implement ClosureType::getReferencedTemplateTypes()

src/Type/ClosureType.php

@@ -36,10 +36,10 @@
 use PHPStan\Type\Generic\TemplateType;
 use PHPStan\Type\Generic\TemplateTypeHelper;
 use PHPStan\Type\Generic\TemplateTypeMap;
+use PHPStan\Type\Generic\TemplateTypeVariance;
 use PHPStan\Type\Generic\TemplateTypeVarianceMap;
 use PHPStan\Type\Traits\NonArrayTypeTrait;
 use PHPStan\Type\Traits\NonGeneralizableTypeTrait;
-use PHPStan\Type\Traits\NonGenericTypeTrait;
 use PHPStan\Type\Traits\NonIterableTypeTrait;
 use PHPStan\Type\Traits\NonOffsetAccessibleTypeTrait;
 use PHPStan\Type\Traits\NonRemoveableTypeTrait;
@@ -53,7 +53,6 @@ class ClosureType implements TypeWithClassName, CallableParametersAcceptor
 {
 
 	use NonArrayTypeTrait;
-	use NonGenericTypeTrait;
 	use NonIterableTypeTrait;
 	use UndecidedComparisonTypeTrait;
 	use NonOffsetAccessibleTypeTrait;
@@ -540,6 +539,23 @@ private function inferTemplateTypesOnParametersAcceptor(ParametersAcceptor $para
 		return $typeMap->union($this->getReturnType()->inferTemplateTypes($returnType));
 	}
 
+	public function getReferencedTemplateTypes(TemplateTypeVariance $positionVariance): array
+	{
+		$references = $this->getReturnType()->getReferencedTemplateTypes(
+			$positionVariance->compose(TemplateTypeVariance::createCovariant()),
+		);
+
+		$paramVariance = $positionVariance->compose(TemplateTypeVariance::createContravariant());
+
+		foreach ($this->getParameters() as $param) {
+			foreach ($param->getType()->getReferencedTemplateTypes($paramVariance) as $reference) {
+				$references[] = $reference;
+			}
+		}
+
+		return $references;
+	}
+
 	public function traverse(callable $cb): Type
 	{
 		if ($this->isCommonCallable) {

tests/PHPStan/Rules/Generics/MethodSignatureVarianceRuleTest.php

@@ -234,4 +234,14 @@ public function testPr2465(): void
 		]);
 	}
 
+	public function testBug10609(): void
+	{
+		$this->analyse([__DIR__ . '/data/bug-10609.php'], [
+			[
+				'Template type A is declared as covariant, but occurs in contravariant position in parameter fn of method Bug10609\Collection::tap().',
+				13,
+			],
+		]);
+	}
+
 }

tests/PHPStan/Rules/Generics/data/bug-10609.php

@@ -0,0 +1,16 @@
+<?php
+
+namespace Bug10609;
+
+/**
+ * @template-covariant A
+ */
+final class Collection
+{
+	/**
+	 * @param \Closure(A): A $fn
+	 */
+	public function tap(mixed $fn): void
+	{
+	}
+}