Fix phpstan/phpstan#11507: false positive for invariant template with HasOffsetValueType

- When setting an explicit array key on a generic array type (e.g. $item['foo'] = '100'),
  PHPStan adds HasOffsetValueType to the intersection, making the type structurally
  unequal to the base array type even though they describe the same type to the user
- The invariance check in TemplateTypeVariance::isValidVariance used strict equals(),
  which failed due to the extra HasOffsetValueType accessory type
- Added a fallback that strips HasOffsetValueType/HasOffsetType before comparing,
  so types differing only in offset tracking are treated as equal for invariance
- New regression test in tests/PHPStan/Rules/Functions/data/bug-11507.php

Author: github-actions[bot]

src/Type/Generic/TemplateTypeVariance.php

@@ -5,11 +5,14 @@
 use PHPStan\PhpDocParser\Ast\Type\GenericTypeNode;
 use PHPStan\ShouldNotHappenException;
 use PHPStan\TrinaryLogic;
+use PHPStan\Type\Accessory\HasOffsetType;
+use PHPStan\Type\Accessory\HasOffsetValueType;
 use PHPStan\Type\BenevolentUnionType;
 use PHPStan\Type\IsSuperTypeOfResult;
 use PHPStan\Type\MixedType;
 use PHPStan\Type\NeverType;
 use PHPStan\Type\Type;
+use PHPStan\Type\TypeTraverser;
 use function sprintf;
 
 /**
@@ -177,6 +180,13 @@ public function isValidVariance(TemplateType $templateType, Type $a, Type $b): I
 
 		if ($this->invariant()) {
 			$result = $a->equals($b);
+			if (!$result) {
+				$strippedA = self::stripHasOffsetTypes($a);
+				$strippedB = self::stripHasOffsetTypes($b);
+				if ($strippedA !== $a || $strippedB !== $b) {
+					$result = $strippedA->equals($strippedB);
+				}
+			}
 			$reasons = [];
 			if (!$result) {
 				if (
@@ -259,4 +269,15 @@ public function toPhpDocNodeVariance(): string
 		throw new ShouldNotHappenException();
 	}
 
+	private static function stripHasOffsetTypes(Type $type): Type
+	{
+		return TypeTraverser::map($type, static function (Type $type, callable $traverse): Type {
+			if ($type instanceof HasOffsetValueType || $type instanceof HasOffsetType) {
+				return new MixedType();
+			}
+
+			return $traverse($type);
+		});
+	}
+
 }

tests/PHPStan/Rules/Functions/ReturnTypeRuleTest.php

@@ -411,4 +411,11 @@ public function testBug12397(): void
 		$this->analyse([__DIR__ . '/data/bug-12397.php'], []);
 	}
 
+	public function testBug11507(): void
+	{
+		$this->checkNullables = true;
+		$this->checkExplicitMixed = true;
+		$this->analyse([__DIR__ . '/data/bug-11507.php'], []);
+	}
+
 }

tests/PHPStan/Rules/Functions/data/bug-11507.php

@@ -0,0 +1,50 @@
+<?php // lint >= 8.0
+
+declare(strict_types = 1);
+
+namespace Bug11507;
+
+/**
+ * @template TValue
+ */
+class Collection
+{
+	/**
+	* @param array<int, TValue> $items
+	*/
+	public function __construct(
+		public array $items,
+	) {}
+
+	 /**
+     * Run a map over each of the items.
+     *
+     * @template TMapValue
+     *
+     * @param  callable(TValue, int=): TMapValue  $callback
+     * @return Collection<TMapValue>
+     */
+	public function map(callable $callback): Collection
+	{
+		$keys = array_keys($this->items);
+
+		$items = array_map($callback, $this->items);
+
+        $result = array_combine($keys, $items);
+
+		return new self($result);
+	}
+}
+
+/**
+ * @param  Collection<non-empty-array<string>>  $collection
+ * @return Collection<non-empty-array<string>>
+ */
+function foo(Collection $collection): Collection
+{
+	return $collection->map(function (array $item) {
+		$item['foo'] = '100';
+
+		return $item;
+	});
+}