diff --git a/src/libexpr/parser.y b/src/libexpr/parser.y
index 55a42fcaba..d89d92c7a2 100644
--- a/src/libexpr/parser.y
+++ b/src/libexpr/parser.y
@@ -414,7 +414,7 @@ expr_simple
 string_parts
   : STR
   | string_parts_interpolated { $$ = new ExprConcatStrings(true, $1); }
-  | { $$ = new ExprString(data->symbols.create("")) }
+  | { $$ = new ExprString(data->symbols.create("")); }
   ;
 
 string_parts_interpolated