From d4da60d38fd7bdc2350677085b6973aae7385d70 Mon Sep 17 00:00:00 2001
From: Robert Griesemer <gri@golang.org>
Date: Fri, 20 Dec 2013 15:17:16 -0800
Subject: [PATCH] go.tools/gc/importer: fix struct tags and parameter names

R=iant
CC=golang-codereviews
https://golang.org/cl/42280046
---
 go/gcimporter/gcimporter.go      | 12 +++++++++---
 go/gcimporter/gcimporter_test.go |  2 +-
 2 files changed, 10 insertions(+), 4 deletions(-)

diff --git a/go/gcimporter/gcimporter.go b/go/gcimporter/gcimporter.go
index 18e6f7b459..0812de7ed9 100644
--- a/go/gcimporter/gcimporter.go
+++ b/go/gcimporter/gcimporter.go
@@ -473,7 +473,12 @@ func (p *parser) parseField() (*types.Var, string) {
 	}
 	tag := ""
 	if p.tok == scanner.String {
-		tag = p.expect(scanner.String)
+		s := p.expect(scanner.String)
+		var err error
+		tag, err = strconv.Unquote(s)
+		if err != nil {
+			p.errorf("invalid struct tag %s: %s", s, err)
+		}
 	}
 	return types.NewField(token.NoPos, pkg, name, typ, anonymous), tag
 }
@@ -509,8 +514,9 @@ func (p *parser) parseStructType() types.Type {
 //
 func (p *parser) parseParameter() (par *types.Var, isVariadic bool) {
 	_, name := p.parseName(false)
-	if name == "" {
-		name = "_" // cannot access unnamed identifiers
+	// remove gc-specific parameter numbering
+	if i := strings.Index(name, "·"); i >= 0 {
+		name = name[:i]
 	}
 	if p.tok == '.' {
 		p.expectSpecial("...")
diff --git a/go/gcimporter/gcimporter_test.go b/go/gcimporter/gcimporter_test.go
index 4e64e79ac2..094c5f5853 100644
--- a/go/gcimporter/gcimporter_test.go
+++ b/go/gcimporter/gcimporter_test.go
@@ -128,7 +128,7 @@ var importedObjectTests = []struct {
 	{"math.Pi", "const Pi untyped float"},
 	{"io.Reader", "type Reader interface{Read(p []byte) (n int, err error)}"},
 	{"io.ReadWriter", "type ReadWriter interface{Read(p []byte) (n int, err error); Write(p []byte) (n int, err error)}"},
-	{"math.Sin", "func Sin(x·2 float64) (_ float64)"},
+	{"math.Sin", "func Sin(x float64) float64"},
 	// TODO(gri) add more tests
 }