Disallow mutating keyword outside of data classes

Author: iluuu1994

Zend/tests/data_classes/mutatin_in_ordinary_class.phpt

@@ -0,0 +1,12 @@
+--TEST--
+Mutating keyword in ordinary class
+--FILE--
+<?php
+
+class Point {
+    public mutating function zero() {}
+}
+
+?>
+--EXPECTF--
+Fatal error: Mutating modifier may only be added to data class methods in %s on line %d

Zend/zend_compile.c

@@ -7776,6 +7776,9 @@ static void zend_compile_func_decl(znode *result, zend_ast *ast, bool toplevel)
 	if (is_method) {
 		bool has_body = stmt_ast != NULL;
 		lcname = zend_begin_method_decl(op_array, decl->name, has_body);
+		if ((op_array->fn_flags & ZEND_ACC_MUTATING) && !(op_array->scope->ce_flags & ZEND_ACC_DATA_CLASS)) {
+			zend_error_noreturn(E_COMPILE_ERROR, "Mutating modifier may only be added to data class methods");
+		}
 	} else {
 		lcname = zend_begin_func_decl(result, op_array, decl, toplevel);
 		if (decl->kind == ZEND_AST_ARROW_FUNC) {