Source file src/go/types/check_test.go

Documentation: go/types

     1  // Copyright 2011 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  // This file implements a typechecker test harness. The packages specified
     6  // in tests are typechecked. Error messages reported by the typechecker are
     7  // compared against the errors expected in the test files.
     8  //
     9  // Expected errors are indicated in the test files by putting comments
    10  // of the form /* ERROR pattern */ or /* ERRORx pattern */ (or a similar
    11  // //-style line comment) immediately following the tokens where errors
    12  // are reported. There must be exactly one blank before and after the
    13  // ERROR/ERRORx indicator, and the pattern must be a properly quoted Go
    14  // string.
    15  //
    16  // The harness will verify that each ERROR pattern is a substring of the
    17  // error reported at that source position, and that each ERRORx pattern
    18  // is a regular expression matching the respective error.
    19  // Consecutive comments may be used to indicate multiple errors reported
    20  // at the same position.
    21  //
    22  // For instance, the following test source indicates that an "undeclared"
    23  // error should be reported for the undeclared variable x:
    24  //
    25  //	package p
    26  //	func f() {
    27  //		_ = x /* ERROR "undeclared" */ + 1
    28  //	}
    29  
    30  package types_test
    31  
    32  import (
    33  	"bytes"
    34  	"flag"
    35  	"fmt"
    36  	"go/ast"
    37  	"go/parser"
    38  	"go/scanner"
    39  	"go/token"
    40  	"internal/buildcfg"
    41  	"internal/testenv"
    42  	"internal/types/errors"
    43  	"os"
    44  	"path/filepath"
    45  	"reflect"
    46  	"regexp"
    47  	"runtime"
    48  	"strconv"
    49  	"strings"
    50  	"testing"
    51  
    52  	. "go/types"
    53  )
    54  
    55  var (
    56  	haltOnError  = flag.Bool("halt", false, "halt on error")
    57  	verifyErrors = flag.Bool("verify", false, "verify errors (rather than list them) in TestManual")
    58  )
    59  
    60  var fset = token.NewFileSet()
    61  
    62  func parseFiles(t *testing.T, filenames []string, srcs [][]byte, mode parser.Mode) ([]*ast.File, []error) {
    63  	var files []*ast.File
    64  	var errlist []error
    65  	for i, filename := range filenames {
    66  		file, err := parser.ParseFile(fset, filename, srcs[i], mode)
    67  		if file == nil {
    68  			t.Fatalf("%s: %s", filename, err)
    69  		}
    70  		files = append(files, file)
    71  		if err != nil {
    72  			if list, _ := err.(scanner.ErrorList); len(list) > 0 {
    73  				for _, err := range list {
    74  					errlist = append(errlist, err)
    75  				}
    76  			} else {
    77  				errlist = append(errlist, err)
    78  			}
    79  		}
    80  	}
    81  	return files, errlist
    82  }
    83  
    84  func unpackError(fset *token.FileSet, err error) (token.Position, string) {
    85  	switch err := err.(type) {
    86  	case *scanner.Error:
    87  		return err.Pos, err.Msg
    88  	case Error:
    89  		return fset.Position(err.Pos), err.Msg
    90  	}
    91  	panic("unreachable")
    92  }
    93  
    94  // absDiff returns the absolute difference between x and y.
    95  func absDiff(x, y int) int {
    96  	if x < y {
    97  		return y - x
    98  	}
    99  	return x - y
   100  }
   101  
   102  // parseFlags parses flags from the first line of the given source if the line
   103  // starts with "//" (line comment) followed by "-" (possibly with spaces
   104  // between). Otherwise the line is ignored.
   105  func parseFlags(src []byte, flags *flag.FlagSet) error {
   106  	// we must have a line comment that starts with a "-"
   107  	const prefix = "//"
   108  	if !bytes.HasPrefix(src, []byte(prefix)) {
   109  		return nil // first line is not a line comment
   110  	}
   111  	src = src[len(prefix):]
   112  	if i := bytes.Index(src, []byte("-")); i < 0 || len(bytes.TrimSpace(src[:i])) != 0 {
   113  		return nil // comment doesn't start with a "-"
   114  	}
   115  	end := bytes.Index(src, []byte("\n"))
   116  	const maxLen = 256
   117  	if end < 0 || end > maxLen {
   118  		return fmt.Errorf("flags comment line too long")
   119  	}
   120  
   121  	return flags.Parse(strings.Fields(string(src[:end])))
   122  }
   123  
   124  // testFiles type-checks the package consisting of the given files, and
   125  // compares the resulting errors with the ERROR annotations in the source.
   126  // Except for manual tests, each package is type-checked twice, once without
   127  // use of Alias types, and once with Alias types.
   128  //
   129  // The srcs slice contains the file content for the files named in the
   130  // filenames slice. The colDelta parameter specifies the tolerance for position
   131  // mismatch when comparing errors. The manual parameter specifies whether this
   132  // is a 'manual' test.
   133  //
   134  // If provided, opts may be used to mutate the Config before type-checking.
   135  func testFiles(t *testing.T, filenames []string, srcs [][]byte, manual bool, opts ...func(*Config)) {
   136  	// Alias types are enabled by default
   137  	testFilesImpl(t, filenames, srcs, manual, opts...)
   138  	if !manual {
   139  		t.Setenv("GODEBUG", "gotypesalias=0")
   140  		testFilesImpl(t, filenames, srcs, manual, opts...)
   141  	}
   142  }
   143  
   144  func testFilesImpl(t *testing.T, filenames []string, srcs [][]byte, manual bool, opts ...func(*Config)) {
   145  	if len(filenames) == 0 {
   146  		t.Fatal("no source files")
   147  	}
   148  
   149  	// parse files
   150  	files, errlist := parseFiles(t, filenames, srcs, parser.AllErrors)
   151  	pkgName := "<no package>"
   152  	if len(files) > 0 {
   153  		pkgName = files[0].Name.Name
   154  	}
   155  	listErrors := manual && !*verifyErrors
   156  	if listErrors && len(errlist) > 0 {
   157  		t.Errorf("--- %s:", pkgName)
   158  		for _, err := range errlist {
   159  			t.Error(err)
   160  		}
   161  	}
   162  
   163  	// set up typechecker
   164  	var conf Config
   165  	*boolFieldAddr(&conf, "_Trace") = manual && testing.Verbose()
   166  	conf.Importer = defaultImporter(fset)
   167  	conf.Error = func(err error) {
   168  		if *haltOnError {
   169  			defer panic(err)
   170  		}
   171  		if listErrors {
   172  			t.Error(err)
   173  			return
   174  		}
   175  		// Ignore secondary error messages starting with "\t";
   176  		// they are clarifying messages for a primary error.
   177  		if !strings.Contains(err.Error(), ": \t") {
   178  			errlist = append(errlist, err)
   179  		}
   180  	}
   181  
   182  	// apply custom configuration
   183  	for _, opt := range opts {
   184  		opt(&conf)
   185  	}
   186  
   187  	// apply flag setting (overrides custom configuration)
   188  	var goexperiment, gotypesalias string
   189  	flags := flag.NewFlagSet("", flag.PanicOnError)
   190  	flags.StringVar(&conf.GoVersion, "lang", "", "")
   191  	flags.StringVar(&goexperiment, "goexperiment", "", "")
   192  	flags.BoolVar(&conf.FakeImportC, "fakeImportC", false, "")
   193  	flags.StringVar(&gotypesalias, "gotypesalias", "", "")
   194  	if err := parseFlags(srcs[0], flags); err != nil {
   195  		t.Fatal(err)
   196  	}
   197  
   198  	if goexperiment != "" {
   199  		revert := setGOEXPERIMENT(goexperiment)
   200  		defer revert()
   201  	}
   202  
   203  	// By default, gotypesalias is not set.
   204  	if gotypesalias != "" {
   205  		t.Setenv("GODEBUG", "gotypesalias="+gotypesalias)
   206  	}
   207  
   208  	// Provide Config.Info with all maps so that info recording is tested.
   209  	info := Info{
   210  		Types:        make(map[ast.Expr]TypeAndValue),
   211  		Instances:    make(map[*ast.Ident]Instance),
   212  		Defs:         make(map[*ast.Ident]Object),
   213  		Uses:         make(map[*ast.Ident]Object),
   214  		Implicits:    make(map[ast.Node]Object),
   215  		Selections:   make(map[*ast.SelectorExpr]*Selection),
   216  		Scopes:       make(map[ast.Node]*Scope),
   217  		FileVersions: make(map[*ast.File]string),
   218  	}
   219  
   220  	// typecheck
   221  	conf.Check(pkgName, fset, files, &info)
   222  	if listErrors {
   223  		return
   224  	}
   225  
   226  	// collect expected errors
   227  	errmap := make(map[string]map[int][]comment)
   228  	for i, filename := range filenames {
   229  		if m := commentMap(srcs[i], regexp.MustCompile("^ ERRORx? ")); len(m) > 0 {
   230  			errmap[filename] = m
   231  		}
   232  	}
   233  
   234  	// match against found errors
   235  	var indices []int // list indices of matching errors, reused for each error
   236  	for _, err := range errlist {
   237  		gotPos, gotMsg := unpackError(fset, err)
   238  
   239  		// find list of errors for the respective error line
   240  		filename := gotPos.Filename
   241  		filemap := errmap[filename]
   242  		line := gotPos.Line
   243  		var errList []comment
   244  		if filemap != nil {
   245  			errList = filemap[line]
   246  		}
   247  
   248  		// At least one of the errors in errList should match the current error.
   249  		indices = indices[:0]
   250  		for i, want := range errList {
   251  			pattern, substr := strings.CutPrefix(want.text, " ERROR ")
   252  			if !substr {
   253  				var found bool
   254  				pattern, found = strings.CutPrefix(want.text, " ERRORx ")
   255  				if !found {
   256  					panic("unreachable")
   257  				}
   258  			}
   259  			unquoted, err := strconv.Unquote(strings.TrimSpace(pattern))
   260  			if err != nil {
   261  				t.Errorf("%s:%d:%d: invalid ERROR pattern (cannot unquote %s)", filename, line, want.col, pattern)
   262  				continue
   263  			}
   264  			if substr {
   265  				if !strings.Contains(gotMsg, unquoted) {
   266  					continue
   267  				}
   268  			} else {
   269  				rx, err := regexp.Compile(unquoted)
   270  				if err != nil {
   271  					t.Errorf("%s:%d:%d: %v", filename, line, want.col, err)
   272  					continue
   273  				}
   274  				if !rx.MatchString(gotMsg) {
   275  					continue
   276  				}
   277  			}
   278  			indices = append(indices, i)
   279  		}
   280  		if len(indices) == 0 {
   281  			t.Errorf("%s: no error expected: %q", gotPos, gotMsg)
   282  			continue
   283  		}
   284  		// len(indices) > 0
   285  
   286  		// If there are multiple matching errors, select the one with the closest column position.
   287  		index := -1 // index of matching error
   288  		var delta int
   289  		for _, i := range indices {
   290  			if d := absDiff(gotPos.Column, errList[i].col); index < 0 || d < delta {
   291  				index, delta = i, d
   292  			}
   293  		}
   294  
   295  		// The closest column position must be within expected colDelta.
   296  		const colDelta = 0 // go/types errors are positioned correctly
   297  		if delta > colDelta {
   298  			t.Errorf("%s: got col = %d; want %d", gotPos, gotPos.Column, errList[index].col)
   299  		}
   300  
   301  		// eliminate from errList
   302  		if n := len(errList) - 1; n > 0 {
   303  			// not the last entry - slide entries down (don't reorder)
   304  			copy(errList[index:], errList[index+1:])
   305  			filemap[line] = errList[:n]
   306  		} else {
   307  			// last entry - remove errList from filemap
   308  			delete(filemap, line)
   309  		}
   310  
   311  		// if filemap is empty, eliminate from errmap
   312  		if len(filemap) == 0 {
   313  			delete(errmap, filename)
   314  		}
   315  	}
   316  
   317  	// there should be no expected errors left
   318  	if len(errmap) > 0 {
   319  		t.Errorf("--- %s: unreported errors:", pkgName)
   320  		for filename, filemap := range errmap {
   321  			for line, errList := range filemap {
   322  				for _, err := range errList {
   323  					t.Errorf("%s:%d:%d: %s", filename, line, err.col, err.text)
   324  				}
   325  			}
   326  		}
   327  	}
   328  }
   329  
   330  func readCode(err Error) errors.Code {
   331  	v := reflect.ValueOf(err)
   332  	return errors.Code(v.FieldByName("go116code").Int())
   333  }
   334  
   335  // boolFieldAddr(conf, name) returns the address of the boolean field conf.<name>.
   336  // For accessing unexported fields.
   337  func boolFieldAddr(conf *Config, name string) *bool {
   338  	v := reflect.Indirect(reflect.ValueOf(conf))
   339  	return (*bool)(v.FieldByName(name).Addr().UnsafePointer())
   340  }
   341  
   342  // stringFieldAddr(conf, name) returns the address of the string field conf.<name>.
   343  // For accessing unexported fields.
   344  func stringFieldAddr(conf *Config, name string) *string {
   345  	v := reflect.Indirect(reflect.ValueOf(conf))
   346  	return (*string)(v.FieldByName(name).Addr().UnsafePointer())
   347  }
   348  
   349  // setGOEXPERIMENT overwrites the existing buildcfg.Experiment with a new one
   350  // based on the provided goexperiment string. Calling the result function
   351  // (typically via defer), reverts buildcfg.Experiment to the prior value.
   352  // For testing use, only.
   353  func setGOEXPERIMENT(goexperiment string) func() {
   354  	exp, err := buildcfg.ParseGOEXPERIMENT(runtime.GOOS, runtime.GOARCH, goexperiment)
   355  	if err != nil {
   356  		panic(err)
   357  	}
   358  	old := buildcfg.Experiment
   359  	buildcfg.Experiment = *exp
   360  	return func() { buildcfg.Experiment = old }
   361  }
   362  
   363  // TestManual is for manual testing of a package - either provided
   364  // as a list of filenames belonging to the package, or a directory
   365  // name containing the package files - after the test arguments
   366  // (and a separating "--"). For instance, to test the package made
   367  // of the files foo.go and bar.go, use:
   368  //
   369  //	go test -run Manual -- foo.go bar.go
   370  //
   371  // If no source arguments are provided, the file testdata/manual.go
   372  // is used instead.
   373  // Provide the -verify flag to verify errors against ERROR comments
   374  // in the input files rather than having a list of errors reported.
   375  // The accepted Go language version can be controlled with the -lang
   376  // flag.
   377  func TestManual(t *testing.T) {
   378  	testenv.MustHaveGoBuild(t)
   379  
   380  	filenames := flag.Args()
   381  	if len(filenames) == 0 {
   382  		filenames = []string{filepath.FromSlash("testdata/manual.go")}
   383  	}
   384  
   385  	info, err := os.Stat(filenames[0])
   386  	if err != nil {
   387  		t.Fatalf("TestManual: %v", err)
   388  	}
   389  
   390  	DefPredeclaredTestFuncs()
   391  	if info.IsDir() {
   392  		if len(filenames) > 1 {
   393  			t.Fatal("TestManual: must have only one directory argument")
   394  		}
   395  		testDir(t, filenames[0], true)
   396  	} else {
   397  		testPkg(t, filenames, true)
   398  	}
   399  }
   400  
   401  func TestLongConstants(t *testing.T) {
   402  	format := `package longconst; const _ = %s /* ERROR "constant overflow" */; const _ = %s // ERROR "excessively long constant"`
   403  	src := fmt.Sprintf(format, strings.Repeat("1", 9999), strings.Repeat("1", 10001))
   404  	testFiles(t, []string{"longconst.go"}, [][]byte{[]byte(src)}, false)
   405  }
   406  
   407  func withSizes(sizes Sizes) func(*Config) {
   408  	return func(cfg *Config) {
   409  		cfg.Sizes = sizes
   410  	}
   411  }
   412  
   413  // TestIndexRepresentability tests that constant index operands must
   414  // be representable as int even if they already have a type that can
   415  // represent larger values.
   416  func TestIndexRepresentability(t *testing.T) {
   417  	const src = `package index; var s []byte; var _ = s[int64 /* ERRORx "int64\\(1\\) << 40 \\(.*\\) overflows int" */ (1) << 40]`
   418  	testFiles(t, []string{"index.go"}, [][]byte{[]byte(src)}, false, withSizes(&StdSizes{4, 4}))
   419  }
   420  
   421  func TestIssue47243_TypedRHS(t *testing.T) {
   422  	// The RHS of the shift expression below overflows uint on 32bit platforms,
   423  	// but this is OK as it is explicitly typed.
   424  	const src = `package issue47243; var a uint64; var _ = a << uint64(4294967296)` // uint64(1<<32)
   425  	testFiles(t, []string{"p.go"}, [][]byte{[]byte(src)}, false, withSizes(&StdSizes{4, 4}))
   426  }
   427  
   428  func TestCheck(t *testing.T) {
   429  	old := buildcfg.Experiment.RangeFunc
   430  	defer func() {
   431  		buildcfg.Experiment.RangeFunc = old
   432  	}()
   433  	buildcfg.Experiment.RangeFunc = true
   434  
   435  	DefPredeclaredTestFuncs()
   436  	testDirFiles(t, "../../internal/types/testdata/check", false)
   437  }
   438  func TestSpec(t *testing.T)      { testDirFiles(t, "../../internal/types/testdata/spec", false) }
   439  func TestExamples(t *testing.T)  { testDirFiles(t, "../../internal/types/testdata/examples", false) }
   440  func TestFixedbugs(t *testing.T) { testDirFiles(t, "../../internal/types/testdata/fixedbugs", false) }
   441  func TestLocal(t *testing.T)     { testDirFiles(t, "testdata/local", false) }
   442  
   443  func testDirFiles(t *testing.T, dir string, manual bool) {
   444  	testenv.MustHaveGoBuild(t)
   445  	dir = filepath.FromSlash(dir)
   446  
   447  	fis, err := os.ReadDir(dir)
   448  	if err != nil {
   449  		t.Error(err)
   450  		return
   451  	}
   452  
   453  	for _, fi := range fis {
   454  		path := filepath.Join(dir, fi.Name())
   455  
   456  		// If fi is a directory, its files make up a single package.
   457  		if fi.IsDir() {
   458  			testDir(t, path, manual)
   459  		} else {
   460  			t.Run(filepath.Base(path), func(t *testing.T) {
   461  				testPkg(t, []string{path}, manual)
   462  			})
   463  		}
   464  	}
   465  }
   466  
   467  func testDir(t *testing.T, dir string, manual bool) {
   468  	testenv.MustHaveGoBuild(t)
   469  
   470  	fis, err := os.ReadDir(dir)
   471  	if err != nil {
   472  		t.Error(err)
   473  		return
   474  	}
   475  
   476  	var filenames []string
   477  	for _, fi := range fis {
   478  		filenames = append(filenames, filepath.Join(dir, fi.Name()))
   479  	}
   480  
   481  	t.Run(filepath.Base(dir), func(t *testing.T) {
   482  		testPkg(t, filenames, manual)
   483  	})
   484  }
   485  
   486  func testPkg(t *testing.T, filenames []string, manual bool) {
   487  	srcs := make([][]byte, len(filenames))
   488  	for i, filename := range filenames {
   489  		src, err := os.ReadFile(filename)
   490  		if err != nil {
   491  			t.Fatalf("could not read %s: %v", filename, err)
   492  		}
   493  		srcs[i] = src
   494  	}
   495  	testFiles(t, filenames, srcs, manual)
   496  }
   497  

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