Default value null does not make promoted property type nullable

Author: ondrejmirtes

Makefile

@@ -72,6 +72,7 @@ lint:
 		--exclude tests/PHPStan/Rules/Keywords/data/declare-strict-nonsense-bool.php \
 		--exclude tests/PHPStan/Rules/Keywords/data/declare-inline-html.php \
 		--exclude tests/PHPStan/Rules/Classes/data/extends-readonly-class.php \
+		--exclude tests/PHPStan/Rules/Classes/data/instantiation-promoted-properties.php \
 		src tests
 
 cs:

src/Analyser/MutatingScope.php

@@ -2664,7 +2664,7 @@ private function getRealParameterTypes(Node\FunctionLike $functionLike): array
 			}
 			$realParameterTypes[$parameter->var->name] = $this->getFunctionType(
 				$parameter->type,
-				$this->isParameterValueNullable($parameter),
+				$this->isParameterValueNullable($parameter) && $parameter->flags === 0,
 				false,
 			);
 		}

src/Rules/Methods/IncompatibleDefaultParameterTypeRule.php

@@ -43,7 +43,8 @@ public function processNode(Node $node, Scope $scope): array
 			}
 
 			$defaultValueType = $scope->getType($param->default);
-			$parameterType = $parameters->getParameters()[$paramI]->getType();
+			$parameter = $parameters->getParameters()[$paramI];
+			$parameterType = $parameter->getType();
 			$parameterType = TemplateTypeHelper::resolveToBounds($parameterType);
 
 			$accepts = $parameterType->acceptsWithReason($defaultValueType, true);

tests/PHPStan/Analyser/data/promoted-properties-types.php

@@ -103,3 +103,16 @@ function (Baz $baz): void {
 	assertType('array<int, string>', $baz->anotherPhpDocArray);
 	assertType('stdClass', $baz->templateProperty);
 };
+
+class PromotedPropertyNotNullable
+{
+
+	public function __construct(
+		public int $intProp = null,
+	) {}
+
+}
+
+function (PromotedPropertyNotNullable $p) {
+	assertType('int', $p->intProp);
+};

tests/PHPStan/Rules/Classes/InstantiationRuleTest.php

@@ -276,6 +276,10 @@ public function testPromotedProperties(): void
 				'Parameter #2 $bar of class InstantiationPromotedProperties\Bar constructor expects array<string>, array<int, int> given.',
 				33,
 			],
+			[
+				'Parameter #1 $intProp of class InstantiationPromotedProperties\PromotedPropertyNotNullable constructor expects int, null given.',
+				46,
+			],
 		]);
 	}
 

tests/PHPStan/Rules/Classes/data/instantiation-promoted-properties.php

@@ -1,4 +1,4 @@
-<?php // lint >= 8.0
+<?php
 
 namespace InstantiationPromotedProperties;
 
@@ -32,3 +32,16 @@ function () {
 	new Bar([], ['foo']);
 	new Bar([], [1]);
 };
+
+class PromotedPropertyNotNullable
+{
+
+	public function __construct(
+		private int $intProp = null,
+	) {}
+
+}
+
+function () {
+	new PromotedPropertyNotNullable(null);
+};

tests/PHPStan/Rules/Methods/IncompatibleDefaultParameterTypeRuleTest.php

@@ -66,6 +66,10 @@ public function testDefaultValueForPromotedProperty(): void
 				'Default value of the parameter #2 $foo (string) of method DefaultValueForPromotedProperty\Foo::__construct() is incompatible with type int.',
 				10,
 			],
+			[
+				'Default value of the parameter #4 $intProp (null) of method DefaultValueForPromotedProperty\Foo::__construct() is incompatible with type int.',
+				12,
+			],
 		]);
 	}
 

tests/PHPStan/Rules/Methods/data/default-value-for-promoted-property.php

@@ -8,7 +8,8 @@ class Foo
 	public function __construct(
 		private int $foo = 'foo',
 		/** @var int */ private $foo = '',
-		private int $baz = 1
+		private int $baz = 1,
+		private int $intProp = null,
 	) {}
 
 }