Fixed bug #81631

We need to save the opline before fetching the operand, as it may
throw an undef var warning.

Author: nikic

NEWS

@@ -9,6 +9,8 @@ PHP                                                                        NEWS
     (Nikita)
   . Fixed bug #81626 (Error on use static:: in __сallStatic() wrapped to
     Closure::fromCallable()). (Nikita)
+  . Fixed bug #81631 (::class with dynamic class name may yield wrong line
+    number). (Nikita)
 
 - FPM:
   . Fixed bug #81513 (Future possibility for heap overflow in FPM zlog).

Zend/tests/bug81631.phpt

@@ -0,0 +1,14 @@
+--TEST--
+Bug #81631: ::class with dynamic class name may yield wrong line number
+--FILE--
+<?php
+$a = 0;
+var_dump($b::class);
+?>
+--EXPECTF--
+Warning: Undefined variable $b in %s on line 3
+
+Fatal error: Uncaught TypeError: Cannot use "::class" on value of type null in %s:3
+Stack trace:
+#0 {main}
+  thrown in %s on line 3

Zend/zend_vm_def.h

@@ -8415,8 +8415,8 @@ ZEND_VM_HANDLER(157, ZEND_FETCH_CLASS_NAME, CV|TMPVAR|UNUSED|CLASS_FETCH, ANY)
 	USE_OPLINE
 
 	if (OP1_TYPE != IS_UNUSED) {
-		zval *op = GET_OP1_ZVAL_PTR(BP_VAR_R);
 		SAVE_OPLINE();
+		zval *op = GET_OP1_ZVAL_PTR(BP_VAR_R);
 		if (UNEXPECTED(Z_TYPE_P(op) != IS_OBJECT)) {
 			ZVAL_DEREF(op);
 			if (Z_TYPE_P(op) != IS_OBJECT) {

Zend/zend_vm_execute.h

@@ -14538,8 +14538,8 @@ static ZEND_OPCODE_HANDLER_RET ZEND_FASTCALL ZEND_FETCH_CLASS_NAME_SPEC_TMPVAR_H
 	USE_OPLINE
 
 	if ((IS_TMP_VAR|IS_VAR) != IS_UNUSED) {
-		zval *op = _get_zval_ptr_var(opline->op1.var EXECUTE_DATA_CC);
 		SAVE_OPLINE();
+		zval *op = _get_zval_ptr_var(opline->op1.var EXECUTE_DATA_CC);
 		if (UNEXPECTED(Z_TYPE_P(op) != IS_OBJECT)) {
 			ZVAL_DEREF(op);
 			if (Z_TYPE_P(op) != IS_OBJECT) {
@@ -30855,8 +30855,8 @@ static ZEND_OPCODE_HANDLER_RET ZEND_FASTCALL ZEND_FETCH_CLASS_NAME_SPEC_UNUSED_H
 	USE_OPLINE
 
 	if (IS_UNUSED != IS_UNUSED) {
-		zval *op = NULL;
 		SAVE_OPLINE();
+		zval *op = NULL;
 		if (UNEXPECTED(Z_TYPE_P(op) != IS_OBJECT)) {
 			ZVAL_DEREF(op);
 			if (Z_TYPE_P(op) != IS_OBJECT) {
@@ -38400,8 +38400,8 @@ static ZEND_OPCODE_HANDLER_RET ZEND_FASTCALL ZEND_FETCH_CLASS_NAME_SPEC_CV_HANDL
 	USE_OPLINE
 
 	if (IS_CV != IS_UNUSED) {
-		zval *op = _get_zval_ptr_cv_BP_VAR_R(opline->op1.var EXECUTE_DATA_CC);
 		SAVE_OPLINE();
+		zval *op = _get_zval_ptr_cv_BP_VAR_R(opline->op1.var EXECUTE_DATA_CC);
 		if (UNEXPECTED(Z_TYPE_P(op) != IS_OBJECT)) {
 			ZVAL_DEREF(op);
 			if (Z_TYPE_P(op) != IS_OBJECT) {