Go patch committed: Correctly parse case <-c <- v

[Ian Lance Taylor]

This patch to the Go frontend correctly parses
        select {
        case <-c <- v:
        }
Bootstrapped and ran Go testsuite on x86_64-unknown-linux-gnu.
Committed to mainline.

Ian


diff -r 51340e536e48 go/parse.cc
--- a/go/parse.cc	Fri Mar 25 13:39:15 2011 -0700
+++ b/go/parse.cc	Fri Mar 25 18:57:25 2011 -0700
@@ -4375,17 +4375,25 @@
   // send or receive expression.  If SAW_COMMA is true, then *VAL is
   // set and we just read a comma.
 
-  if (!saw_comma && this->peek_token()->is_op(OPERATOR_CHANOP))
+  Expression* e;
+  if (saw_comma || !this->peek_token()->is_op(OPERATOR_CHANOP))
+    e = this->expression(PRECEDENCE_NORMAL, true, true, NULL);
+  else
     {
       // case <-c:
       *is_send = false;
       this->advance_token();
       *channel = this->expression(PRECEDENCE_NORMAL, false, true, NULL);
-      return true;
+
+      // The next token should be ':'.  If it is '<-', then we have
+      // case <-c <- v:
+      // which is to say, send on a channel received from a channel.
+      if (!this->peek_token()->is_op(OPERATOR_CHANOP))
+	return true;
+
+      e = Expression::make_receive(*channel, (*channel)->location());
     }
 
-  Expression* e = this->expression(PRECEDENCE_NORMAL, true, true, NULL);
-
   if (this->peek_token()->is_op(OPERATOR_EQ))
     {
       if (!this->advance_token()->is_op(OPERATOR_CHANOP))