cmd/vet: switch to go/types from std repo

Depends on https://golang.org/cl/8767/.

With this change, cmd/vet does not depend on x/tools anymore
and could be moved into the std repo if so desired.

Change-Id: Ia205c6e1a6a63eebb27776064e5c24491043b683
Reviewed-on: https://go-review.googlesource.com/8791
Reviewed-by: Rob Pike <r@golang.org>

cmd/vet/copylock.go

@@ -11,8 +11,7 @@ import (
 	"fmt"
 	"go/ast"
 	"go/token"
-
-	"golang.org/x/tools/go/types"
+	"go/types"
 )
 
 func init() {

cmd/vet/main.go

@@ -15,14 +15,12 @@ import (
 	"go/parser"
 	"go/printer"
 	"go/token"
+	"go/types"
 	"io/ioutil"
 	"os"
 	"path/filepath"
 	"strconv"
 	"strings"
-
-	_ "golang.org/x/tools/go/gcimporter"
-	"golang.org/x/tools/go/types"
 )
 
 // TODO: Need a flag to set build tags when parsing the package.

cmd/vet/nilfunc.go

@@ -12,8 +12,7 @@ package main
 import (
 	"go/ast"
 	"go/token"
-
-	"golang.org/x/tools/go/types"
+	"go/types"
 )
 
 func init() {

cmd/vet/print.go

@@ -10,13 +10,12 @@ import (
 	"bytes"
 	"flag"
 	"go/ast"
+	"go/exact"
 	"go/token"
+	"go/types"
 	"strconv"
 	"strings"
 	"unicode/utf8"
-
-	"golang.org/x/tools/go/exact"
-	"golang.org/x/tools/go/types"
 )
 
 var printfuncs = flag.String("printfuncs", "", "comma-separated list of print function names to check")

cmd/vet/shadow.go

@@ -34,8 +34,7 @@ import (
 	"flag"
 	"go/ast"
 	"go/token"
-
-	"golang.org/x/tools/go/types"
+	"go/types"
 )
 
 var strictShadowing = flag.Bool("shadowstrict", false, "whether to be strict about shadowing; can be noisy")

cmd/vet/shift.go

@@ -10,10 +10,9 @@ package main
 
 import (
 	"go/ast"
+	"go/exact"
 	"go/token"
-
-	"golang.org/x/tools/go/exact"
-	"golang.org/x/tools/go/types"
+	"go/types"
 )
 
 func init() {

cmd/vet/types.go

@@ -8,14 +8,14 @@ package main
 
 import (
 	"go/ast"
+	"go/importer"
 	"go/token"
-
-	"golang.org/x/tools/go/types"
+	"go/types"
 )
 
-// imports is the canonical map of imported packages we need for typechecking.
-// It is created during initialization.
-var imports = make(map[string]*types.Package)
+// The stdImporter implements importing from package files created by
+// the compiler that built this binary.
+var stdImporter = importer.Default()
 
 var (
 	stringerMethodType = types.New("func() string")
@@ -35,7 +35,7 @@ func init() {
 // path.name, and adds the respective package to the imports map
 // as a side effect.
 func importType(path, name string) types.Type {
-	pkg, err := types.DefaultImport(imports, path)
+	pkg, err := stdImporter.Import(path)
 	if err != nil {
 		// This can happen if fmt hasn't been compiled yet.
 		// Since nothing uses formatterType anyway, don't complain.
@@ -56,12 +56,12 @@ func (pkg *Package) check(fs *token.FileSet, astFiles []*ast.File) error {
 	pkg.spans = make(map[types.Object]Span)
 	pkg.types = make(map[ast.Expr]types.TypeAndValue)
 	config := types.Config{
-		// We provide the same packages map for all imports to ensure
-		// that everybody sees identical packages for the given paths.
-		Packages: imports,
 		// By providing a Config with our own error function, it will continue
 		// past the first error. There is no need for that function to do anything.
 		Error: func(error) {},
+		// We use the same importer for all imports to ensure
+		// that everybody sees identical packages for the given paths.
+		Importer: stdImporter,
 	}
 	info := &types.Info{
 		Selections: pkg.selectors,

cmd/vet/unsafeptr.go

@@ -9,8 +9,7 @@ package main
 import (
 	"go/ast"
 	"go/token"
-
-	"golang.org/x/tools/go/types"
+	"go/types"
 )
 
 func init() {

cmd/vet/unused.go

@@ -11,10 +11,8 @@ import (
 	"flag"
 	"go/ast"
 	"go/token"
+	"go/types"
 	"strings"
-
-	"golang.org/x/tools/go/ast/astutil"
-	"golang.org/x/tools/go/types"
 )
 
 var unusedFuncsFlag = flag.String("unusedfuncs",
@@ -56,11 +54,11 @@ func initUnusedFlags() {
 }
 
 func checkUnusedResult(f *File, n ast.Node) {
-	call, ok := astutil.Unparen(n.(*ast.ExprStmt).X).(*ast.CallExpr)
+	call, ok := unparen(n.(*ast.ExprStmt).X).(*ast.CallExpr)
 	if !ok {
 		return // not a call statement
 	}
-	fun := astutil.Unparen(call.Fun)
+	fun := unparen(call.Fun)
 
 	if f.pkg.types[fun].IsType() {
 		return // a conversion, not a call