Fix that memory leak that I spent hours trying to find months ago and didn't succeed at.

Makefile

@@ -129,7 +129,6 @@ SPLINTFLAGS =            \
     -nullstate           \
     -varuse              \
     -mustfreefresh       \
-    -compdestroy         \
     -compmempass         \
     -nullpass            \
     -onlytrans           \

parser.c

@@ -5814,6 +5814,7 @@ static ast_expression* parse_expression_leave(parser_t *parser, bool stopatcomma
                 }
                 vec_free(sy.out);
                 vec_free(sy.ops);
+                vec_free(sy.argc);
                 var->cvq = cvq;
             }
         }