From 3c22e5ca271ca4ad17b34d965e6a9baf7b5cf94d Mon Sep 17 00:00:00 2001
From: Robert Griesemer <gri@golang.org>
Date: Wed, 8 Feb 2017 17:56:41 -0800
Subject: [PATCH] cmd/compile/internal/parser: improved syntax error for
 incorrect if/for/switch header

Starting the error message with "expecting" rather than "missing"
causes the syntax error mechanism to add additional helpful info
(it recognizes "expecting" but not "missing").

Fixes #17328.

Change-Id: I8482ca5e5a6a6b22e0ed0d831b7328e264156334
Reviewed-on: https://go-review.googlesource.com/36637
Run-TryBot: Robert Griesemer <gri@golang.org>
Reviewed-by: Matthew Dempsky <mdempsky@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
---
 src/cmd/compile/internal/syntax/parser.go |  2 +-
 test/fixedbugs/issue17328.go              | 13 +++++++++++++
 test/syntax/semi1.go                      |  2 +-
 test/syntax/semi3.go                      |  2 +-
 test/syntax/semi4.go                      |  4 ++--
 5 files changed, 18 insertions(+), 5 deletions(-)
 create mode 100644 test/fixedbugs/issue17328.go

diff --git a/src/cmd/compile/internal/syntax/parser.go b/src/cmd/compile/internal/syntax/parser.go
index f016a6adbe..c1faa27894 100644
--- a/src/cmd/compile/internal/syntax/parser.go
+++ b/src/cmd/compile/internal/syntax/parser.go
@@ -1690,7 +1690,7 @@ func (p *parser) stmtBody(context string) []Stmt {
 	}
 
 	if !p.got(_Lbrace) {
-		p.syntax_error("missing { after " + context)
+		p.syntax_error("expecting { after " + context)
 		p.advance(_Name, _Rbrace)
 	}
 
diff --git a/test/fixedbugs/issue17328.go b/test/fixedbugs/issue17328.go
new file mode 100644
index 0000000000..abe4daa353
--- /dev/null
+++ b/test/fixedbugs/issue17328.go
@@ -0,0 +1,13 @@
+// errorcheck
+
+// 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.
+
+package main
+
+func main() {
+	i := 0
+	for ; ; i++) { // ERROR "unexpected \), expecting { after for clause"
+	}
+}
diff --git a/test/syntax/semi1.go b/test/syntax/semi1.go
index c755445b42..8eed05c1ca 100644
--- a/test/syntax/semi1.go
+++ b/test/syntax/semi1.go
@@ -7,7 +7,7 @@
 package main
 
 func main() {
-	if x; y		// ERROR "missing .*{.* after if clause|undefined"
+	if x; y		// ERROR "expected .*{.* after if clause|undefined"
 	{
 		z	// GCCGO_ERROR "undefined"
 
diff --git a/test/syntax/semi3.go b/test/syntax/semi3.go
index d625d08350..d064ce631c 100644
--- a/test/syntax/semi3.go
+++ b/test/syntax/semi3.go
@@ -7,7 +7,7 @@
 package main
 
 func main() {
-	for x; y; z	// ERROR "missing .*{.* after for clause|undefined"
+	for x; y; z	// ERROR "expected .*{.* after for clause|undefined"
 	{
 		z	// GCCGO_ERROR "undefined"
 
diff --git a/test/syntax/semi4.go b/test/syntax/semi4.go
index 6f5592ef0e..0b5e677680 100644
--- a/test/syntax/semi4.go
+++ b/test/syntax/semi4.go
@@ -13,5 +13,5 @@ package main
 
 func main() {
 	for x		// GCCGO_ERROR "undefined"
-	{		// ERROR "missing .*{.* after for clause|missing operand"
-		z	// ERROR "undefined|missing { after for clause"
+	{		// ERROR "expecting .*{.* after for clause|missing operand"
+		z	// ERROR "undefined|expecting { after for clause"