Add an integration test case for generic variance

Author: jiripudil

tests/PHPStan/Rules/Methods/CallMethodsRuleTest.php

@@ -2512,6 +2512,32 @@ public function testGenericsInferCollectionLevel8(): void
 		]);
 	}
 
+	public function testGenericVariance(): void
+	{
+		$this->checkThisOnly = false;
+		$this->checkNullables = true;
+		$this->checkUnionTypes = true;
+		$this->checkExplicitMixed = false;
+		$this->analyse([__DIR__ . '/data/generic-variance.php'], [
+			[
+				'Parameter #1 $param of method GenericVarianceCall\Foo::invariant() expects GenericVarianceCall\Invariant<GenericVarianceCall\B>, GenericVarianceCall\Invariant<GenericVarianceCall\A> given.',
+				45,
+			],
+			[
+				'Parameter #1 $param of method GenericVarianceCall\Foo::invariant() expects GenericVarianceCall\Invariant<GenericVarianceCall\B>, GenericVarianceCall\Invariant<GenericVarianceCall\C> given.',
+				53,
+			],
+			[
+				'Parameter #1 $param of method GenericVarianceCall\Foo::covariant() expects GenericVarianceCall\Covariant<GenericVarianceCall\B>, GenericVarianceCall\Covariant<GenericVarianceCall\A> given.',
+				60,
+			],
+			[
+				'Parameter #1 $param of method GenericVarianceCall\Foo::contravariant() expects GenericVarianceCall\Contravariant<GenericVarianceCall\B>, GenericVarianceCall\Contravariant<GenericVarianceCall\C> given.',
+				83,
+			],
+		]);
+	}
+
 	public function testBug6904(): void
 	{
 		if (PHP_VERSION_ID < 80100) {

tests/PHPStan/Rules/Methods/data/generic-variance.php

@@ -0,0 +1,85 @@
+<?php
+
+namespace GenericVarianceCall;
+
+class A {}
+class B extends A {}
+class C extends B {}
+
+/** @template T */
+class Invariant {}
+
+/** @template-covariant T */
+class Covariant {}
+
+/** @template-contravariant T */
+class Contravariant {}
+
+class Foo
+{
+	/**
+	 * @param Invariant<B> $param
+	 */
+	public function invariant(Invariant $param): void
+	{
+	}
+
+	/**
+	 * @param Covariant<B> $param
+	 */
+	public function covariant(Covariant $param): void
+	{
+	}
+
+	/**
+	 * @param Contravariant<B> $param
+	 */
+	public function contravariant(Contravariant $param): void
+	{
+	}
+
+	public function testInvariant(): void
+	{
+		/** @var Invariant<A> $invariantA */
+		$invariantA = new Invariant();
+		$this->invariant($invariantA);
+
+		/** @var Invariant<B> $invariantB */
+		$invariantB = new Invariant();
+		$this->invariant($invariantB);
+
+		/** @var Invariant<C> $invariantC */
+		$invariantC = new Invariant();
+		$this->invariant($invariantC);
+	}
+
+	public function testCovariant(): void
+	{
+		/** @var Covariant<A> $covariantA */
+		$covariantA = new Covariant();
+		$this->covariant($covariantA);
+
+		/** @var Covariant<B> $covariantB */
+		$covariantB = new Covariant();
+		$this->covariant($covariantB);
+
+		/** @var Covariant<C> $covariantC */
+		$covariantC = new Covariant();
+		$this->covariant($covariantC);
+	}
+
+	public function testContravariant(): void
+	{
+		/** @var Contravariant<A> $contravariantA */
+		$contravariantA = new Contravariant();
+		$this->contravariant($contravariantA);
+
+		/** @var Contravariant<B> $contravariantB */
+		$contravariantB = new Contravariant();
+		$this->contravariant($contravariantB);
+
+		/** @var Contravariant<C> $contravariantC */
+		$contravariantC = new Contravariant();
+		$this->contravariant($contravariantC);
+	}
+}