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Source file src/go/types/check_test.go

Documentation: go/types

  // Copyright 2011 The Go Authors. All rights reserved.
  // Use of this source code is governed by a BSD-style
  // license that can be found in the LICENSE file.
  
  // This file implements a typechecker test harness. The packages specified
  // in tests are typechecked. Error messages reported by the typechecker are
  // compared against the error messages expected in the test files.
  //
  // Expected errors are indicated in the test files by putting a comment
  // of the form /* ERROR "rx" */ immediately following an offending token.
  // The harness will verify that an error matching the regular expression
  // rx is reported at that source position. Consecutive comments may be
  // used to indicate multiple errors for the same token position.
  //
  // For instance, the following test file indicates that a "not declared"
  // error should be reported for the undeclared variable x:
  //
  //	package p
  //	func f() {
  //		_ = x /* ERROR "not declared" */ + 1
  //	}
  
  // TODO(gri) Also collect strict mode errors of the form /* STRICT ... */
  //           and test against strict mode.
  
  package types_test
  
  import (
  	"flag"
  	"go/ast"
  	"go/importer"
  	"go/parser"
  	"go/scanner"
  	"go/token"
  	"internal/testenv"
  	"io/ioutil"
  	"regexp"
  	"strings"
  	"testing"
  
  	. "go/types"
  )
  
  var (
  	listErrors = flag.Bool("list", false, "list errors")
  	testFiles  = flag.String("files", "", "space-separated list of test files")
  )
  
  // The test filenames do not end in .go so that they are invisible
  // to gofmt since they contain comments that must not change their
  // positions relative to surrounding tokens.
  
  // Each tests entry is list of files belonging to the same package.
  var tests = [][]string{
  	{"testdata/errors.src"},
  	{"testdata/importdecl0a.src", "testdata/importdecl0b.src"},
  	{"testdata/importdecl1a.src", "testdata/importdecl1b.src"},
  	{"testdata/importC.src"}, // special handling in checkFiles
  	{"testdata/cycles.src"},
  	{"testdata/cycles1.src"},
  	{"testdata/cycles2.src"},
  	{"testdata/cycles3.src"},
  	{"testdata/cycles4.src"},
  	{"testdata/init0.src"},
  	{"testdata/init1.src"},
  	{"testdata/init2.src"},
  	{"testdata/decls0.src"},
  	{"testdata/decls1.src"},
  	{"testdata/decls2a.src", "testdata/decls2b.src"},
  	{"testdata/decls3.src"},
  	{"testdata/decls4.src"},
  	{"testdata/const0.src"},
  	{"testdata/const1.src"},
  	{"testdata/constdecl.src"},
  	{"testdata/vardecl.src"},
  	{"testdata/expr0.src"},
  	{"testdata/expr1.src"},
  	{"testdata/expr2.src"},
  	{"testdata/expr3.src"},
  	{"testdata/methodsets.src"},
  	{"testdata/shifts.src"},
  	{"testdata/builtins.src"},
  	{"testdata/conversions.src"},
  	{"testdata/conversions2.src"},
  	{"testdata/stmt0.src"},
  	{"testdata/stmt1.src"},
  	{"testdata/gotos.src"},
  	{"testdata/labels.src"},
  	{"testdata/issues.src"},
  	{"testdata/blank.src"},
  }
  
  var fset = token.NewFileSet()
  
  // Positioned errors are of the form filename:line:column: message .
  var posMsgRx = regexp.MustCompile(`^(.*:[0-9]+:[0-9]+): *(.*)`)
  
  // splitError splits an error's error message into a position string
  // and the actual error message. If there's no position information,
  // pos is the empty string, and msg is the entire error message.
  //
  func splitError(err error) (pos, msg string) {
  	msg = err.Error()
  	if m := posMsgRx.FindStringSubmatch(msg); len(m) == 3 {
  		pos = m[1]
  		msg = m[2]
  	}
  	return
  }
  
  func parseFiles(t *testing.T, filenames []string) ([]*ast.File, []error) {
  	var files []*ast.File
  	var errlist []error
  	for _, filename := range filenames {
  		file, err := parser.ParseFile(fset, filename, nil, parser.AllErrors)
  		if file == nil {
  			t.Fatalf("%s: %s", filename, err)
  		}
  		files = append(files, file)
  		if err != nil {
  			if list, _ := err.(scanner.ErrorList); len(list) > 0 {
  				for _, err := range list {
  					errlist = append(errlist, err)
  				}
  			} else {
  				errlist = append(errlist, err)
  			}
  		}
  	}
  	return files, errlist
  }
  
  // ERROR comments must start with text `ERROR "rx"` or `ERROR rx` where
  // rx is a regular expression that matches the expected error message.
  // Space around "rx" or rx is ignored. Use the form `ERROR HERE "rx"`
  // for error messages that are located immediately after rather than
  // at a token's position.
  //
  var errRx = regexp.MustCompile(`^ *ERROR *(HERE)? *"?([^"]*)"?`)
  
  // errMap collects the regular expressions of ERROR comments found
  // in files and returns them as a map of error positions to error messages.
  //
  func errMap(t *testing.T, testname string, files []*ast.File) map[string][]string {
  	// map of position strings to lists of error message patterns
  	errmap := make(map[string][]string)
  
  	for _, file := range files {
  		filename := fset.Position(file.Package).Filename
  		src, err := ioutil.ReadFile(filename)
  		if err != nil {
  			t.Fatalf("%s: could not read %s", testname, filename)
  		}
  
  		var s scanner.Scanner
  		s.Init(fset.AddFile(filename, -1, len(src)), src, nil, scanner.ScanComments)
  		var prev token.Pos // position of last non-comment, non-semicolon token
  		var here token.Pos // position immediately after the token at position prev
  
  	scanFile:
  		for {
  			pos, tok, lit := s.Scan()
  			switch tok {
  			case token.EOF:
  				break scanFile
  			case token.COMMENT:
  				if lit[1] == '*' {
  					lit = lit[:len(lit)-2] // strip trailing */
  				}
  				if s := errRx.FindStringSubmatch(lit[2:]); len(s) == 3 {
  					pos := prev
  					if s[1] == "HERE" {
  						pos = here
  					}
  					p := fset.Position(pos).String()
  					errmap[p] = append(errmap[p], strings.TrimSpace(s[2]))
  				}
  			case token.SEMICOLON:
  				// ignore automatically inserted semicolon
  				if lit == "\n" {
  					continue scanFile
  				}
  				fallthrough
  			default:
  				prev = pos
  				var l int // token length
  				if tok.IsLiteral() {
  					l = len(lit)
  				} else {
  					l = len(tok.String())
  				}
  				here = prev + token.Pos(l)
  			}
  		}
  	}
  
  	return errmap
  }
  
  func eliminate(t *testing.T, errmap map[string][]string, errlist []error) {
  	for _, err := range errlist {
  		pos, gotMsg := splitError(err)
  		list := errmap[pos]
  		index := -1 // list index of matching message, if any
  		// we expect one of the messages in list to match the error at pos
  		for i, wantRx := range list {
  			rx, err := regexp.Compile(wantRx)
  			if err != nil {
  				t.Errorf("%s: %v", pos, err)
  				continue
  			}
  			if rx.MatchString(gotMsg) {
  				index = i
  				break
  			}
  		}
  		if index >= 0 {
  			// eliminate from list
  			if n := len(list) - 1; n > 0 {
  				// not the last entry - swap in last element and shorten list by 1
  				list[index] = list[n]
  				errmap[pos] = list[:n]
  			} else {
  				// last entry - remove list from map
  				delete(errmap, pos)
  			}
  		} else {
  			t.Errorf("%s: no error expected: %q", pos, gotMsg)
  		}
  	}
  }
  
  func checkFiles(t *testing.T, testfiles []string) {
  	// parse files and collect parser errors
  	files, errlist := parseFiles(t, testfiles)
  
  	pkgName := "<no package>"
  	if len(files) > 0 {
  		pkgName = files[0].Name.Name
  	}
  
  	if *listErrors && len(errlist) > 0 {
  		t.Errorf("--- %s:", pkgName)
  		for _, err := range errlist {
  			t.Error(err)
  		}
  	}
  
  	// typecheck and collect typechecker errors
  	var conf Config
  	// special case for importC.src
  	if len(testfiles) == 1 && testfiles[0] == "testdata/importC.src" {
  		conf.FakeImportC = true
  	}
  	conf.Importer = importer.Default()
  	conf.Error = func(err error) {
  		if *listErrors {
  			t.Error(err)
  			return
  		}
  		// Ignore secondary error messages starting with "\t";
  		// they are clarifying messages for a primary error.
  		if !strings.Contains(err.Error(), ": \t") {
  			errlist = append(errlist, err)
  		}
  	}
  	conf.Check(pkgName, fset, files, nil)
  
  	if *listErrors {
  		return
  	}
  
  	// match and eliminate errors;
  	// we are expecting the following errors
  	errmap := errMap(t, pkgName, files)
  	eliminate(t, errmap, errlist)
  
  	// there should be no expected errors left
  	if len(errmap) > 0 {
  		t.Errorf("--- %s: %d source positions with expected (but not reported) errors:", pkgName, len(errmap))
  		for pos, list := range errmap {
  			for _, rx := range list {
  				t.Errorf("%s: %q", pos, rx)
  			}
  		}
  	}
  }
  
  func TestCheck(t *testing.T) {
  	testenv.MustHaveGoBuild(t)
  
  	// Declare builtins for testing.
  	DefPredeclaredTestFuncs()
  
  	// If explicit test files are specified, only check those.
  	if files := *testFiles; files != "" {
  		checkFiles(t, strings.Split(files, " "))
  		return
  	}
  
  	// Otherwise, run all the tests.
  	for _, files := range tests {
  		checkFiles(t, files)
  	}
  }
  

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