the out type.
  4088  		vout2 := v1.Convert(t2)
  4089  		out2 := vout2.Interface()
  4090  		if vout2.Type() != tt.out.Type() || !DeepEqual(out2, tt.out.Interface()) {
  4091  			t.Errorf("ValueOf(%T(%[1]v)).Convert(%s) = %T(%[3]v), want %T(%[4]v)", tt.in.Interface(), t2, out2, tt.out.Interface())
  4092  		}
  4093  
  4094  		// vout3 represents a new value of the out type, set to vout2.  This makes
  4095  		// sure the converted value vout2 is really usable as a regular value.
  4096  		vout3 := New(t2).Elem()
  4097  		vout3.Set(vout2)
  4098  		out3 := vout3.Interface()
  4099  		if vout3.Type() != tt.out.Type() || !DeepEqual(out3, tt.out.Interface()) {
  4100  			t.Errorf("Set(ValueOf(%T(%[1]v)).Convert(%s)) = %T(%[3]v), want %T(%[4]v)", tt.in.Interface(), t2, out3, tt.out.Interface())
  4101  		}
  4102  
  4103  		if IsRO(v1) {
  4104  			t.Errorf("table entry %v is RO, should not be", v1)
  4105  		}
  4106  		if IsRO(vout1) {
  4107  			t.Errorf("self-conversion output %v is RO, should not be", vout1)
  4108  		}
  4109  		if IsRO(vout2) {
  4110  			t.Errorf("conversion output %v is RO, should not be", vout2)
  4111  		}
  4112  		if IsRO(vout3) {
  4113  			t.Errorf("set(conversion output) %v is RO, should not be", vout3)
  4114  		}
  4115  		if !IsRO(MakeRO(v1).Convert(t1)) {
  4116  			t.Errorf("RO self-conversion output %v is not RO, should be", v1)
  4117  		}
  4118  		if !IsRO(MakeRO(v1).Convert(t2)) {
  4119  			t.Errorf("RO conversion output %v is not RO, should be", v1)
  4120  		}
  4121  	}
  4122  
  4123  	// Assume that of all the types we saw during the tests,
  4124  	// if there wasn't an explicit entry for a conversion between
  4125  	// a pair of types, then it's not to be allowed. This checks for
  4126  	// things like 'int64' converting to '*int'.
  4127  	for t1 := range all {
  4128  		for t2 := range all {
  4129  			expectOK := t1 == t2 || canConvert[[2]Type{t1, t2}] || t2.Kind() == Interface && t2.NumMethod() == 0
  4130  			if ok := t1.ConvertibleTo(t2); ok != expectOK {
  4131  				t.Errorf("(%s).ConvertibleTo(%s) = %v, want %v", t1, t2, ok, expectOK)
  4132  			}
  4133  		}
  4134  	}
  4135  }
  4136  
  4137  type ComparableStruct struct {
  4138  	X int
  4139  }
  4140  
  4141  type NonComparableStruct struct {
  4142  	X int
  4143  	Y map[string]int
  4144  }
  4145  
  4146  var comparableTests = []struct {
  4147  	typ Type
  4148  	ok  bool
  4149  }{
  4150  	{TypeOf(1), true},
  4151  	{TypeOf("hello"), true},
  4152  	{TypeOf(new(byte)), true},
  4153  	{TypeOf((func())(nil)), false},
  4154  	{TypeOf([]byte{}), false},
  4155  	{TypeOf(map[string]int{}), false},
  4156  	{TypeOf(make(chan int)), true},
  4157  	{TypeOf(1.5), true},
  4158  	{TypeOf(false), true},
  4159  	{TypeOf(1i), true},
  4160  	{TypeOf(ComparableStruct{}), true},
  4161  	{TypeOf(NonComparableStruct{}), false},
  4162  	{TypeOf([10]map[string]int{}), false},
  4163  	{TypeOf([10]string{}), true},
  4164  	{TypeOf(new(interface{})).Elem(), true},
  4165  }
  4166  
  4167  func TestComparable(t *testing.T) {
  4168  	for _, tt := range comparableTests {
  4169  		if ok := tt.typ.Comparable(); ok != tt.ok {
  4170  			t.Errorf("TypeOf(%v).Comparable() = %v, want %v", tt.typ, ok, tt.ok)
  4171  		}
  4172  	}
  4173  }
  4174  
  4175  func TestOverflow(t *testing.T) {
  4176  	if ovf := V(float64(0)).OverflowFloat(1e300); ovf {
  4177  		t.Errorf("%v wrongly overflows float64", 1e300)
  4178  	}
  4179  
  4180  	maxFloat32 := float64((1<<24 - 1) << (127 - 23))
  4181  	if ovf := V(float32(0)).OverflowFloat(maxFloat32); ovf {
  4182  		t.Errorf("%v wrongly overflows float32", maxFloat32)
  4183  	}
  4184  	ovfFloat32 := float64((1<<24-1)<<(127-23) + 1<<(127-52))
  4185  	if ovf := V(float32(0)).OverflowFloat(ovfFloat32); !ovf {
  4186  		t.Errorf("%v should overflow float32", ovfFloat32)
  4187  	}
  4188  	if ovf := V(float32(0)).OverflowFloat(-ovfFloat32); !ovf {
  4189  		t.Errorf("%v should overflow float32", -ovfFloat32)
  4190  	}
  4191  
  4192  	maxInt32 := int64(0x7fffffff)
  4193  	if ovf := V(int32(0)).OverflowInt(maxInt32); ovf {
  4194  		t.Errorf("%v wrongly overflows int32", maxInt32)
  4195  	}
  4196  	if ovf := V(int32(0)).OverflowInt(-1 << 31); ovf {
  4197  		t.Errorf("%v wrongly overflows int32", -int64(1)<<31)
  4198  	}
  4199  	ovfInt32 := int64(1 << 31)
  4200  	if ovf := V(int32(0)).OverflowInt(ovfInt32); !ovf {
  4201  		t.Errorf("%v should overflow int32", ovfInt32)
  4202  	}
  4203  
  4204  	maxUint32 := uint64(0xffffffff)
  4205  	if ovf := V(uint32(0)).OverflowUint(maxUint32); ovf {
  4206  		t.Errorf("%v wrongly overflows uint32", maxUint32)
  4207  	}
  4208  	ovfUint32 := uint64(1 << 32)
  4209  	if ovf := V(uint32(0)).OverflowUint(ovfUint32); !ovf {
  4210  		t.Errorf("%v should overflow uint32", ovfUint32)
  4211  	}
  4212  }
  4213  
  4214  func checkSameType(t *testing.T, x Type, y interface{}) {
  4215  	if x != TypeOf(y) || TypeOf(Zero(x).Interface()) != TypeOf(y) {
  4216  		t.Errorf("did not find preexisting type for %s (vs %s)", TypeOf(x), TypeOf(y))
  4217  	}
  4218  }
  4219  
  4220  func TestArrayOf(t *testing.T) {
  4221  	// check construction and use of type not in binary
  4222  	tests := []struct {
  4223  		n          int
  4224  		value      func(i int) interface{}
  4225  		comparable bool
  4226  		want       string
  4227  	}{
  4228  		{
  4229  			n:          0,
  4230  			value:      func(i int) interface{} { type Tint int; return Tint(i) },
  4231  			comparable: true,
  4232  			want:       "[]",
  4233  		},
  4234  		{
  4235  			n:          10,
  4236  			value:      func(i int) interface{} { type Tint int; return Tint(i) },
  4237  			comparable: true,
  4238  			want:       "[0 1 2 3 4 5 6 7 8 9]",
  4239  		},
  4240  		{
  4241  			n:          10,
  4242  			value:      func(i int) interface{} { type Tfloat float64; return Tfloat(i) },
  4243  			comparable: true,
  4244  			want:       "[0 1 2 3 4 5 6 7 8 9]",
  4245  		},
  4246  		{
  4247  			n:          10,
  4248  			value:      func(i int) interface{} { type Tstring string; return Tstring(strconv.Itoa(i)) },
  4249  			comparable: true,
  4250  			want:       "[0 1 2 3 4 5 6 7 8 9]",
  4251  		},
  4252  		{
  4253  			n:          10,
  4254  			value:      func(i int) interface{} { type Tstruct struct{ V int }; return Tstruct{i} },
  4255  			comparable: true,
  4256  			want:       "[{0} {1} {2} {3} {4} {5} {6} {7} {8} {9}]",
  4257  		},
  4258  		{
  4259  			n:          10,
  4260  			value:      func(i int) interface{} { type Tint int; return []Tint{Tint(i)} },
  4261  			comparable: false,
  4262  			want:       "[[0] [1] [2] [3] [4] [5] [6] [7] [8] [9]]",
  4263  		},
  4264  		{
  4265  			n:          10,
  4266  			value:      func(i int) interface{} { type Tint int; return [1]Tint{Tint(i)} },
  4267  			comparable: true,
  4268  			want:       "[[0] [1] [2] [3] [4] [5] [6] [7] [8] [9]]",
  4269  		},
  4270  		{
  4271  			n:          10,
  4272  			value:      func(i int) interface{} { type Tstruct struct{ V [1]int }; return Tstruct{[1]int{i}} },
  4273  			comparable: true,
  4274  			want:       "[{[0]} {[1]} {[2]} {[3]} {[4]} {[5]} {[6]} {[7]} {[8]} {[9]}]",
  4275  		},
  4276  		{
  4277  			n:          10,
  4278  			value:      func(i int) interface{} { type Tstruct struct{ V []int }; return Tstruct{[]int{i}} },
  4279  			comparable: false,
  4280  			want:       "[{[0]} {[1]} {[2]} {[3]} {[4]} {[5]} {[6]} {[7]} {[8]} {[9]}]",
  4281  		},
  4282  		{
  4283  			n:          10,
  4284  			value:      func(i int) interface{} { type TstructUV struct{ U, V int }; return TstructUV{i, i} },
  4285  			comparable: true,
  4286  			want:       "[{0 0} {1 1} {2 2} {3 3} {4 4} {5 5} {6 6} {7 7} {8 8} {9 9}]",
  4287  		},
  4288  		{
  4289  			n: 10,
  4290  			value: func(i int) interface{} {
  4291  				type TstructUV struct {
  4292  					U int
  4293  					V float64
  4294  				}
  4295  				return TstructUV{i, float64(i)}
  4296  			},
  4297  			comparable: true,
  4298  			want:       "[{0 0} {1 1} {2 2} {3 3} {4 4} {5 5} {6 6} {7 7} {8 8} {9 9}]",
  4299  		},
  4300  	}
  4301  
  4302  	for _, table := range tests {
  4303  		at := ArrayOf(table.n, TypeOf(table.value(0)))
  4304  		v := New(at).Elem()
  4305  		vok := New(at).Elem()
  4306  		vnot := New(at).Elem()
  4307  		for i := 0; i < v.Len(); i++ {
  4308  			v.Index(i).Set(ValueOf(table.value(i)))
  4309  			vok.Index(i).Set(ValueOf(table.value(i)))
  4310  			j := i
  4311  			if i+1 == v.Len() {
  4312  				j = i + 1
  4313  			}
  4314  			vnot.Index(i).Set(ValueOf(table.value(j))) // make it differ only by last element
  4315  		}
  4316  		s := fmt.Sprint(v.Interface())
  4317  		if s != table.want {
  4318  			t.Errorf("constructed array = %s, want %s", s, table.want)
  4319  		}
  4320  
  4321  		if table.comparable != at.Comparable() {
  4322  			t.Errorf("constructed array (%#v) is comparable=%v, want=%v", v.Interface(), at.Comparable(), table.comparable)
  4323  		}
  4324  		if table.comparable {
  4325  			if table.n > 0 {
  4326  				if DeepEqual(vnot.Interface(), v.Interface()) {
  4327  					t.Errorf(
  4328  						"arrays (%#v) compare ok (but should not)",
  4329  						v.Interface(),
  4330  					)
  4331  				}
  4332  			}
  4333  			if !DeepEqual(vok.Interface(), v.Interface()) {
  4334  				t.Errorf(
  4335  					"arrays (%#v) compare NOT-ok (but should)",
  4336  					v.Interface(),
  4337  				)
  4338  			}
  4339  		}
  4340  	}
  4341  
  4342  	// check that type already in binary is found
  4343  	type T int
  4344  	checkSameType(t, ArrayOf(5, TypeOf(T(1))), [5]T{})
  4345  }
  4346  
  4347  func TestArrayOfGC(t *testing.T) {
  4348  	type T *uintptr
  4349  	tt := TypeOf(T(nil))
  4350  	const n = 100
  4351  	var x []interface{}
  4352  	for i := 0; i < n; i++ {
  4353  		v := New(ArrayOf(n, tt)).Elem()
  4354  		for j := 0; j < v.Len(); j++ {
  4355  			p := new(uintptr)
  4356  			*p = uintptr(i*n + j)
  4357  			v.Index(j).Set(ValueOf(p).Convert(tt))
  4358  		}
  4359  		x = append(x, v.Interface())
  4360  	}
  4361  	runtime.GC()
  4362  
  4363  	for i, xi := range x {
  4364  		v := ValueOf(xi)
  4365  		for j := 0; j < v.Len(); j++ {
  4366  			k := v.Index(j).Elem().Interface()
  4367  			if k != uintptr(i*n+j) {
  4368  				t.Errorf("lost x[%d][%d] = %d, want %d", i, j, k, i*n+j)
  4369  			}
  4370  		}
  4371  	}
  4372  }
  4373  
  4374  func TestArrayOfAlg(t *testing.T) {
  4375  	at := ArrayOf(6, TypeOf(byte(0)))
  4376  	v1 := New(at).Elem()
  4377  	v2 := New(at).Elem()
  4378  	if v1.Interface() != v1.Interface() {
  4379  		t.Errorf("constructed array %v not equal to itself", v1.Interface())
  4380  	}
  4381  	v1.Index(5).Set(ValueOf(byte(1)))
  4382  	if i1, i2 := v1.Interface(), v2.Interface(); i1 == i2 {
  4383  		t.Errorf("constructed arrays %v and %v should not be equal", i1, i2)
  4384  	}
  4385  
  4386  	at = ArrayOf(6, TypeOf([]int(nil)))
  4387  	v1 = New(at).Elem()
  4388  	shouldPanic(func() { _ = v1.Interface() == v1.Interface() })
  4389  }
  4390  
  4391  func TestArrayOfGenericAlg(t *testing.T) {
  4392  	at1 := ArrayOf(5, TypeOf(string("")))
  4393  	at := ArrayOf(6, at1)
  4394  	v1 := New(at).Elem()
  4395  	v2 := New(at).Elem()
  4396  	if v1.Interface() != v1.Interface() {
  4397  		t.Errorf("constructed array %v not equal to itself", v1.Interface())
  4398  	}
  4399  
  4400  	v1.Index(0).Index(0).Set(ValueOf("abc"))
  4401  	v2.Index(0).Index(0).Set(ValueOf("efg"))
  4402  	if i1, i2 := v1.Interface(), v2.Interface(); i1 == i2 {
  4403  		t.Errorf("constructed arrays %v and %v should not be equal", i1, i2)
  4404  	}
  4405  
  4406  	v1.Index(0).Index(0).Set(ValueOf("abc"))
  4407  	v2.Index(0).Index(0).Set(ValueOf((v1.Index(0).Index(0).String() + " ")[:3]))
  4408  	if i1, i2 := v1.Interface(), v2.Interface(); i1 != i2 {
  4409  		t.Errorf("constructed arrays %v and %v should be equal", i1, i2)
  4410  	}
  4411  
  4412  	// Test hash
  4413  	m := MakeMap(MapOf(at, TypeOf(int(0))))
  4414  	m.SetMapIndex(v1, ValueOf(1))
  4415  	if i1, i2 := v1.Interface(), v2.Interface(); !m.MapIndex(v2).IsValid() {
  4416  		t.Errorf("constructed arrays %v and %v have different hashes", i1, i2)
  4417  	}
  4418  }
  4419  
  4420  func TestArrayOfDirectIface(t *testing.T) {
  4421  	{
  4422  		type T [1]*byte
  4423  		i1 := Zero(TypeOf(T{})).Interface()
  4424  		v1 := ValueOf(&i1).Elem()
  4425  		p1 := v1.InterfaceData()[1]
  4426  
  4427  		i2 := Zero(ArrayOf(1, PtrTo(TypeOf(int8(0))))).Interface()
  4428  		v2 := ValueOf(&i2).Elem()
  4429  		p2 := v2.InterfaceData()[1]
  4430  
  4431  		if p1 != 0 {
  4432  			t.Errorf("got p1=%v. want=%v", p1, nil)
  4433  		}
  4434  
  4435  		if p2 != 0 {
  4436  			t.Errorf("got p2=%v. want=%v", p2, nil)
  4437  		}
  4438  	}
  4439  	{
  4440  		type T [0]*byte
  4441  		i1 := Zero(TypeOf(T{})).Interface()
  4442  		v1 := ValueOf(&i1).Elem()
  4443  		p1 := v1.InterfaceData()[1]
  4444  
  4445  		i2 := Zero(ArrayOf(0, PtrTo(TypeOf(int8(0))))).Interface()
  4446  		v2 := ValueOf(&i2).Elem()
  4447  		p2 := v2.InterfaceData()[1]
  4448  
  4449  		if p1 == 0 {
  4450  			t.Errorf("got p1=%v. want=not-%v", p1, nil)
  4451  		}
  4452  
  4453  		if p2 == 0 {
  4454  			t.Errorf("got p2=%v. want=not-%v", p2, nil)
  4455  		}
  4456  	}
  4457  }
  4458  
  4459  func TestSliceOf(t *testing.T) {
  4460  	// check construction and use of type not in binary
  4461  	type T int
  4462  	st := SliceOf(TypeOf(T(1)))
  4463  	if got, want := st.String(), "[]reflect_test.T"; got != want {
  4464  		t.Errorf("SliceOf(T(1)).String()=%q, want %q", got, want)
  4465  	}
  4466  	v := MakeSlice(st, 10, 10)
  4467  	runtime.GC()
  4468  	for i := 0; i < v.Len(); i++ {
  4469  		v.Index(i).Set(ValueOf(T(i)))
  4470  		runtime.GC()
  4471  	}
  4472  	s := fmt.Sprint(v.Interface())
  4473  	want := "[0 1 2 3 4 5 6 7 8 9]"
  4474  	if s != want {
  4475  		t.Errorf("constructed slice = %s, want %s", s, want)
  4476  	}
  4477  
  4478  	// check that type already in binary is found
  4479  	type T1 int
  4480  	checkSameType(t, SliceOf(TypeOf(T1(1))), []T1{})
  4481  }
  4482  
  4483  func TestSliceOverflow(t *testing.T) {
  4484  	// check that MakeSlice panics when size of slice overflows uint
  4485  	const S = 1e6
  4486  	s := uint(S)
  4487  	l := (1<<(unsafe.Sizeof((*byte)(nil))*8)-1)/s + 1
  4488  	if l*s >= s {
  4489  		t.Fatal("slice size does not overflow")
  4490  	}
  4491  	var x [S]byte
  4492  	st := SliceOf(TypeOf(x))
  4493  	defer func() {
  4494  		err := recover()
  4495  		if err == nil {
  4496  			t.Fatal("slice overflow does not panic")
  4497  		}
  4498  	}()
  4499  	MakeSlice(st, int(l), int(l))
  4500  }
  4501  
  4502  func TestSliceOfGC(t *testing.T) {
  4503  	type T *uintptr
  4504  	tt := TypeOf(T(nil))
  4505  	st := SliceOf(tt)
  4506  	const n = 100
  4507  	var x []interface{}
  4508  	for i := 0; i < n; i++ {
  4509  		v := MakeSlice(st, n, n)
  4510  		for j := 0; j < v.Len(); j++ {
  4511  			p := new(uintptr)
  4512  			*p = uintptr(i*n + j)
  4513  			v.Index(j).Set(ValueOf(p).Convert(tt))
  4514  		}
  4515  		x = append(x, v.Interface())
  4516  	}
  4517  	runtime.GC()
  4518  
  4519  	for i, xi := range x {
  4520  		v := ValueOf(xi)
  4521  		for j := 0; j < v.Len(); j++ {
  4522  			k := v.Index(j).Elem().Interface()
  4523  			if k != uintptr(i*n+j) {
  4524  				t.Errorf("lost x[%d][%d] = %d, want %d", i, j, k, i*n+j)
  4525  			}
  4526  		}
  4527  	}
  4528  }
  4529  
  4530  func TestStructOfFieldName(t *testing.T) {
  4531  	// invalid field name "1nvalid"
  4532  	shouldPanic(func() {
  4533  		StructOf([]StructField{
  4534  			{Name: "valid", Type: TypeOf("")},
  4535  			{Name: "1nvalid", Type: TypeOf("")},
  4536  		})
  4537  	})
  4538  
  4539  	// invalid field name "+"
  4540  	shouldPanic(func() {
  4541  		StructOf([]StructField{
  4542  			{Name: "val1d", Type: TypeOf("")},
  4543  			{Name: "+", Type: TypeOf("")},
  4544  		})
  4545  	})
  4546  
  4547  	// no field name
  4548  	shouldPanic(func() {
  4549  		StructOf([]StructField{
  4550  			{Name: "", Type: TypeOf("")},
  4551  		})
  4552  	})
  4553  
  4554  	// verify creation of a struct with valid struct fields
  4555  	validFields := []StructField{
  4556  		{
  4557  			Name: "φ",
  4558  			Type: TypeOf(""),
  4559  		},
  4560  		{
  4561  			Name: "ValidName",
  4562  			Type: TypeOf(""),
  4563  		},
  4564  		{
  4565  			Name: "Val1dNam5",
  4566  			Type: TypeOf(""),
  4567  		},
  4568  	}
  4569  
  4570  	validStruct := StructOf(validFields)
  4571  
  4572  	const structStr = `struct { φ string; ValidName string; Val1dNam5 string }`
  4573  	if got, want := validStruct.String(), structStr; got != want {
  4574  		t.Errorf("StructOf(validFields).String()=%q, want %q", got, want)
  4575  	}
  4576  }
  4577  
  4578  func TestStructOf(t *testing.T) {
  4579  	// check construction and use of type not in binary
  4580  	fields := []StructField{
  4581  		{
  4582  			Name: "S",
  4583  			Tag:  "s",
  4584  			Type: TypeOf(""),
  4585  		},
  4586  		{
  4587  			Name: "X",
  4588  			Tag:  "x",
  4589  			Type: TypeOf(byte(0)),
  4590  		},
  4591  		{
  4592  			Name: "Y",
  4593  			Type: TypeOf(uint64(0)),
  4594  		},
  4595  		{
  4596  			Name: "Z",
  4597  			Type: TypeOf([3]uint16{}),
  4598  		},
  4599  	}
  4600  
  4601  	st := StructOf(fields)
  4602  	v := New(st).Elem()
  4603  	runtime.GC()
  4604  	v.FieldByName("X").Set(ValueOf(byte(2)))
  4605  	v.FieldByIndex([]int{1}).Set(ValueOf(byte(1)))
  4606  	runtime.GC()
  4607  
  4608  	s := fmt.Sprint(v.Interface())
  4609  	want := `{ 1 0 [0 0 0]}`
  4610  	if s != want {
  4611  		t.Errorf("constructed struct = %s, want %s", s, want)
  4612  	}
  4613  	const stStr = `struct { S string "s"; X uint8 "x"; Y uint64; Z [3]uint16 }`
  4614  	if got, want := st.String(), stStr; got != want {
  4615  		t.Errorf("StructOf(fields).String()=%q, want %q", got, want)
  4616  	}
  4617  
  4618  	// check the size, alignment and field offsets
  4619  	stt := TypeOf(struct {
  4620  		String string
  4621  		X      byte
  4622  		Y      uint64
  4623  		Z      [3]uint16
  4624  	}{})
  4625  	if st.Size() != stt.Size() {
  4626  		t.Errorf("constructed struct size = %v, want %v", st.Size(), stt.Size())
  4627  	}
  4628  	if st.Align() != stt.Align() {
  4629  		t.Errorf("constructed struct align = %v, want %v", st.Align(), stt.Align())
  4630  	}
  4631  	if st.FieldAlign() != stt.FieldAlign() {
  4632  		t.Errorf("constructed struct field align = %v, want %v", st.FieldAlign(), stt.FieldAlign())
  4633  	}
  4634  	for i := 0; i < st.NumField(); i++ {
  4635  		o1 := st.Field(i).Offset
  4636  		o2 := stt.Field(i).Offset
  4637  		if o1 != o2 {
  4638  			t.Errorf("constructed struct field %v offset = %v, want %v", i, o1, o2)
  4639  		}
  4640  	}
  4641  
  4642  	// Check size and alignment with a trailing zero-sized field.
  4643  	st = StructOf([]StructField{
  4644  		{
  4645  			Name: "F1",
  4646  			Type: TypeOf(byte(0)),
  4647  		},
  4648  		{
  4649  			Name: "F2",
  4650  			Type: TypeOf([0]*byte{}),
  4651  		},
  4652  	})
  4653  	stt = TypeOf(struct {
  4654  		G1 byte
  4655  		G2 [0]*byte
  4656  	}{})
  4657  	if st.Size() != stt.Size() {
  4658  		t.Errorf("constructed zero-padded struct size = %v, want %v", st.Size(), stt.Size())
  4659  	}
  4660  	if st.Align() != stt.Align() {
  4661  		t.Errorf("constructed zero-padded struct align = %v, want %v", st.Align(), stt.Align())
  4662  	}
  4663  	if st.FieldAlign() != stt.FieldAlign() {
  4664  		t.Errorf("constructed zero-padded struct field align = %v, want %v", st.FieldAlign(), stt.FieldAlign())
  4665  	}
  4666  	for i := 0; i < st.NumField(); i++ {
  4667  		o1 := st.Field(i).Offset
  4668  		o2 := stt.Field(i).Offset
  4669  		if o1 != o2 {
  4670  			t.Errorf("constructed zero-padded struct field %v offset = %v, want %v", i, o1, o2)
  4671  		}
  4672  	}
  4673  
  4674  	// check duplicate names
  4675  	shouldPanic(func() {
  4676  		StructOf([]StructField{
  4677  			{Name: "string", Type: TypeOf("")},
  4678  			{Name: "string", Type: TypeOf("")},
  4679  		})
  4680  	})
  4681  	shouldPanic(func() {
  4682  		StructOf([]StructField{
  4683  			{Type: TypeOf("")},
  4684  			{Name: "string", Type: TypeOf("")},
  4685  		})
  4686  	})
  4687  	shouldPanic(func() {
  4688  		StructOf([]StructField{
  4689  			{Type: TypeOf("")},
  4690  			{Type: TypeOf("")},
  4691  		})
  4692  	})
  4693  	// check that type already in binary is found
  4694  	checkSameType(t, StructOf(fields[2:3]), struct{ Y uint64 }{})
  4695  
  4696  	// gccgo used to fail this test.
  4697  	type structFieldType interface{}
  4698  	checkSameType(t,
  4699  		StructOf([]StructField{
  4700  			{
  4701  				Name: "F",
  4702  				Type: TypeOf((*structFieldType)(nil)).Elem(),
  4703  			},
  4704  		}),
  4705  		struct{ F structFieldType }{})
  4706  }
  4707  
  4708  func TestStructOfExportRules(t *testing.T) {
  4709  	type S1 struct{}
  4710  	type s2 struct{}
  4711  	type ΦType struct{}
  4712  	type φType struct{}
  4713  
  4714  	testPanic := func(i int, mustPanic bool, f func()) {
  4715  		defer func() {
  4716  			err := recover()
  4717  			if err == nil && mustPanic {
  4718  				t.Errorf("test-%d did not panic", i)
  4719  			}
  4720  			if err != nil && !mustPanic {
  4721  				t.Errorf("test-%d panicked: %v\n", i, err)
  4722  			}
  4723  		}()
  4724  		f()
  4725  	}
  4726  
  4727  	tests := []struct {
  4728  		field     StructField
  4729  		mustPanic bool
  4730  		exported  bool
  4731  	}{
  4732  		{
  4733  			field:    StructField{Name: "S1", Anonymous: true, Type: TypeOf(S1{})},
  4734  			exported: true,
  4735  		},
  4736  		{
  4737  			field:    StructField{Name: "S1", Anonymous: true, Type: TypeOf((*S1)(nil))},
  4738  			exported: true,
  4739  		},
  4740  		{
  4741  			field:     StructField{Name: "s2", Anonymous: true, Type: TypeOf(s2{})},
  4742  			mustPanic: true,
  4743  		},
  4744  		{
  4745  			field:     StructField{Name: "s2", Anonymous: true, Type: TypeOf((*s2)(nil))},
  4746  			mustPanic: true,
  4747  		},
  4748  		{
  4749  			field:     StructField{Name: "Name", Type: nil, PkgPath: ""},
  4750  			mustPanic: true,
  4751  		},
  4752  		{
  4753  			field:     StructField{Name: "", Type: TypeOf(S1{}), PkgPath: ""},
  4754  			mustPanic: true,
  4755  		},
  4756  		{
  4757  			field:     StructField{Name: "S1", Anonymous: true, Type: TypeOf(S1{}), PkgPath: "other/pkg"},
  4758  			mustPanic: true,
  4759  		},
  4760  		{
  4761  			field:     StructField{Name: "S1", Anonymous: true, Type: TypeOf((*S1)(nil)), PkgPath: "other/pkg"},
  4762  			mustPanic: true,
  4763  		},
  4764  		{
  4765  			field:     StructField{Name: "s2", Anonymous: true, Type: TypeOf(s2{}), PkgPath: "other/pkg"},
  4766  			mustPanic: true,
  4767  		},
  4768  		{
  4769  			field:     StructField{Name: "s2", Anonymous: true, Type: TypeOf((*s2)(nil)), PkgPath: "other/pkg"},
  4770  			mustPanic: true,
  4771  		},
  4772  		{
  4773  			field: StructField{Name: "s2", Type: TypeOf(int(0)), PkgPath: "other/pkg"},
  4774  		},
  4775  		{
  4776  			field: StructField{Name: "s2", Type: TypeOf(int(0)), PkgPath: "other/pkg"},
  4777  		},
  4778  		{
  4779  			field:    StructField{Name: "S", Type: TypeOf(S1{})},
  4780  			exported: true,
  4781  		},
  4782  		{
  4783  			field:    StructField{Name: "S", Type: TypeOf((*S1)(nil))},
  4784  			exported: true,
  4785  		},
  4786  		{
  4787  			field:    StructField{Name: "S", Type: TypeOf(s2{})},
  4788  			exported: true,
  4789  		},
  4790  		{
  4791  			field:    StructField{Name: "S", Type: TypeOf((*s2)(nil))},
  4792  			exported: true,
  4793  		},
  4794  		{
  4795  			field:     StructField{Name: "s", Type: TypeOf(S1{})},
  4796  			mustPanic: true,
  4797  		},
  4798  		{
  4799  			field:     StructField{Name: "s", Type: TypeOf((*S1)(nil))},
  4800  			mustPanic: true,
  4801  		},
  4802  		{
  4803  			field:     StructField{Name: "s", Type: TypeOf(s2{})},
  4804  			mustPanic: true,
  4805  		},
  4806  		{
  4807  			field:     StructField{Name: "s", Type: TypeOf((*s2)(nil))},
  4808  			mustPanic: true,
  4809  		},
  4810  		{
  4811  			field: StructField{Name: "s", Type: TypeOf(S1{}), PkgPath: "other/pkg"},
  4812  		},
  4813  		{
  4814  			field: StructField{Name: "s", Type: TypeOf((*S1)(nil)), PkgPath: "other/pkg"},
  4815  		},
  4816  		{
  4817  			field: StructField{Name: "s", Type: TypeOf(s2{}), PkgPath: "other/pkg"},
  4818  		},
  4819  		{
  4820  			field: StructField{Name: "s", Type: TypeOf((*s2)(nil)), PkgPath: "other/pkg"},
  4821  		},
  4822  		{
  4823  			field:     StructField{Name: "", Type: TypeOf(ΦType{})},
  4824  			mustPanic: true,
  4825  		},
  4826  		{
  4827  			field:     StructField{Name: "", Type: TypeOf(φType{})},
  4828  			mustPanic: true,
  4829  		},
  4830  		{
  4831  			field:    StructField{Name: "Φ", Type: TypeOf(0)},
  4832  			exported: true,
  4833  		},
  4834  		{
  4835  			field:    StructField{Name: "φ", Type: TypeOf(0)},
  4836  			exported: false,
  4837  		},
  4838  	}
  4839  
  4840  	for i, test := range tests {
  4841  		testPanic(i, test.mustPanic, func() {
  4842  			typ := StructOf([]StructField{test.field})
  4843  			if typ == nil {
  4844  				t.Errorf("test-%d: error creating struct type", i)
  4845  				return
  4846  			}
  4847  			field := typ.Field(0)
  4848  			n := field.Name
  4849  			if n == "" {
  4850  				panic("field.Name must not be empty")
  4851  			}
  4852  			exported := token.IsExported(n)
  4853  			if exported != test.exported {
  4854  				t.Errorf("test-%d: got exported=%v want exported=%v", i, exported, test.exported)
  4855  			}
  4856  			if field.PkgPath != test.field.PkgPath {
  4857  				t.Errorf("test-%d: got PkgPath=%q want pkgPath=%q", i, field.PkgPath, test.field.PkgPath)
  4858  			}
  4859  		})
  4860  	}
  4861  }
  4862  
  4863  func TestStructOfGC(t *testing.T) {
  4864  	type T *uintptr
  4865  	tt := TypeOf(T(nil))
  4866  	fields := []StructField{
  4867  		{Name: "X", Type: tt},
  4868  		{Name: "Y", Type: tt},
  4869  	}
  4870  	st := StructOf(fields)
  4871  
  4872  	const n = 10000
  4873  	var x []interface{}
  4874  	for i := 0; i < n; i++ {
  4875  		v := New(st).Elem()
  4876  		for j := 0; j < v.NumField(); j++ {
  4877  			p := new(uintptr)
  4878  			*p = uintptr(i*n + j)
  4879  			v.Field(j).Set(ValueOf(p).Convert(tt))
  4880  		}
  4881  		x = append(x, v.Interface())
  4882  	}
  4883  	runtime.GC()
  4884  
  4885  	for i, xi := range x {
  4886  		v := ValueOf(xi)
  4887  		for j := 0; j < v.NumField(); j++ {
  4888  			k := v.Field(j).Elem().Interface()
  4889  			if k != uintptr(i*n+j) {
  4890  				t.Errorf("lost x[%d].%c = %d, want %d", i, "XY"[j], k, i*n+j)
  4891  			}
  4892  		}
  4893  	}
  4894  }
  4895  
  4896  func TestStructOfAlg(t *testing.T) {
  4897  	st := StructOf([]StructField{{Name: "X", Tag: "x", Type: TypeOf(int(0))}})
  4898  	v1 := New(st).Elem()
  4899  	v2 := New(st).Elem()
  4900  	if !DeepEqual(v1.Interface(), v1.Interface()) {
  4901  		t.Errorf("constructed struct %v not equal to itself", v1.Interface())
  4902  	}
  4903  	v1.FieldByName("X").Set(ValueOf(int(1)))
  4904  	if i1, i2 := v1.Interface(), v2.Interface(); DeepEqual(i1, i2) {
  4905  		t.Errorf("constructed structs %v and %v should not be equal", i1, i2)
  4906  	}
  4907  
  4908  	st = StructOf([]StructField{{Name: "X", Tag: "x", Type: TypeOf([]int(nil))}})
  4909  	v1 = New(st).Elem()
  4910  	shouldPanic(func() { _ = v1.Interface() == v1.Interface() })
  4911  }
  4912  
  4913  func TestStructOfGenericAlg(t *testing.T) {
  4914  	st1 := StructOf([]StructField{
  4915  		{Name: "X", Tag: "x", Type: TypeOf(int64(0))},
  4916  		{Name: "Y", Type: TypeOf(string(""))},
  4917  	})
  4918  	st := StructOf([]StructField{
  4919  		{Name: "S0", Type: st1},
  4920  		{Name: "S1", Type: st1},
  4921  	})
  4922  
  4923  	tests := []struct {
  4924  		rt  Type
  4925  		idx []int
  4926  	}{
  4927  		{
  4928  			rt:  st,
  4929  			idx: []int{0, 1},
  4930  		},
  4931  		{
  4932  			rt:  st1,
  4933  			idx: []int{1},
  4934  		},
  4935  		{
  4936  			rt: StructOf(
  4937  				[]StructField{
  4938  					{Name: "XX", Type: TypeOf([0]int{})},
  4939  					{Name: "YY", Type: TypeOf("")},
  4940  				},
  4941  			),
  4942  			idx: []int{1},
  4943  		},
  4944  		{
  4945  			rt: StructOf(
  4946  				[]StructField{
  4947  					{Name: "XX", Type: TypeOf([0]int{})},
  4948  					{Name: "YY", Type: TypeOf("")},
  4949  					{Name: "ZZ", Type: TypeOf([2]int{})},
  4950  				},
  4951  			),
  4952  			idx: []int{1},
  4953  		},
  4954  		{
  4955  			rt: StructOf(
  4956  				[]StructField{
  4957  					{Name: "XX", Type: TypeOf([1]int{})},
  4958  					{Name: "YY", Type: TypeOf("")},
  4959  				},
  4960  			),
  4961  			idx: []int{1},
  4962  		},
  4963  		{
  4964  			rt: StructOf(
  4965  				[]StructField{
  4966  					{Name: "XX", Type: TypeOf([1]int{})},
  4967  					{Name: "YY", Type: TypeOf("")},
  4968  					{Name: "ZZ", Type: TypeOf([1]int{})},
  4969  				},
  4970  			),
  4971  			idx: []int{1},
  4972  		},
  4973  		{
  4974  			rt: StructOf(
  4975  				[]StructField{
  4976  					{Name: "XX", Type: TypeOf([2]int{})},
  4977  					{Name: "YY", Type: TypeOf("")},
  4978  					{Name: "ZZ", Type: TypeOf([2]int{})},
  4979  				},
  4980  			),
  4981  			idx: []int{1},
  4982  		},
  4983  		{
  4984  			rt: StructOf(
  4985  				[]StructField{
  4986  					{Name: "XX", Type: TypeOf(int64(0))},
  4987  					{Name: "YY", Type: TypeOf(byte(0))},
  4988  					{Name: "ZZ", Type: TypeOf("")},
  4989  				},
  4990  			),
  4991  			idx: []int{2},
  4992  		},
  4993  		{
  4994  			rt: StructOf(
  4995  				[]StructField{
  4996  					{Name: "XX", Type: TypeOf(int64(0))},
  4997  					{Name: "YY", Type: TypeOf(int64(0))},
  4998  					{Name: "ZZ", Type: TypeOf("")},
  4999  					{Name: "AA", Type: TypeOf([1]int64{})},
  5000  				},
  5001  			),
  5002  			idx: []int{2},
  5003  		},
  5004  	}
  5005  
  5006  	for _, table := range tests {
  5007  		v1 := New(table.rt).Elem()
  5008  		v2 := New(table.rt).Elem()
  5009  
  5010  		if !DeepEqual(v1.Interface(), v1.Interface()) {
  5011  			t.Errorf("constructed struct %v not equal to itself", v1.Interface())
  5012  		}
  5013  
  5014  		v1.FieldByIndex(table.idx).Set(ValueOf("abc"))
  5015  		v2.FieldByIndex(table.idx).Set(ValueOf("def"))
  5016  		if i1, i2 := v1.Interface(), v2.Interface(); DeepEqual(i1, i2) {
  5017  			t.Errorf("constructed structs %v and %v should not be equal", i1, i2)
  5018  		}
  5019  
  5020  		abc := "abc"
  5021  		v1.FieldByIndex(table.idx).Set(ValueOf(abc))
  5022  		val := "+" + abc + "-"
  5023  		v2.FieldByIndex(table.idx).Set(ValueOf(val[1:4]))
  5024  		if i1, i2 := v1.Interface(), v2.Interface(); !DeepEqual(i1, i2) {
  5025  			t.Errorf("constructed structs %v and %v should be equal", i1, i2)
  5026  		}
  5027  
  5028  		// Test hash
  5029  		m := MakeMap(MapOf(table.rt, TypeOf(int(0))))
  5030  		m.SetMapIndex(v1, ValueOf(1))
  5031  		if i1, i2 := v1.Interface(), v2.Interface(); !m.MapIndex(v2).IsValid() {
  5032  			t.Errorf("constructed structs %#v and %#v have different hashes", i1, i2)
  5033  		}
  5034  
  5035  		v2.FieldByIndex(table.idx).Set(ValueOf("abc"))
  5036  		if i1, i2 := v1.Interface(), v2.Interface(); !DeepEqual(i1, i2) {
  5037  			t.Errorf("constructed structs %v and %v should be equal", i1, i2)
  5038  		}
  5039  
  5040  		if i1, i2 := v1.Interface(), v2.Interface(); !m.MapIndex(v2).IsValid() {
  5041  			t.Errorf("constructed structs %v and %v have different hashes", i1, i2)
  5042  		}
  5043  	}
  5044  }
  5045  
  5046  func TestStructOfDirectIface(t *testing.T) {
  5047  	{
  5048  		type T struct{ X [1]*byte }
  5049  		i1 := Zero(TypeOf(T{})).Interface()
  5050  		v1 := ValueOf(&i1).Elem()
  5051  		p1 := v1.InterfaceData()[1]
  5052  
  5053  		i2 := Zero(StructOf([]StructField{
  5054  			{
  5055  				Name: "X",
  5056  				Type: ArrayOf(1, TypeOf((*int8)(nil))),
  5057  			},
  5058  		})).Interface()
  5059  		v2 := ValueOf(&i2).Elem()
  5060  		p2 := v2.InterfaceData()[1]
  5061  
  5062  		if p1 != 0 {
  5063  			t.Errorf("got p1=%v. want=%v", p1, nil)
  5064  		}
  5065  
  5066  		if p2 != 0 {
  5067  			t.Errorf("got p2=%v. want=%v", p2, nil)
  5068  		}
  5069  	}
  5070  	{
  5071  		type T struct{ X [0]*byte }
  5072  		i1 := Zero(TypeOf(T{})).Interface()
  5073  		v1 := ValueOf(&i1).Elem()
  5074  		p1 := v1.InterfaceData()[1]
  5075  
  5076  		i2 := Zero(StructOf([]StructField{
  5077  			{
  5078  				Name: "X",
  5079  				Type: ArrayOf(0, TypeOf((*int8)(nil))),
  5080  			},
  5081  		})).Interface()
  5082  		v2 := ValueOf(&i2).Elem()
  5083  		p2 := v2.InterfaceData()[1]
  5084  
  5085  		if p1 == 0 {
  5086  			t.Errorf("got p1=%v. want=not-%v", p1, nil)
  5087  		}
  5088  
  5089  		if p2 == 0 {
  5090  			t.Errorf("got p2=%v. want=not-%v", p2, nil)
  5091  		}
  5092  	}
  5093  }
  5094  
  5095  type StructI int
  5096  
  5097  func (i StructI) Get() int { return int(i) }
  5098  
  5099  type StructIPtr int
  5100  
  5101  func (i *StructIPtr) Get() int  { return int(*i) }
  5102  func (i *StructIPtr) Set(v int) { *(*int)(i) = v }
  5103  
  5104  type SettableStruct struct {
  5105  	SettableField int
  5106  }
  5107  
  5108  func (p *SettableStruct) Set(v int) { p.SettableField = v }
  5109  
  5110  type SettablePointer struct {
  5111  	SettableField *int
  5112  }
  5113  
  5114  func (p *SettablePointer) Set(v int) { *p.SettableField = v }
  5115  
  5116  func TestStructOfWithInterface(t *testing.T) {
  5117  	const want = 42
  5118  	type Iface interface {
  5119  		Get() int
  5120  	}
  5121  	type IfaceSet interface {
  5122  		Set(int)
  5123  	}
  5124  	tests := []struct {
  5125  		name string
  5126  		typ  Type
  5127  		val  Value
  5128  		impl bool
  5129  	}{
  5130  		{
  5131  			name: "StructI",
  5132  			typ:  TypeOf(StructI(want)),
  5133  			val:  ValueOf(StructI(want)),
  5134  			impl: true,
  5135  		},
  5136  		{
  5137  			name: "StructI",
  5138  			typ:  PtrTo(TypeOf(StructI(want))),
  5139  			val: ValueOf(func() interface{} {
  5140  				v := StructI(want)
  5141  				return &v
  5142  			}()),
  5143  			impl: true,
  5144  		},
  5145  		{
  5146  			name: "StructIPtr",
  5147  			typ:  PtrTo(TypeOf(StructIPtr(want))),
  5148  			val: ValueOf(func() interface{} {
  5149  				v := StructIPtr(want)
  5150  				return &v
  5151  			}()),
  5152  			impl: true,
  5153  		},
  5154  		{
  5155  			name: "StructIPtr",
  5156  			typ:  TypeOf(StructIPtr(want)),
  5157  			val:  ValueOf(StructIPtr(want)),
  5158  			impl: false,
  5159  		},
  5160  		// {
  5161  		//	typ:  TypeOf((*Iface)(nil)).Elem(), // FIXME(sbinet): fix method.ifn/tfn
  5162  		//	val:  ValueOf(StructI(want)),
  5163  		//	impl: true,
  5164  		// },
  5165  	}
  5166  
  5167  	for i, table := range tests {
  5168  		for j := 0; j < 2; j++ {
  5169  			var fields []StructField
  5170  			if j == 1 {
  5171  				fields = append(fields, StructField{
  5172  					Name:    "Dummy",
  5173  					PkgPath: "",
  5174  					Type:    TypeOf(int(0)),
  5175  				})
  5176  			}
  5177  			fields = append(fields, StructField{
  5178  				Name:      table.name,
  5179  				Anonymous: true,
  5180  				PkgPath:   "",
  5181  				Type:      table.typ,
  5182  			})
  5183  
  5184  			// We currently do not correctly implement methods
  5185  			// for embedded fields other than the first.
  5186  			// Therefore, for now, we expect those methods
  5187  			// to not exist.  See issues 15924 and 20824.
  5188  			// When those issues are fixed, this test of panic
  5189  			// should be removed.
  5190  			if j == 1 && table.impl {
  5191  				func() {
  5192  					defer func() {
  5193  						if err := recover(); err == nil {
  5194  							t.Errorf("test-%d-%d did not panic", i, j)
  5195  						}
  5196  					}()
  5197  					_ = StructOf(fields)
  5198  				}()
  5199  				continue
  5200  			}
  5201  
  5202  			rt := StructOf(fields)
  5203  			rv := New(rt).Elem()
  5204  			rv.Field(j).Set(table.val)
  5205  
  5206  			if _, ok := rv.Interface().(Iface); ok != table.impl {
  5207  				if table.impl {
  5208  					t.Errorf("test-%d-%d: type=%v fails to implement Iface.\n", i, j, table.typ)
  5209  				} else {
  5210  					t.Errorf("test-%d-%d: type=%v should NOT implement Iface\n", i, j, table.typ)
  5211  				}
  5212  				continue
  5213  			}
  5214  
  5215  			if !table.impl {
  5216  				continue
  5217  			}
  5218  
  5219  			v := rv.Interface().(Iface).Get()
  5220  			if v != want {
  5221  				t.Errorf("test-%d-%d: x.Get()=%v. want=%v\n", i, j, v, want)
  5222  			}
  5223  
  5224  			fct := rv.MethodByName("Get")
  5225  			out := fct.Call(nil)
  5226  			if !DeepEqual(out[0].Interface(), want) {
  5227  				t.Errorf("test-%d-%d: x.Get()=%v. want=%v\n", i, j, out[0].Interface(), want)
  5228  			}
  5229  		}
  5230  	}
  5231  
  5232  	// Test an embedded nil pointer with pointer methods.
  5233  	fields := []StructField{{
  5234  		Name:      "StructIPtr",
  5235  		Anonymous: true,
  5236  		Type:      PtrTo(TypeOf(StructIPtr(want))),
  5237  	}}
  5238  	rt := StructOf(fields)
  5239  	rv := New(rt).Elem()
  5240  	// This should panic since the pointer is nil.
  5241  	shouldPanic(func() {
  5242  		rv.Interface().(IfaceSet).Set(want)
  5243  	})
  5244  
  5245  	// Test an embedded nil pointer to a struct with pointer methods.
  5246  
  5247  	fields = []StructField{{
  5248  		Name:      "SettableStruct",
  5249  		Anonymous: true,
  5250  		Type:      PtrTo(TypeOf(SettableStruct{})),
  5251  	}}
  5252  	rt = StructOf(fields)
  5253  	rv = New(rt).Elem()
  5254  	// This should panic since the pointer is nil.
  5255  	shouldPanic(func() {
  5256  		rv.Interface().(IfaceSet).Set(want)
  5257  	})
  5258  
  5259  	// The behavior is different if there is a second field,
  5260  	// since now an interface value holds a pointer to the struct
  5261  	// rather than just holding a copy of the struct.
  5262  	fields = []StructField{
  5263  		{
  5264  			Name:      "SettableStruct",
  5265  			Anonymous: true,
  5266  			Type:      PtrTo(TypeOf(SettableStruct{})),
  5267  		},
  5268  		{
  5269  			Name:      "EmptyStruct",
  5270  			Anonymous: true,
  5271  			Type:      StructOf(nil),
  5272  		},
  5273  	}
  5274  	// With the current implementation this is expected to panic.
  5275  	// Ideally it should work and we should be able to see a panic
  5276  	// if we call the Set method.
  5277  	shouldPanic(func() {
  5278  		StructOf(fields)
  5279  	})
  5280  
  5281  	// Embed a field that can be stored directly in an interface,
  5282  	// with a second field.
  5283  	fields = []StructField{
  5284  		{
  5285  			Name:      "SettablePointer",
  5286  			Anonymous: true,
  5287  			Type:      TypeOf(SettablePointer{}),
  5288  		},
  5289  		{
  5290  			Name:      "EmptyStruct",
  5291  			Anonymous: true,
  5292  			Type:      StructOf(nil),
  5293  		},
  5294  	}
  5295  	// With the current implementation this is expected to panic.
  5296  	// Ideally it should work and we should be able to call the
  5297  	// Set and Get methods.
  5298  	shouldPanic(func() {
  5299  		StructOf(fields)
  5300  	})
  5301  }
  5302  
  5303  func TestStructOfTooManyFields(t *testing.T) {
  5304  	// Bug Fix: #25402 - this should not panic
  5305  	tt := StructOf([]StructField{
  5306  		{Name: "Time", Type: TypeOf(time.Time{}), Anonymous: true},
  5307  	})
  5308  
  5309  	if _, present := tt.MethodByName("After"); !present {
  5310  		t.Errorf("Expected method `After` to be found")
  5311  	}
  5312  }
  5313  
  5314  func TestStructOfDifferentPkgPath(t *testing.T) {
  5315  	fields := []StructField{
  5316  		{
  5317  			Name:    "f1",
  5318  			PkgPath: "p1",
  5319  			Type:    TypeOf(int(0)),
  5320  		},
  5321  		{
  5322  			Name:    "f2",
  5323  			PkgPath: "p2",
  5324  			Type:    TypeOf(int(0)),
  5325  		},
  5326  	}
  5327  	shouldPanic(func() {
  5328  		StructOf(fields)
  5329  	})
  5330  }
  5331  
  5332  func TestChanOf(t *testing.T) {
  5333  	// check construction and use of type not in binary
  5334  	type T string
  5335  	ct := ChanOf(BothDir, TypeOf(T("")))
  5336  	v := MakeChan(ct, 2)
  5337  	runtime.GC()
  5338  	v.Send(ValueOf(T("hello")))
  5339  	runtime.GC()
  5340  	v.Send(ValueOf(T("world")))
  5341  	runtime.GC()
  5342  
  5343  	sv1, _ := v.Recv()
  5344  	sv2, _ := v.Recv()
  5345  	s1 := sv1.String()
  5346  	s2 := sv2.String()
  5347  	if s1 != "hello" || s2 != "world" {
  5348  		t.Errorf("constructed chan: have %q, %q, want %q, %q", s1, s2, "hello", "world")
  5349  	}
  5350  
  5351  	// check that type already in binary is found
  5352  	type T1 int
  5353  	checkSameType(t, ChanOf(BothDir, TypeOf(T1(1))), (chan T1)(nil))
  5354  }
  5355  
  5356  func TestChanOfDir(t *testing.T) {
  5357  	// check construction and use of type not in binary
  5358  	type T string
  5359  	crt := ChanOf(RecvDir, TypeOf(T("")))
  5360  	cst := ChanOf(SendDir, TypeOf(T("")))
  5361  
  5362  	// check that type already in binary is found
  5363  	type T1 int
  5364  	checkSameType(t, ChanOf(RecvDir, TypeOf(T1(1))), (<-chan T1)(nil))
  5365  	checkSameType(t, ChanOf(SendDir, TypeOf(T1(1))), (chan<- T1)(nil))
  5366  
  5367  	// check String form of ChanDir
  5368  	if crt.ChanDir().String() != "<-chan" {
  5369  		t.Errorf("chan dir: have %q, want %q", crt.ChanDir().String(), "<-chan")
  5370  	}
  5371  	if cst.ChanDir().String() != "chan<-" {
  5372  		t.Errorf("chan dir: have %q, want %q", cst.ChanDir().String(), "chan<-")
  5373  	}
  5374  }
  5375  
  5376  func TestChanOfGC(t *testing.T) {
  5377  	done := make(chan bool, 1)
  5378  	go func() {
  5379  		select {
  5380  		case <-done:
  5381  		case <-time.After(5 * time.Second):
  5382  			panic("deadlock in TestChanOfGC")
  5383  		}
  5384  	}()
  5385  
  5386  	defer func() {
  5387  		done <- true
  5388  	}()
  5389  
  5390  	type T *uintptr
  5391  	tt := TypeOf(T(nil))
  5392  	ct := ChanOf(BothDir, tt)
  5393  
  5394  	// NOTE: The garbage collector handles allocated channels specially,
  5395  	// so we have to save pointers to channels in x; the pointer code will
  5396  	// use the gc info in the newly constructed chan type.
  5397  	const n = 100
  5398  	var x []interface{}
  5399  	for i := 0; i < n; i++ {
  5400  		v := MakeChan(ct, n)
  5401  		for j := 0; j < n; j++ {
  5402  			p := new(uintptr)
  5403  			*p = uintptr(i*n + j)
  5404  			v.Send(ValueOf(p).Convert(tt))
  5405  		}
  5406  		pv := New(ct)
  5407  		pv.Elem().Set(v)
  5408  		x = append(x, pv.Interface())
  5409  	}
  5410  	runtime.GC()
  5411  
  5412  	for i, xi := range x {
  5413  		v := ValueOf(xi).Elem()
  5414  		for j := 0; j < n; j++ {
  5415  			pv, _ := v.Recv()
  5416  			k := pv.Elem().Interface()
  5417  			if k != uintptr(i*n+j) {
  5418  				t.Errorf("lost x[%d][%d] = %d, want %d", i, j, k, i*n+j)
  5419  			}
  5420  		}
  5421  	}
  5422  }
  5423  
  5424  func TestMapOf(t *testing.T) {
  5425  	// check construction and use of type not in binary
  5426  	type K string
  5427  	type V float64
  5428  
  5429  	v := MakeMap(MapOf(TypeOf(K("")), TypeOf(V(0))))
  5430  	runtime.GC()
  5431  	v.SetMapIndex(ValueOf(K("a")), ValueOf(V(1)))
  5432  	runtime.GC()
  5433  
  5434  	s := fmt.Sprint(v.Interface())
  5435  	want := "map[a:1]"
  5436  	if s != want {
  5437  		t.Errorf("constructed map = %s, want %s", s, want)
  5438  	}
  5439  
  5440  	// check that type already in binary is found
  5441  	checkSameType(t, MapOf(TypeOf(V(0)), TypeOf(K(""))), map[V]K(nil))
  5442  
  5443  	// check that invalid key type panics
  5444  	shouldPanic(func() { MapOf(TypeOf((func())(nil)), TypeOf(false)) })
  5445  }
  5446  
  5447  func TestMapOfGCKeys(t *testing.T) {
  5448  	type T *uintptr
  5449  	tt := TypeOf(T(nil))
  5450  	mt := MapOf(tt, TypeOf(false))
  5451  
  5452  	// NOTE: The garbage collector handles allocated maps specially,
  5453  	// so we have to save pointers to maps in x; the pointer code will
  5454  	// use the gc info in the newly constructed map type.
  5455  	const n = 100
  5456  	var x []interface{}
  5457  	for i := 0; i < n; i++ {
  5458  		v := MakeMap(mt)
  5459  		for j := 0; j < n; j++ {
  5460  			p := new(uintptr)
  5461  			*p = uintptr(i*n + j)
  5462  			v.SetMapIndex(ValueOf(p).Convert(tt), ValueOf(true))
  5463  		}
  5464  		pv := New(mt)
  5465  		pv.Elem().Set(v)
  5466  		x = append(x, pv.Interface())
  5467  	}
  5468  	runtime.GC()
  5469  
  5470  	for i, xi := range x {
  5471  		v := ValueOf(xi).Elem()
  5472  		var out []int
  5473  		for _, kv := range v.MapKeys() {
  5474  			out = append(out, int(kv.Elem().Interface().(uintptr)))
  5475  		}
  5476  		sort.Ints(out)
  5477  		for j, k := range out {
  5478  			if k != i*n+j {
  5479  				t.Errorf("lost x[%d][%d] = %d, want %d", i, j, k, i*n+j)
  5480  			}
  5481  		}
  5482  	}
  5483  }
  5484  
  5485  func TestMapOfGCValues(t *testing.T) {
  5486  	type T *uintptr
  5487  	tt := TypeOf(T(nil))
  5488  	mt := MapOf(TypeOf(1), tt)
  5489  
  5490  	// NOTE: The garbage collector handles allocated maps specially,
  5491  	// so we have to save pointers to maps in x; the pointer code will
  5492  	// use the gc info in the newly constructed map type.
  5493  	const n = 100
  5494  	var x []interface{}
  5495  	for i := 0; i < n; i++ {
  5496  		v := MakeMap(mt)
  5497  		for j := 0; j < n; j++ {
  5498  			p := new(uintptr)
  5499  			*p = uintptr(i*n + j)
  5500  			v.SetMapIndex(ValueOf(j), ValueOf(p).Convert(tt))
  5501  		}
  5502  		pv := New(mt)
  5503  		pv.Elem().Set(v)
  5504  		x = append(x, pv.Interface())
  5505  	}
  5506  	runtime.GC()
  5507  
  5508  	for i, xi := range x {
  5509  		v := ValueOf(xi).Elem()
  5510  		for j := 0; j < n; j++ {
  5511  			k := v.MapIndex(ValueOf(j)).Elem().Interface().(uintptr)
  5512  			if k != uintptr(i*n+j) {
  5513  				t.Errorf("lost x[%d][%d] = %d, want %d", i, j, k, i*n+j)
  5514  			}
  5515  		}
  5516  	}
  5517  }
  5518  
  5519  func TestTypelinksSorted(t *testing.T) {
  5520  	var last string
  5521  	for i, n := range TypeLinks() {
  5522  		if n < last {
  5523  			t.Errorf("typelinks not sorted: %q [%d] > %q [%d]", last, i-1, n, i)
  5524  		}
  5525  		last = n
  5526  	}
  5527  }
  5528  
  5529  func TestFuncOf(t *testing.T) {
  5530  	// check construction and use of type not in binary
  5531  	type K string
  5532  	type V float64
  5533  
  5534  	fn := func(args []Value) []Value {
  5535  		if len(args) != 1 {
  5536  			t.Errorf("args == %v, want exactly one arg", args)
  5537  		} else if args[0].Type() != TypeOf(K("")) {
  5538  			t.Errorf("args[0] is type %v, want %v", args[0].Type(), TypeOf(K("")))
  5539  		} else if args[0].String() != "gopher" {
  5540  			t.Errorf("args[0] = %q, want %q", args[0].String(), "gopher")
  5541  		}
  5542  		return []Value{ValueOf(V(3.14))}
  5543  	}
  5544  	v := MakeFunc(FuncOf([]Type{TypeOf(K(""))}, []Type{TypeOf(V(0))}, false), fn)
  5545  
  5546  	outs := v.Call([]Value{ValueOf(K("gopher"))})
  5547  	if len(outs) != 1 {
  5548  		t.Fatalf("v.Call returned %v, want exactly one result", outs)
  5549  	} else if outs[0].Type() != TypeOf(V(0)) {
  5550  		t.Fatalf("c.Call[0] is type %v, want %v", outs[0].Type(), TypeOf(V(0)))
  5551  	}
  5552  	f := outs[0].Float()
  5553  	if f != 3.14 {
  5554  		t.Errorf("constructed func returned %f, want %f", f, 3.14)
  5555  	}
  5556  
  5557  	// check that types already in binary are found
  5558  	type T1 int
  5559  	testCases := []struct {
  5560  		in, out  []Type
  5561  		variadic bool
  5562  		want     interface{}
  5563  	}{
  5564  		{in: []Type{TypeOf(T1(0))}, want: (func(T1))(nil)},
  5565  		{in: []Type{TypeOf(int(0))}, want: (func(int))(nil)},
  5566  		{in: []Type{SliceOf(TypeOf(int(0)))}, variadic: true, want: (func(...int))(nil)},
  5567  		{in: []Type{TypeOf(int(0))}, out: []Type{TypeOf(false)}, want: (func(int) bool)(nil)},
  5568  		{in: []Type{TypeOf(int(0))}, out: []Type{TypeOf(false), TypeOf("")}, want: (func(int) (bool, string))(nil)},
  5569  	}
  5570  	for _, tt := range testCases {
  5571  		checkSameType(t, FuncOf(tt.in, tt.out, tt.variadic), tt.want)
  5572  	}
  5573  
  5574  	// check that variadic requires last element be a slice.
  5575  	FuncOf([]Type{TypeOf(1), TypeOf(""), SliceOf(TypeOf(false))}, nil, true)
  5576  	shouldPanic(func() { FuncOf([]Type{TypeOf(0), TypeOf(""), TypeOf(false)}, nil, true) })
  5577  	shouldPanic(func() { FuncOf(nil, nil, true) })
  5578  }
  5579  
  5580  type B1 struct {
  5581  	X int
  5582  	Y int
  5583  	Z int
  5584  }
  5585  
  5586  func BenchmarkFieldByName1(b *testing.B) {
  5587  	t := TypeOf(B1{})
  5588  	b.RunParallel(func(pb *testing.PB) {
  5589  		for pb.Next() {
  5590  			t.FieldByName("Z")
  5591  		}
  5592  	})
  5593  }
  5594  
  5595  func BenchmarkFieldByName2(b *testing.B) {
  5596  	t := TypeOf(S3{})
  5597  	b.RunParallel(func(pb *testing.PB) {
  5598  		for pb.Next() {
  5599  			t.FieldByName("B")
  5600  		}
  5601  	})
  5602  }
  5603  
  5604  type R0 struct {
  5605  	*R1
  5606  	*R2
  5607  	*R3
  5608  	*R4
  5609  }
  5610  
  5611  type R1 struct {
  5612  	*R5
  5613  	*R6
  5614  	*R7
  5615  	*R8
  5616  }
  5617  
  5618  type R2 R1
  5619  type R3 R1
  5620  type R4 R1
  5621  
  5622  type R5 struct {
  5623  	*R9
  5624  	*R10
  5625  	*R11
  5626  	*R12
  5627  }
  5628  
  5629  type R6 R5
  5630  type R7 R5
  5631  type R8 R5
  5632  
  5633  type R9 struct {
  5634  	*R13
  5635  	*R14
  5636  	*R15
  5637  	*R16
  5638  }
  5639  
  5640  type R10 R9
  5641  type R11 R9
  5642  type R12 R9
  5643  
  5644  type R13 struct {
  5645  	*R17
  5646  	*R18
  5647  	*R19
  5648  	*R20
  5649  }
  5650  
  5651  type R14 R13
  5652  type R15 R13
  5653  type R16 R13
  5654  
  5655  type R17 struct {
  5656  	*R21
  5657  	*R22
  5658  	*R23
  5659  	*R24
  5660  }
  5661  
  5662  type R18 R17
  5663  type R19 R17
  5664  type R20 R17
  5665  
  5666  type R21 struct {
  5667  	X int
  5668  }
  5669  
  5670  type R22 R21
  5671  type R23 R21
  5672  type R24 R21
  5673  
  5674  func TestEmbed(t *testing.T) {
  5675  	typ := TypeOf(R0{})
  5676  	f, ok := typ.FieldByName("X")
  5677  	if ok {
  5678  		t.Fatalf(`FieldByName("X") should fail, returned %v`, f.Index)
  5679  	}
  5680  }
  5681  
  5682  func BenchmarkFieldByName3(b *testing.B) {
  5683  	t := TypeOf(R0{})
  5684  	b.RunParallel(func(pb *testing.PB) {
  5685  		for pb.Next() {
  5686  			t.FieldByName("X")
  5687  		}
  5688  	})
  5689  }
  5690  
  5691  type S struct {
  5692  	i1 int64
  5693  	i2 int64
  5694  }
  5695  
  5696  func BenchmarkInterfaceBig(b *testing.B) {
  5697  	v := ValueOf(S{})
  5698  	b.RunParallel(func(pb *testing.PB) {
  5699  		for pb.Next() {
  5700  			v.Interface()
  5701  		}
  5702  	})
  5703  	b.StopTimer()
  5704  }
  5705  
  5706  func TestAllocsInterfaceBig(t *testing.T) {
  5707  	if testing.Short() {
  5708  		t.Skip("skipping malloc count in short mode")
  5709  	}
  5710  	v := ValueOf(S{})
  5711  	if allocs := testing.AllocsPerRun(100, func() { v.Interface() }); allocs > 0 {
  5712  		t.Error("allocs:", allocs)
  5713  	}
  5714  }
  5715  
  5716  func BenchmarkInterfaceSmall(b *testing.B) {
  5717  	v := ValueOf(int64(0))
  5718  	b.RunParallel(func(pb *testing.PB) {
  5719  		for pb.Next() {
  5720  			v.Interface()
  5721  		}
  5722  	})
  5723  }
  5724  
  5725  func TestAllocsInterfaceSmall(t *testing.T) {
  5726  	if testing.Short() {
  5727  		t.Skip("skipping malloc count in short mode")
  5728  	}
  5729  	v := ValueOf(int64(0))
  5730  	if allocs := testing.AllocsPerRun(100, func() { v.Interface() }); allocs > 0 {
  5731  		t.Error("allocs:", allocs)
  5732  	}
  5733  }
  5734  
  5735  // An exhaustive is a mechanism for writing exhaustive or stochastic tests.
  5736  // The basic usage is:
  5737  //
  5738  //	for x.Next() {
  5739  //		... code using x.Maybe() or x.Choice(n) to create test cases ...
  5740  //	}
  5741  //
  5742  // Each iteration of the loop returns a different set of results, until all
  5743  // possible result sets have been explored. It is okay for different code paths
  5744  // to make different method call sequences on x, but there must be no
  5745  // other source of non-determinism in the call sequences.
  5746  //
  5747  // When faced with a new decision, x chooses randomly. Future explorations
  5748  // of that path will choose successive values for the result. Thus, stopping
  5749  // the loop after a fixed number of iterations gives somewhat stochastic
  5750  // testing.
  5751  //
  5752  // Example:
  5753  //
  5754  //	for x.Next() {
  5755  //		v := make([]bool, x.Choose(4))
  5756  //		for i := range v {
  5757  //			v[i] = x.Maybe()
  5758  //		}
  5759  //		fmt.Println(v)
  5760  //	}
  5761  //
  5762  // prints (in some order):
  5763  //
  5764  //	[]
  5765  //	[false]
  5766  //	[true]
  5767  //	[false false]
  5768  //	[false true]
  5769  //	...
  5770  //	[true true]
  5771  //	[false false false]
  5772  //	...
  5773  //	[true true true]
  5774  //	[false false false false]
  5775  //	...
  5776  //	[true true true true]
  5777  //
  5778  type exhaustive struct {
  5779  	r    *rand.Rand
  5780  	pos  int
  5781  	last []choice
  5782  }
  5783  
  5784  type choice struct {
  5785  	off int
  5786  	n   int
  5787  	max int
  5788  }
  5789  
  5790  func (x *exhaustive) Next() bool {
  5791  	if x.r == nil {
  5792  		x.r = rand.New(rand.NewSource(time.Now().UnixNano()))
  5793  	}
  5794  	x.pos = 0
  5795  	if x.last == nil {
  5796  		x.last = []choice{}
  5797  		return true
  5798  	}
  5799  	for i := len(x.last) - 1; i >= 0; i-- {
  5800  		c := &x.last[i]
  5801  		if c.n+1 < c.max {
  5802  			c.n++
  5803  			x.last = x.last[:i+1]
  5804  			return true
  5805  		}
  5806  	}
  5807  	return false
  5808  }
  5809  
  5810  func (x *exhaustive) Choose(max int) int {
  5811  	if x.pos >= len(x.last) {
  5812  		x.last = append(x.last, choice{x.r.Intn(max), 0, max})
  5813  	}
  5814  	c := &x.last[x.pos]
  5815  	x.pos++
  5816  	if c.max != max {
  5817  		panic("inconsistent use of exhaustive tester")
  5818  	}
  5819  	return (c.n + c.off) % max
  5820  }
  5821  
  5822  func (x *exhaustive) Maybe() bool {
  5823  	return x.Choose(2) == 1
  5824  }
  5825  
  5826  func GCFunc(args []Value) []Value {
  5827  	runtime.GC()
  5828  	return []Value{}
  5829  }
  5830  
  5831  func TestReflectFuncTraceback(t *testing.T) {
  5832  	f := MakeFunc(TypeOf(func() {}), GCFunc)
  5833  	f.Call([]Value{})
  5834  }
  5835  
  5836  func TestReflectMethodTraceback(t *testing.T) {
  5837  	p := Point{3, 4}
  5838  	m := ValueOf(p).MethodByName("GCMethod")
  5839  	i := ValueOf(m.Interface()).Call([]Value{ValueOf(5)})[0].Int()
  5840  	if i != 8 {
  5841  		t.Errorf("Call returned %d; want 8", i)
  5842  	}
  5843  }
  5844  
  5845  func TestBigZero(t *testing.T) {
  5846  	const size = 1 << 10
  5847  	var v [size]byte
  5848  	z := Zero(ValueOf(v).Type()).Interface().([size]byte)
  5849  	for i := 0; i < size; i++ {
  5850  		if z[i] != 0 {
  5851  			t.Fatalf("Zero object not all zero, index %d", i)
  5852  		}
  5853  	}
  5854  }
  5855  
  5856  func TestFieldByIndexNil(t *testing.T) {
  5857  	type P struct {
  5858  		F int
  5859  	}
  5860  	type T struct {
  5861  		*P
  5862  	}
  5863  	v := ValueOf(T{})
  5864  
  5865  	v.FieldByName("P") // should be fine
  5866  
  5867  	defer func() {
  5868  		if err := recover(); err == nil {
  5869  			t.Fatalf("no error")
  5870  		} else if !strings.Contains(fmt.Sprint(err), "nil pointer to embedded struct") {
  5871  			t.Fatalf(`err=%q, wanted error containing "nil pointer to embedded struct"`, err)
  5872  		}
  5873  	}()
  5874  	v.FieldByName("F") // should panic
  5875  
  5876  	t.Fatalf("did not panic")
  5877  }
  5878  
  5879  // Given
  5880  //	type Outer struct {
  5881  //		*Inner
  5882  //		...
  5883  //	}
  5884  // the compiler generates the implementation of (*Outer).M dispatching to the embedded Inner.
  5885  // The implementation is logically:
  5886  //	func (p *Outer) M() {
  5887  //		(p.Inner).M()
  5888  //	}
  5889  // but since the only change here is the replacement of one pointer receiver with another,
  5890  // the actual generated code overwrites the original receiver with the p.Inner pointer and
  5891  // then jumps to the M method expecting the *Inner receiver.
  5892  //
  5893  // During reflect.Value.Call, we create an argument frame and the associated data structures
  5894  // to describe it to the garbage collector, populate the frame, call reflect.call to
  5895  // run a function call using that frame, and then copy the results back out of the frame.
  5896  // The reflect.call function does a memmove of the frame structure onto the
  5897  // stack (to set up the inputs), runs the call, and the memmoves the stack back to
  5898  // the frame structure (to preserve the outputs).
  5899  //
  5900  // Originally reflect.call did not distinguish inputs from outputs: both memmoves
  5901  // were for the full stack frame. However, in the case where the called function was
  5902  // one of these wrappers, the rewritten receiver is almost certainly a different type
  5903  // than the original receiver. This is not a problem on the stack, where we use the
  5904  // program counter to determine the type information and understand that
  5905  // during (*Outer).M the receiver is an *Outer while during (*Inner).M the receiver in the same
  5906  // memory word is now an *Inner. But in the statically typed argument frame created
  5907  // by reflect, the receiver is always an *Outer. Copying the modified receiver pointer
  5908  // off the stack into the frame will store an *Inner there, and then if a garbage collection
  5909  // happens to scan that argument frame before it is discarded, it will scan the *Inner
  5910  // memory as if it were an *Outer. If the two have different memory layouts, the
  5911  // collection will interpret the memory incorrectly.
  5912  //
  5913  // One such possible incorrect interpretation is to treat two arbitrary memory words
  5914  // (Inner.P1 and Inner.P2 below) as an interface (Outer.R below). Because interpreting
  5915  // an interface requires dereferencing the itab word, the misinterpretation will try to
  5916  // deference Inner.P1, causing a crash during garbage collection.
  5917  //
  5918  // This came up in a real program in issue 7725.
  5919  
  5920  type Outer struct {
  5921  	*Inner
  5922  	R io.Reader
  5923  }
  5924  
  5925  type Inner struct {
  5926  	X  *Outer
  5927  	P1 uintptr
  5928  	P2 uintptr
  5929  }
  5930  
  5931  func (pi *Inner) M() {
  5932  	// Clear references to pi so that the only way the
  5933  	// garbage collection will find the pointer is in the
  5934  	// argument frame, typed as a *Outer.
  5935  	pi.X.Inner = nil
  5936  
  5937  	// Set up an interface value that will cause a crash.
  5938  	// P1 = 1 is a non-zero, so the interface looks non-nil.
  5939  	// P2 = pi ensures that the data word points into the
  5940  	// allocated heap; if not the collection skips the interface
  5941  	// value as irrelevant, without dereferencing P1.
  5942  	pi.P1 = 1
  5943  	pi.P2 = uintptr(unsafe.Pointer(pi))
  5944  }
  5945  
  5946  func TestCallMethodJump(t *testing.T) {
  5947  	// In reflect.Value.Call, trigger a garbage collection after reflect.call
  5948  	// returns but before the args frame has been discarded.
  5949  	// This is a little clumsy but makes the failure repeatable.
  5950  	*CallGC = true
  5951  
  5952  	p := &Outer{Inner: new(Inner)}
  5953  	p.Inner.X = p
  5954  	ValueOf(p).Method(0).Call(nil)
  5955  
  5956  	// Stop garbage collecting during reflect.call.
  5957  	*CallGC = false
  5958  }
  5959  
  5960  func TestMakeFuncStackCopy(t *testing.T) {
  5961  	target := func(in []Value) []Value {
  5962  		runtime.GC()
  5963  		useStack(16)
  5964  		return []Value{ValueOf(9)}
  5965  	}
  5966  
  5967  	var concrete func(*int, int) int
  5968  	fn := MakeFunc(ValueOf(concrete).Type(), target)
  5969  	ValueOf(&concrete).Elem().Set(fn)
  5970  	x := concrete(nil, 7)
  5971  	if x != 9 {
  5972  		t.Errorf("have %#q want 9", x)
  5973  	}
  5974  }
  5975  
  5976  // use about n KB of stack
  5977  func useStack(n int) {
  5978  	if n == 0 {
  5979  		return
  5980  	}
  5981  	var b [1024]byte // makes frame about 1KB
  5982  	useStack(n - 1 + int(b[99]))
  5983  }
  5984  
  5985  type Impl struct{}
  5986  
  5987  func (Impl) F() {}
  5988  
  5989  func TestValueString(t *testing.T) {
  5990  	rv := ValueOf(Impl{})
  5991  	if rv.String() != "<reflect_test.Impl Value>" {
  5992  		t.Errorf("ValueOf(Impl{}).String() = %q, want %q", rv.String(), "<reflect_test.Impl Value>")
  5993  	}
  5994  
  5995  	method := rv.Method(0)
  5996  	if method.String() != "<func() Value>" {
  5997  		t.Errorf("ValueOf(Impl{}).Method(0).String() = %q, want %q", method.String(), "<func() Value>")
  5998  	}
  5999  }
  6000  
  6001  func TestInvalid(t *testing.T) {
  6002  	// Used to have inconsistency between IsValid() and Kind() != Invalid.
  6003  	type T struct{ v interface{} }
  6004  
  6005  	v := ValueOf(T{}).Field(0)
  6006  	if v.IsValid() != true || v.Kind() != Interface {
  6007  		t.Errorf("field: IsValid=%v, Kind=%v, want true, Interface", v.IsValid(), v.Kind())
  6008  	}
  6009  	v = v.Elem()
  6010  	if v.IsValid() != false || v.Kind() != Invalid {
  6011  		t.Errorf("field elem: IsValid=%v, Kind=%v, want false, Invalid", v.IsValid(), v.Kind())
  6012  	}
  6013  }
  6014  
  6015  // Issue 8917.
  6016  func TestLargeGCProg(t *testing.T) {
  6017  	fv := ValueOf(func([256]*byte) {})
  6018  	fv.Call([]Value{ValueOf([256]*byte{})})
  6019  }
  6020  
  6021  func fieldIndexRecover(t Type, i int) (recovered interface{}) {
  6022  	defer func() {
  6023  		recovered = recover()
  6024  	}()
  6025  
  6026  	t.Field(i)
  6027  	return
  6028  }
  6029  
  6030  // Issue 15046.
  6031  func TestTypeFieldOutOfRangePanic(t *testing.T) {
  6032  	typ := TypeOf(struct{ X int }{10})
  6033  	testIndices := [...]struct {
  6034  		i         int
  6035  		mustPanic bool
  6036  	}{
  6037  		0: {-2, true},
  6038  		1: {0, false},
  6039  		2: {1, true},
  6040  		3: {1 << 10, true},
  6041  	}
  6042  	for i, tt := range testIndices {
  6043  		recoveredErr := fieldIndexRecover(typ, tt.i)
  6044  		if tt.mustPanic {
  6045  			if recoveredErr == nil {
  6046  				t.Errorf("#%d: fieldIndex %d expected to panic", i, tt.i)
  6047  			}
  6048  		} else {
  6049  			if recoveredErr != nil {
  6050  				t.Errorf("#%d: got err=%v, expected no panic", i, recoveredErr)
  6051  			}
  6052  		}
  6053  	}
  6054  }
  6055  
  6056  // Issue 9179.
  6057  func TestCallGC(t *testing.T) {
  6058  	f := func(a, b, c, d, e string) {
  6059  	}
  6060  	g := func(in []Value) []Value {
  6061  		runtime.GC()
  6062  		return nil
  6063  	}
  6064  	typ := ValueOf(f).Type()
  6065  	f2 := MakeFunc(typ, g).Interface().(func(string, string, string, string, string))
  6066  	f2("four", "five5", "six666", "seven77", "eight888")
  6067  }
  6068  
  6069  // Issue 18635 (function version).
  6070  func TestKeepFuncLive(t *testing.T) {
  6071  	// Test that we keep makeFuncImpl live as long as it is
  6072  	// referenced on the stack.
  6073  	typ := TypeOf(func(i int) {})
  6074  	var f, g func(in []Value) []Value
  6075  	f = func(in []Value) []Value {
  6076  		clobber()
  6077  		i := int(in[0].Int())
  6078  		if i > 0 {
  6079  			// We can't use Value.Call here because
  6080  			// runtime.call* will keep the makeFuncImpl
  6081  			// alive. However, by converting it to an
  6082  			// interface value and calling that,
  6083  			// reflect.callReflect is the only thing that
  6084  			// can keep the makeFuncImpl live.
  6085  			//
  6086  			// Alternate between f and g so that if we do
  6087  			// reuse the memory prematurely it's more
  6088  			// likely to get obviously corrupted.
  6089  			MakeFunc(typ, g).Interface().(func(i int))(i - 1)
  6090  		}
  6091  		return nil
  6092  	}
  6093  	g = func(in []Value) []Value {
  6094  		clobber()
  6095  		i := int(in[0].Int())
  6096  		MakeFunc(typ, f).Interface().(func(i int))(i)
  6097  		return nil
  6098  	}
  6099  	MakeFunc(typ, f).Call([]Value{ValueOf(10)})
  6100  }
  6101  
  6102  type UnExportedFirst int
  6103  
  6104  func (i UnExportedFirst) ΦExported()  {}
  6105  func (i UnExportedFirst) unexported() {}
  6106  
  6107  // Issue 21177
  6108  func TestMethodByNameUnExportedFirst(t *testing.T) {
  6109  	defer func() {
  6110  		if recover() != nil {
  6111  			t.Errorf("should not panic")
  6112  		}
  6113  	}()
  6114  	typ := TypeOf(UnExportedFirst(0))
  6115  	m, _ := typ.MethodByName("ΦExported")
  6116  	if m.Name != "ΦExported" {
  6117  		t.Errorf("got %s, expected ΦExported", m.Name)
  6118  	}
  6119  }
  6120  
  6121  // Issue 18635 (method version).
  6122  type KeepMethodLive struct{}
  6123  
  6124  func (k KeepMethodLive) Method1(i int) {
  6125  	clobber()
  6126  	if i > 0 {
  6127  		ValueOf(k).MethodByName("Method2").Interface().(func(i int))(i - 1)
  6128  	}
  6129  }
  6130  
  6131  func (k KeepMethodLive) Method2(i int) {
  6132  	clobber()
  6133  	ValueOf(k).MethodByName("Method1").Interface().(func(i int))(i)
  6134  }
  6135  
  6136  func TestKeepMethodLive(t *testing.T) {
  6137  	// Test that we keep methodValue live as long as it is
  6138  	// referenced on the stack.
  6139  	KeepMethodLive{}.Method1(10)
  6140  }
  6141  
  6142  // clobber tries to clobber unreachable memory.
  6143  func clobber() {
  6144  	runtime.GC()
  6145  	for i := 1; i < 32; i++ {
  6146  		for j := 0; j < 10; j++ {
  6147  			obj := make([]*byte, i)
  6148  			sink = obj
  6149  		}
  6150  	}
  6151  	runtime.GC()
  6152  }
  6153  
  6154  type funcLayoutTest struct {
  6155  	rcvr, t                  Type
  6156  	size, argsize, retOffset uintptr
  6157  	stack                    []byte // pointer bitmap: 1 is pointer, 0 is scalar
  6158  	gc                       []byte
  6159  }
  6160  
  6161  var funcLayoutTests []funcLayoutTest
  6162  
  6163  func init() {
  6164  	var argAlign uintptr = PtrSize
  6165  	roundup := func(x uintptr, a uintptr) uintptr {
  6166  		return (x + a - 1) / a * a
  6167  	}
  6168  
  6169  	funcLayoutTests = append(funcLayoutTests,
  6170  		funcLayoutTest{
  6171  			nil,
  6172  			ValueOf(func(a, b string) string { return "" }).Type(),
  6173  			6 * PtrSize,
  6174  			4 * PtrSize,
  6175  			4 * PtrSize,
  6176  			[]byte{1, 0, 1, 0, 1},
  6177  			[]byte{1, 0, 1, 0, 1},
  6178  		})
  6179  
  6180  	var r []byte
  6181  	if PtrSize == 4 {
  6182  		r = []byte{0, 0, 0, 1}
  6183  	} else {
  6184  		r = []byte{0, 0, 1}
  6185  	}
  6186  	funcLayoutTests = append(funcLayoutTests,
  6187  		funcLayoutTest{
  6188  			nil,
  6189  			ValueOf(func(a, b, c uint32, p *byte, d uint16) {}).Type(),
  6190  			roundup(roundup(3*4, PtrSize)+PtrSize+2, argAlign),
  6191  			roundup(3*4, PtrSize) + PtrSize + 2,
  6192  			roundup(roundup(3*4, PtrSize)+PtrSize+2, argAlign),
  6193  			r,
  6194  			r,
  6195  		})
  6196  
  6197  	funcLayoutTests = append(funcLayoutTests,
  6198  		funcLayoutTest{
  6199  			nil,
  6200  			ValueOf(func(a map[int]int, b uintptr, c interface{}) {}).Type(),
  6201  			4 * PtrSize,
  6202  			4 * PtrSize,
  6203  			4 * PtrSize,
  6204  			[]byte{1, 0, 1, 1},
  6205  			[]byte{1, 0, 1, 1},
  6206  		})
  6207  
  6208  	type S struct {
  6209  		a, b uintptr
  6210  		c, d *byte
  6211  	}
  6212  	funcLayoutTests = append(funcLayoutTests,
  6213  		funcLayoutTest{
  6214  			nil,
  6215  			ValueOf(func(a S) {}).Type(),
  6216  			4 * PtrSize,
  6217  			4 * PtrSize,
  6218  			4 * PtrSize,
  6219  			[]byte{0, 0, 1, 1},
  6220  			[]byte{0, 0, 1, 1},
  6221  		})
  6222  
  6223  	funcLayoutTests = append(funcLayoutTests,
  6224  		funcLayoutTest{
  6225  			ValueOf((*byte)(nil)).Type(),
  6226  			ValueOf(func(a uintptr, b *int) {}).Type(),
  6227  			roundup(3*PtrSize, argAlign),
  6228  			3 * PtrSize,
  6229  			roundup(3*PtrSize, argAlign),
  6230  			[]byte{1, 0, 1},
  6231  			[]byte{1, 0, 1},
  6232  		})
  6233  
  6234  	funcLayoutTests = append(funcLayoutTests,
  6235  		funcLayoutTest{
  6236  			nil,
  6237  			ValueOf(func(a uintptr) {}).Type(),
  6238  			roundup(PtrSize, argAlign),
  6239  			PtrSize,
  6240  			roundup(PtrSize, argAlign),
  6241  			[]byte{},
  6242  			[]byte{},
  6243  		})
  6244  
  6245  	funcLayoutTests = append(funcLayoutTests,
  6246  		funcLayoutTest{
  6247  			nil,
  6248  			ValueOf(func() uintptr { return 0 }).Type(),
  6249  			PtrSize,
  6250  			0,
  6251  			0,
  6252  			[]byte{},
  6253  			[]byte{},
  6254  		})
  6255  
  6256  	funcLayoutTests = append(funcLayoutTests,
  6257  		funcLayoutTest{
  6258  			ValueOf(uintptr(0)).Type(),
  6259  			ValueOf(func(a uintptr) {}).Type(),
  6260  			2 * PtrSize,
  6261  			2 * PtrSize,
  6262  			2 * PtrSize,
  6263  			[]byte{1},
  6264  			[]byte{1},
  6265  			// Note: this one is tricky, as the receiver is not a pointer. But we
  6266  			// pass the receiver by reference to the autogenerated pointer-receiver
  6267  			// version of the function.
  6268  		})
  6269  }
  6270  
  6271  func TestFuncLayout(t *testing.T) {
  6272  	for _, lt := range funcLayoutTests {
  6273  		typ, argsize, retOffset, stack, gc, ptrs := FuncLayout(lt.t, lt.rcvr)
  6274  		if typ.Size() != lt.size {
  6275  			t.Errorf("funcLayout(%v, %v).size=%d, want %d", lt.t, lt.rcvr, typ.Size(), lt.size)
  6276  		}
  6277  		if argsize != lt.argsize {
  6278  			t.Errorf("funcLayout(%v, %v).argsize=%d, want %d", lt.t, lt.rcvr, argsize, lt.argsize)
  6279  		}
  6280  		if retOffset != lt.retOffset {
  6281  			t.Errorf("funcLayout(%v, %v).retOffset=%d, want %d", lt.t, lt.rcvr, retOffset, lt.retOffset)
  6282  		}
  6283  		if !bytes.Equal(stack, lt.stack) {
  6284  			t.Errorf("funcLayout(%v, %v).stack=%v, want %v", lt.t, lt.rcvr, stack, lt.stack)
  6285  		}
  6286  		if !bytes.Equal(gc, lt.gc) {
  6287  			t.Errorf("funcLayout(%v, %v).gc=%v, want %v", lt.t, lt.rcvr, gc, lt.gc)
  6288  		}
  6289  		if ptrs && len(stack) == 0 || !ptrs && len(stack) > 0 {
  6290  			t.Errorf("funcLayout(%v, %v) pointers flag=%v, want %v", lt.t, lt.rcvr, ptrs, !ptrs)
  6291  		}
  6292  	}
  6293  }
  6294  
  6295  func verifyGCBits(t *testing.T, typ Type, bits []byte) {
  6296  	heapBits := GCBits(New(typ).Interface())
  6297  	if !bytes.Equal(heapBits, bits) {
  6298  		_, _, line, _ := runtime.Caller(1)
  6299  		t.Errorf("line %d: heapBits incorrect for %v\nhave %v\nwant %v", line, typ, heapBits, bits)
  6300  	}
  6301  }
  6302  
  6303  func verifyGCBitsSlice(t *testing.T, typ Type, cap int, bits []byte) {
  6304  	// Creating a slice causes the runtime to repeat a bitmap,
  6305  	// which exercises a different path from making the compiler
  6306  	// repeat a bitmap for a small array or executing a repeat in
  6307  	// a GC program.
  6308  	val := MakeSlice(typ, 0, cap)
  6309  	data := NewAt(ArrayOf(cap, typ), unsafe.Pointer(val.Pointer()))
  6310  	heapBits := GCBits(data.Interface())
  6311  	// Repeat the bitmap for the slice size, trimming scalars in
  6312  	// the last element.
  6313  	bits = rep(cap, bits)
  6314  	for len(bits) > 2 && bits[len(bits)-1] == 0 {
  6315  		bits = bits[:len(bits)-1]
  6316  	}
  6317  	if len(bits) == 2 && bits[0] == 0 && bits[1] == 0 {
  6318  		bits = bits[:0]
  6319  	}
  6320  	if !bytes.Equal(heapBits, bits) {
  6321  		t.Errorf("heapBits incorrect for make(%v, 0, %v)\nhave %v\nwant %v", typ, cap, heapBits, bits)
  6322  	}
  6323  }
  6324  
  6325  func TestGCBits(t *testing.T) {
  6326  	verifyGCBits(t, TypeOf((*byte)(nil)), []byte{1})
  6327  
  6328  	// Building blocks for types seen by the compiler (like [2]Xscalar).
  6329  	// The compiler will create the type structures for the derived types,
  6330  	// including their GC metadata.
  6331  	type Xscalar struct{ x uintptr }
  6332  	type Xptr struct{ x *byte }
  6333  	type Xptrscalar struct {
  6334  		*byte
  6335  		uintptr
  6336  	}
  6337  	type Xscalarptr struct {
  6338  		uintptr
  6339  		*byte
  6340  	}
  6341  	type Xbigptrscalar struct {
  6342  		_ [100]*byte
  6343  		_ [100]uintptr
  6344  	}
  6345  
  6346  	var Tscalar, Tint64, Tptr, Tscalarptr, Tptrscalar, Tbigptrscalar Type
  6347  	{
  6348  		// Building blocks for types constructed by reflect.
  6349  		// This code is in a separate block so that code below
  6350  		// cannot accidentally refer to these.
  6351  		// The compiler must NOT see types derived from these
  6352  		// (for example, [2]Scalar must NOT appear in the program),
  6353  		// or else reflect will use it instead of having to construct one.
  6354  		// The goal is to test the construction.
  6355  		type Scalar struct{ x uintptr }
  6356  		type Ptr struct{ x *byte }
  6357  		type Ptrscalar struct {
  6358  			*byte
  6359  			uintptr
  6360  		}
  6361  		type Scalarptr struct {
  6362  			uintptr
  6363  			*byte
  6364  		}
  6365  		type Bigptrscalar struct {
  6366  			_ [100]*byte
  6367  			_ [100]uintptr
  6368  		}
  6369  		type Int64 int64
  6370  		Tscalar = TypeOf(Scalar{})
  6371  		Tint64 = TypeOf(Int64(0))
  6372  		Tptr = TypeOf(Ptr{})
  6373  		Tscalarptr = TypeOf(Scalarptr{})
  6374  		Tptrscalar = TypeOf(Ptrscalar{})
  6375  		Tbigptrscalar = TypeOf(Bigptrscalar{})
  6376  	}
  6377  
  6378  	empty := []byte{}
  6379  
  6380  	verifyGCBits(t, TypeOf(Xscalar{}), empty)
  6381  	verifyGCBits(t, Tscalar, empty)
  6382  	verifyGCBits(t, TypeOf(Xptr{}), lit(1))
  6383  	verifyGCBits(t, Tptr, lit(1))
  6384  	verifyGCBits(t, TypeOf(Xscalarptr{}), lit(0, 1))
  6385  	verifyGCBits(t, Tscalarptr, lit(0, 1))
  6386  	verifyGCBits(t, TypeOf(Xptrscalar{}), lit(1))
  6387  	verifyGCBits(t, Tptrscalar, lit(1))
  6388  
  6389  	verifyGCBits(t, TypeOf([0]Xptr{}), empty)
  6390  	verifyGCBits(t, ArrayOf(0, Tptr), empty)
  6391  	verifyGCBits(t, TypeOf([1]Xptrscalar{}), lit(1))
  6392  	verifyGCBits(t, ArrayOf(1, Tptrscalar), lit(1))
  6393  	verifyGCBits(t, TypeOf([2]Xscalar{}), empty)
  6394  	verifyGCBits(t, ArrayOf(2, Tscalar), empty)
  6395  	verifyGCBits(t, TypeOf([10000]Xscalar{}), empty)
  6396  	verifyGCBits(t, ArrayOf(10000, Tscalar), empty)
  6397  	verifyGCBits(t, TypeOf([2]Xptr{}), lit(1, 1))
  6398  	verifyGCBits(t, ArrayOf(2, Tptr), lit(1, 1))
  6399  	verifyGCBits(t, TypeOf([10000]Xptr{}), rep(10000, lit(1)))
  6400  	verifyGCBits(t, ArrayOf(10000, Tptr), rep(10000, lit(1)))
  6401  	verifyGCBits(t, TypeOf([2]Xscalarptr{}), lit(0, 1, 0, 1))
  6402  	verifyGCBits(t, ArrayOf(2, Tscalarptr), lit(0, 1, 0, 1))
  6403  	verifyGCBits(t, TypeOf([10000]Xscalarptr{}), rep(10000, lit(0, 1)))
  6404  	verifyGCBits(t, ArrayOf(10000, Tscalarptr), rep(10000, lit(0, 1)))
  6405  	verifyGCBits(t, TypeOf([2]Xptrscalar{}), lit(1, 0, 1))
  6406  	verifyGCBits(t, ArrayOf(2, Tptrscalar), lit(1, 0, 1))
  6407  	verifyGCBits(t, TypeOf([10000]Xptrscalar{}), rep(10000, lit(1, 0)))
  6408  	verifyGCBits(t, ArrayOf(10000, Tptrscalar), rep(10000, lit(1, 0)))
  6409  	verifyGCBits(t, TypeOf([1][10000]Xptrscalar{}), rep(10000, lit(1, 0)))
  6410  	verifyGCBits(t, ArrayOf(1, ArrayOf(10000, Tptrscalar)), rep(10000, lit(1, 0)))
  6411  	verifyGCBits(t, TypeOf([2][10000]Xptrscalar{}), rep(2*10000, lit(1, 0)))
  6412  	verifyGCBits(t, ArrayOf(2, ArrayOf(10000, Tptrscalar)), rep(2*10000, lit(1, 0)))
  6413  	verifyGCBits(t, TypeOf([4]Xbigptrscalar{}), join(rep(3, join(rep(100, lit(1)), rep(100, lit(0)))), rep(100, lit(1))))
  6414  	verifyGCBits(t, ArrayOf(4, Tbigptrscalar), join(rep(3, join(rep(100, lit(1)), rep(100, lit(0)))), rep(100, lit(1))))
  6415  
  6416  	verifyGCBitsSlice(t, TypeOf([]Xptr{}), 0, empty)
  6417  	verifyGCBitsSlice(t, SliceOf(Tptr), 0, empty)
  6418  	verifyGCBitsSlice(t, TypeOf([]Xptrscalar{}), 1, lit(1))
  6419  	verifyGCBitsSlice(t, SliceOf(Tptrscalar), 1, lit(1))
  6420  	verifyGCBitsSlice(t, TypeOf([]Xscalar{}), 2, lit(0))
  6421  	verifyGCBitsSlice(t, SliceOf(Tscalar), 2, lit(0))
  6422  	verifyGCBitsSlice(t, TypeOf([]Xscalar{}), 10000, lit(0))
  6423  	verifyGCBitsSlice(t, SliceOf(Tscalar), 10000, lit(0))
  6424  	verifyGCBitsSlice(t, TypeOf([]Xptr{}), 2, lit(1))
  6425  	verifyGCBitsSlice(t, SliceOf(Tptr), 2, lit(1))
  6426  	verifyGCBitsSlice(t, TypeOf([]Xptr{}), 10000, lit(1))
  6427  	verifyGCBitsSlice(t, SliceOf(Tptr), 10000, lit(1))
  6428  	verifyGCBitsSlice(t, TypeOf([]Xscalarptr{}), 2, lit(0, 1))
  6429  	verifyGCBitsSlice(t, SliceOf(Tscalarptr), 2, lit(0, 1))
  6430  	verifyGCBitsSlice(t, TypeOf([]Xscalarptr{}), 10000, lit(0, 1))
  6431  	verifyGCBitsSlice(t, SliceOf(Tscalarptr), 10000, lit(0, 1))
  6432  	verifyGCBitsSlice(t, TypeOf([]Xptrscalar{}), 2, lit(1, 0))
  6433  	verifyGCBitsSlice(t, SliceOf(Tptrscalar), 2, lit(1, 0))
  6434  	verifyGCBitsSlice(t, TypeOf([]Xptrscalar{}), 10000, lit(1, 0))
  6435  	verifyGCBitsSlice(t, SliceOf(Tptrscalar), 10000, lit(1, 0))
  6436  	verifyGCBitsSlice(t, TypeOf([][10000]Xptrscalar{}), 1, rep(10000, lit(1, 0)))
  6437  	verifyGCBitsSlice(t, SliceOf(ArrayOf(10000, Tptrscalar)), 1, rep(10000, lit(1, 0)))
  6438  	verifyGCBitsSlice(t, TypeOf([][10000]Xptrscalar{}), 2, rep(10000, lit(1, 0)))
  6439  	verifyGCBitsSlice(t, SliceOf(ArrayOf(10000, Tptrscalar)), 2, rep(10000, lit(1, 0)))
  6440  	verifyGCBitsSlice(t, TypeOf([]Xbigptrscalar{}), 4, join(rep(100, lit(1)), rep(100, lit(0))))
  6441  	verifyGCBitsSlice(t, SliceOf(Tbigptrscalar), 4, join(rep(100, lit(1)), rep(100, lit(0))))
  6442  
  6443  	verifyGCBits(t, TypeOf((chan [100]Xscalar)(nil)), lit(1))
  6444  	verifyGCBits(t, ChanOf(BothDir, ArrayOf(100, Tscalar)), lit(1))
  6445  
  6446  	verifyGCBits(t, TypeOf((func([10000]Xscalarptr))(nil)), lit(1))
  6447  	verifyGCBits(t, FuncOf([]Type{ArrayOf(10000, Tscalarptr)}, nil, false), lit(1))
  6448  
  6449  	verifyGCBits(t, TypeOf((map[[10000]Xscalarptr]Xscalar)(nil)), lit(1))
  6450  	verifyGCBits(t, MapOf(ArrayOf(10000, Tscalarptr), Tscalar), lit(1))
  6451  
  6452  	verifyGCBits(t, TypeOf((*[10000]Xscalar)(nil)), lit(1))
  6453  	verifyGCBits(t, PtrTo(ArrayOf(10000, Tscalar)), lit(1))
  6454  
  6455  	verifyGCBits(t, TypeOf(([][10000]Xscalar)(nil)), lit(1))
  6456  	verifyGCBits(t, SliceOf(ArrayOf(10000, Tscalar)), lit(1))
  6457  
  6458  	hdr := make([]byte, 8/PtrSize)
  6459  
  6460  	verifyMapBucket := func(t *testing.T, k, e Type, m interface{}, want []byte) {
  6461  		verifyGCBits(t, MapBucketOf(k, e), want)
  6462  		verifyGCBits(t, CachedBucketOf(TypeOf(m)), want)
  6463  	}
  6464  	verifyMapBucket(t,
  6465  		Tscalar, Tptr,
  6466  		map[Xscalar]Xptr(nil),
  6467  		join(hdr, rep(8, lit(0)), rep(8, lit(1)), lit(1)))
  6468  	verifyMapBucket(t,
  6469  		Tscalarptr, Tptr,
  6470  		map[Xscalarptr]Xptr(nil),
  6471  		join(hdr, rep(8, lit(0, 1)), rep(8, lit(1)), lit(1)))
  6472  	verifyMapBucket(t, Tint64, Tptr,
  6473  		map[int64]Xptr(nil),
  6474  		join(hdr, rep(8, rep(8/PtrSize, lit(0))), rep(8, lit(1)), lit(1)))
  6475  	verifyMapBucket(t,
  6476  		Tscalar, Tscalar,
  6477  		map[Xscalar]Xscalar(nil),
  6478  		empty)
  6479  	verifyMapBucket(t,
  6480  		ArrayOf(2, Tscalarptr), ArrayOf(3, Tptrscalar),
  6481  		map[[2]Xscalarptr][3]Xptrscalar(nil),
  6482  		join(hdr, rep(8*2, lit(0, 1)), rep(8*3, lit(1, 0)), lit(1)))
  6483  	verifyMapBucket(t,
  6484  		ArrayOf(64/PtrSize, Tscalarptr), ArrayOf(64/PtrSize, Tptrscalar),
  6485  		map[[64 / PtrSize]Xscalarptr][64 / PtrSize]Xptrscalar(nil),
  6486  		join(hdr, rep(8*64/PtrSize, lit(0, 1)), rep(8*64/PtrSize, lit(1, 0)), lit(1)))
  6487  	verifyMapBucket(t,
  6488  		ArrayOf(64/PtrSize+1, Tscalarptr), ArrayOf(64/PtrSize, Tptrscalar),
  6489  		map[[64/PtrSize + 1]Xscalarptr][64 / PtrSize]Xptrscalar(nil),
  6490  		join(hdr, rep(8, lit(1)), rep(8*64/PtrSize, lit(1, 0)), lit(1)))
  6491  	verifyMapBucket(t,
  6492  		ArrayOf(64/PtrSize, Tscalarptr), ArrayOf(64/PtrSize+1, Tptrscalar),
  6493  		map[[64 / PtrSize]Xscalarptr][64/PtrSize + 1]Xptrscalar(nil),
  6494  		join(hdr, rep(8*64/PtrSize, lit(0, 1)), rep(8, lit(1)), lit(1)))
  6495  	verifyMapBucket(t,
  6496  		ArrayOf(64/PtrSize+1, Tscalarptr), ArrayOf(64/PtrSize+1, Tptrscalar),
  6497  		map[[64/PtrSize + 1]Xscalarptr][64/PtrSize + 1]Xptrscalar(nil),
  6498  		join(hdr, rep(8, lit(1)), rep(8, lit(1)), lit(1)))
  6499  }
  6500  
  6501  func rep(n int, b []byte) []byte { return bytes.Repeat(b, n) }
  6502  func join(b ...[]byte) []byte    { return bytes.Join(b, nil) }
  6503  func lit(x ...byte) []byte       { return x }
  6504  
  6505  func TestTypeOfTypeOf(t *testing.T) {
  6506  	// Check that all the type constructors return concrete *rtype implementations.
  6507  	// It's difficult to test directly because the reflect package is only at arm's length.
  6508  	// The easiest thing to do is just call a function that crashes if it doesn't get an *rtype.
  6509  	check := func(name string, typ Type) {
  6510  		if underlying := TypeOf(typ).String(); underlying != "*reflect.rtype" {
  6511  			t.Errorf("%v returned %v, not *reflect.rtype", name, underlying)
  6512  		}
  6513  	}
  6514  
  6515  	type T struct{ int }
  6516  	check("TypeOf", TypeOf(T{}))
  6517  
  6518  	check("ArrayOf", ArrayOf(10, TypeOf(T{})))
  6519  	check("ChanOf", ChanOf(BothDir, TypeOf(T{})))
  6520  	check("FuncOf", FuncOf([]Type{TypeOf(T{})}, nil, false))
  6521  	check("MapOf", MapOf(TypeOf(T{}), TypeOf(T{})))
  6522  	check("PtrTo", PtrTo(TypeOf(T{})))
  6523  	check("SliceOf", SliceOf(TypeOf(T{})))
  6524  }
  6525  
  6526  type XM struct{ _ bool }
  6527  
  6528  func (*XM) String() string { return "" }
  6529  
  6530  func TestPtrToMethods(t *testing.T) {
  6531  	var y struct{ XM }
  6532  	yp := New(TypeOf(y)).Interface()
  6533  	_, ok := yp.(fmt.Stringer)
  6534  	if !ok {
  6535  		t.Fatal("does not implement Stringer, but should")
  6536  	}
  6537  }
  6538  
  6539  func TestMapAlloc(t *testing.T) {
  6540  	m := ValueOf(make(map[int]int, 10))
  6541  	k := ValueOf(5)
  6542  	v := ValueOf(7)
  6543  	allocs := testing.AllocsPerRun(100, func() {
  6544  		m.SetMapIndex(k, v)
  6545  	})
  6546  	if allocs > 0.5 {
  6547  		t.Errorf("allocs per map assignment: want 0 got %f", allocs)
  6548  	}
  6549  
  6550  	const size = 1000
  6551  	tmp := 0
  6552  	val := ValueOf(&tmp).Elem()
  6553  	allocs = testing.AllocsPerRun(100, func() {
  6554  		mv := MakeMapWithSize(TypeOf(map[int]int{}), size)
  6555  		// Only adding half of the capacity to not trigger re-allocations due too many overloaded buckets.
  6556  		for i := 0; i < size/2; i++ {
  6557  			val.SetInt(int64(i))
  6558  			mv.SetMapIndex(val, val)
  6559  		}
  6560  	})
  6561  	if allocs > 10 {
  6562  		t.Errorf("allocs per map assignment: want at most 10 got %f", allocs)
  6563  	}
  6564  	// Empirical testing shows that with capacity hint single run will trigger 3 allocations and without 91. I set
  6565  	// the threshold to 10, to not make it overly brittle if something changes in the initial allocation of the
  6566  	// map, but to still catch a regression where we keep re-allocating in the hashmap as new entries are added.
  6567  }
  6568  
  6569  func TestChanAlloc(t *testing.T) {
  6570  	// Note: for a chan int, the return Value must be allocated, so we
  6571  	// use a chan *int instead.
  6572  	c := ValueOf(make(chan *int, 1))
  6573  	v := ValueOf(new(int))
  6574  	allocs := testing.AllocsPerRun(100, func() {
  6575  		c.Send(v)
  6576  		_, _ = c.Recv()
  6577  	})
  6578  	if allocs < 0.5 || allocs > 1.5 {
  6579  		t.Errorf("allocs per chan send/recv: want 1 got %f", allocs)
  6580  	}
  6581  	// Note: there is one allocation in reflect.recv which seems to be
  6582  	// a limitation of escape analysis. If that is ever fixed the
  6583  	// allocs < 0.5 condition will trigger and this test should be fixed.
  6584  }
  6585  
  6586  type TheNameOfThisTypeIsExactly255BytesLongSoWhenTheCompilerPrependsTheReflectTestPackageNameAndExtraStarTheLinkerRuntimeAndReflectPackagesWillHaveToCorrectlyDecodeTheSecondLengthByte0123456789_0123456789_0123456789_0123456789_0123456789_012345678 int
  6587  
  6588  type nameTest struct {
  6589  	v    interface{}
  6590  	want string
  6591  }
  6592  
  6593  var nameTests = []nameTest{
  6594  	{(*int32)(nil), "int32"},
  6595  	{(*D1)(nil), "D1"},
  6596  	{(*[]D1)(nil), ""},
  6597  	{(*chan D1)(nil), ""},
  6598  	{(*func() D1)(nil), ""},
  6599  	{(*<-chan D1)(nil), ""},
  6600  	{(*chan<- D1)(nil), ""},
  6601  	{(*interface{})(nil), ""},
  6602  	{(*interface {
  6603  		F()
  6604  	})(nil), ""},
  6605  	{(*TheNameOfThisTypeIsExactly255BytesLongSoWhenTheCompilerPrependsTheReflectTestPackageNameAndExtraStarTheLinkerRuntimeAndReflectPackagesWillHaveToCorrectlyDecodeTheSecondLengthByte0123456789_0123456789_0123456789_0123456789_0123456789_012345678)(nil), "TheNameOfThisTypeIsExactly255BytesLongSoWhenTheCompilerPrependsTheReflectTestPackageNameAndExtraStarTheLinkerRuntimeAndReflectPackagesWillHaveToCorrectlyDecodeTheSecondLengthByte0123456789_0123456789_0123456789_0123456789_0123456789_012345678"},
  6606  }
  6607  
  6608  func TestNames(t *testing.T) {
  6609  	for _, test := range nameTests {
  6610  		typ := TypeOf(test.v).Elem()
  6611  		if got := typ.Name(); got != test.want {
  6612  			t.Errorf("%v Name()=%q, want %q", typ, got, test.want)
  6613  		}
  6614  	}
  6615  }
  6616  
  6617  func TestExported(t *testing.T) {
  6618  	type ΦExported struct{}
  6619  	type φUnexported struct{}
  6620  	type BigP *big
  6621  	type P int
  6622  	type p *P
  6623  	type P2 p
  6624  	type p3 p
  6625  
  6626  	type exportTest struct {
  6627  		v    interface{}
  6628  		want bool
  6629  	}
  6630  	exportTests := []exportTest{
  6631  		{D1{}, true},
  6632  		{(*D1)(nil), true},
  6633  		{big{}, false},
  6634  		{(*big)(nil), false},
  6635  		{(BigP)(nil), true},
  6636  		{(*BigP)(nil), true},
  6637  		{ΦExported{}, true},
  6638  		{φUnexported{}, false},
  6639  		{P(0), true},
  6640  		{(p)(nil), false},
  6641  		{(P2)(nil), true},
  6642  		{(p3)(nil), false},
  6643  	}
  6644  
  6645  	for i, test := range exportTests {
  6646  		typ := TypeOf(test.v)
  6647  		if got := IsExported(typ); got != test.want {
  6648  			t.Errorf("%d: %s exported=%v, want %v", i, typ.Name(), got, test.want)
  6649  		}
  6650  	}
  6651  }
  6652  
  6653  type embed struct {
  6654  	EmbedWithUnexpMeth
  6655  }
  6656  
  6657  func TestNameBytesAreAligned(t *testing.T) {
  6658  	typ := TypeOf(embed{})
  6659  	b := FirstMethodNameBytes(typ)
  6660  	v := uintptr(unsafe.Pointer(b))
  6661  	if v%unsafe.Alignof((*byte)(nil)) != 0 {
  6662  		t.Errorf("reflect.name.bytes pointer is not aligned: %x", v)
  6663  	}
  6664  }
  6665  
  6666  func TestTypeStrings(t *testing.T) {
  6667  	type stringTest struct {
  6668  		typ  Type
  6669  		want string
  6670  	}
  6671  	stringTests := []stringTest{
  6672  		{TypeOf(func(int) {}), "func(int)"},
  6673  		{FuncOf([]Type{TypeOf(int(0))}, nil, false), "func(int)"},
  6674  		{TypeOf(XM{}), "reflect_test.XM"},
  6675  		{TypeOf(new(XM)), "*reflect_test.XM"},
  6676  		{TypeOf(new(XM).String), "func() string"},
  6677  		{TypeOf(new(XM)).Method(0).Type, "func(*reflect_test.XM) string"},
  6678  		{ChanOf(3, TypeOf(XM{})), "chan reflect_test.XM"},
  6679  		{MapOf(TypeOf(int(0)), TypeOf(XM{})), "map[int]reflect_test.XM"},
  6680  		{ArrayOf(3, TypeOf(XM{})), "[3]reflect_test.XM"},
  6681  		{ArrayOf(3, TypeOf(struct{}{})), "[3]struct {}"},
  6682  	}
  6683  
  6684  	for i, test := range stringTests {
  6685  		if got, want := test.typ.String(), test.want; got != want {
  6686  			t.Errorf("type %d String()=%q, want %q", i, got, want)
  6687  		}
  6688  	}
  6689  }
  6690  
  6691  func TestOffsetLock(t *testing.T) {
  6692  	var wg sync.WaitGroup
  6693  	for i := 0; i < 4; i++ {
  6694  		i := i
  6695  		wg.Add(1)
  6696  		go func() {
  6697  			for j := 0; j < 50; j++ {
  6698  				ResolveReflectName(fmt.Sprintf("OffsetLockName:%d:%d", i, j))
  6699  			}
  6700  			wg.Done()
  6701  		}()
  6702  	}
  6703  	wg.Wait()
  6704  }
  6705  
  6706  func BenchmarkNew(b *testing.B) {
  6707  	v := TypeOf(XM{})
  6708  	b.RunParallel(func(pb *testing.PB) {
  6709  		for pb.Next() {
  6710  			New(v)
  6711  		}
  6712  	})
  6713  }
  6714  
  6715  func TestSwapper(t *testing.T) {
  6716  	type I int
  6717  	var a, b, c I
  6718  	type pair struct {
  6719  		x, y int
  6720  	}
  6721  	type pairPtr struct {
  6722  		x, y int
  6723  		p    *I
  6724  	}
  6725  	type S string
  6726  
  6727  	tests := []struct {
  6728  		in   interface{}
  6729  		i, j int
  6730  		want interface{}
  6731  	}{
  6732  		{
  6733  			in:   []int{1, 20, 300},
  6734  			i:    0,
  6735  			j:    2,
  6736  			want: []int{300, 20, 1},
  6737  		},
  6738  		{
  6739  			in:   []uintptr{1, 20, 300},
  6740  			i:    0,
  6741  			j:    2,
  6742  			want: []uintptr{300, 20, 1},
  6743  		},
  6744  		{
  6745  			in:   []int16{1, 20, 300},
  6746  			i:    0,
  6747  			j:    2,
  6748  			want: []int16{300, 20, 1},
  6749  		},
  6750  		{
  6751  			in:   []int8{1, 20, 100},
  6752  			i:    0,
  6753  			j:    2,
  6754  			want: []int8{100, 20, 1},
  6755  		},
  6756  		{
  6757  			in:   []*I{&a, &b, &c},
  6758  			i:    0,
  6759  			j:    2,
  6760  			want: []*I{&c, &b, &a},
  6761  		},
  6762  		{
  6763  			in:   []string{"eric", "sergey", "larry"},
  6764  			i:    0,
  6765  			j:    2,
  6766  			want: []string{"larry", "sergey", "eric"},
  6767  		},
  6768  		{
  6769  			in:   []S{"eric", "sergey", "larry"},
  6770  			i:    0,
  6771  			j:    2,
  6772  			want: []S{"larry", "sergey", "eric"},
  6773  		},
  6774  		{
  6775  			in:   []pair{{1, 2}, {3, 4}, {5, 6}},
  6776  			i:    0,
  6777  			j:    2,
  6778  			want: []pair{{5, 6}, {3, 4}, {1, 2}},
  6779  		},
  6780  		{
  6781  			in:   []pairPtr{{1, 2, &a}, {3, 4, &b}, {5, 6, &c}},
  6782  			i:    0,
  6783  			j:    2,
  6784  			want: []pairPtr{{5, 6, &c}, {3, 4, &b}, {1, 2, &a}},
  6785  		},
  6786  	}
  6787  
  6788  	for i, tt := range tests {
  6789  		inStr := fmt.Sprint(tt.in)
  6790  		Swapper(tt.in)(tt.i, tt.j)
  6791  		if !DeepEqual(tt.in, tt.want) {
  6792  			t.Errorf("%d. swapping %v and %v of %v = %v; want %v", i, tt.i, tt.j, inStr, tt.in, tt.want)
  6793  		}
  6794  	}
  6795  }
  6796  
  6797  // TestUnaddressableField tests that the reflect package will not allow
  6798  // a type from another package to be used as a named type with an
  6799  // unexported field.
  6800  //
  6801  // This ensures that unexported fields cannot be modified by other packages.
  6802  func TestUnaddressableField(t *testing.T) {
  6803  	var b Buffer // type defined in reflect, a different package
  6804  	var localBuffer struct {
  6805  		buf []byte
  6806  	}
  6807  	lv := ValueOf(&localBuffer).Elem()
  6808  	rv := ValueOf(b)
  6809  	shouldPanic(func() {
  6810  		lv.Set(rv)
  6811  	})
  6812  }
  6813  
  6814  type Tint int
  6815  
  6816  type Tint2 = Tint
  6817  
  6818  type Talias1 struct {
  6819  	byte
  6820  	uint8
  6821  	int
  6822  	int32
  6823  	rune
  6824  }
  6825  
  6826  type Talias2 struct {
  6827  	Tint
  6828  	Tint2
  6829  }
  6830  
  6831  func TestAliasNames(t *testing.T) {
  6832  	t1 := Talias1{byte: 1, uint8: 2, int: 3, int32: 4, rune: 5}
  6833  	out := fmt.Sprintf("%#v", t1)
  6834  	want := "reflect_test.Talias1{byte:0x1, uint8:0x2, int:3, int32:4, rune:5}"
  6835  	if out != want {
  6836  		t.Errorf("Talias1 print:\nhave: %s\nwant: %s", out, want)
  6837  	}
  6838  
  6839  	t2 := Talias2{Tint: 1, Tint2: 2}
  6840  	out = fmt.Sprintf("%#v", t2)
  6841  	want = "reflect_test.Talias2{Tint:1, Tint2:2}"
  6842  	if out != want {
  6843  		t.Errorf("Talias2 print:\nhave: %s\nwant: %s", out, want)
  6844  	}
  6845  }
  6846  
  6847  func TestIssue22031(t *testing.T) {
  6848  	type s []struct{ C int }
  6849  
  6850  	type t1 struct{ s }
  6851  	type t2 struct{ f s }
  6852  
  6853  	tests := []Value{
  6854  		ValueOf(t1{s{{}}}).Field(0).Index(0).Field(0),
  6855  		ValueOf(t2{s{{}}}).Field(0).Index(0).Field(0),
  6856  	}
  6857  
  6858  	for i, test := range tests {
  6859  		if test.CanSet() {
  6860  			t.Errorf("%d: CanSet: got true, want false", i)
  6861  		}
  6862  	}
  6863  }
  6864  
  6865  type NonExportedFirst int
  6866  
  6867  func (i NonExportedFirst) ΦExported()       {}
  6868  func (i NonExportedFirst) nonexported() int { panic("wrong") }
  6869  
  6870  func TestIssue22073(t *testing.T) {
  6871  	m := ValueOf(NonExportedFirst(0)).Method(0)
  6872  
  6873  	if got := m.Type().NumOut(); got != 0 {
  6874  		t.Errorf("NumOut: got %v, want 0", got)
  6875  	}
  6876  
  6877  	// Shouldn't panic.
  6878  	m.Call(nil)
  6879  }
  6880  
  6881  func TestMapIterNonEmptyMap(t *testing.T) {
  6882  	m := map[string]int{"one": 1, "two": 2, "three": 3}
  6883  	iter := ValueOf(m).MapRange()
  6884  	if got, want := iterateToString(iter), `[one: 1, three: 3, two: 2]`; got != want {
  6885  		t.Errorf("iterator returned %s (after sorting), want %s", got, want)
  6886  	}
  6887  }
  6888  
  6889  func TestMapIterNilMap(t *testing.T) {
  6890  	var m map[string]int
  6891  	iter := ValueOf(m).MapRange()
  6892  	if got, want := iterateToString(iter), `[]`; got != want {
  6893  		t.Errorf("non-empty result iteratoring nil map: %s", got)
  6894  	}
  6895  }
  6896  
  6897  func TestMapIterSafety(t *testing.T) {
  6898  	// Using a zero MapIter causes a panic, but not a crash.
  6899  	func() {
  6900  		defer func() { recover() }()
  6901  		new(MapIter).Key()
  6902  		t.Fatal("Key did not panic")
  6903  	}()
  6904  	func() {
  6905  		defer func() { recover() }()
  6906  		new(MapIter).Value()
  6907  		t.Fatal("Value did not panic")
  6908  	}()
  6909  	func() {
  6910  		defer func() { recover() }()
  6911  		new(MapIter).Next()
  6912  		t.Fatal("Next did not panic")
  6913  	}()
  6914  
  6915  	// Calling Key/Value on a MapIter before Next
  6916  	// causes a panic, but not a crash.
  6917  	var m map[string]int
  6918  	iter := ValueOf(m).MapRange()
  6919  
  6920  	func() {
  6921  		defer func() { recover() }()
  6922  		iter.Key()
  6923  		t.Fatal("Key did not panic")
  6924  	}()
  6925  	func() {
  6926  		defer func() { recover() }()
  6927  		iter.Value()
  6928  		t.Fatal("Value did not panic")
  6929  	}()
  6930  
  6931  	// Calling Next, Key, or Value on an exhausted iterator
  6932  	// causes a panic, but not a crash.
  6933  	iter.Next() // -> false
  6934  	func() {
  6935  		defer func() { recover() }()
  6936  		iter.Key()
  6937  		t.Fatal("Key did not panic")
  6938  	}()
  6939  	func() {
  6940  		defer func() { recover() }()
  6941  		iter.Value()
  6942  		t.Fatal("Value did not panic")
  6943  	}()
  6944  	func() {
  6945  		defer func() { recover() }()
  6946  		iter.Next()
  6947  		t.Fatal("Next did not panic")
  6948  	}()
  6949  }
  6950  
  6951  func TestMapIterNext(t *testing.T) {
  6952  	// The first call to Next should reflect any
  6953  	// insertions to the map since the iterator was created.
  6954  	m := map[string]int{}
  6955  	iter := ValueOf(m).MapRange()
  6956  	m["one"] = 1
  6957  	if got, want := iterateToString(iter), `[one: 1]`; got != want {
  6958  		t.Errorf("iterator returned deleted elements: got %s, want %s", got, want)
  6959  	}
  6960  }
  6961  
  6962  func TestMapIterDelete0(t *testing.T) {
  6963  	// Delete all elements before first iteration.
  6964  	m := map[string]int{"one": 1, "two": 2, "three": 3}
  6965  	iter := ValueOf(m).MapRange()
  6966  	delete(m, "one")
  6967  	delete(m, "two")
  6968  	delete(m, "three")
  6969  	if got, want := iterateToString(iter), `[]`; got != want {
  6970  		t.Errorf("iterator returned deleted elements: got %s, want %s", got, want)
  6971  	}
  6972  }
  6973  
  6974  func TestMapIterDelete1(t *testing.T) {
  6975  	// Delete all elements after first iteration.
  6976  	m := map[string]int{"one": 1, "two": 2, "three": 3}
  6977  	iter := ValueOf(m).MapRange()
  6978  	var got []string
  6979  	for iter.Next() {
  6980  		got = append(got, fmt.Sprint(iter.Key(), iter.Value()))
  6981  		delete(m, "one")
  6982  		delete(m, "two")
  6983  		delete(m, "three")
  6984  	}
  6985  	if len(got) != 1 {
  6986  		t.Errorf("iterator returned wrong number of elements: got %d, want 1", len(got))
  6987  	}
  6988  }
  6989  
  6990  // iterateToString returns the set of elements
  6991  // returned by an iterator in readable form.
  6992  func iterateToString(it *MapIter) string {
  6993  	var got []string
  6994  	for it.Next() {
  6995  		line := fmt.Sprintf("%v: %v", it.Key(), it.Value())
  6996  		got = append(got, line)
  6997  	}
  6998  	sort.Strings(got)
  6999  	return "[" + strings.Join(got, ", ") + "]"
  7000  }
  7001  

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