[PRISM] Implement opt_str_uminus

prism_compile.c

@@ -3972,13 +3972,18 @@ pm_compile_node(rb_iseq_t *iseq, const pm_node_t *node, LINK_ANCHOR *const ret,
             PM_PUTSELF;
             pm_compile_call(iseq, call_node, ret, src, popped, scope_node, method_id, start);
         }
-        else if (method_id == idFreeze &&
+        else if ((method_id == idUMinus || method_id == idFreeze) &&
                 PM_NODE_TYPE_P(call_node->receiver, PM_STRING_NODE) &&
                 call_node->arguments == NULL &&
                 call_node->block == NULL &&
                 ISEQ_COMPILE_DATA(iseq)->option->specialized_instruction) {
             VALUE str = rb_fstring(parse_string_encoded(call_node->receiver, &((pm_string_node_t *)call_node->receiver)->unescaped, parser));
-            ADD_INSN2(ret, &dummy_line_node, opt_str_freeze, str, new_callinfo(iseq, idFreeze, 0, 0, NULL, FALSE));
+            if (method_id == idUMinus) {
+                ADD_INSN2(ret, &dummy_line_node, opt_str_uminus, str, new_callinfo(iseq, idUMinus, 0, 0, NULL, FALSE));
+            }
+            else {
+                ADD_INSN2(ret, &dummy_line_node, opt_str_freeze, str, new_callinfo(iseq, idFreeze, 0, 0, NULL, FALSE));
+            }
         }
         else {
             PM_COMPILE_NOT_POPPED(call_node->receiver);