From: Russ Cox <rsc@golang.org>
Date: Mon, 20 Jul 2009 20:29:56 +0000 (-0700)
Subject: explain selectsend problem
X-Git-Tag: weekly.2009-11-06~1096
X-Git-Url: http://www.git.cypherpunks.su/?a=commitdiff_plain;h=f664d0e90421cf7b6257ce2f0ad197a7d76ff7a0;p=gostls13.git

explain selectsend problem

R=ken
OCL=31865
CL=31867
---

diff --git a/src/cmd/gc/walk.c b/src/cmd/gc/walk.c
index 65c4f7efd6..be3f0b9cb7 100644
--- a/src/cmd/gc/walk.c
+++ b/src/cmd/gc/walk.c
@@ -606,7 +606,10 @@ reswitch:
 			ll = ascompatte(n->op, getinarg(t), n->list, 0, init);
 			n->list = reorder1(ll);
 			if(isselect(n)) {
-				// clear output bool - special prob with selectsend
+				// special prob with selectsend and selectrecv:
+				// if chan is nil, they don't know big the channel
+				// element is and therefore don't know how to find
+				// the output bool, so we clear it before the call.
 				Node *b;
 				b = nodbool(0);
 				lr = ascompatte(n->op, getoutarg(t), list1(b), 0, init);