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Source file src/go/types/api_test.go

Documentation: go/types

     1  // Copyright 2013 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 types_test
     6  
     7  import (
     8  	"bytes"
     9  	"fmt"
    10  	"go/ast"
    11  	"go/importer"
    12  	"go/parser"
    13  	"go/token"
    14  	"internal/testenv"
    15  	"reflect"
    16  	"regexp"
    17  	"strings"
    18  	"testing"
    19  
    20  	. "go/types"
    21  )
    22  
    23  func pkgFor(path, source string, info *Info) (*Package, error) {
    24  	fset := token.NewFileSet()
    25  	f, err := parser.ParseFile(fset, path, source, 0)
    26  	if err != nil {
    27  		return nil, err
    28  	}
    29  
    30  	conf := Config{Importer: importer.Default()}
    31  	return conf.Check(f.Name.Name, fset, []*ast.File{f}, info)
    32  }
    33  
    34  func mustTypecheck(t *testing.T, path, source string, info *Info) string {
    35  	pkg, err := pkgFor(path, source, info)
    36  	if err != nil {
    37  		name := path
    38  		if pkg != nil {
    39  			name = "package " + pkg.Name()
    40  		}
    41  		t.Fatalf("%s: didn't type-check (%s)", name, err)
    42  	}
    43  	return pkg.Name()
    44  }
    45  
    46  func TestValuesInfo(t *testing.T) {
    47  	var tests = []struct {
    48  		src  string
    49  		expr string // constant expression
    50  		typ  string // constant type
    51  		val  string // constant value
    52  	}{
    53  		{`package a0; const _ = false`, `false`, `untyped bool`, `false`},
    54  		{`package a1; const _ = 0`, `0`, `untyped int`, `0`},
    55  		{`package a2; const _ = 'A'`, `'A'`, `untyped rune`, `65`},
    56  		{`package a3; const _ = 0.`, `0.`, `untyped float`, `0`},
    57  		{`package a4; const _ = 0i`, `0i`, `untyped complex`, `(0 + 0i)`},
    58  		{`package a5; const _ = "foo"`, `"foo"`, `untyped string`, `"foo"`},
    59  
    60  		{`package b0; var _ = false`, `false`, `bool`, `false`},
    61  		{`package b1; var _ = 0`, `0`, `int`, `0`},
    62  		{`package b2; var _ = 'A'`, `'A'`, `rune`, `65`},
    63  		{`package b3; var _ = 0.`, `0.`, `float64`, `0`},
    64  		{`package b4; var _ = 0i`, `0i`, `complex128`, `(0 + 0i)`},
    65  		{`package b5; var _ = "foo"`, `"foo"`, `string`, `"foo"`},
    66  
    67  		{`package c0a; var _ = bool(false)`, `false`, `bool`, `false`},
    68  		{`package c0b; var _ = bool(false)`, `bool(false)`, `bool`, `false`},
    69  		{`package c0c; type T bool; var _ = T(false)`, `T(false)`, `c0c.T`, `false`},
    70  
    71  		{`package c1a; var _ = int(0)`, `0`, `int`, `0`},
    72  		{`package c1b; var _ = int(0)`, `int(0)`, `int`, `0`},
    73  		{`package c1c; type T int; var _ = T(0)`, `T(0)`, `c1c.T`, `0`},
    74  
    75  		{`package c2a; var _ = rune('A')`, `'A'`, `rune`, `65`},
    76  		{`package c2b; var _ = rune('A')`, `rune('A')`, `rune`, `65`},
    77  		{`package c2c; type T rune; var _ = T('A')`, `T('A')`, `c2c.T`, `65`},
    78  
    79  		{`package c3a; var _ = float32(0.)`, `0.`, `float32`, `0`},
    80  		{`package c3b; var _ = float32(0.)`, `float32(0.)`, `float32`, `0`},
    81  		{`package c3c; type T float32; var _ = T(0.)`, `T(0.)`, `c3c.T`, `0`},
    82  
    83  		{`package c4a; var _ = complex64(0i)`, `0i`, `complex64`, `(0 + 0i)`},
    84  		{`package c4b; var _ = complex64(0i)`, `complex64(0i)`, `complex64`, `(0 + 0i)`},
    85  		{`package c4c; type T complex64; var _ = T(0i)`, `T(0i)`, `c4c.T`, `(0 + 0i)`},
    86  
    87  		{`package c5a; var _ = string("foo")`, `"foo"`, `string`, `"foo"`},
    88  		{`package c5b; var _ = string("foo")`, `string("foo")`, `string`, `"foo"`},
    89  		{`package c5c; type T string; var _ = T("foo")`, `T("foo")`, `c5c.T`, `"foo"`},
    90  		{`package c5d; var _ = string(65)`, `65`, `untyped int`, `65`},
    91  		{`package c5e; var _ = string('A')`, `'A'`, `untyped rune`, `65`},
    92  		{`package c5f; type T string; var _ = T('A')`, `'A'`, `untyped rune`, `65`},
    93  		{`package c5g; var s uint; var _ = string(1 << s)`, `1 << s`, `untyped int`, ``},
    94  
    95  		{`package d0; var _ = []byte("foo")`, `"foo"`, `string`, `"foo"`},
    96  		{`package d1; var _ = []byte(string("foo"))`, `"foo"`, `string`, `"foo"`},
    97  		{`package d2; var _ = []byte(string("foo"))`, `string("foo")`, `string`, `"foo"`},
    98  		{`package d3; type T []byte; var _ = T("foo")`, `"foo"`, `string`, `"foo"`},
    99  
   100  		{`package e0; const _ = float32( 1e-200)`, `float32(1e-200)`, `float32`, `0`},
   101  		{`package e1; const _ = float32(-1e-200)`, `float32(-1e-200)`, `float32`, `0`},
   102  		{`package e2; const _ = float64( 1e-2000)`, `float64(1e-2000)`, `float64`, `0`},
   103  		{`package e3; const _ = float64(-1e-2000)`, `float64(-1e-2000)`, `float64`, `0`},
   104  		{`package e4; const _ = complex64( 1e-200)`, `complex64(1e-200)`, `complex64`, `(0 + 0i)`},
   105  		{`package e5; const _ = complex64(-1e-200)`, `complex64(-1e-200)`, `complex64`, `(0 + 0i)`},
   106  		{`package e6; const _ = complex128( 1e-2000)`, `complex128(1e-2000)`, `complex128`, `(0 + 0i)`},
   107  		{`package e7; const _ = complex128(-1e-2000)`, `complex128(-1e-2000)`, `complex128`, `(0 + 0i)`},
   108  
   109  		{`package f0 ; var _ float32 =  1e-200`, `1e-200`, `float32`, `0`},
   110  		{`package f1 ; var _ float32 = -1e-200`, `-1e-200`, `float32`, `0`},
   111  		{`package f2a; var _ float64 =  1e-2000`, `1e-2000`, `float64`, `0`},
   112  		{`package f3a; var _ float64 = -1e-2000`, `-1e-2000`, `float64`, `0`},
   113  		{`package f2b; var _         =  1e-2000`, `1e-2000`, `float64`, `0`},
   114  		{`package f3b; var _         = -1e-2000`, `-1e-2000`, `float64`, `0`},
   115  		{`package f4 ; var _ complex64  =  1e-200 `, `1e-200`, `complex64`, `(0 + 0i)`},
   116  		{`package f5 ; var _ complex64  = -1e-200 `, `-1e-200`, `complex64`, `(0 + 0i)`},
   117  		{`package f6a; var _ complex128 =  1e-2000i`, `1e-2000i`, `complex128`, `(0 + 0i)`},
   118  		{`package f7a; var _ complex128 = -1e-2000i`, `-1e-2000i`, `complex128`, `(0 + 0i)`},
   119  		{`package f6b; var _            =  1e-2000i`, `1e-2000i`, `complex128`, `(0 + 0i)`},
   120  		{`package f7b; var _            = -1e-2000i`, `-1e-2000i`, `complex128`, `(0 + 0i)`},
   121  
   122  		{`package g0; const (a = len([iota]int{}); b; c); const _ = c`, `c`, `int`, `2`}, // issue #22341
   123  	}
   124  
   125  	for _, test := range tests {
   126  		info := Info{
   127  			Types: make(map[ast.Expr]TypeAndValue),
   128  		}
   129  		name := mustTypecheck(t, "ValuesInfo", test.src, &info)
   130  
   131  		// look for expression
   132  		var expr ast.Expr
   133  		for e := range info.Types {
   134  			if ExprString(e) == test.expr {
   135  				expr = e
   136  				break
   137  			}
   138  		}
   139  		if expr == nil {
   140  			t.Errorf("package %s: no expression found for %s", name, test.expr)
   141  			continue
   142  		}
   143  		tv := info.Types[expr]
   144  
   145  		// check that type is correct
   146  		if got := tv.Type.String(); got != test.typ {
   147  			t.Errorf("package %s: got type %s; want %s", name, got, test.typ)
   148  			continue
   149  		}
   150  
   151  		// if we have a constant, check that value is correct
   152  		if tv.Value != nil {
   153  			if got := tv.Value.ExactString(); got != test.val {
   154  				t.Errorf("package %s: got value %s; want %s", name, got, test.val)
   155  			}
   156  		} else {
   157  			if test.val != "" {
   158  				t.Errorf("package %s: no constant found; want %s", name, test.val)
   159  			}
   160  		}
   161  	}
   162  }
   163  
   164  func TestTypesInfo(t *testing.T) {
   165  	var tests = []struct {
   166  		src  string
   167  		expr string // expression
   168  		typ  string // value type
   169  	}{
   170  		// single-valued expressions of untyped constants
   171  		{`package b0; var x interface{} = false`, `false`, `bool`},
   172  		{`package b1; var x interface{} = 0`, `0`, `int`},
   173  		{`package b2; var x interface{} = 0.`, `0.`, `float64`},
   174  		{`package b3; var x interface{} = 0i`, `0i`, `complex128`},
   175  		{`package b4; var x interface{} = "foo"`, `"foo"`, `string`},
   176  
   177  		// comma-ok expressions
   178  		{`package p0; var x interface{}; var _, _ = x.(int)`,
   179  			`x.(int)`,
   180  			`(int, bool)`,
   181  		},
   182  		{`package p1; var x interface{}; func _() { _, _ = x.(int) }`,
   183  			`x.(int)`,
   184  			`(int, bool)`,
   185  		},
   186  		{`package p2a; type mybool bool; var m map[string]complex128; var b mybool; func _() { _, b = m["foo"] }`,
   187  			`m["foo"]`,
   188  			`(complex128, p2a.mybool)`,
   189  		},
   190  		{`package p2b; var m map[string]complex128; var b bool; func _() { _, b = m["foo"] }`,
   191  			`m["foo"]`,
   192  			`(complex128, bool)`,
   193  		},
   194  		{`package p3; var c chan string; var _, _ = <-c`,
   195  			`<-c`,
   196  			`(string, bool)`,
   197  		},
   198  
   199  		// issue 6796
   200  		{`package issue6796_a; var x interface{}; var _, _ = (x.(int))`,
   201  			`x.(int)`,
   202  			`(int, bool)`,
   203  		},
   204  		{`package issue6796_b; var c chan string; var _, _ = (<-c)`,
   205  			`(<-c)`,
   206  			`(string, bool)`,
   207  		},
   208  		{`package issue6796_c; var c chan string; var _, _ = (<-c)`,
   209  			`<-c`,
   210  			`(string, bool)`,
   211  		},
   212  		{`package issue6796_d; var c chan string; var _, _ = ((<-c))`,
   213  			`(<-c)`,
   214  			`(string, bool)`,
   215  		},
   216  		{`package issue6796_e; func f(c chan string) { _, _ = ((<-c)) }`,
   217  			`(<-c)`,
   218  			`(string, bool)`,
   219  		},
   220  
   221  		// issue 7060
   222  		{`package issue7060_a; var ( m map[int]string; x, ok = m[0] )`,
   223  			`m[0]`,
   224  			`(string, bool)`,
   225  		},
   226  		{`package issue7060_b; var ( m map[int]string; x, ok interface{} = m[0] )`,
   227  			`m[0]`,
   228  			`(string, bool)`,
   229  		},
   230  		{`package issue7060_c; func f(x interface{}, ok bool, m map[int]string) { x, ok = m[0] }`,
   231  			`m[0]`,
   232  			`(string, bool)`,
   233  		},
   234  		{`package issue7060_d; var ( ch chan string; x, ok = <-ch )`,
   235  			`<-ch`,
   236  			`(string, bool)`,
   237  		},
   238  		{`package issue7060_e; var ( ch chan string; x, ok interface{} = <-ch )`,
   239  			`<-ch`,
   240  			`(string, bool)`,
   241  		},
   242  		{`package issue7060_f; func f(x interface{}, ok bool, ch chan string) { x, ok = <-ch }`,
   243  			`<-ch`,
   244  			`(string, bool)`,
   245  		},
   246  	}
   247  
   248  	for _, test := range tests {
   249  		info := Info{Types: make(map[ast.Expr]TypeAndValue)}
   250  		name := mustTypecheck(t, "TypesInfo", test.src, &info)
   251  
   252  		// look for expression type
   253  		var typ Type
   254  		for e, tv := range info.Types {
   255  			if ExprString(e) == test.expr {
   256  				typ = tv.Type
   257  				break
   258  			}
   259  		}
   260  		if typ == nil {
   261  			t.Errorf("package %s: no type found for %s", name, test.expr)
   262  			continue
   263  		}
   264  
   265  		// check that type is correct
   266  		if got := typ.String(); got != test.typ {
   267  			t.Errorf("package %s: got %s; want %s", name, got, test.typ)
   268  		}
   269  	}
   270  }
   271  
   272  func TestImplicitsInfo(t *testing.T) {
   273  	testenv.MustHaveGoBuild(t)
   274  
   275  	var tests = []struct {
   276  		src  string
   277  		want string
   278  	}{
   279  		{`package p2; import . "fmt"; var _ = Println`, ""},           // no Implicits entry
   280  		{`package p0; import local "fmt"; var _ = local.Println`, ""}, // no Implicits entry
   281  		{`package p1; import "fmt"; var _ = fmt.Println`, "importSpec: package fmt"},
   282  
   283  		{`package p3; func f(x interface{}) { switch x.(type) { case int: } }`, ""}, // no Implicits entry
   284  		{`package p4; func f(x interface{}) { switch t := x.(type) { case int: _ = t } }`, "caseClause: var t int"},
   285  		{`package p5; func f(x interface{}) { switch t := x.(type) { case int, uint: _ = t } }`, "caseClause: var t interface{}"},
   286  		{`package p6; func f(x interface{}) { switch t := x.(type) { default: _ = t } }`, "caseClause: var t interface{}"},
   287  
   288  		{`package p7; func f(x int) {}`, ""}, // no Implicits entry
   289  		{`package p8; func f(int) {}`, "field: var  int"},
   290  		{`package p9; func f() (complex64) { return 0 }`, "field: var  complex64"},
   291  		{`package p10; type T struct{}; func (*T) f() {}`, "field: var  *p10.T"},
   292  	}
   293  
   294  	for _, test := range tests {
   295  		info := Info{
   296  			Implicits: make(map[ast.Node]Object),
   297  		}
   298  		name := mustTypecheck(t, "ImplicitsInfo", test.src, &info)
   299  
   300  		// the test cases expect at most one Implicits entry
   301  		if len(info.Implicits) > 1 {
   302  			t.Errorf("package %s: %d Implicits entries found", name, len(info.Implicits))
   303  			continue
   304  		}
   305  
   306  		// extract Implicits entry, if any
   307  		var got string
   308  		for n, obj := range info.Implicits {
   309  			switch x := n.(type) {
   310  			case *ast.ImportSpec:
   311  				got = "importSpec"
   312  			case *ast.CaseClause:
   313  				got = "caseClause"
   314  			case *ast.Field:
   315  				got = "field"
   316  			default:
   317  				t.Fatalf("package %s: unexpected %T", name, x)
   318  			}
   319  			got += ": " + obj.String()
   320  		}
   321  
   322  		// verify entry
   323  		if got != test.want {
   324  			t.Errorf("package %s: got %q; want %q", name, got, test.want)
   325  		}
   326  	}
   327  }
   328  
   329  func predString(tv TypeAndValue) string {
   330  	var buf bytes.Buffer
   331  	pred := func(b bool, s string) {
   332  		if b {
   333  			if buf.Len() > 0 {
   334  				buf.WriteString(", ")
   335  			}
   336  			buf.WriteString(s)
   337  		}
   338  	}
   339  
   340  	pred(tv.IsVoid(), "void")
   341  	pred(tv.IsType(), "type")
   342  	pred(tv.IsBuiltin(), "builtin")
   343  	pred(tv.IsValue() && tv.Value != nil, "const")
   344  	pred(tv.IsValue() && tv.Value == nil, "value")
   345  	pred(tv.IsNil(), "nil")
   346  	pred(tv.Addressable(), "addressable")
   347  	pred(tv.Assignable(), "assignable")
   348  	pred(tv.HasOk(), "hasOk")
   349  
   350  	if buf.Len() == 0 {
   351  		return "invalid"
   352  	}
   353  	return buf.String()
   354  }
   355  
   356  func TestPredicatesInfo(t *testing.T) {
   357  	testenv.MustHaveGoBuild(t)
   358  
   359  	var tests = []struct {
   360  		src  string
   361  		expr string
   362  		pred string
   363  	}{
   364  		// void
   365  		{`package n0; func f() { f() }`, `f()`, `void`},
   366  
   367  		// types
   368  		{`package t0; type _ int`, `int`, `type`},
   369  		{`package t1; type _ []int`, `[]int`, `type`},
   370  		{`package t2; type _ func()`, `func()`, `type`},
   371  
   372  		// built-ins
   373  		{`package b0; var _ = len("")`, `len`, `builtin`},
   374  		{`package b1; var _ = (len)("")`, `(len)`, `builtin`},
   375  
   376  		// constants
   377  		{`package c0; var _ = 42`, `42`, `const`},
   378  		{`package c1; var _ = "foo" + "bar"`, `"foo" + "bar"`, `const`},
   379  		{`package c2; const (i = 1i; _ = i)`, `i`, `const`},
   380  
   381  		// values
   382  		{`package v0; var (a, b int; _ = a + b)`, `a + b`, `value`},
   383  		{`package v1; var _ = &[]int{1}`, `([]int literal)`, `value`},
   384  		{`package v2; var _ = func(){}`, `(func() literal)`, `value`},
   385  		{`package v4; func f() { _ = f }`, `f`, `value`},
   386  		{`package v3; var _ *int = nil`, `nil`, `value, nil`},
   387  		{`package v3; var _ *int = (nil)`, `(nil)`, `value, nil`},
   388  
   389  		// addressable (and thus assignable) operands
   390  		{`package a0; var (x int; _ = x)`, `x`, `value, addressable, assignable`},
   391  		{`package a1; var (p *int; _ = *p)`, `*p`, `value, addressable, assignable`},
   392  		{`package a2; var (s []int; _ = s[0])`, `s[0]`, `value, addressable, assignable`},
   393  		{`package a3; var (s struct{f int}; _ = s.f)`, `s.f`, `value, addressable, assignable`},
   394  		{`package a4; var (a [10]int; _ = a[0])`, `a[0]`, `value, addressable, assignable`},
   395  		{`package a5; func _(x int) { _ = x }`, `x`, `value, addressable, assignable`},
   396  		{`package a6; func _()(x int) { _ = x; return }`, `x`, `value, addressable, assignable`},
   397  		{`package a7; type T int; func (x T) _() { _ = x }`, `x`, `value, addressable, assignable`},
   398  		// composite literals are not addressable
   399  
   400  		// assignable but not addressable values
   401  		{`package s0; var (m map[int]int; _ = m[0])`, `m[0]`, `value, assignable, hasOk`},
   402  		{`package s1; var (m map[int]int; _, _ = m[0])`, `m[0]`, `value, assignable, hasOk`},
   403  
   404  		// hasOk expressions
   405  		{`package k0; var (ch chan int; _ = <-ch)`, `<-ch`, `value, hasOk`},
   406  		{`package k1; var (ch chan int; _, _ = <-ch)`, `<-ch`, `value, hasOk`},
   407  
   408  		// missing entries
   409  		// - package names are collected in the Uses map
   410  		// - identifiers being declared are collected in the Defs map
   411  		{`package m0; import "os"; func _() { _ = os.Stdout }`, `os`, `<missing>`},
   412  		{`package m1; import p "os"; func _() { _ = p.Stdout }`, `p`, `<missing>`},
   413  		{`package m2; const c = 0`, `c`, `<missing>`},
   414  		{`package m3; type T int`, `T`, `<missing>`},
   415  		{`package m4; var v int`, `v`, `<missing>`},
   416  		{`package m5; func f() {}`, `f`, `<missing>`},
   417  		{`package m6; func _(x int) {}`, `x`, `<missing>`},
   418  		{`package m6; func _()(x int) { return }`, `x`, `<missing>`},
   419  		{`package m6; type T int; func (x T) _() {}`, `x`, `<missing>`},
   420  	}
   421  
   422  	for _, test := range tests {
   423  		info := Info{Types: make(map[ast.Expr]TypeAndValue)}
   424  		name := mustTypecheck(t, "PredicatesInfo", test.src, &info)
   425  
   426  		// look for expression predicates
   427  		got := "<missing>"
   428  		for e, tv := range info.Types {
   429  			//println(name, ExprString(e))
   430  			if ExprString(e) == test.expr {
   431  				got = predString(tv)
   432  				break
   433  			}
   434  		}
   435  
   436  		if got != test.pred {
   437  			t.Errorf("package %s: got %s; want %s", name, got, test.pred)
   438  		}
   439  	}
   440  }
   441  
   442  func TestScopesInfo(t *testing.T) {
   443  	testenv.MustHaveGoBuild(t)
   444  
   445  	var tests = []struct {
   446  		src    string
   447  		scopes []string // list of scope descriptors of the form kind:varlist
   448  	}{
   449  		{`package p0`, []string{
   450  			"file:",
   451  		}},
   452  		{`package p1; import ( "fmt"; m "math"; _ "os" ); var ( _ = fmt.Println; _ = m.Pi )`, []string{
   453  			"file:fmt m",
   454  		}},
   455  		{`package p2; func _() {}`, []string{
   456  			"file:", "func:",
   457  		}},
   458  		{`package p3; func _(x, y int) {}`, []string{
   459  			"file:", "func:x y",
   460  		}},
   461  		{`package p4; func _(x, y int) { x, z := 1, 2; _ = z }`, []string{
   462  			"file:", "func:x y z", // redeclaration of x
   463  		}},
   464  		{`package p5; func _(x, y int) (u, _ int) { return }`, []string{
   465  			"file:", "func:u x y",
   466  		}},
   467  		{`package p6; func _() { { var x int; _ = x } }`, []string{
   468  			"file:", "func:", "block:x",
   469  		}},
   470  		{`package p7; func _() { if true {} }`, []string{
   471  			"file:", "func:", "if:", "block:",
   472  		}},
   473  		{`package p8; func _() { if x := 0; x < 0 { y := x; _ = y } }`, []string{
   474  			"file:", "func:", "if:x", "block:y",
   475  		}},
   476  		{`package p9; func _() { switch x := 0; x {} }`, []string{
   477  			"file:", "func:", "switch:x",
   478  		}},
   479  		{`package p10; func _() { switch x := 0; x { case 1: y := x; _ = y; default: }}`, []string{
   480  			"file:", "func:", "switch:x", "case:y", "case:",
   481  		}},
   482  		{`package p11; func _(t interface{}) { switch t.(type) {} }`, []string{
   483  			"file:", "func:t", "type switch:",
   484  		}},
   485  		{`package p12; func _(t interface{}) { switch t := t; t.(type) {} }`, []string{
   486  			"file:", "func:t", "type switch:t",
   487  		}},
   488  		{`package p13; func _(t interface{}) { switch x := t.(type) { case int: _ = x } }`, []string{
   489  			"file:", "func:t", "type switch:", "case:x", // x implicitly declared
   490  		}},
   491  		{`package p14; func _() { select{} }`, []string{
   492  			"file:", "func:",
   493  		}},
   494  		{`package p15; func _(c chan int) { select{ case <-c: } }`, []string{
   495  			"file:", "func:c", "comm:",
   496  		}},
   497  		{`package p16; func _(c chan int) { select{ case i := <-c: x := i; _ = x} }`, []string{
   498  			"file:", "func:c", "comm:i x",
   499  		}},
   500  		{`package p17; func _() { for{} }`, []string{
   501  			"file:", "func:", "for:", "block:",
   502  		}},
   503  		{`package p18; func _(n int) { for i := 0; i < n; i++ { _ = i } }`, []string{
   504  			"file:", "func:n", "for:i", "block:",
   505  		}},
   506  		{`package p19; func _(a []int) { for i := range a { _ = i} }`, []string{
   507  			"file:", "func:a", "range:i", "block:",
   508  		}},
   509  		{`package p20; var s int; func _(a []int) { for i, x := range a { s += x; _ = i } }`, []string{
   510  			"file:", "func:a", "range:i x", "block:",
   511  		}},
   512  	}
   513  
   514  	for _, test := range tests {
   515  		info := Info{Scopes: make(map[ast.Node]*Scope)}
   516  		name := mustTypecheck(t, "ScopesInfo", test.src, &info)
   517  
   518  		// number of scopes must match
   519  		if len(info.Scopes) != len(test.scopes) {
   520  			t.Errorf("package %s: got %d scopes; want %d", name, len(info.Scopes), len(test.scopes))
   521  		}
   522  
   523  		// scope descriptions must match
   524  		for node, scope := range info.Scopes {
   525  			kind := "<unknown node kind>"
   526  			switch node.(type) {
   527  			case *ast.File:
   528  				kind = "file"
   529  			case *ast.FuncType:
   530  				kind = "func"
   531  			case *ast.BlockStmt:
   532  				kind = "block"
   533  			case *ast.IfStmt:
   534  				kind = "if"
   535  			case *ast.SwitchStmt:
   536  				kind = "switch"
   537  			case *ast.TypeSwitchStmt:
   538  				kind = "type switch"
   539  			case *ast.CaseClause:
   540  				kind = "case"
   541  			case *ast.CommClause:
   542  				kind = "comm"
   543  			case *ast.ForStmt:
   544  				kind = "for"
   545  			case *ast.RangeStmt:
   546  				kind = "range"
   547  			}
   548  
   549  			// look for matching scope description
   550  			desc := kind + ":" + strings.Join(scope.Names(), " ")
   551  			found := false
   552  			for _, d := range test.scopes {
   553  				if desc == d {
   554  					found = true
   555  					break
   556  				}
   557  			}
   558  			if !found {
   559  				t.Errorf("package %s: no matching scope found for %s", name, desc)
   560  			}
   561  		}
   562  	}
   563  }
   564  
   565  func TestInitOrderInfo(t *testing.T) {
   566  	var tests = []struct {
   567  		src   string
   568  		inits []string
   569  	}{
   570  		{`package p0; var (x = 1; y = x)`, []string{
   571  			"x = 1", "y = x",
   572  		}},
   573  		{`package p1; var (a = 1; b = 2; c = 3)`, []string{
   574  			"a = 1", "b = 2", "c = 3",
   575  		}},
   576  		{`package p2; var (a, b, c = 1, 2, 3)`, []string{
   577  			"a = 1", "b = 2", "c = 3",
   578  		}},
   579  		{`package p3; var _ = f(); func f() int { return 1 }`, []string{
   580  			"_ = f()", // blank var
   581  		}},
   582  		{`package p4; var (a = 0; x = y; y = z; z = 0)`, []string{
   583  			"a = 0", "z = 0", "y = z", "x = y",
   584  		}},
   585  		{`package p5; var (a, _ = m[0]; m map[int]string)`, []string{
   586  			"a, _ = m[0]", // blank var
   587  		}},
   588  		{`package p6; var a, b = f(); func f() (_, _ int) { return z, z }; var z = 0`, []string{
   589  			"z = 0", "a, b = f()",
   590  		}},
   591  		{`package p7; var (a = func() int { return b }(); b = 1)`, []string{
   592  			"b = 1", "a = (func() int literal)()",
   593  		}},
   594  		{`package p8; var (a, b = func() (_, _ int) { return c, c }(); c = 1)`, []string{
   595  			"c = 1", "a, b = (func() (_, _ int) literal)()",
   596  		}},
   597  		{`package p9; type T struct{}; func (T) m() int { _ = y; return 0 }; var x, y = T.m, 1`, []string{
   598  			"y = 1", "x = T.m",
   599  		}},
   600  		{`package p10; var (d = c + b; a = 0; b = 0; c = 0)`, []string{
   601  			"a = 0", "b = 0", "c = 0", "d = c + b",
   602  		}},
   603  		{`package p11; var (a = e + c; b = d + c; c = 0; d = 0; e = 0)`, []string{
   604  			"c = 0", "d = 0", "b = d + c", "e = 0", "a = e + c",
   605  		}},
   606  		// emit an initializer for n:1 initializations only once (not for each node
   607  		// on the lhs which may appear in different order in the dependency graph)
   608  		{`package p12; var (a = x; b = 0; x, y = m[0]; m map[int]int)`, []string{
   609  			"b = 0", "x, y = m[0]", "a = x",
   610  		}},
   611  		// test case from spec section on package initialization
   612  		{`package p12
   613  
   614  		var (
   615  			a = c + b
   616  			b = f()
   617  			c = f()
   618  			d = 3
   619  		)
   620  
   621  		func f() int {
   622  			d++
   623  			return d
   624  		}`, []string{
   625  			"d = 3", "b = f()", "c = f()", "a = c + b",
   626  		}},
   627  		// test case for issue 7131
   628  		{`package main
   629  
   630  		var counter int
   631  		func next() int { counter++; return counter }
   632  
   633  		var _ = makeOrder()
   634  		func makeOrder() []int { return []int{f, b, d, e, c, a} }
   635  
   636  		var a       = next()
   637  		var b, c    = next(), next()
   638  		var d, e, f = next(), next(), next()
   639  		`, []string{
   640  			"a = next()", "b = next()", "c = next()", "d = next()", "e = next()", "f = next()", "_ = makeOrder()",
   641  		}},
   642  		// test case for issue 10709
   643  		{`package p13
   644  
   645  		var (
   646  		    v = t.m()
   647  		    t = makeT(0)
   648  		)
   649  
   650  		type T struct{}
   651  
   652  		func (T) m() int { return 0 }
   653  
   654  		func makeT(n int) T {
   655  		    if n > 0 {
   656  		        return makeT(n-1)
   657  		    }
   658  		    return T{}
   659  		}`, []string{
   660  			"t = makeT(0)", "v = t.m()",
   661  		}},
   662  		// test case for issue 10709: same as test before, but variable decls swapped
   663  		{`package p14
   664  
   665  		var (
   666  		    t = makeT(0)
   667  		    v = t.m()
   668  		)
   669  
   670  		type T struct{}
   671  
   672  		func (T) m() int { return 0 }
   673  
   674  		func makeT(n int) T {
   675  		    if n > 0 {
   676  		        return makeT(n-1)
   677  		    }
   678  		    return T{}
   679  		}`, []string{
   680  			"t = makeT(0)", "v = t.m()",
   681  		}},
   682  		// another candidate possibly causing problems with issue 10709
   683  		{`package p15
   684  
   685  		var y1 = f1()
   686  
   687  		func f1() int { return g1() }
   688  		func g1() int { f1(); return x1 }
   689  
   690  		var x1 = 0
   691  
   692  		var y2 = f2()
   693  
   694  		func f2() int { return g2() }
   695  		func g2() int { return x2 }
   696  
   697  		var x2 = 0`, []string{
   698  			"x1 = 0", "y1 = f1()", "x2 = 0", "y2 = f2()",
   699  		}},
   700  	}
   701  
   702  	for _, test := range tests {
   703  		info := Info{}
   704  		name := mustTypecheck(t, "InitOrderInfo", test.src, &info)
   705  
   706  		// number of initializers must match
   707  		if len(info.InitOrder) != len(test.inits) {
   708  			t.Errorf("package %s: got %d initializers; want %d", name, len(info.InitOrder), len(test.inits))
   709  			continue
   710  		}
   711  
   712  		// initializers must match
   713  		for i, want := range test.inits {
   714  			got := info.InitOrder[i].String()
   715  			if got != want {
   716  				t.Errorf("package %s, init %d: got %s; want %s", name, i, got, want)
   717  				continue
   718  			}
   719  		}
   720  	}
   721  }
   722  
   723  func TestMultiFileInitOrder(t *testing.T) {
   724  	fset := token.NewFileSet()
   725  	mustParse := func(src string) *ast.File {
   726  		f, err := parser.ParseFile(fset, "main", src, 0)
   727  		if err != nil {
   728  			t.Fatal(err)
   729  		}
   730  		return f
   731  	}
   732  
   733  	fileA := mustParse(`package main; var a = 1`)
   734  	fileB := mustParse(`package main; var b = 2`)
   735  
   736  	// The initialization order must not depend on the parse
   737  	// order of the files, only on the presentation order to
   738  	// the type-checker.
   739  	for _, test := range []struct {
   740  		files []*ast.File
   741  		want  string
   742  	}{
   743  		{[]*ast.File{fileA, fileB}, "[a = 1 b = 2]"},
   744  		{[]*ast.File{fileB, fileA}, "[b = 2 a = 1]"},
   745  	} {
   746  		var info Info
   747  		if _, err := new(Config).Check("main", fset, test.files, &info); err != nil {
   748  			t.Fatal(err)
   749  		}
   750  		if got := fmt.Sprint(info.InitOrder); got != test.want {
   751  			t.Fatalf("got %s; want %s", got, test.want)
   752  		}
   753  	}
   754  }
   755  
   756  func TestFiles(t *testing.T) {
   757  	var sources = []string{
   758  		"package p; type T struct{}; func (T) m1() {}",
   759  		"package p; func (T) m2() {}; var x interface{ m1(); m2() } = T{}",
   760  		"package p; func (T) m3() {}; var y interface{ m1(); m2(); m3() } = T{}",
   761  		"package p",
   762  	}
   763  
   764  	var conf Config
   765  	fset := token.NewFileSet()
   766  	pkg := NewPackage("p", "p")
   767  	var info Info
   768  	check := NewChecker(&conf, fset, pkg, &info)
   769  
   770  	for i, src := range sources {
   771  		filename := fmt.Sprintf("sources%d", i)
   772  		f, err := parser.ParseFile(fset, filename, src, 0)
   773  		if err != nil {
   774  			t.Fatal(err)
   775  		}
   776  		if err := check.Files([]*ast.File{f}); err != nil {
   777  			t.Error(err)
   778  		}
   779  	}
   780  
   781  	// check InitOrder is [x y]
   782  	var vars []string
   783  	for _, init := range info.InitOrder {
   784  		for _, v := range init.Lhs {
   785  			vars = append(vars, v.Name())
   786  		}
   787  	}
   788  	if got, want := fmt.Sprint(vars), "[x y]"; got != want {
   789  		t.Errorf("InitOrder == %s, want %s", got, want)
   790  	}
   791  }
   792  
   793  type testImporter map[string]*Package
   794  
   795  func (m testImporter) Import(path string) (*Package, error) {
   796  	if pkg := m[path]; pkg != nil {
   797  		return pkg, nil
   798  	}
   799  	return nil, fmt.Errorf("package %q not found", path)
   800  }
   801  
   802  func TestSelection(t *testing.T) {
   803  	selections := make(map[*ast.SelectorExpr]*Selection)
   804  
   805  	fset := token.NewFileSet()
   806  	imports := make(testImporter)
   807  	conf := Config{Importer: imports}
   808  	makePkg := func(path, src string) {
   809  		f, err := parser.ParseFile(fset, path+".go", src, 0)
   810  		if err != nil {
   811  			t.Fatal(err)
   812  		}
   813  		pkg, err := conf.Check(path, fset, []*ast.File{f}, &Info{Selections: selections})
   814  		if err != nil {
   815  			t.Fatal(err)
   816  		}
   817  		imports[path] = pkg
   818  	}
   819  
   820  	const libSrc = `
   821  package lib
   822  type T float64
   823  const C T = 3
   824  var V T
   825  func F() {}
   826  func (T) M() {}
   827  `
   828  	const mainSrc = `
   829  package main
   830  import "lib"
   831  
   832  type A struct {
   833  	*B
   834  	C
   835  }
   836  
   837  type B struct {
   838  	b int
   839  }
   840  
   841  func (B) f(int)
   842  
   843  type C struct {
   844  	c int
   845  }
   846  
   847  func (C) g()
   848  func (*C) h()
   849  
   850  func main() {
   851  	// qualified identifiers
   852  	var _ lib.T
   853          _ = lib.C
   854          _ = lib.F
   855          _ = lib.V
   856  	_ = lib.T.M
   857  
   858  	// fields
   859  	_ = A{}.B
   860  	_ = new(A).B
   861  
   862  	_ = A{}.C
   863  	_ = new(A).C
   864  
   865  	_ = A{}.b
   866  	_ = new(A).b
   867  
   868  	_ = A{}.c
   869  	_ = new(A).c
   870  
   871  	// methods
   872          _ = A{}.f
   873          _ = new(A).f
   874          _ = A{}.g
   875          _ = new(A).g
   876          _ = new(A).h
   877  
   878          _ = B{}.f
   879          _ = new(B).f
   880  
   881          _ = C{}.g
   882          _ = new(C).g
   883          _ = new(C).h
   884  
   885  	// method expressions
   886          _ = A.f
   887          _ = (*A).f
   888          _ = B.f
   889          _ = (*B).f
   890  }`
   891  
   892  	wantOut := map[string][2]string{
   893  		"lib.T.M": {"method expr (lib.T) M(lib.T)", ".[0]"},
   894  
   895  		"A{}.B":    {"field (main.A) B *main.B", ".[0]"},
   896  		"new(A).B": {"field (*main.A) B *main.B", "->[0]"},
   897  		"A{}.C":    {"field (main.A) C main.C", ".[1]"},
   898  		"new(A).C": {"field (*main.A) C main.C", "->[1]"},
   899  		"A{}.b":    {"field (main.A) b int", "->[0 0]"},
   900  		"new(A).b": {"field (*main.A) b int", "->[0 0]"},
   901  		"A{}.c":    {"field (main.A) c int", ".[1 0]"},
   902  		"new(A).c": {"field (*main.A) c int", "->[1 0]"},
   903  
   904  		"A{}.f":    {"method (main.A) f(int)", "->[0 0]"},
   905  		"new(A).f": {"method (*main.A) f(int)", "->[0 0]"},
   906  		"A{}.g":    {"method (main.A) g()", ".[1 0]"},
   907  		"new(A).g": {"method (*main.A) g()", "->[1 0]"},
   908  		"new(A).h": {"method (*main.A) h()", "->[1 1]"}, // TODO(gri) should this report .[1 1] ?
   909  		"B{}.f":    {"method (main.B) f(int)", ".[0]"},
   910  		"new(B).f": {"method (*main.B) f(int)", "->[0]"},
   911  		"C{}.g":    {"method (main.C) g()", ".[0]"},
   912  		"new(C).g": {"method (*main.C) g()", "->[0]"},
   913  		"new(C).h": {"method (*main.C) h()", "->[1]"}, // TODO(gri) should this report .[1] ?
   914  
   915  		"A.f":    {"method expr (main.A) f(main.A, int)", "->[0 0]"},
   916  		"(*A).f": {"method expr (*main.A) f(*main.A, int)", "->[0 0]"},
   917  		"B.f":    {"method expr (main.B) f(main.B, int)", ".[0]"},
   918  		"(*B).f": {"method expr (*main.B) f(*main.B, int)", "->[0]"},
   919  	}
   920  
   921  	makePkg("lib", libSrc)
   922  	makePkg("main", mainSrc)
   923  
   924  	for e, sel := range selections {
   925  		_ = sel.String() // assertion: must not panic
   926  
   927  		start := fset.Position(e.Pos()).Offset
   928  		end := fset.Position(e.End()).Offset
   929  		syntax := mainSrc[start:end] // (all SelectorExprs are in main, not lib)
   930  
   931  		direct := "."
   932  		if sel.Indirect() {
   933  			direct = "->"
   934  		}
   935  		got := [2]string{
   936  			sel.String(),
   937  			fmt.Sprintf("%s%v", direct, sel.Index()),
   938  		}
   939  		want := wantOut[syntax]
   940  		if want != got {
   941  			t.Errorf("%s: got %q; want %q", syntax, got, want)
   942  		}
   943  		delete(wantOut, syntax)
   944  
   945  		// We must explicitly assert properties of the
   946  		// Signature's receiver since it doesn't participate
   947  		// in Identical() or String().
   948  		sig, _ := sel.Type().(*Signature)
   949  		if sel.Kind() == MethodVal {
   950  			got := sig.Recv().Type()
   951  			want := sel.Recv()
   952  			if !Identical(got, want) {
   953  				t.Errorf("%s: Recv() = %s, want %s", syntax, got, want)
   954  			}
   955  		} else if sig != nil && sig.Recv() != nil {
   956  			t.Errorf("%s: signature has receiver %s", sig, sig.Recv().Type())
   957  		}
   958  	}
   959  	// Assert that all wantOut entries were used exactly once.
   960  	for syntax := range wantOut {
   961  		t.Errorf("no ast.Selection found with syntax %q", syntax)
   962  	}
   963  }
   964  
   965  func TestIssue8518(t *testing.T) {
   966  	fset := token.NewFileSet()
   967  	imports := make(testImporter)
   968  	conf := Config{
   969  		Error:    func(err error) { t.Log(err) }, // don't exit after first error
   970  		Importer: imports,
   971  	}
   972  	makePkg := func(path, src string) {
   973  		f, err := parser.ParseFile(fset, path, src, 0)
   974  		if err != nil {
   975  			t.Fatal(err)
   976  		}
   977  		pkg, _ := conf.Check(path, fset, []*ast.File{f}, nil) // errors logged via conf.Error
   978  		imports[path] = pkg
   979  	}
   980  
   981  	const libSrc = `
   982  package a
   983  import "missing"
   984  const C1 = foo
   985  const C2 = missing.C
   986  `
   987  
   988  	const mainSrc = `
   989  package main
   990  import "a"
   991  var _ = a.C1
   992  var _ = a.C2
   993  `
   994  
   995  	makePkg("a", libSrc)
   996  	makePkg("main", mainSrc) // don't crash when type-checking this package
   997  }
   998  
   999  func TestLookupFieldOrMethod(t *testing.T) {
  1000  	// Test cases assume a lookup of the form a.f or x.f, where a stands for an
  1001  	// addressable value, and x for a non-addressable value (even though a variable
  1002  	// for ease of test case writing).
  1003  	var tests = []struct {
  1004  		src      string
  1005  		found    bool
  1006  		index    []int
  1007  		indirect bool
  1008  	}{
  1009  		// field lookups
  1010  		{"var x T; type T struct{}", false, nil, false},
  1011  		{"var x T; type T struct{ f int }", true, []int{0}, false},
  1012  		{"var x T; type T struct{ a, b, f, c int }", true, []int{2}, false},
  1013  
  1014  		// method lookups
  1015  		{"var a T; type T struct{}; func (T) f() {}", true, []int{0}, false},
  1016  		{"var a *T; type T struct{}; func (T) f() {}", true, []int{0}, true},
  1017  		{"var a T; type T struct{}; func (*T) f() {}", true, []int{0}, false},
  1018  		{"var a *T; type T struct{}; func (*T) f() {}", true, []int{0}, true}, // TODO(gri) should this report indirect = false?
  1019  
  1020  		// collisions
  1021  		{"type ( E1 struct{ f int }; E2 struct{ f int }; x struct{ E1; *E2 })", false, []int{1, 0}, false},
  1022  		{"type ( E1 struct{ f int }; E2 struct{}; x struct{ E1; *E2 }); func (E2) f() {}", false, []int{1, 0}, false},
  1023  
  1024  		// outside methodset
  1025  		// (*T).f method exists, but value of type T is not addressable
  1026  		{"var x T; type T struct{}; func (*T) f() {}", false, nil, true},
  1027  	}
  1028  
  1029  	for _, test := range tests {
  1030  		pkg, err := pkgFor("test", "package p;"+test.src, nil)
  1031  		if err != nil {
  1032  			t.Errorf("%s: incorrect test case: %s", test.src, err)
  1033  			continue
  1034  		}
  1035  
  1036  		obj := pkg.Scope().Lookup("a")
  1037  		if obj == nil {
  1038  			if obj = pkg.Scope().Lookup("x"); obj == nil {
  1039  				t.Errorf("%s: incorrect test case - no object a or x", test.src)
  1040  				continue
  1041  			}
  1042  		}
  1043  
  1044  		f, index, indirect := LookupFieldOrMethod(obj.Type(), obj.Name() == "a", pkg, "f")
  1045  		if (f != nil) != test.found {
  1046  			if f == nil {
  1047  				t.Errorf("%s: got no object; want one", test.src)
  1048  			} else {
  1049  				t.Errorf("%s: got object = %v; want none", test.src, f)
  1050  			}
  1051  		}
  1052  		if !sameSlice(index, test.index) {
  1053  			t.Errorf("%s: got index = %v; want %v", test.src, index, test.index)
  1054  		}
  1055  		if indirect != test.indirect {
  1056  			t.Errorf("%s: got indirect = %v; want %v", test.src, indirect, test.indirect)
  1057  		}
  1058  	}
  1059  }
  1060  
  1061  func sameSlice(a, b []int) bool {
  1062  	if len(a) != len(b) {
  1063  		return false
  1064  	}
  1065  	for i, x := range a {
  1066  		if x != b[i] {
  1067  			return false
  1068  		}
  1069  	}
  1070  	return true
  1071  }
  1072  
  1073  // TestScopeLookupParent ensures that (*Scope).LookupParent returns
  1074  // the correct result at various positions with the source.
  1075  func TestScopeLookupParent(t *testing.T) {
  1076  	fset := token.NewFileSet()
  1077  	imports := make(testImporter)
  1078  	conf := Config{Importer: imports}
  1079  	mustParse := func(src string) *ast.File {
  1080  		f, err := parser.ParseFile(fset, "dummy.go", src, parser.ParseComments)
  1081  		if err != nil {
  1082  			t.Fatal(err)
  1083  		}
  1084  		return f
  1085  	}
  1086  	var info Info
  1087  	makePkg := func(path string, files ...*ast.File) {
  1088  		var err error
  1089  		imports[path], err = conf.Check(path, fset, files, &info)
  1090  		if err != nil {
  1091  			t.Fatal(err)
  1092  		}
  1093  	}
  1094  
  1095  	makePkg("lib", mustParse("package lib; var X int"))
  1096  	// Each /*name=kind:line*/ comment makes the test look up the
  1097  	// name at that point and checks that it resolves to a decl of
  1098  	// the specified kind and line number.  "undef" means undefined.
  1099  	mainSrc := `
  1100  /*lib=pkgname:5*/ /*X=var:1*/ /*Pi=const:8*/ /*T=typename:9*/ /*Y=var:10*/ /*F=func:12*/
  1101  package main
  1102  
  1103  import "lib"
  1104  import . "lib"
  1105  
  1106  const Pi = 3.1415
  1107  type T struct{}
  1108  var Y, _ = lib.X, X
  1109  
  1110  func F(){
  1111  	const pi, e = 3.1415, /*pi=undef*/ 2.71828 /*pi=const:13*/ /*e=const:13*/
  1112  	type /*t=undef*/ t /*t=typename:14*/ *t
  1113  	print(Y) /*Y=var:10*/
  1114  	x, Y := Y, /*x=undef*/ /*Y=var:10*/ Pi /*x=var:16*/ /*Y=var:16*/ ; _ = x; _ = Y
  1115  	var F = /*F=func:12*/ F /*F=var:17*/ ; _ = F
  1116  
  1117  	var a []int
  1118  	for i, x := range /*i=undef*/ /*x=var:16*/ a /*i=var:20*/ /*x=var:20*/ { _ = i; _ = x }
  1119  
  1120  	var i interface{}
  1121  	switch y := i.(type) { /*y=undef*/
  1122  	case /*y=undef*/ int /*y=var:23*/ :
  1123  	case float32, /*y=undef*/ float64 /*y=var:23*/ :
  1124  	default /*y=var:23*/:
  1125  		println(y)
  1126  	}
  1127  	/*y=undef*/
  1128  
  1129          switch int := i.(type) {
  1130          case /*int=typename:0*/ int /*int=var:31*/ :
  1131          	println(int)
  1132          default /*int=var:31*/ :
  1133          }
  1134  }
  1135  /*main=undef*/
  1136  `
  1137  
  1138  	info.Uses = make(map[*ast.Ident]Object)
  1139  	f := mustParse(mainSrc)
  1140  	makePkg("main", f)
  1141  	mainScope := imports["main"].Scope()
  1142  	rx := regexp.MustCompile(`^/\*(\w*)=([\w:]*)\*/$`)
  1143  	for _, group := range f.Comments {
  1144  		for _, comment := range group.List {
  1145  			// Parse the assertion in the comment.
  1146  			m := rx.FindStringSubmatch(comment.Text)
  1147  			if m == nil {
  1148  				t.Errorf("%s: bad comment: %s",
  1149  					fset.Position(comment.Pos()), comment.Text)
  1150  				continue
  1151  			}
  1152  			name, want := m[1], m[2]
  1153  
  1154  			// Look up the name in the innermost enclosing scope.
  1155  			inner := mainScope.Innermost(comment.Pos())
  1156  			if inner == nil {
  1157  				t.Errorf("%s: at %s: can't find innermost scope",
  1158  					fset.Position(comment.Pos()), comment.Text)
  1159  				continue
  1160  			}
  1161  			got := "undef"
  1162  			if _, obj := inner.LookupParent(name, comment.Pos()); obj != nil {
  1163  				kind := strings.ToLower(strings.TrimPrefix(reflect.TypeOf(obj).String(), "*types."))
  1164  				got = fmt.Sprintf("%s:%d", kind, fset.Position(obj.Pos()).Line)
  1165  			}
  1166  			if got != want {
  1167  				t.Errorf("%s: at %s: %s resolved to %s, want %s",
  1168  					fset.Position(comment.Pos()), comment.Text, name, got, want)
  1169  			}
  1170  		}
  1171  	}
  1172  
  1173  	// Check that for each referring identifier,
  1174  	// a lookup of its name on the innermost
  1175  	// enclosing scope returns the correct object.
  1176  
  1177  	for id, wantObj := range info.Uses {
  1178  		inner := mainScope.Innermost(id.Pos())
  1179  		if inner == nil {
  1180  			t.Errorf("%s: can't find innermost scope enclosing %q",
  1181  				fset.Position(id.Pos()), id.Name)
  1182  			continue
  1183  		}
  1184  
  1185  		// Exclude selectors and qualified identifiers---lexical
  1186  		// refs only.  (Ideally, we'd see if the AST parent is a
  1187  		// SelectorExpr, but that requires PathEnclosingInterval
  1188  		// from golang.org/x/tools/go/ast/astutil.)
  1189  		if id.Name == "X" {
  1190  			continue
  1191  		}
  1192  
  1193  		_, gotObj := inner.LookupParent(id.Name, id.Pos())
  1194  		if gotObj != wantObj {
  1195  			t.Errorf("%s: got %v, want %v",
  1196  				fset.Position(id.Pos()), gotObj, wantObj)
  1197  			continue
  1198  		}
  1199  	}
  1200  }
  1201  
  1202  func TestIdentical_issue15173(t *testing.T) {
  1203  	// Identical should allow nil arguments and be symmetric.
  1204  	for _, test := range []struct {
  1205  		x, y Type
  1206  		want bool
  1207  	}{
  1208  		{Typ[Int], Typ[Int], true},
  1209  		{Typ[Int], nil, false},
  1210  		{nil, Typ[Int], false},
  1211  		{nil, nil, true},
  1212  	} {
  1213  		if got := Identical(test.x, test.y); got != test.want {
  1214  			t.Errorf("Identical(%v, %v) = %t", test.x, test.y, got)
  1215  		}
  1216  	}
  1217  }
  1218  
  1219  func TestIssue15305(t *testing.T) {
  1220  	const src = "package p; func f() int16; var _ = f(undef)"
  1221  	fset := token.NewFileSet()
  1222  	f, err := parser.ParseFile(fset, "issue15305.go", src, 0)
  1223  	if err != nil {
  1224  		t.Fatal(err)
  1225  	}
  1226  	conf := Config{
  1227  		Error: func(err error) {}, // allow errors
  1228  	}
  1229  	info := &Info{
  1230  		Types: make(map[ast.Expr]TypeAndValue),
  1231  	}
  1232  	conf.Check("p", fset, []*ast.File{f}, info) // ignore result
  1233  	for e, tv := range info.Types {
  1234  		if _, ok := e.(*ast.CallExpr); ok {
  1235  			if tv.Type != Typ[Int16] {
  1236  				t.Errorf("CallExpr has type %v, want int16", tv.Type)
  1237  			}
  1238  			return
  1239  		}
  1240  	}
  1241  	t.Errorf("CallExpr has no type")
  1242  }
  1243  
  1244  // TestCompositeLitTypes verifies that Info.Types registers the correct
  1245  // types for composite literal expressions and composite literal type
  1246  // expressions.
  1247  func TestCompositeLitTypes(t *testing.T) {
  1248  	for _, test := range []struct {
  1249  		lit, typ string
  1250  	}{
  1251  		{`[16]byte{}`, `[16]byte`},
  1252  		{`[...]byte{}`, `[0]byte`},                // test for issue #14092
  1253  		{`[...]int{1, 2, 3}`, `[3]int`},           // test for issue #14092
  1254  		{`[...]int{90: 0, 98: 1, 2}`, `[100]int`}, // test for issue #14092
  1255  		{`[]int{}`, `[]int`},
  1256  		{`map[string]bool{"foo": true}`, `map[string]bool`},
  1257  		{`struct{}{}`, `struct{}`},
  1258  		{`struct{x, y int; z complex128}{}`, `struct{x int; y int; z complex128}`},
  1259  	} {
  1260  		fset := token.NewFileSet()
  1261  		f, err := parser.ParseFile(fset, test.lit, "package p; var _ = "+test.lit, 0)
  1262  		if err != nil {
  1263  			t.Fatalf("%s: %v", test.lit, err)
  1264  		}
  1265  
  1266  		info := &Info{
  1267  			Types: make(map[ast.Expr]TypeAndValue),
  1268  		}
  1269  		if _, err = new(Config).Check("p", fset, []*ast.File{f}, info); err != nil {
  1270  			t.Fatalf("%s: %v", test.lit, err)
  1271  		}
  1272  
  1273  		cmptype := func(x ast.Expr, want string) {
  1274  			tv, ok := info.Types[x]
  1275  			if !ok {
  1276  				t.Errorf("%s: no Types entry found", test.lit)
  1277  				return
  1278  			}
  1279  			if tv.Type == nil {
  1280  				t.Errorf("%s: type is nil", test.lit)
  1281  				return
  1282  			}
  1283  			if got := tv.Type.String(); got != want {
  1284  				t.Errorf("%s: got %v, want %s", test.lit, got, want)
  1285  			}
  1286  		}
  1287  
  1288  		// test type of composite literal expression
  1289  		rhs := f.Decls[0].(*ast.GenDecl).Specs[0].(*ast.ValueSpec).Values[0]
  1290  		cmptype(rhs, test.typ)
  1291  
  1292  		// test type of composite literal type expression
  1293  		cmptype(rhs.(*ast.CompositeLit).Type, test.typ)
  1294  	}
  1295  }
  1296  
  1297  // TestObjectParents verifies that objects have parent scopes or not
  1298  // as specified by the Object interface.
  1299  func TestObjectParents(t *testing.T) {
  1300  	const src = `
  1301  package p
  1302  
  1303  const C = 0
  1304  
  1305  type T1 struct {
  1306  	a, b int
  1307  	T2
  1308  }
  1309  
  1310  type T2 interface {
  1311  	im1()
  1312  	im2()
  1313  }
  1314  
  1315  func (T1) m1() {}
  1316  func (*T1) m2() {}
  1317  
  1318  func f(x int) { y := x; print(y) }
  1319  `
  1320  
  1321  	fset := token.NewFileSet()
  1322  	f, err := parser.ParseFile(fset, "src", src, 0)
  1323  	if err != nil {
  1324  		t.Fatal(err)
  1325  	}
  1326  
  1327  	info := &Info{
  1328  		Defs: make(map[*ast.Ident]Object),
  1329  	}
  1330  	if _, err = new(Config).Check("p", fset, []*ast.File{f}, info); err != nil {
  1331  		t.Fatal(err)
  1332  	}
  1333  
  1334  	for ident, obj := range info.Defs {
  1335  		if obj == nil {
  1336  			// only package names and implicit vars have a nil object
  1337  			// (in this test we only need to handle the package name)
  1338  			if ident.Name != "p" {
  1339  				t.Errorf("%v has nil object", ident)
  1340  			}
  1341  			continue
  1342  		}
  1343  
  1344  		// struct fields, type-associated and interface methods
  1345  		// have no parent scope
  1346  		wantParent := true
  1347  		switch obj := obj.(type) {
  1348  		case *Var:
  1349  			if obj.IsField() {
  1350  				wantParent = false
  1351  			}
  1352  		case *Func:
  1353  			if obj.Type().(*Signature).Recv() != nil { // method
  1354  				wantParent = false
  1355  			}
  1356  		}
  1357  
  1358  		gotParent := obj.Parent() != nil
  1359  		switch {
  1360  		case gotParent && !wantParent:
  1361  			t.Errorf("%v: want no parent, got %s", ident, obj.Parent())
  1362  		case !gotParent && wantParent:
  1363  			t.Errorf("%v: no parent found", ident)
  1364  		}
  1365  	}
  1366  }
  1367  
  1368  // TestFailedImport tests that we don't get follow-on errors
  1369  // elsewhere in a package due to failing to import a package.
  1370  func TestFailedImport(t *testing.T) {
  1371  	testenv.MustHaveGoBuild(t)
  1372  
  1373  	const src = `
  1374  package p
  1375  
  1376  import foo "go/types/thisdirectorymustnotexistotherwisethistestmayfail/foo" // should only see an error here
  1377  
  1378  const c = foo.C
  1379  type T = foo.T
  1380  var v T = c
  1381  func f(x T) T { return foo.F(x) }
  1382  `
  1383  	fset := token.NewFileSet()
  1384  	f, err := parser.ParseFile(fset, "src", src, 0)
  1385  	if err != nil {
  1386  		t.Fatal(err)
  1387  	}
  1388  	files := []*ast.File{f}
  1389  
  1390  	// type-check using all possible importers
  1391  	for _, compiler := range []string{"gc", "gccgo", "source"} {
  1392  		errcount := 0
  1393  		conf := Config{
  1394  			Error: func(err error) {
  1395  				// we should only see the import error
  1396  				if errcount > 0 || !strings.Contains(err.Error(), "could not import") {
  1397  					t.Errorf("for %s importer, got unexpected error: %v", compiler, err)
  1398  				}
  1399  				errcount++
  1400  			},
  1401  			Importer: importer.For(compiler, nil),
  1402  		}
  1403  
  1404  		info := &Info{
  1405  			Uses: make(map[*ast.Ident]Object),
  1406  		}
  1407  		pkg, _ := conf.Check("p", fset, files, info)
  1408  		if pkg == nil {
  1409  			t.Errorf("for %s importer, type-checking failed to return a package", compiler)
  1410  			continue
  1411  		}
  1412  
  1413  		imports := pkg.Imports()
  1414  		if len(imports) != 1 {
  1415  			t.Errorf("for %s importer, got %d imports, want 1", compiler, len(imports))
  1416  			continue
  1417  		}
  1418  		imp := imports[0]
  1419  		if imp.Name() != "foo" {
  1420  			t.Errorf(`for %s importer, got %q, want "foo"`, compiler, imp.Name())
  1421  			continue
  1422  		}
  1423  
  1424  		// verify that all uses of foo refer to the imported package foo (imp)
  1425  		for ident, obj := range info.Uses {
  1426  			if ident.Name == "foo" {
  1427  				if obj, ok := obj.(*PkgName); ok {
  1428  					if obj.Imported() != imp {
  1429  						t.Errorf("%s resolved to %v; want %v", ident, obj.Imported(), imp)
  1430  					}
  1431  				} else {
  1432  					t.Errorf("%s resolved to %v; want package name", ident, obj)
  1433  				}
  1434  			}
  1435  		}
  1436  	}
  1437  }
  1438  

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