Improve

Author: VincentLanglet

src/Type/UnionType.php

@@ -25,6 +25,7 @@
 use PHPStan\TrinaryLogic;
 use PHPStan\Type\Enum\EnumCaseObjectType;
 use PHPStan\Type\Generic\GenericClassStringType;
+use PHPStan\Type\Generic\GenericObjectType;
 use PHPStan\Type\Generic\TemplateIterableType;
 use PHPStan\Type\Generic\TemplateMixedType;
 use PHPStan\Type\Generic\TemplateType;
@@ -33,6 +34,7 @@
 use PHPStan\Type\Generic\TemplateUnionType;
 use PHPStan\Type\Traits\NonGeneralizableTypeTrait;
 use Throwable;
+use Traversable;
 use function array_diff_assoc;
 use function array_fill_keys;
 use function array_map;
@@ -194,6 +196,16 @@ public function getConstantStrings(): array
 
 	public function accepts(Type $type, bool $strictTypes): AcceptsResult
 	{
+		if ($type instanceof IterableType) {
+			return $this->accepts(new UnionType([
+				new ArrayType($type->getIterableKeyType(), $type->getIterableValueType()),
+				new GenericObjectType(Traversable::class, [
+					$type->getIterableKeyType(),
+					$type->getIterableValueType(),
+				]),
+			]), $strictTypes);
+		}
+
 		foreach (self::EQUAL_UNION_CLASSES as $baseClass => $classes) {
 			if (!$type->equals(new ObjectType($baseClass))) {
 				continue;
@@ -1073,6 +1085,16 @@ public function toCoercedArgumentType(bool $strictTypes): Type
 
 	public function inferTemplateTypes(Type $receivedType): TemplateTypeMap
 	{
+		if ($receivedType instanceof IterableType) {
+			$receivedType = new UnionType([
+				new ArrayType($receivedType->getIterableKeyType(), $receivedType->getIterableValueType()),
+				new GenericObjectType(Traversable::class, [
+					$receivedType->getIterableKeyType(),
+					$receivedType->getIterableValueType(),
+				]),
+			]);
+		}
+
 		$types = TemplateTypeMap::createEmpty();
 		if ($receivedType instanceof UnionType) {
 			$myTypes = [];

tests/PHPStan/Rules/Functions/data/bug-13247.php

@@ -7,18 +7,24 @@
 use Traversable;
 
 /**
- * @param array<int, int>|Traversable<int, int> $input
+ * @template K as array-key
+ * @template V
  *
- * @return array<int, int>
+ * @param array<K, V>|Traversable<K, V> $input
+ *
+ * @return array<K, V>
  */
 function as_array(array|Traversable $input): array {
 	return iter_as_array($input);
 }
 
 /**
- * @param iterable<int, int> $input
+ * @template K as array-key
+ * @template V
  *
- * @return array<int, int>
+ * @param iterable<K, V> $input
+ *
+ * @return array<K, V>
  */
 function iter_as_array(iterable $input): array {
 	return as_array($input);
@@ -41,3 +47,49 @@ function as_array2(array|Traversable $input): array {
 function iter_as_array2(iterable $input): array {
 	return as_array2($input);
 }
+
+/**
+ * @param array<int, int>|Traversable<int, int> $input
+ *
+ * @return array<int, int>
+ */
+function as_array3(array|Traversable $input): array {
+	return iter_as_array3($input);
+}
+
+/**
+ * @param iterable<int, int> $input
+ *
+ * @return array<int, int>
+ */
+function iter_as_array3(iterable $input): array {
+	return as_array3($input);
+}
+
+/**
+ * @phpstan-template T of iterable<int, int>
+ *
+ * @param T $input
+ *
+ * @return mixed
+ */
+function test1(iterable $input) {
+	test2($input);
+	iter_as_array($input);
+
+	return as_array($input);
+}
+
+/**
+ * @phpstan-template U of Traversable<int, int>|array<int, int>
+ *
+ * @param U $input
+ *
+ * @return mixed
+ */
+function test2($input) {
+	test1($input);
+	iter_as_array($input);
+
+	return as_array($input);
+}