Fix inferring type of new with generic type with constructor in parent class

Author: ondrejmirtes

src/Analyser/MutatingScope.php

@@ -5525,13 +5525,77 @@ private function exactInstantiation(New_ $node, string $className): ?Type
 			}
 		}
 
-		if ($constructorMethod instanceof DummyConstructorReflection || $constructorMethod->getDeclaringClass()->getName() !== $classReflection->getName()) {
+		if ($constructorMethod instanceof DummyConstructorReflection) {
 			return new GenericObjectType(
 				$resolvedClassName,
 				$classReflection->typeMapToList($classReflection->getTemplateTypeMap()->resolveToBounds()),
 			);
 		}
 
+		if ($constructorMethod->getDeclaringClass()->getName() !== $classReflection->getName()) {
+			if (!$constructorMethod->getDeclaringClass()->isGeneric()) {
+				return new GenericObjectType(
+					$resolvedClassName,
+					$classReflection->typeMapToList($classReflection->getTemplateTypeMap()->resolveToBounds()),
+				);
+			}
+			$newType = new GenericObjectType($resolvedClassName, $classReflection->typeMapToList($classReflection->getTemplateTypeMap()));
+			$ancestorType = $newType->getAncestorWithClassName($constructorMethod->getDeclaringClass()->getName());
+			if ($ancestorType === null) {
+				return new GenericObjectType(
+					$resolvedClassName,
+					$classReflection->typeMapToList($classReflection->getTemplateTypeMap()->resolveToBounds()),
+				);
+			}
+			$ancestorClassReflections = $ancestorType->getObjectClassReflections();
+			if (count($ancestorClassReflections) !== 1) {
+				return new GenericObjectType(
+					$resolvedClassName,
+					$classReflection->typeMapToList($classReflection->getTemplateTypeMap()->resolveToBounds()),
+				);
+			}
+
+			$newParentNode = new New_(new Name($constructorMethod->getDeclaringClass()->getName()), $node->args);
+			$newParentType = $this->getType($newParentNode);
+			$newParentTypeClassReflections = $newParentType->getObjectClassReflections();
+			if (count($newParentTypeClassReflections) !== 1) {
+				return new GenericObjectType(
+					$resolvedClassName,
+					$classReflection->typeMapToList($classReflection->getTemplateTypeMap()->resolveToBounds()),
+				);
+			}
+			$newParentTypeClassReflection = $newParentTypeClassReflections[0];
+
+			$ancestorClassReflection = $ancestorClassReflections[0];
+			$ancestorMapping = [];
+			foreach ($ancestorClassReflection->getActiveTemplateTypeMap()->getTypes() as $typeName => $templateType) {
+				if (!$templateType instanceof TemplateType) {
+					continue;
+				}
+
+				$ancestorMapping[$typeName] = $templateType->getName();
+			}
+
+			$resolvedTypeMap = [];
+			foreach ($newParentTypeClassReflection->getActiveTemplateTypeMap()->getTypes() as $typeName => $type) {
+				if (!array_key_exists($typeName, $ancestorMapping)) {
+					continue;
+				}
+
+				if (!array_key_exists($ancestorMapping[$typeName], $resolvedTypeMap)) {
+					$resolvedTypeMap[$ancestorMapping[$typeName]] = $type;
+					continue;
+				}
+
+				$resolvedTypeMap[$ancestorMapping[$typeName]] = TypeCombinator::union($resolvedTypeMap[$ancestorMapping[$typeName]], $type);
+			}
+
+			return new GenericObjectType(
+				$resolvedClassName,
+				$classReflection->typeMapToList(new TemplateTypeMap($resolvedTypeMap)),
+			);
+		}
+
 		$parametersAcceptor = ParametersAcceptorSelector::selectFromArgs(
 			$this,
 			$methodCall->getArgs(),

tests/PHPStan/Analyser/nsrt/bug-2735.php

@@ -0,0 +1,134 @@
+<?php
+
+namespace Bug2735;
+
+use function PHPStan\Testing\assertType;
+
+class Dog {}
+
+class Cat {}
+
+/**
+ * @template T
+ */
+class Collection {
+	/** @var array<T> */
+	protected $arr = [];
+
+	/**
+	 * @param array<T> $arr
+	 */
+	public function __construct(array $arr) {
+		$this->arr = $arr;
+	}
+
+	/**
+	 * @return T
+	 */
+	public function last()
+	{
+		if (!$this->arr) {
+			throw new \Exception('bad');
+		}
+		return end($this->arr);
+	}
+}
+
+/**
+ * @template T
+ * @extends Collection<T>
+ */
+class CollectionChild extends Collection {
+}
+
+$dogs = new CollectionChild([new Dog(), new Dog()]);
+assertType('Bug2735\\CollectionChild<Bug2735\\Dog>', $dogs);
+
+/**
+ * @template X
+ * @template Y
+ */
+class ParentWithConstructor
+{
+
+	/**
+	 * @param X $x
+	 * @param Y $y
+	 */
+	public function __construct($x, $y)
+	{
+	}
+
+}
+
+/**
+ * @template T
+ * @extends ParentWithConstructor<int, T>
+ */
+class ChildOne extends ParentWithConstructor
+{
+
+}
+
+function (): void {
+	$a = new ChildOne(1, new Dog());
+	assertType('Bug2735\\ChildOne<Bug2735\\Dog>', $a);
+};
+
+/**
+ * @template T
+ * @extends ParentWithConstructor<T, int>
+ */
+class ChildTwo extends ParentWithConstructor
+{
+
+}
+
+function (): void {
+	$a = new ChildTwo(new Cat(), 2);
+	assertType('Bug2735\\ChildTwo<Bug2735\\Cat>', $a);
+};
+
+/**
+ * @template T
+ * @extends ParentWithConstructor<T, T>
+ */
+class ChildThree extends ParentWithConstructor
+{
+
+}
+
+function (): void {
+	$a = new ChildThree(new Cat(), new Dog());
+	assertType('Bug2735\\ChildThree<Bug2735\\Cat|Bug2735\\Dog>', $a);
+};
+
+/**
+ * @template T
+ * @template U
+ * @extends ParentWithConstructor<T, U>
+ */
+class ChildFour extends ParentWithConstructor
+{
+
+}
+
+function (): void {
+	$a = new ChildFour(new Cat(), new Dog());
+	assertType('Bug2735\\ChildFour<Bug2735\\Cat, Bug2735\\Dog>', $a);
+};
+
+/**
+ * @template T
+ * @template U
+ * @extends ParentWithConstructor<U, T>
+ */
+class ChildFive extends ParentWithConstructor
+{
+
+}
+
+function (): void {
+	$a = new ChildFive(new Cat(), new Dog());
+	assertType('Bug2735\\ChildFive<Bug2735\\Dog, Bug2735\\Cat>', $a);
+};

tests/PHPStan/Analyser/nsrt/generics.php

@@ -741,7 +741,7 @@ function testClasses()
 	assertType('DateTime', $ab->getB(new \DateTime()));
 
 	$noConstructor = new NoConstructor(1);
-	assertType('PHPStan\Generics\FunctionsAssertType\NoConstructor<mixed>', $noConstructor);
+	assertType('PHPStan\Generics\FunctionsAssertType\NoConstructor<int>', $noConstructor);
 
 	assertType('stdClass', acceptsClassString(\stdClass::class));
 	assertType('class-string<stdClass>', returnsClassString(new \stdClass()));