From: Robert Griesemer <gri@golang.org>
Date: Tue, 19 Apr 2016 18:27:52 +0000 (-0700)
Subject: go/types: accept trailing empty stmts in terminating stmt lists
X-Git-Tag: go1.7beta1~605
X-Git-Url: http://www.git.cypherpunks.su/?a=commitdiff_plain;h=562d398aef1378c781a3164f59f54dd1b0f4638f;p=gostls13.git

go/types: accept trailing empty stmts in terminating stmt lists

Per the latest spec refinement (https://golang.org/cl/19981).

Fixes #14537.

Change-Id: I2dedee942c4da21dc94bdeda466f133827ab5bb9
Reviewed-on: https://go-review.googlesource.com/22241
Run-TryBot: Robert Griesemer <gri@golang.org>
Reviewed-by: Alan Donovan <adonovan@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
---

diff --git a/src/go/types/return.go b/src/go/types/return.go
index 6628985214..0c1447f89b 100644
--- a/src/go/types/return.go
+++ b/src/go/types/return.go
@@ -83,8 +83,13 @@ func (check *Checker) isTerminating(s ast.Stmt, label string) bool {
 }
 
 func (check *Checker) isTerminatingList(list []ast.Stmt, label string) bool {
-	n := len(list)
-	return n > 0 && check.isTerminating(list[n-1], label)
+	// trailing empty statements are permitted - skip them
+	for i := len(list) - 1; i >= 0; i-- {
+		if _, ok := list[i].(*ast.EmptyStmt); !ok {
+			return check.isTerminating(list[i], label)
+		}
+	}
+	return false // all statements are empty
 }
 
 func (check *Checker) isTerminatingSwitch(body *ast.BlockStmt, label string) bool {
diff --git a/src/go/types/testdata/stmt1.src b/src/go/types/testdata/stmt1.src
index a2955e6fd0..24ad6ebdf1 100644
--- a/src/go/types/testdata/stmt1.src
+++ b/src/go/types/testdata/stmt1.src
@@ -20,17 +20,41 @@ func _(x, y int) (z int) {
 	}
 }
 
+func _(x, y int) (z int) {
+	{
+		return; ; ; // trailing empty statements are ok
+	}
+	; ; ;
+}
+
 func _(x, y int) (z int) {
 	{
 	}
 } /* ERROR "missing return" */
 
+func _(x, y int) (z int) {
+	{
+		; ; ;
+	}
+	; ; ;
+} /* ERROR "missing return" */
+
 // if statements
 func _(x, y int) (z int) {
 	if x < y { return }
 	return 1
 }
 
+func _(x, y int) (z int) {
+	if x < y { return; ; ; ; }
+	return 1
+}
+
+func _(x, y int) (z int) {
+	if x < y { return }
+	return 1; ;
+}
+
 func _(x, y int) (z int) {
 	if x < y { return }
 } /* ERROR "missing return" */
@@ -60,11 +84,18 @@ func _(x, y int) (z int) {
 	}
 }
 
+func _(x, y int) (z int) {
+	for {
+		return; ; ; ;
+	}
+}
+
 func _(x, y int) (z int) {
 	for {
 		return
 		break
 	}
+	; ; ;
 } /* ERROR "missing return" */
 
 func _(x, y int) (z int) {
@@ -74,6 +105,14 @@ func _(x, y int) (z int) {
 	}
 }
 
+func _(x, y int) (z int) {
+	for {
+		for { break }
+		return ; ;
+	}
+	;
+}
+
 func _(x, y int) (z int) {
 L:	for {
 		for { break L }
@@ -89,6 +128,13 @@ func _(x, y int) (z int) {
 	}
 }
 
+func _(x, y int) (z int) {
+	switch x {
+	case 0: return;
+	default: return; ; ;
+	}
+}
+
 func _(x, y int) (z int) {
 	switch x {
 	case 0: return
@@ -113,6 +159,18 @@ func _(x, y int) (z int) {
 	}
 }
 
+func _(x, y int) (z int) {
+	switch x {
+	case 0: return
+	default:
+		switch y {
+		case 0: break
+		}
+		panic(0); ; ;
+	}
+	;
+}
+
 func _(x, y int) (z int) {
 L:	switch x {
 	case 0: return
@@ -129,6 +187,11 @@ func _(ch chan int) (z int) {
 	select {}
 } // nice!
 
+func _(ch chan int) (z int) {
+	select {}
+	; ;
+}
+
 func _(ch chan int) (z int) {
 	select {
 	default: break
@@ -153,6 +216,18 @@ func _(ch chan int) (z int) {
 	}
 }
 
+func _(ch chan int) (z int) {
+	select {
+	case <-ch: return; ; ;
+	default:
+		for i := 0; i < 10; i++ {
+			break
+		}
+		return; ; ;
+	}
+	; ; ;
+}
+
 func _(ch chan int) (z int) {
 L:	select {
 	case <-ch: return
@@ -162,4 +237,5 @@ L:	select {
 		}
 		return
 	}
+	; ; ;
 } /* ERROR "missing return" */