Treat ArrayType as covariant in its keys and values

Author: jiripudil

src/Type/ArrayType.php

@@ -22,7 +22,6 @@
 use PHPStan\Type\Constant\ConstantIntegerType;
 use PHPStan\Type\Constant\ConstantStringType;
 use PHPStan\Type\Generic\TemplateMixedType;
-use PHPStan\Type\Generic\TemplateType;
 use PHPStan\Type\Generic\TemplateTypeMap;
 use PHPStan\Type\Generic\TemplateTypeVariance;
 use PHPStan\Type\Traits\MaybeCallableTypeTrait;
@@ -636,24 +635,11 @@ public function inferTemplateTypes(Type $receivedType): TemplateTypeMap
 
 public function getReferencedTemplateTypes(TemplateTypeVariance $positionVariance): array
 {
-$keyVariance = $positionVariance;
-$itemVariance = $positionVariance;
-
-if (!$positionVariance->contravariant()) {
-$keyType = $this->getKeyType();
-if ($keyType instanceof TemplateType) {
-$keyVariance = $keyType->getVariance();
-}
-
-$itemType = $this->getItemType();
-if ($itemType instanceof TemplateType) {
-$itemVariance = $itemType->getVariance();
-}
-}
+$variance = $positionVariance->compose(TemplateTypeVariance::createCovariant());
 
 return array_merge(
-$this->getKeyType()->getReferencedTemplateTypes($keyVariance),
-$this->getItemType()->getReferencedTemplateTypes($itemVariance),
+$this->getKeyType()->getReferencedTemplateTypes($variance),
+$this->getItemType()->getReferencedTemplateTypes($variance),
 );
 }
 

tests/PHPStan/Rules/Generics/MethodSignatureVarianceRuleTest.php

@@ -224,4 +224,14 @@ public function testBug9161(): void
 $this->analyse([__DIR__ . '/data/bug-9161.php'], []);
 }
 
+public function testPr2465(): void
+{
+$this->analyse([__DIR__ . '/data/pr-2465.php'], [
+[
+'Template type T is declared as covariant, but occurs in invariant position in parameter thing of method Pr2465\UnitOfTest::foo().',
+16,
+],
+]);
+}
+
 }

tests/PHPStan/Rules/Generics/data/pr-2465.php

@@ -0,0 +1,17 @@
+<?php declare(strict_types = 1);
+
+namespace Pr2465;
+
+/** @template T */
+class InvariantThing {}
+
+/**
+ * @template-covariant T
+ */
+class UnitOfTest
+{
+/**
+ * @param InvariantThing<array<T>> $thing
+ */
+public function foo(InvariantThing $thing): void {}
+}