Handle self::class separately from __CLASS__ in const eval

Author: nikic

Zend/tests/self_class_const_in_unknown_scope.phpt

@@ -13,11 +13,14 @@ class Test {
 }
 (new Test)->foobar();
 
-// This should error, but doesn't
 const BAR = self::class;
 var_dump(BAR);
 
 ?>
---EXPECT--
+--EXPECTF--
 string(4) "Test"
-string(0) ""
+
+Fatal error: Uncaught Error: Cannot use "self" when no class scope is active in %s:%d
+Stack trace:
+#0 {main}
+  thrown in %s on line %d

Zend/zend_ast.c

@@ -511,13 +511,21 @@ ZEND_API int ZEND_FASTCALL zend_ast_evaluate(zval *result, zend_ast *ast, zend_c
 			break;
 		}
 		case ZEND_AST_CONSTANT_CLASS:
-			ZEND_ASSERT(EG(current_execute_data));
 			if (scope && scope->name) {
 				ZVAL_STR_COPY(result, scope->name);
 			} else {
 				ZVAL_EMPTY_STRING(result);
 			}
 			break;
+		case ZEND_AST_CLASS_NAME:
+			ZEND_ASSERT(ast->attr == ZEND_FETCH_CLASS_SELF);
+			if (scope && scope->name) {
+				ZVAL_STR_COPY(result, scope->name);
+			} else {
+				zend_throw_error(NULL, "Cannot use \"self\" when no class scope is active");
+				ret = FAILURE;
+			}
+			break;
 		case ZEND_AST_AND:
 			if (UNEXPECTED(zend_ast_evaluate(&op1, ast->child[0], scope) != SUCCESS)) {
 				ret = FAILURE;

Zend/zend_compile.c

@@ -7953,14 +7953,16 @@ void zend_compile_const_expr_class_const(zend_ast **ast_ptr) /* {{{ */
 
 void zend_compile_const_expr_class_name(zend_ast **ast_ptr) /* {{{ */
 {
-	zend_ast *class_ast = (*ast_ptr)->child[0];
-	uint32_t fetch_type = zend_get_class_fetch_type(zend_ast_get_str(class_ast));
+	zend_ast *ast = *ast_ptr;
+	zend_ast *class_ast = ast->child[0];
+	zend_string *class_name = zend_ast_get_str(class_ast);
+	uint32_t fetch_type = zend_get_class_fetch_type(class_name);
 
-	/* TODO We should not use AST_CONSTANT_CLASS for this, because the semantics are slightly
-	 * different. */
+	/* For the const-eval representation store the fetch type instead of the name. */
 	if (fetch_type == ZEND_FETCH_CLASS_SELF) {
-		zend_ast_destroy(*ast_ptr);
-		*ast_ptr = zend_ast_create(ZEND_AST_CONSTANT_CLASS);
+		zend_string_release(class_name);
+		ast->child[0] = NULL;
+		ast->attr = fetch_type;
 		return;
 	}