go/types: update FileVersions API to match proposal changes

For #62605.

Change-Id: I6e9032eb92db758bf359e7cc9c4cedc1e0fb2309
Reviewed-on: https://go-review.googlesource.com/c/go/+/534018
Auto-Submit: Robert Griesemer <gri@google.com>
TryBot-Result: Gopher Robot <gobot@golang.org>
Run-TryBot: Robert Griesemer <gri@google.com>
Reviewed-by: Robert Griesemer <gri@google.com>
Reviewed-by: Robert Findley <rfindley@google.com>

src/go/types/api.go

@@ -286,10 +286,11 @@ type Info struct {
 	// appear in this list.
 	InitOrder []*Initializer
 
-	// _FileVersions maps a file's start position to the file's Go version.
+	// _FileVersions maps a file to the file's Go version string.
-	// If the file doesn't specify a version and Config.GoVersion is not
+	// If the file doesn't specify a version and Config.GoVersion
-	// given, the reported version is the zero version (Major, Minor = 0, 0).
+	// is not given, the reported version is the empty string.
-	_FileVersions map[token.Pos]_Version
+	// TODO(gri) should this be "go0.0" instead in that case?
+	_FileVersions map[*ast.File]string
 }
 
 func (info *Info) recordTypes() bool {
@@ -414,12 +415,6 @@ func (init *Initializer) String() string {
 	return buf.String()
 }
 
-// A _Version represents a released Go version.
-type _Version struct {
-	_Major int
-	_Minor int
-}
-
 // Check type-checks a package and returns the resulting package object and
 // the first error if any. Additionally, if info != nil, Check populates each
 // of the non-nil maps in the Info struct.

src/go/types/api_test.go

@@ -2778,14 +2778,14 @@ func TestFileVersions(t *testing.T) {
 	for _, test := range []struct {
 		moduleVersion string
 		fileVersion   string
-		want          Version
+		wantVersion   string
 	}{
-		{"", "", Version{0, 0}},              // no versions specified
+		{"", "", ""},                   // no versions specified
-		{"go1.19", "", Version{1, 19}},       // module version specified
+		{"go1.19", "", "go1.19"},       // module version specified
-		{"", "go1.20", Version{0, 0}},        // file upgrade ignored
+		{"", "go1.20", ""},             // file upgrade ignored
-		{"go1.19", "go1.20", Version{1, 20}}, // file upgrade permitted
+		{"go1.19", "go1.20", "go1.20"}, // file upgrade permitted
-		{"go1.20", "go1.19", Version{1, 20}}, // file downgrade not permitted
+		{"go1.20", "go1.19", "go1.20"}, // file downgrade not permitted
-		{"go1.21", "go1.19", Version{1, 19}}, // file downgrade permitted (module version is >= go1.21)
+		{"go1.21", "go1.19", "go1.19"}, // file downgrade permitted (module version is >= go1.21)
 	} {
 		var src string
 		if test.fileVersion != "" {
@@ -2794,16 +2794,16 @@ func TestFileVersions(t *testing.T) {
 		src += "package p"
 
 		conf := Config{GoVersion: test.moduleVersion}
-		versions := make(map[*token.File]Version)
+		versions := make(map[*ast.File]string)
 		var info Info
 		*_FileVersionsAddr(&info) = versions
 		mustTypecheck(src, &conf, &info)
 
 		n := 0
 		for _, v := range versions {
-			want := test.want
+			want := test.wantVersion
-			if v.Major != want.Major || v.Minor != want.Minor {
+			if v != want {
-				t.Errorf("%q: unexpected file version: got %v, want %v", src, v, want)
+				t.Errorf("%q: unexpected file version: got %q, want %q", src, v, want)
 			}
 			n++
 		}
@@ -2813,15 +2813,8 @@ func TestFileVersions(t *testing.T) {
 	}
 }
 
-// Version must match types._Version exactly.
-// TODO(gri) remove this declaration once types.Version is exported.
-type Version struct {
-	Major int
-	Minor int
-}
-
 // _FileVersionsAddr(conf) returns the address of the field info._FileVersions.
-func _FileVersionsAddr(info *Info) *map[*token.File]Version {
+func _FileVersionsAddr(info *Info) *map[*ast.File]string {
 	v := reflect.Indirect(reflect.ValueOf(info))
-	return (*map[*token.File]Version)(v.FieldByName("_FileVersions").Addr().UnsafePointer())
+	return (*map[*ast.File]string)(v.FieldByName("_FileVersions").Addr().UnsafePointer())
 }

src/go/types/check.go

@@ -287,11 +287,10 @@ func (check *Checker) initFiles(files []*ast.File) {
 		}
 	}
 
+	// collect file versions
 	for _, file := range check.files {
-		fbase := file.FileStart
+		check.recordFileVersion(file, check.conf.GoVersion)
-		check.recordFileVersion(fbase, check.version) // record package version (possibly zero version)
+		if v, _ := parseGoVersion(file.GoVersion); v.major > 0 {
-		v, _ := parseGoVersion(file.GoVersion)
-		if v.major > 0 {
 			if v.equal(check.version) {
 				continue
 			}
@@ -314,18 +313,12 @@ func (check *Checker) initFiles(files []*ast.File) {
 			if check.posVers == nil {
 				check.posVers = make(map[token.Pos]version)
 			}
-			check.posVers[fbase] = v
+			check.posVers[file.FileStart] = v
-			check.recordFileVersion(fbase, v) // overwrite package version
+			check.recordFileVersion(file, file.GoVersion) // overwrite package version
 		}
 	}
 }
 
-// A posVers records that the file starting at pos declares the Go version vers.
-type posVers struct {
-	pos  token.Pos
-	vers version
-}
-
 // A bailout panic is used for early termination.
 type bailout struct{}
 
@@ -640,8 +633,8 @@ func (check *Checker) recordScope(node ast.Node, scope *Scope) {
 	}
 }
 
-func (check *Checker) recordFileVersion(pos token.Pos, v version) {
+func (check *Checker) recordFileVersion(file *ast.File, version string) {
 	if m := check._FileVersions; m != nil {
-		m[pos] = _Version{v.major, v.minor}
+		m[file] = version
 	}
 }