Add nullable parameter types

This works off of Dmitry's commit for nullable return types

Zend/tests/bug71428.1.phpt

@@ -11,5 +11,5 @@ class B extends A {
     public function m(array $a = []) {}
 }
 --EXPECTF--
-Warning: Declaration of B::m(array $a = Array) should be compatible with A::m(array $a = NULL) in %sbug71428.1.php on line 7
+Warning: Declaration of B::m(array $a = Array) should be compatible with A::m(?array $a = NULL) in %sbug71428.1.php on line 7
 

Zend/tests/bug71428.3.phpt

@@ -9,5 +9,5 @@ class B           {  public function m(A $a = NULL, $n) { echo "B.m";} };
 class C extends B {  public function m(A $a       , $n) { echo "C.m";} };
 ?>
 --EXPECTF--
-Warning: Declaration of C::m(A $a, $n) should be compatible with B::m(A $a = NULL, $n) in %sbug71428.3.php on line 4
+Warning: Declaration of C::m(A $a, $n) should be compatible with B::m(?A $a, $n) in %sbug71428.3.php on line 4
 

Zend/tests/bug72119.phpt

@@ -16,3 +16,4 @@ echo "OK\n";
 ?>
 --EXPECT--
 OK
+

Zend/tests/nullable_types/array.phpt

@@ -0,0 +1,17 @@
+--TEST--
+Explicitly nullable array type
+--FILE--
+<?php
+
+function _array_(?array $v): ?array {
+    return $v;
+}
+
+var_dump(_array_(null));
+var_dump(_array_([]));
+
+--EXPECT--
+NULL
+array(0) {
+}
+

Zend/tests/nullable_types/contravariant_nullable_param_succeeds.phpt

@@ -0,0 +1,19 @@
+--TEST--
+Subtype can add nullability to a parameter (contravariance)
+
+--FILE--
+<?php
+
+interface A {
+    function method(int $p);
+}
+
+class B implements A {
+    function method(?int $p) { }
+}
+
+$b = new B();
+$b->method(null);
+
+--EXPECT--
+

Zend/tests/nullable_types/contravariant_nullable_return_fails.phpt

@@ -0,0 +1,17 @@
+--TEST--
+Return type cannot add nullability (contravariance)
+
+--FILE--
+<?php
+
+interface A {
+    function method(): int;
+}
+
+interface B extends A {
+    function method(): ?int;
+}
+
+--EXPECTF--
+Fatal error: Declaration of B::method(): ?int must be compatible with A::method(): int in %s on line %d
+

Zend/tests/nullable_types/covariant_nullable_param_fails.phpt

@@ -0,0 +1,17 @@
+--TEST--
+Subtype cannot remove nullable parameter (covariance)
+
+--FILE--
+<?php
+
+interface A {
+    function method(?int $p);
+}
+
+class B implements A {
+    function method(int $p) { }
+}
+
+--EXPECTF--
+Fatal error: Declaration of B::method(int $p) must be compatible with A::method(?int $p) in %s on line %d
+

Zend/tests/nullable_types/covariant_nullable_return_succeds.phpt

@@ -0,0 +1,16 @@
+--TEST--
+Nullable covariant return types
+
+--FILE--
+<?php
+
+interface A {
+    function method(): ?int;
+}
+
+interface B extends A {
+    function method(): int;
+}
+
+--EXPECT--
+

Zend/tests/nullable_types/float.phpt

@@ -0,0 +1,16 @@
+--TEST--
+Explicitly nullable float type
+--FILE--
+<?php
+
+function _float_(?float $v): ?float {
+    return $v;
+}
+
+var_dump(_float_(null));
+var_dump(_float_(1.3));
+
+--EXPECT--
+NULL
+float(1.3)
+

Zend/tests/nullable_types/int.phpt

@@ -0,0 +1,16 @@
+--TEST--
+Explicitly nullable int type
+--FILE--
+<?php
+
+function _int_(?int $v): ?int {
+    return $v;
+}
+
+var_dump(_int_(null));
+var_dump(_int_(1));
+
+--EXPECT--
+NULL
+int(1)
+

Zend/tests/nullable_types/invariant_param_and_return_succeeds.phpt

@@ -0,0 +1,24 @@
+--TEST--
+Invariant parameter and return types work with nullable types
+
+--FILE--
+<?php
+
+interface A {
+    function method(?int $i): ?int;
+}
+
+class B implements A {
+    function method(?int $i): ?int {
+        return $i;
+    }
+}
+
+$b = new B();
+var_dump($b->method(null));
+var_dump($b->method(1));
+
+--EXPECT--
+NULL
+int(1)
+

Zend/tests/nullable_types/nullable_type_parameters_do_not_have_default_value.phpt

@@ -0,0 +1,17 @@
+--TEST--
+Explicit nullable types do not imply a default value
+
+--FILE--
+<?php
+
+function f(?callable $p) {}
+
+f();
+
+--EXPECTF--
+Fatal error: Uncaught TypeError: Argument 1 passed to f() must be callable, none given, called in %s on line %d and defined in %s:%d
+Stack trace:
+#%d %s
+#%d %s
+  thrown in %s on line %d
+

Zend/tests/nullable_types/string.phpt

@@ -0,0 +1,16 @@
+--TEST--
+Explicitly nullable string type
+--FILE--
+<?php
+
+function _string_(?string $v): ?string {
+    return $v;
+}
+
+var_dump(_string_(null));
+var_dump(_string_("php"));
+
+--EXPECT--
+NULL
+string(3) "php"
+

Zend/tests/variadic/adding_additional_optional_parameter_error.phpt

@@ -13,4 +13,4 @@ class MySQL implements DB {
 
 ?>
 --EXPECTF--
-Fatal error: Declaration of MySQL::query($query, int $extraParam = NULL, string ...$params) must be compatible with DB::query($query, string ...$params) in %s on line %d
+Fatal error: Declaration of MySQL::query($query, ?int $extraParam = NULL, string ...$params) must be compatible with DB::query($query, string ...$params) in %s on line %d

Zend/zend_compile.c

@@ -4866,7 +4866,7 @@ static void zend_compile_typename(zend_ast *ast, zend_arg_info *arg_info) /* {{{
 		zend_uchar type = zend_lookup_builtin_type_by_name(class_name);
 
 		if (type != 0) {
-			if (ast->attr != ZEND_NAME_NOT_FQ) {
+			if ((ast->attr & ZEND_NAME_NOT_FQ) != ZEND_NAME_NOT_FQ) {
 				zend_error_noreturn(E_COMPILE_ERROR,
 					"Scalar type declaration '%s' must be unqualified",
 					ZSTR_VAL(zend_string_tolower(class_name)));
@@ -4999,9 +4999,10 @@ void zend_compile_params(zend_ast *ast, zend_ast *return_type_ast) /* {{{ */
 				&& (Z_TYPE(default_node.u.constant) == IS_NULL
 					|| (Z_TYPE(default_node.u.constant) == IS_CONSTANT
 						&& strcasecmp(Z_STRVAL(default_node.u.constant), "NULL") == 0));
+			zend_bool is_explicitly_nullable = (type_ast->attr & ZEND_TYPE_NULLABLE) == ZEND_TYPE_NULLABLE;
 
 			op_array->fn_flags |= ZEND_ACC_HAS_TYPE_HINTS;
-			arg_info->allow_null = has_null_default;
+			arg_info->allow_null = has_null_default || is_explicitly_nullable;
 
 			zend_compile_typename(type_ast, arg_info);
 

Zend/zend_inheritance.c

@@ -355,6 +355,11 @@ static zend_bool zend_do_perform_implementation_check(const zend_function *fe, c
 
 static ZEND_COLD void zend_append_type_hint(smart_str *str, const zend_function *fptr, zend_arg_info *arg_info, int return_hint) /* {{{ */
 {
+
+	if (arg_info->type_hint != IS_UNDEF && arg_info->allow_null) {
+		smart_str_appendc(str, '?');
+	}
+
 	if (arg_info->class_name) {
 		const char *class_name;
 		size_t class_name_len;
@@ -495,8 +500,6 @@ static ZEND_COLD zend_string *zend_get_function_declaration(const zend_function
 				} else {
 					smart_str_appends(&str, "NULL");
 				}
-			} else if (arg_info->type_hint && arg_info->allow_null) {
-				smart_str_appends(&str, " = NULL");
 			}
 
 			if (++i < num_args) {
@@ -510,9 +513,6 @@ static ZEND_COLD zend_string *zend_get_function_declaration(const zend_function
 
 	if (fptr->common.fn_flags & ZEND_ACC_HAS_RETURN_TYPE) {
 		smart_str_appends(&str, ": ");
-		if (fptr->common.arg_info[-1].allow_null) {
-			smart_str_appendc(&str, '?');
-		}
 		zend_append_type_hint(&str, fptr, fptr->common.arg_info - 1, 1);
 	}
 	smart_str_0(&str);

Zend/zend_language_parser.y

@@ -252,7 +252,7 @@ static YYSIZE_T zend_yytnamerr(char*, const char*);
 %type <ast> ctor_arguments alt_if_stmt_without_else trait_adaptation_list lexical_vars
 %type <ast> lexical_var_list encaps_list array_pair_list non_empty_array_pair_list
 %type <ast> assignment_list unkeyed_assignment_list keyed_assignment_list
-%type <ast> isset_variable type return_type
+%type <ast> isset_variable type return_type type_expr
 %type <ast> identifier
 
 %type <num> returns_ref function is_reference is_variadic variable_modifiers
@@ -644,7 +644,12 @@ parameter:
 
 optional_type:
 		/* empty */	{ $$ = NULL; }
-	|	type		{ $$ = $1; }
+	|	type_expr	{ $$ = $1; }
+;
+
+type_expr:
+		type		{ $$ = $1; }
+	|	'?' type	{ $$ = $2; $$->attr |= ZEND_TYPE_NULLABLE; }
 ;
 
 type:
@@ -655,8 +660,7 @@ type:
 
 return_type:
 		/* empty */	{ $$ = NULL; }
-	|	':' type	{ $$ = $2; }
-	|	':' '?' type	{ $$ = $3; $$->attr |= ZEND_TYPE_NULLABLE; }
+	|	':' type_expr	{ $$ = $2; }
 ;
 
 argument_list: