cmd/vet: roll back update of go/types import

(from importing golang.org/x/tools/go/types to std lib go/types)

The cmd/vet package should never have been included in this change.

Tested with 1.4.1, 1.5 and ~1.6 (tip).

Change-Id: I6d915619cbfa0297dbb9aa9ba033c1320a08c367
Reviewed-on: https://go-review.googlesource.com/18385
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>

cmd/vet/copylock.go

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

cmd/vet/example.go

@@ -6,10 +6,11 @@ package main
 
 import (
 	"go/ast"
-	"go/types"
 	"strings"
 	"unicode"
 	"unicode/utf8"
+
+	"golang.org/x/tools/go/types"
 )
 
 func init() {

cmd/vet/main.go

@@ -18,12 +18,14 @@ 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"
 )
 
 var (

cmd/vet/nilfunc.go

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

cmd/vet/print.go

@@ -10,12 +10,13 @@ import (
 	"bytes"
 	"flag"
 	"go/ast"
-	exact "go/constant"
 	"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

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

cmd/vet/shift.go

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

cmd/vet/types.go

@@ -8,9 +8,9 @@ package main
 
 import (
 	"go/ast"
-	"go/importer"
 	"go/token"
-	"go/types"
+
+	"golang.org/x/tools/go/types"
 )
 
 // imports is the canonical map of imported packages we need for typechecking.
@@ -18,8 +18,6 @@ import (
 var imports = make(map[string]*types.Package)
 
 var (
-	defaultImporter = importer.Default()
-
 	errorType     *types.Interface
 	stringerType  *types.Interface // possibly nil
 	formatterType *types.Interface // possibly nil
@@ -41,7 +39,7 @@ func init() {
 // path.name, and adds the respective package to the imports map
 // as a side effect. In case of an error, importType returns nil.
 func importType(path, name string) types.Type {
-	pkg, err := defaultImporter.Import(path)
+	pkg, err := types.DefaultImport(imports, path)
 	if err != nil {
 		// This can happen if the package at path hasn't been compiled yet.
 		warnf("import failed: %v", err)
@@ -61,7 +59,9 @@ 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{
-		Importer: defaultImporter,
+		// 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) {},

cmd/vet/unsafeptr.go

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

cmd/vet/unused.go

@@ -11,8 +11,9 @@ import (
 	"flag"
 	"go/ast"
 	"go/token"
-	"go/types"
 	"strings"
+
+	"golang.org/x/tools/go/types"
 )
 
 var unusedFuncsFlag = flag.String("unusedfuncs",