diff --git a/cmd/stringer/endtoend_test.go b/cmd/stringer/endtoend_test.go
index 91f34092..273f29bd 100644
--- a/cmd/stringer/endtoend_test.go
+++ b/cmd/stringer/endtoend_test.go
@@ -9,7 +9,6 @@
 package main
 
 import (
-	"bytes"
 	"fmt"
 	"go/build"
 	"io"
@@ -27,8 +26,17 @@ import (
 // binary panics if the String method for X is not correct, including for error cases.
 
 func TestEndToEnd(t *testing.T) {
-	dir, stringer := buildStringer(t)
+	dir, err := ioutil.TempDir("", "stringer")
+	if err != nil {
+		t.Fatal(err)
+	}
 	defer os.RemoveAll(dir)
+	// Create stringer in temporary directory.
+	stringer := filepath.Join(dir, "stringer.exe")
+	err = run("go", "build", "-o", stringer)
+	if err != nil {
+		t.Fatalf("building stringer: %s", err)
+	}
 	// Read the testdata directory.
 	fd, err := os.Open("testdata")
 	if err != nil {
@@ -45,10 +53,6 @@ func TestEndToEnd(t *testing.T) {
 			t.Errorf("%s is not a Go file", name)
 			continue
 		}
-		if strings.HasPrefix(name, "tag_") {
-			// This file is used for tag processing in TestTags, below.
-			continue
-		}
 		if name == "cgo.go" && !build.Default.CgoEnabled {
 			t.Logf("cgo is not enabled for %s", name)
 			continue
@@ -59,69 +63,9 @@ func TestEndToEnd(t *testing.T) {
 	}
 }
 
-// TestTags verifies that the -tags flag works as advertised.
-func TestTags(t *testing.T) {
-	dir, stringer := buildStringer(t)
-	defer os.RemoveAll(dir)
-	var (
-		protectedConst = []byte("TagProtected")
-		output         = filepath.Join(dir, "const_string.go")
-	)
-	for _, file := range []string{"tag_main.go", "tag_tag.go"} {
-
-		err := copy(filepath.Join(dir, file), filepath.Join("testdata", file))
-		if err != nil {
-			t.Fatal(err)
-		}
-
-	}
-	err := run(stringer, "-type", "Const", dir)
-	if err != nil {
-		t.Fatal(err)
-	}
-	result, err := ioutil.ReadFile(output)
-	if err != nil {
-		t.Fatal(err)
-	}
-	if bytes.Contains(result, protectedConst) {
-		t.Fatal("tagged variable appears in untagged run")
-	}
-	err = os.Remove(output)
-	if err != nil {
-		t.Fatal(err)
-	}
-	err = run(stringer, "-type", "Const", "-tags", "tag", dir)
-	if err != nil {
-		t.Fatal(err)
-	}
-	result, err = ioutil.ReadFile(output)
-	if err != nil {
-		t.Fatal(err)
-	}
-	if !bytes.Contains(result, protectedConst) {
-		t.Fatal("tagged variable does not appear in tagged run")
-	}
-}
-
-// buildStringer creates a temporary directory and installs stringer there.
-func buildStringer(t *testing.T) (dir string, stringer string) {
-	t.Helper()
-	dir, err := ioutil.TempDir("", "stringer")
-	if err != nil {
-		t.Fatal(err)
-	}
-	stringer = filepath.Join(dir, "stringer.exe")
-	err = run("go", "build", "-o", stringer, "stringer.go")
-	if err != nil {
-		t.Fatalf("building stringer: %s", err)
-	}
-	return dir, stringer
-}
-
 // stringerCompileAndRun runs stringer for the named file and compiles and
 // runs the target binary in directory dir. That binary will panic if the String method is incorrect.
 func stringerCompileAndRun(t *testing.T, dir, stringer, typeName, fileName string) {
-	t.Helper()
 	t.Logf("run: %s %s\n", fileName, typeName)
 	source := filepath.Join(dir, fileName)
 	err := copy(source, filepath.Join("testdata", fileName))
diff --git a/cmd/stringer/importer18.go b/cmd/stringer/importer18.go
new file mode 100644
index 00000000..fd21873c
--- /dev/null
+++ b/cmd/stringer/importer18.go
@@ -0,0 +1,16 @@
+// Copyright 2017 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.
+
+// +build !go1.9
+
+package main
+
+import (
+	"go/importer"
+	"go/types"
+)
+
+func defaultImporter() types.Importer {
+	return importer.Default()
+}
diff --git a/cmd/stringer/importer19.go b/cmd/stringer/importer19.go
new file mode 100644
index 00000000..deddadb1
--- /dev/null
+++ b/cmd/stringer/importer19.go
@@ -0,0 +1,16 @@
+// Copyright 2017 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.
+
+// +build go1.9
+
+package main
+
+import (
+	"go/importer"
+	"go/types"
+)
+
+func defaultImporter() types.Importer {
+	return importer.For("source", nil)
+}
diff --git a/cmd/stringer/stringer.go b/cmd/stringer/stringer.go
index bed6b6b4..4b8d1ba4 100644
--- a/cmd/stringer/stringer.go
+++ b/cmd/stringer/stringer.go
@@ -66,7 +66,6 @@ import (
 	"go/build"
 	exact "go/constant"
 	"go/format"
-	"go/importer"
 	"go/parser"
 	"go/token"
 	"go/types"
@@ -83,7 +82,6 @@ var (
 	output      = flag.String("output", "", "output file name; default srcdir/<type>_string.go")
 	trimprefix  = flag.String("trimprefix", "", "trim the `prefix` from the generated constant names")
 	linecomment = flag.Bool("linecomment", false, "use line comment text as printed text when present")
-	buildTags   = flag.String("tags", "", "comma-separated list of build tags to apply")
 )
 
 // Usage is a replacement usage function for the flags package.
@@ -107,10 +105,6 @@ func main() {
 		os.Exit(2)
 	}
 	types := strings.Split(*typeNames, ",")
-	var tags []string
-	if len(*buildTags) > 0 {
-		tags = strings.Split(*buildTags, ",")
-	}
 
 	// We accept either one directory or a list of files. Which do we have?
 	args := flag.Args()
@@ -127,11 +121,8 @@ func main() {
 	}
 	if len(args) == 1 && isDirectory(args[0]) {
 		dir = args[0]
-		g.parsePackageDir(args[0], tags)
+		g.parsePackageDir(args[0])
 	} else {
-		if len(tags) != 0 {
-			log.Fatal("-tags option applies only to directories, not when files are specified")
-		}
 		dir = filepath.Dir(args[0])
 		g.parsePackageFiles(args)
 	}
@@ -206,15 +197,9 @@ type Package struct {
 	typesPkg *types.Package
 }
 
-func buildContext(tags []string) *build.Context {
-	ctx := build.Default
-	ctx.BuildTags = tags
-	return &ctx
-}
-
 // parsePackageDir parses the package residing in the directory.
-func (g *Generator) parsePackageDir(directory string, tags []string) {
-	pkg, err := buildContext(tags).ImportDir(directory, 0)
+func (g *Generator) parsePackageDir(directory string) {
+	pkg, err := build.Default.ImportDir(directory, 0)
 	if err != nil {
 		log.Fatalf("cannot process directory %s: %s", directory, err)
 	}
@@ -276,17 +261,14 @@ func (g *Generator) parsePackage(directory string, names []string, text interfac
 	g.pkg.name = astFiles[0].Name.Name
 	g.pkg.files = files
 	g.pkg.dir = directory
-	g.pkg.typeCheck(fs, astFiles)
+	// Type check the package.
+	g.pkg.check(fs, astFiles)
 }
 
-// check type-checks the package so we can evaluate contants whose values we are printing.
-func (pkg *Package) typeCheck(fs *token.FileSet, astFiles []*ast.File) {
+// check type-checks the package. The package must be OK to proceed.
+func (pkg *Package) check(fs *token.FileSet, astFiles []*ast.File) {
 	pkg.defs = make(map[*ast.Ident]types.Object)
-	config := types.Config{
-		IgnoreFuncBodies: true, // We only need to evaluate constants.
-		Importer:         importer.Default(),
-		FakeImportC:      true,
-	}
+	config := types.Config{Importer: defaultImporter(), FakeImportC: true}
 	info := &types.Info{
 		Defs: pkg.defs,
 	}
diff --git a/cmd/stringer/testdata/tag_main.go b/cmd/stringer/testdata/tag_main.go
deleted file mode 100644
index 449ea0d4..00000000
--- a/cmd/stringer/testdata/tag_main.go
+++ /dev/null
@@ -1,11 +0,0 @@
-// No build tag in this file.
-
-package main
-
-type Const int
-
-const (
-	A Const = iota
-	B
-	C
-)
diff --git a/cmd/stringer/testdata/tag_tag.go b/cmd/stringer/testdata/tag_tag.go
deleted file mode 100644
index 6844cb00..00000000
--- a/cmd/stringer/testdata/tag_tag.go
+++ /dev/null
@@ -1,7 +0,0 @@
-// This file has a build tag "tag"
-
-// +build tag
-
-package main
-
-const TagProtected Const = C + 1