cmd/compile: fix some C to Go translation leftovers

Following the C to Go translation, some useless variables
were left in the code. In fmt.go, this was harmless.
In lex.go, it broke the error message related to
non-canonical import paths.

Fix it, and remove the useless variables.

The added test case is ignored in the go/types tests, since
the behavior of the non-canonical import path check seems
to be different.

Fixes #11362

Change-Id: Ic9129139ede90357dc79ebf167af638cf44536fa
Reviewed-on: https://go-review.googlesource.com/15580Reviewed-by: Marvin Stenger <marvin.stenger94@gmail.com>
Reviewed-by: Minux Ma <minux@golang.org>
Run-TryBot: Minux Ma <minux@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>

src/cmd/compile/internal/gc/fmt.go

@@ -1595,8 +1595,6 @@ func Sconv(s *Sym, flag int) string {
 
 	sf := flag
 	sm := setfmode(&flag)
-	var r int
-	_ = r
 	str := symfmt(s, flag)
 	flag = sf
 	fmtmode = sm
@@ -1631,8 +1629,6 @@ func Tconv(t *Type, flag int) string {
 		flag |= obj.FmtUnsigned
 	}
 
-	var r int
-	_ = r
 	str := typefmt(t, flag)
 
 	if fmtmode == FTypeId && (sf&obj.FmtUnsigned != 0) {
@@ -1659,8 +1655,6 @@ func Nconv(n *Node, flag int) string {
 	sf := flag
 	sm := setfmode(&flag)
 
-	var r int
-	_ = r
 	var str string
 	switch fmtmode {
 	case FErr, FExp:
@@ -1693,8 +1687,6 @@ func Hconv(l *NodeList, flag int) string {
 
 	sf := flag
 	sm := setfmode(&flag)
-	var r int
-	_ = r
 	sep := "; "
 	if fmtmode == FDbg {
 		sep = "\n"

src/cmd/compile/internal/gc/lex.go

@@ -595,9 +595,7 @@ func findpkg(name string) (file string, ok bool) {
 	// local imports should be canonicalized already.
 	// don't want to see "encoding/../encoding/base64"
 	// as different from "encoding/base64".
-	var q string
-	_ = q
-	if path.Clean(name) != name {
+	if q := path.Clean(name); q != name {
 		Yyerror("non-canonical import path %q (should be %q)", name, q)
 		return "", false
 	}

src/go/types/stdlib_test.go

@@ -150,6 +150,7 @@ func TestStdFixed(t *testing.T) {
 		"issue7746.go",   // large constants - consumes too much memory
 		"issue11326.go",  // large constants
 		"issue11326b.go", // large constants
+		"issue11362.go",  // canonical import path check
 	)
 }
 

test/fixedbugs/issue11362.go

+// errorcheck
+
+// Copyright 2015 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.
+
+// Issue 11362: prints empty canonical import path
+
+package main
+
+import _ "unicode//utf8" // ERROR "non-canonical import path .unicode//utf8. \(should be .unicode/utf8.\)" "can't find import: .unicode//utf8."
+
+func main() {
+}
+