Avoid early-binding on unresolved types

Fixes bug #76451, and more importantly lays necessary groundwork for
covariant/contravariant types. Bug #76451 is just an edge case, but
once covariance is introduced this will become a common problem instead.

Author: nikic

Zend/tests/bug76451.inc

@@ -0,0 +1,4 @@
+<?php
+
+class Foo {}
+class_alias('Foo', 'Bar');

Zend/tests/bug76451.phpt

@@ -0,0 +1,16 @@
+--TEST--
+Bug #76451: Aliases during inheritance type checks affected by opcache
+--FILE--
+<?php
+require __DIR__ . "/bug76451.inc";
+
+class A {
+    public function test(Foo $foo) {}
+}
+class B extends A {
+    public function test(Bar $foo) {}
+}
+?>
+===DONE===
+--EXPECT--
+===DONE===

Zend/tests/bug76451_2.inc

@@ -0,0 +1,8 @@
+<?php
+class A {
+    public function test(Foo $foo) {}
+}
+class B extends A {
+    public function test(Bar $foo) {}
+}
+?>

Zend/tests/bug76451_2.phpt

@@ -0,0 +1,12 @@
+--TEST--
+Bug #76451: Aliases during inheritance type checks affected by opcache (variation)
+--FILE--
+<?php
+class Foo {}
+class_alias('Foo', 'Bar');
+
+require __DIR__ . '/bug76451_2.inc';
+?>
+===DONE===
+--EXPECT--
+===DONE===

Zend/zend_compile.c

@@ -1131,14 +1131,16 @@ ZEND_API void zend_do_delayed_early_binding(const zend_op_array *op_array, uint3
 	if (first_early_binding_opline != (uint32_t)-1) {
 		zend_bool orig_in_compilation = CG(in_compilation);
 		uint32_t opline_num = first_early_binding_opline;
-		zend_class_entry *ce;
 
 		CG(in_compilation) = 1;
 		while (opline_num != (uint32_t)-1) {
 			const zend_op *opline = &op_array->opcodes[opline_num];
+			zval *lcname = RT_CONSTANT(opline, opline->op1);
 			zval *parent_name = RT_CONSTANT(opline, opline->op2);
-			if ((ce = zend_lookup_class_ex(Z_STR_P(parent_name), Z_STR_P(parent_name + 1), 0)) != NULL) {
-				do_bind_class(RT_CONSTANT(&op_array->opcodes[opline_num], op_array->opcodes[opline_num].op1), ce);
+			zend_class_entry *ce = zend_hash_find_ptr(EG(class_table), Z_STR_P(lcname + 1));
+			zend_class_entry *parent_ce = zend_lookup_class_ex(Z_STR_P(parent_name), Z_STR_P(parent_name + 1), 0);
+			if (ce && parent_ce && zend_can_early_bind(ce, parent_ce)) {
+				do_bind_class(lcname, parent_ce);
 			}
 			opline_num = op_array->opcodes[opline_num].result.opline_num;
 		}
@@ -6392,6 +6394,7 @@ zend_op *zend_compile_class_decl(zend_ast *ast, zend_bool toplevel) /* {{{ */
 			 && !(CG(compiler_options) & ZEND_COMPILE_PRELOAD) /* delay inheritance till preloading */
 			 && ((parent_ce->type != ZEND_INTERNAL_CLASS) || !(CG(compiler_options) & ZEND_COMPILE_IGNORE_INTERNAL_CLASSES))
 			 && ((parent_ce->type != ZEND_USER_CLASS) || !(CG(compiler_options) & ZEND_COMPILE_IGNORE_OTHER_FILES) || (parent_ce->info.user.filename == ce->info.user.filename))
+			 && zend_can_early_bind(ce, parent_ce)
 				) {
 				if (EXPECTED(zend_hash_add_ptr(CG(class_table), lcname, ce) != NULL)) {
 					CG(zend_lineno) = decl->end_lineno;