Fixed variance check for abstract constructor during erlay binding

Author: dstogov

Zend/tests/type_declarations/variance/abstract_constructor.phpt

@@ -0,0 +1,18 @@
+--TEST--
+Variance check for abstract constructor
+--FILE--
+<?php
+class X {
+}
+abstract class A {
+    abstract function __construct(X $x);
+}
+class B extends A {
+    function __construct(object $x) {}
+}
+class C extends B {
+    function __construct(Y $x) {}
+}
+?>
+--EXPECTF--
+Fatal error: Could not check compatibility between C::__construct(Y $x) and A::__construct(X $x), because class Y is not available in %s on line %d

Zend/zend_inheritance.c

@@ -2395,9 +2395,19 @@ zend_bool zend_can_early_bind(zend_class_entry *ce, zend_class_entry *parent_ce)
 		zval *zv;
 		zend_string *unresolved_class;
 
-		if ((parent_flags & ZEND_ACC_PRIVATE) ||
-			((parent_flags & ZEND_ACC_CTOR) && !(parent_flags & ZEND_ACC_ABSTRACT))) {
+		if (parent_flags & ZEND_ACC_PRIVATE) {
 			continue;
+		} else if (parent_flags & ZEND_ACC_CTOR) {
+			zend_function *proto = parent_func->common.prototype ?
+				parent_func->common.prototype : parent_func;
+
+			/* ctors only have a prototype if is abstract (or comes from an interface) */
+			/* and if that is the case, we want to check inheritance against it */
+			if (proto->common.fn_flags & ZEND_ACC_ABSTRACT) {
+				parent_func = proto;
+			} else {
+				continue;
+			}
 		}
 
 		zv = zend_hash_find_ex(&ce->function_table, key, 1);