This patch to the Go frontend corrects parsing of parenthesized select
cases. The frontend used to mishandle `select { case (<-c): }` and
friends. The test case for this is https://golang.org/cl/91657. This
fixes https://golang.org/issue/20923. Bootstrapped and ran Go
testsuite on x86_64-pc-linux-gnu. Committed to mainline.
Ian
Index: gcc/go/gofrontend/MERGE
===================================================================
--- gcc/go/gofrontend/MERGE (revision 257373)
+++ gcc/go/gofrontend/MERGE (working copy)
@@ -1,4 +1,4 @@
-9057b8f71e6078f140938fe60be9aaa7d59a3a2b
+2f7ac42a3f83b78d97912ce1e86296b2af4f52b7
The first line of this file holds the git revision number of the last
merge done from the gofrontend repository.
Index: gcc/go/gofrontend/parse.cc
===================================================================
--- gcc/go/gofrontend/parse.cc (revision 257357)
+++ gcc/go/gofrontend/parse.cc (working copy)
@@ -5160,7 +5160,18 @@ Parse::send_or_recv_stmt(bool* is_send,
Expression* e;
if (saw_comma || !this->peek_token()->is_op(OPERATOR_CHANOP))
- e = this->expression(PRECEDENCE_NORMAL, true, true, NULL, NULL);
+ {
+ e = this->expression(PRECEDENCE_NORMAL, true, true, NULL, NULL);
+ if (e->receive_expression() != NULL)
+ {
+ *is_send = false;
+ *channel = e->receive_expression()->channel();
+ // This is 'case (<-c):'. We now expect ':'. If we see
+ // '<-', then we have case (<-c)<-v:
+ if (!this->peek_token()->is_op(OPERATOR_CHANOP))
+ return true;
+ }
+ }
else
{
// case <-c:
@@ -5189,14 +5200,17 @@ Parse::send_or_recv_stmt(bool* is_send,
if (this->peek_token()->is_op(OPERATOR_EQ))
{
- if (!this->advance_token()->is_op(OPERATOR_CHANOP))
+ *is_send = false;
+ this->advance_token();
+ Location recvloc = this->location();
+ Expression* recvexpr = this->expression(PRECEDENCE_NORMAL, false,
+ true, NULL, NULL);
+ if (recvexpr->receive_expression() == NULL)
{
- go_error_at(this->location(), "missing %<<-%>");
+ go_error_at(recvloc, "missing %<<-%>");
return false;
}
- *is_send = false;
- this->advance_token();
- *channel = this->expression(PRECEDENCE_NORMAL, false, true, NULL, NULL);
+ *channel = recvexpr->receive_expression()->channel();
if (saw_comma)
{
// case v, e = <-c:
