diff --git a/src/cmd/compile/internal/syntax/scanner.go b/src/cmd/compile/internal/syntax/scanner.go
index 2ce6203dd98..fc2efcced26 100644
--- a/src/cmd/compile/internal/syntax/scanner.go
+++ b/src/cmd/compile/internal/syntax/scanner.go
@@ -704,7 +704,7 @@ func (s *scanner) rawString() {
 }
 
 func (s *scanner) comment(text string) {
-	s.errorAtf(0, text)
+	s.errorAtf(0, "%s", text)
 }
 
 func (s *scanner) skipLine() {