py/parse: Only replace constants that are standalone identifiers.

This fixes constant substitution so that only standalone identifiers are
replaced with their constant value (if they have one).  I.e. don't
replace NAME in expressions like obj.NAME or NAME = expr.

py/parse.c

@@ -398,21 +398,24 @@ STATIC mp_parse_node_t make_node_const_object(parser_t *parser, size_t src_line,
     return (mp_parse_node_t)pn;
 }
 
-STATIC void push_result_token(parser_t *parser) {
+STATIC void push_result_token(parser_t *parser, const rule_t *rule) {
     mp_parse_node_t pn;
     mp_lexer_t *lex = parser->lexer;
     if (lex->tok_kind == MP_TOKEN_NAME) {
         qstr id = qstr_from_strn(lex->vstr.buf, lex->vstr.len);
         #if MICROPY_COMP_CONST
-        // lookup identifier in table of dynamic constants
-        mp_map_elem_t *elem = mp_map_lookup(&parser->consts, MP_OBJ_NEW_QSTR(id), MP_MAP_LOOKUP);
-        if (elem != NULL) {
+        // if name is a standalone identifier, look it up in the table of dynamic constants
+        mp_map_elem_t *elem;
+        if (rule->rule_id == RULE_atom
+            && (elem = mp_map_lookup(&parser->consts, MP_OBJ_NEW_QSTR(id), MP_MAP_LOOKUP)) != NULL) {
             pn = mp_parse_node_new_leaf(MP_PARSE_NODE_SMALL_INT, MP_OBJ_SMALL_INT_VALUE(elem->value));
-        } else
-        #endif
-        {
+        } else {
             pn = mp_parse_node_new_leaf(MP_PARSE_NODE_ID, id);
         }
+        #else
+        (void)rule;
+        pn = mp_parse_node_new_leaf(MP_PARSE_NODE_ID, id);
+        #endif
     } else if (lex->tok_kind == MP_TOKEN_INTEGER) {
         mp_obj_t o = mp_parse_num_integer(lex->vstr.buf, lex->vstr.len, 0, lex);
         if (MP_OBJ_IS_SMALL_INT(o)) {
@@ -765,7 +768,7 @@ mp_parse_tree_t mp_parse(mp_lexer_t *lex, mp_parse_input_kind_t input_kind) {
                     uint16_t kind = rule->arg[i] & RULE_ARG_KIND_MASK;
                     if (kind == RULE_ARG_TOK) {
                         if (lex->tok_kind == (rule->arg[i] & RULE_ARG_ARG_MASK)) {
-                            push_result_token(&parser);
+                            push_result_token(&parser, rule);
                             mp_lexer_to_next(lex);
                             goto next_rule;
                         }
@@ -810,7 +813,7 @@ mp_parse_tree_t mp_parse(mp_lexer_t *lex, mp_parse_input_kind_t input_kind) {
                             if (lex->tok_kind == tok_kind) {
                                 // matched token
                                 if (tok_kind == MP_TOKEN_NAME) {
-                                    push_result_token(&parser);
+                                    push_result_token(&parser, rule);
                                 }
                                 mp_lexer_to_next(lex);
                             } else {
@@ -950,7 +953,7 @@ mp_parse_tree_t mp_parse(mp_lexer_t *lex, mp_parse_input_kind_t input_kind) {
                                     if (i & 1 & n) {
                                         // separators which are tokens are not pushed to result stack
                                     } else {
-                                        push_result_token(&parser);
+                                        push_result_token(&parser, rule);
                                     }
                                     mp_lexer_to_next(lex);
                                     // got element of list, so continue parsing list