From e9d65160e85fb08d9bd08202b60a8b19b446c646 Mon Sep 17 00:00:00 2001
From: Dmitry Stogov <dmitry@zend.com>
Date: Wed, 6 Apr 2016 17:17:10 +0300
Subject: [PATCH] Fixed bug #71978 (Existence of return type hint affects other
 compatibility rules)

---
 NEWS                                  |  2 ++
 Zend/tests/return_types/bug71978.phpt | 21 +++++++++++++++
 Zend/zend_inheritance.c               | 38 ++++++++++++++++++---------
 3 files changed, 49 insertions(+), 12 deletions(-)
 create mode 100644 Zend/tests/return_types/bug71978.phpt

diff --git a/NEWS b/NEWS
index 24da274e03..56e81c9d92 100644
--- a/NEWS
+++ b/NEWS
@@ -3,6 +3,8 @@ PHP                                                                        NEWS
 ?? ??? 2016 PHP 7.0.6
 
 - Core:
+  . Fixed bug #71978 (Existence of return type hint affects other compatibility
+    rules). (Dmitry)
   . Fixed bug #71930 (_zval_dtor_func: Assertion `(arr)->gc.refcount <= 1'
     failed). (Laruence)
   . Fixed bug #71922 (Crash on assert(new class{})). (Nikita)
diff --git a/Zend/tests/return_types/bug71978.phpt b/Zend/tests/return_types/bug71978.phpt
new file mode 100644
index 0000000000..e3c8440212
--- /dev/null
+++ b/Zend/tests/return_types/bug71978.phpt
@@ -0,0 +1,21 @@
+--TEST--
+Bug #71978 (Existence of return type hint affects other compatibility rules)
+--FILE--
+<?php
+class A {
+	function foo(int $a) {}
+}
+class B extends A {
+	function foo(string $a) {}
+}
+class A1 {
+	function foo(int $a): int {}
+}
+class B1 extends A1 {
+	function foo(string $a): int {}
+}
+?>
+--EXPECTF--
+Warning: Declaration of B::foo(string $a) should be compatible with A::foo(int $a) in %s on line %d
+
+Warning: Declaration of B1::foo(string $a): int should be compatible with A1::foo(int $a): int in %s on line %d
diff --git a/Zend/zend_inheritance.c b/Zend/zend_inheritance.c
index 55a9fdc909..e6721879ee 100644
--- a/Zend/zend_inheritance.c
+++ b/Zend/zend_inheritance.c
@@ -243,11 +243,6 @@ static int zend_do_perform_type_hint_check(const zend_function *fe, zend_arg_inf
 		return 0;
 	}
 
-	if (proto_arg_info->type_hint && proto_arg_info->allow_null && !fe_arg_info->allow_null) {
-		/* incompatible nullability */
-		return 0;
-	}
-
 	return 1;
 }
 /* }}} */
@@ -324,6 +319,11 @@ static zend_bool zend_do_perform_implementation_check(const zend_function *fe, c
 			return 0;
 		}
 
+		if (proto_arg_info->type_hint && proto_arg_info->allow_null && !fe_arg_info->allow_null) {
+			/* incompatible nullability */
+			return 0;
+		}
+
 		/* by-ref constraints on arguments are invariant */
 		if (fe_arg_info->pass_by_reference != proto_arg_info->pass_by_reference) {
 			return 0;
@@ -570,17 +570,31 @@ static void do_inheritance_check_on_method(zend_function *child, zend_function *
 	}
 
 	if (child->common.prototype && (
-		child->common.prototype->common.fn_flags & (ZEND_ACC_ABSTRACT | ZEND_ACC_HAS_RETURN_TYPE)
+		child->common.prototype->common.fn_flags & ZEND_ACC_ABSTRACT
 	)) {
-		if (UNEXPECTED(!zend_do_perform_implementation_check(child, child->common.prototype))) {
-			zend_string *method_prototype = zend_get_function_declaration(child->common.prototype);
-			zend_string *child_prototype = zend_get_function_declaration(child);
-			zend_error_noreturn(E_COMPILE_ERROR, "Declaration of %s must be compatible with %s", ZSTR_VAL(child_prototype), ZSTR_VAL(method_prototype));
+		parent = child->common.prototype;
+	}
+	if (UNEXPECTED(!zend_do_perform_implementation_check(child, parent))) {
+		int error_level;
+		const char *error_verb;
+
+		if (child->common.prototype && (
+			child->common.prototype->common.fn_flags & ZEND_ACC_ABSTRACT
+		)) {
+			error_level = E_COMPILE_ERROR;
+			error_verb = "must";
+		} else if ((parent->common.fn_flags & ZEND_ACC_HAS_RETURN_TYPE) &&
+                   (!(child->common.fn_flags & ZEND_ACC_HAS_RETURN_TYPE) ||
+		            !zend_do_perform_type_hint_check(child, child->common.arg_info - 1, parent, parent->common.arg_info - 1))) {
+			error_level = E_COMPILE_ERROR;
+			error_verb = "must";
+		} else {
+			error_level = E_WARNING;
+			error_verb = "should";
 		}
-	} else if (UNEXPECTED(!zend_do_perform_implementation_check(child, parent))) {
 		zend_string *method_prototype = zend_get_function_declaration(parent);
 		zend_string *child_prototype = zend_get_function_declaration(child);
-		zend_error(E_WARNING, "Declaration of %s should be compatible with %s", ZSTR_VAL(child_prototype), ZSTR_VAL(method_prototype));
+		zend_error(error_level, "Declaration of %s %s be compatible with %s", ZSTR_VAL(child_prototype), error_verb, ZSTR_VAL(method_prototype));
 		zend_string_free(child_prototype);
 		zend_string_free(method_prototype);
 	}
-- 
2.50.1