Go patch committed: Better errors for missing chan element type

[Ian Lance Taylor]

This patch to the Go frontend gives better error messages for the common
error of omitting a channel element type.  Bootstrapped and ran Go
testsuite on x86_64-unknown-linux-gnu.  Committed to mainline.

Ian


diff -r 5e8176633433 go/parse.cc
--- a/go/parse.cc	Mon Mar 28 14:34:54 2011 -0700
+++ b/go/parse.cc	Mon Mar 28 14:46:43 2011 -0700
@@ -656,6 +656,23 @@
 	  this->advance_token();
 	}
     }
+
+  // Better error messages for the common error of omitting the
+  // channel element type.
+  if (!this->type_may_start_here())
+    {
+      token = this->peek_token();
+      if (token->is_op(OPERATOR_RCURLY))
+	error_at(this->location(), "unexpected %<}%> in channel type");
+      else if (token->is_op(OPERATOR_RPAREN))
+	error_at(this->location(), "unexpected %<)%> in channel type");
+      else if (token->is_op(OPERATOR_COMMA))
+	error_at(this->location(), "unexpected comma in channel type");
+      else
+	error_at(this->location(), "expected channel element type");
+      return Type::make_error_type();
+    }
+
   Type* element_type = this->type();
   return Type::make_channel_type(send, receive, element_type);
 }