1 files changed, 425 insertions, 0 deletions
diff --git a/src/go/types/check_test.go b/src/go/types/check_test.go
new file mode 100644
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--- /dev/null
+++ b/src/go/types/check_test.go
@@ -0,0 +1,425 @@
+// 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
+//	}
+
+package types_test
+
+import (
+	"bytes"
+	"flag"
+	"fmt"
+	"go/ast"
+	"go/importer"
+	"go/parser"
+	"go/scanner"
+	"go/token"
+	"internal/testenv"
+	"os"
+	"path/filepath"
+	"reflect"
+	"regexp"
+	"strings"
+	"testing"
+
+	. "go/types"
+)
+
+var (
+	haltOnError  = flag.Bool("halt", false, "halt on error")
+	verifyErrors = flag.Bool("verify", false, "verify errors (rather than list them) in TestManual")
+)
+
+var fset = token.NewFileSet()
+
+// Positioned errors are of the form filename:line:column: message .
+var posMsgRx = regexp.MustCompile(`^(.*:\d+:\d+): *(?s)(.*)`)
+
+// 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, srcs [][]byte, mode parser.Mode) ([]*ast.File, []error) {
+	var files []*ast.File
+	var errlist []error
+	for i, filename := range filenames {
+		file, err := parser.ParseFile(fset, filename, srcs[i], mode)
+		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.
+var errRx = regexp.MustCompile(`^ *ERROR *"?([^"]*)"?`)
+
+// errMap collects the regular expressions of ERROR comments found
+// in files and returns them as a map of error positions to error messages.
+//
+// srcs must be a slice of the same length as files, containing the original
+// source for the parsed AST.
+func errMap(t *testing.T, files []*ast.File, srcs [][]byte) map[string][]string {
+	// map of position strings to lists of error message patterns
+	errmap := make(map[string][]string)
+
+	for i, file := range files {
+		tok := fset.File(file.Package)
+		src := srcs[i]
+		var s scanner.Scanner
+		s.Init(tok, src, nil, scanner.ScanComments)
+		var prev token.Pos // position of last non-comment, non-semicolon token
+
+	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) == 2 {
+					p := fset.Position(prev).String()
+					errmap[p] = append(errmap[p], strings.TrimSpace(s[1]))
+				}
+			case token.SEMICOLON:
+				// ignore automatically inserted semicolon
+				if lit == "\n" {
+					continue scanFile
+				}
+				fallthrough
+			default:
+				prev = pos
+			}
+		}
+	}
+
+	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)
+		}
+	}
+}
+
+// parseFlags parses flags from the first line of the given source
+// (from src if present, or by reading from the file) if the line
+// starts with "//" (line comment) followed by "-" (possibly with
+// spaces between). Otherwise the line is ignored.
+func parseFlags(filename string, src []byte, flags *flag.FlagSet) error {
+	// If there is no src, read from the file.
+	const maxLen = 256
+	if len(src) == 0 {
+		f, err := os.Open(filename)
+		if err != nil {
+			return err
+		}
+
+		var buf [maxLen]byte
+		n, err := f.Read(buf[:])
+		if err != nil {
+			return err
+		}
+		src = buf[:n]
+	}
+
+	// we must have a line comment that starts with a "-"
+	const prefix = "//"
+	if !bytes.HasPrefix(src, []byte(prefix)) {
+		return nil // first line is not a line comment
+	}
+	src = src[len(prefix):]
+	if i := bytes.Index(src, []byte("-")); i < 0 || len(bytes.TrimSpace(src[:i])) != 0 {
+		return nil // comment doesn't start with a "-"
+	}
+	end := bytes.Index(src, []byte("\n"))
+	if end < 0 || end > maxLen {
+		return fmt.Errorf("flags comment line too long")
+	}
+
+	return flags.Parse(strings.Fields(string(src[:end])))
+}
+
+func testFiles(t *testing.T, sizes Sizes, filenames []string, srcs [][]byte, manual bool, imp Importer) {
+	if len(filenames) == 0 {
+		t.Fatal("no source files")
+	}
+
+	var conf Config
+	conf.Sizes = sizes
+	flags := flag.NewFlagSet("", flag.PanicOnError)
+	flags.StringVar(&conf.GoVersion, "lang", "", "")
+	flags.BoolVar(&conf.FakeImportC, "fakeImportC", false, "")
+	flags.BoolVar(addrOldComparableSemantics(&conf), "oldComparableSemantics", false, "")
+	if err := parseFlags(filenames[0], srcs[0], flags); err != nil {
+		t.Fatal(err)
+	}
+
+	files, errlist := parseFiles(t, filenames, srcs, parser.AllErrors)
+
+	pkgName := "<no package>"
+	if len(files) > 0 {
+		pkgName = files[0].Name.Name
+	}
+
+	listErrors := manual && !*verifyErrors
+	if listErrors && len(errlist) > 0 {
+		t.Errorf("--- %s:", pkgName)
+		for _, err := range errlist {
+			t.Error(err)
+		}
+	}
+
+	// typecheck and collect typechecker errors
+	if imp == nil {
+		imp = importer.Default()
+	}
+	conf.Importer = imp
+	conf.Error = func(err error) {
+		if *haltOnError {
+			defer panic(err)
+		}
+		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
+	}
+
+	for _, err := range errlist {
+		err, ok := err.(Error)
+		if !ok {
+			continue
+		}
+		code := readCode(err)
+		if code == 0 {
+			t.Errorf("missing error code: %v", err)
+		}
+	}
+
+	// match and eliminate errors;
+	// we are expecting the following errors
+	errmap := errMap(t, files, srcs)
+	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 readCode(err Error) int {
+	v := reflect.ValueOf(err)
+	return int(v.FieldByName("go116code").Int())
+}
+
+// addrOldComparableSemantics(conf) returns &conf.oldComparableSemantics (unexported field).
+func addrOldComparableSemantics(conf *Config) *bool {
+	v := reflect.Indirect(reflect.ValueOf(conf))
+	return (*bool)(v.FieldByName("oldComparableSemantics").Addr().UnsafePointer())
+}
+
+// TestManual is for manual testing of a package - either provided
+// as a list of filenames belonging to the package, or a directory
+// name containing the package files - after the test arguments
+// (and a separating "--"). For instance, to test the package made
+// of the files foo.go and bar.go, use:
+//
+//	go test -run Manual -- foo.go bar.go
+//
+// If no source arguments are provided, the file testdata/manual.go
+// is used instead.
+// Provide the -verify flag to verify errors against ERROR comments
+// in the input files rather than having a list of errors reported.
+// The accepted Go language version can be controlled with the -lang
+// flag.
+func TestManual(t *testing.T) {
+	testenv.MustHaveGoBuild(t)
+
+	filenames := flag.Args()
+	if len(filenames) == 0 {
+		filenames = []string{filepath.FromSlash("testdata/manual.go")}
+	}
+
+	info, err := os.Stat(filenames[0])
+	if err != nil {
+		t.Fatalf("TestManual: %v", err)
+	}
+
+	DefPredeclaredTestFuncs()
+	if info.IsDir() {
+		if len(filenames) > 1 {
+			t.Fatal("TestManual: must have only one directory argument")
+		}
+		testDir(t, filenames[0], true)
+	} else {
+		testPkg(t, filenames, true)
+	}
+}
+
+func TestLongConstants(t *testing.T) {
+	format := "package longconst\n\nconst _ = %s /* ERROR constant overflow */ \nconst _ = %s // ERROR excessively long constant"
+	src := fmt.Sprintf(format, strings.Repeat("1", 9999), strings.Repeat("1", 10001))
+	testFiles(t, nil, []string{"longconst.go"}, [][]byte{[]byte(src)}, false, nil)
+}
+
+// TestIndexRepresentability tests that constant index operands must
+// be representable as int even if they already have a type that can
+// represent larger values.
+func TestIndexRepresentability(t *testing.T) {
+	const src = "package index\n\nvar s []byte\nvar _ = s[int64 /* ERROR \"int64\\(1\\) << 40 \\(.*\\) overflows int\" */ (1) << 40]"
+	testFiles(t, &StdSizes{4, 4}, []string{"index.go"}, [][]byte{[]byte(src)}, false, nil)
+}
+
+func TestIssue47243_TypedRHS(t *testing.T) {
+	// The RHS of the shift expression below overflows uint on 32bit platforms,
+	// but this is OK as it is explicitly typed.
+	const src = "package issue47243\n\nvar a uint64; var _ = a << uint64(4294967296)" // uint64(1<<32)
+	testFiles(t, &StdSizes{4, 4}, []string{"p.go"}, [][]byte{[]byte(src)}, false, nil)
+}
+
+func TestCheck(t *testing.T) {
+	DefPredeclaredTestFuncs()
+	testDirFiles(t, "../../internal/types/testdata/check", false)
+}
+func TestSpec(t *testing.T)      { testDirFiles(t, "../../internal/types/testdata/spec", false) }
+func TestExamples(t *testing.T)  { testDirFiles(t, "../../internal/types/testdata/examples", false) }
+func TestFixedbugs(t *testing.T) { testDirFiles(t, "../../internal/types/testdata/fixedbugs", false) }
+func TestLocal(t *testing.T)     { testDirFiles(t, "testdata/local", false) }
+
+func testDirFiles(t *testing.T, dir string, manual bool) {
+	testenv.MustHaveGoBuild(t)
+	dir = filepath.FromSlash(dir)
+
+	fis, err := os.ReadDir(dir)
+	if err != nil {
+		t.Error(err)
+		return
+	}
+
+	for _, fi := range fis {
+		path := filepath.Join(dir, fi.Name())
+
+		// If fi is a directory, its files make up a single package.
+		if fi.IsDir() {
+			testDir(t, path, manual)
+		} else {
+			t.Run(filepath.Base(path), func(t *testing.T) {
+				testPkg(t, []string{path}, manual)
+			})
+		}
+	}
+}
+
+func testDir(t *testing.T, dir string, manual bool) {
+	testenv.MustHaveGoBuild(t)
+
+	fis, err := os.ReadDir(dir)
+	if err != nil {
+		t.Error(err)
+		return
+	}
+
+	var filenames []string
+	for _, fi := range fis {
+		filenames = append(filenames, filepath.Join(dir, fi.Name()))
+	}
+
+	t.Run(filepath.Base(dir), func(t *testing.T) {
+		testPkg(t, filenames, manual)
+	})
+}
+
+// TODO(rFindley) reconcile the different test setup in go/types with types2.
+func testPkg(t *testing.T, filenames []string, manual bool) {
+	srcs := make([][]byte, len(filenames))
+	for i, filename := range filenames {
+		src, err := os.ReadFile(filename)
+		if err != nil {
+			t.Fatalf("could not read %s: %v", filename, err)
+		}
+		srcs[i] = src
+	}
+	testFiles(t, nil, filenames, srcs, manual, nil)
+}