go/types, types2: better variable names, cleanups in test

For #54258.

Change-Id: Ib0d326af2719bca1579f84c125f6573f87dce982
Reviewed-on: https://go-review.googlesource.com/c/go/+/452455
Run-TryBot: Robert Findley <rfindley@google.com>
Auto-Submit: Robert Griesemer <gri@google.com>
Reviewed-by: Robert Griesemer <gri@google.com>
TryBot-Result: Gopher Robot <gobot@golang.org>
Reviewed-by: Robert Findley <rfindley@google.com>
Run-TryBot: Robert Griesemer <gri@google.com>

src/cmd/compile/internal/types2/issues_test.go

@@ -806,18 +806,18 @@ func (S) M5(struct {S;t}) {}
 .*want M5[(]struct{b[.]S; t}[)]`},
 	}
 
-	test := func(main, imported, want string) {
+	test := func(main, b, want string) {
 		re := regexp.MustCompile(want)
-		a := mustTypecheck("b", imported, nil)
-		bast := mustParse("", main)
-		conf := Config{Importer: importHelper{pkg: a}}
-		_, err := conf.Check(bast.PkgName.Value, []*syntax.File{bast}, nil)
+		bpkg := mustTypecheck("b", b, nil)
+		mast := mustParse("main.go", main)
+		conf := Config{Importer: importHelper{pkg: bpkg}}
+		_, err := conf.Check(mast.PkgName.Value, []*syntax.File{mast}, nil)
 		if err == nil {
-			t.Errorf("Expected failure, but it did not")
+			t.Error("Expected failure, but it did not")
 		} else if got := err.Error(); !re.MatchString(got) {
-			t.Errorf("Wanted match for\n%s\n but got \n%s", want, got)
+			t.Errorf("Wanted match for\n\t%s\n but got\n\t%s", want, got)
 		} else if testing.Verbose() {
-			t.Logf("Saw expected\n%s", err.Error())
+			t.Logf("Saw expected\n\t%s", err.Error())
 		}
 	}
 	for _, t := range tests {

src/go/types/issues_test.go

@@ -833,18 +833,19 @@ func (S) M5(struct {S;t}) {}
 .*want M5[(]struct{b[.]S; t}[)]`},
 	}
 
-	test := func(main, imported, want string) {
+	fset := token.NewFileSet()
+	test := func(main, b, want string) {
 		re := regexp.MustCompile(want)
-		a := mustTypecheck("b", imported, nil)
-		bast := mustParse(fset, "", main)
-		conf := Config{Importer: importHelper{pkg: a}}
-		_, err := conf.Check(bast.Name.Name, fset, []*ast.File{bast}, nil)
+		bpkg := mustTypecheck("b", b, nil)
+		mast := mustParse(fset, "main.go", main)
+		conf := Config{Importer: importHelper{pkg: bpkg}}
+		_, err := conf.Check(mast.Name.Name, fset, []*ast.File{mast}, nil)
 		if err == nil {
-			t.Errorf("Expected failure, but it did not")
+			t.Error("Expected failure, but it did not")
 		} else if got := err.Error(); !re.MatchString(got) {
-			t.Errorf("Wanted match for\n%s\n but got \n%s", want, got)
+			t.Errorf("Wanted match for\n\t%s\n but got\n\t%s", want, got)
 		} else if testing.Verbose() {
-			t.Logf("Saw expected\n%s", err.Error())
+			t.Logf("Saw expected\n\t%s", err.Error())
 		}
 	}
 	for _, t := range tests {

src/go/types/object.go

@@ -9,8 +9,6 @@ import (
 	"fmt"
 	"go/constant"
 	"go/token"
-	"unicode"
-	"unicode/utf8"
 )
 
 // An Object describes a named language entity such as a package,
@@ -59,11 +57,6 @@ type Object interface {
 	setScopePos(pos token.Pos)
 }
 
-func isExported(name string) bool {
-	ch, _ := utf8.DecodeRuneInString(name)
-	return unicode.IsUpper(ch)
-}
-
 // Id returns name if it is exported, otherwise it
 // returns the name qualified with the package path.
 func Id(pkg *Package, name string) string {

src/go/types/typestring.go

@@ -153,7 +153,7 @@ func (w *typeWriter) typ(typ Type) {
 			// If disambiguating one struct for another, look for the first unexported field.
 			// Do this first in case of nested structs; tag the first-outermost field.
 			pkgAnnotate := false
-			if w.qf == nil && w.pkgInfo && !isExported(f.name) {
+			if w.qf == nil && w.pkgInfo && !token.IsExported(f.name) {
 				// note for embedded types, type name is field name, and "string" etc are lower case hence unexported.
 				pkgAnnotate = true
 				w.pkgInfo = false // only tag once