Emulate docComment on CONST_ELEM for PHP 7.0

Author: nikic

README.md

@@ -405,6 +405,7 @@ AST_COALESCE:         left, right            // prior to version 40
 AST_CONDITIONAL:      cond, true, false
 AST_CONST:            name
 AST_CONST_ELEM:       name, value
+                      docComment             // since version 50
 AST_CONTINUE:         depth
 AST_DECLARE:          declares, stmts
 AST_DIM:              expr, dim
@@ -445,6 +446,7 @@ AST_PRE_INC:          var
 AST_PRINT:            expr
 AST_PROP:             expr, prop
 AST_PROP_ELEM:        name, default
+                      docComment             // since version 50
 AST_REF:              var                    // only used in foreach ($a as &$v)
 AST_RETURN:           expr
 AST_SHELL_EXEC:       expr
@@ -517,7 +519,8 @@ Supported since 2017-07-19.
   `AST_CLOSURE` and `AST_CLASS` now also use the normal `ast\Node` class. The `name` and
   `docComment` properties are now represented as children. The `endLineno` is still represented as
   an (undeclared) property.
-* `AST_PROP_ELEM` now store the `docComment` as a child, rather than a property.
+* `AST_PROP_ELEM` and `AST_CONST_ELEM` now store the `docComment` as a child, rather than a
+  property.
 * An integer `__declId` has been added to declaration nodes of kind `AST_FUNCTION`, `AST_METHOD`,
   `AST_CLOSURE` and `AST_CLASS`. The `__declId` uniquely identifies a declaration within the parsed
   code and will remain the same if the code is parsed again. This is useful to distinguish closures

ast.c

@@ -637,6 +637,15 @@ static void ast_fill_children_ht(HashTable *ht, zend_ast *ast, ast_state_info_t
 
 	}
 
+#if PHP_VERSION_ID < 70100
+	/* Emulate docComment on constants, which is not available in PHP 7.0 */
+	if (state->version >= 50 && ast->kind == ZEND_AST_CONST_ELEM) {
+		zval tmp;
+		ZVAL_NULL(&tmp);
+		zend_hash_add_new(ht, AST_STR(str_docComment), &tmp);
+	}
+#endif
+
 	if (state->version >= 50 && ast_kind_is_decl(ast->kind)) {
 		zval id_zval;
 		ZVAL_LONG(&id_zval, state->declIdCounter);