From: Luuk van Dijk <lvd@golang.org>
Date: Sun, 6 Nov 2011 21:14:15 +0000 (+0100)
Subject: gc: Better error message for range over non-receive channel.
X-Git-Tag: weekly.2011-11-08~25
X-Git-Url: http://www.git.cypherpunks.su/?a=commitdiff_plain;h=ea9e93862d9b6fc0c5b53cdb204204923d653b8a;p=gostls13.git

gc: Better error message for range over non-receive channel.

Fixes #2354

R=rsc
CC=golang-dev
https://golang.org/cl/5346044
---

diff --git a/src/cmd/gc/range.c b/src/cmd/gc/range.c
index 1909c9ec77..25d1131ec3 100644
--- a/src/cmd/gc/range.c
+++ b/src/cmd/gc/range.c
@@ -46,6 +46,10 @@ typecheckrange(Node *n)
 		break;
 
 	case TCHAN:
+		if(!(t->chan & Crecv)) {
+			yyerror("invalid operation: range %N (receive from send-only type %T)", n->right, n->right->type);
+			goto out;
+		}
 		t1 = t->type;
 		t2 = nil;
 		if(count(n->list) == 2)
diff --git a/test/chan/perm.go b/test/chan/perm.go
index af054450ea..a43df19821 100644
--- a/test/chan/perm.go
+++ b/test/chan/perm.go
@@ -48,7 +48,10 @@ func main() {
 	case x := <-cs: // ERROR "receive"
 		_ = x
 	}
-	
+
+	for _ = range cs {// ERROR "receive"
+	}
+
 	close(c)
 	close(cs)
 	close(cr)  // ERROR "receive"