Check key type compatibility when narrowing ArrayType with callable

A plain ArrayType carries a key type (e.g. array<string, mixed> has
StringType keys). Since callable arrays always require integer keys 0
and 1, verify the key type is compatible with integers before narrowing.
Extract the inline logic into narrowArrayTypeWithCallable for clarity.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

Author: phpstan-bot

src/Type/TypeCombinator.php

@@ -1688,18 +1688,11 @@ public static function intersect(Type ...$types): Type
 						&& get_class($types[$i]) === ArrayType::class
 						&& $types[$j] instanceof CallableType
 					) {
-						$existingValueType = $types[$i]->getItemType();
-						$offset0ValueType = self::intersect($existingValueType, new UnionType([new ClassStringType(), new ObjectWithoutClassType()]));
-						$offset1ValueType = self::intersect($existingValueType, new StringType());
-						if ($offset0ValueType instanceof NeverType || $offset1ValueType instanceof NeverType) {
+						$narrowed = self::narrowArrayTypeWithCallable($types[$i]);
+						if ($narrowed instanceof NeverType) {
 							return new NeverType();
 						}
-						$types[$i] = new ConstantArrayType(
-							[new ConstantIntegerType(0), new ConstantIntegerType(1)],
-							[$offset0ValueType, $offset1ValueType],
-							[2],
-							isList: TrinaryLogic::createYes(),
-						);
+						$types[$i] = $narrowed;
 						continue;
 					}
 
@@ -1708,18 +1701,11 @@ public static function intersect(Type ...$types): Type
 						&& get_class($types[$j]) === ArrayType::class
 						&& $types[$i] instanceof CallableType
 					) {
-						$existingValueType = $types[$j]->getItemType();
-						$offset0ValueType = self::intersect($existingValueType, new UnionType([new ClassStringType(), new ObjectWithoutClassType()]));
-						$offset1ValueType = self::intersect($existingValueType, new StringType());
-						if ($offset0ValueType instanceof NeverType || $offset1ValueType instanceof NeverType) {
+						$narrowed = self::narrowArrayTypeWithCallable($types[$j]);
+						if ($narrowed instanceof NeverType) {
 							return new NeverType();
 						}
-						$types[$j] = new ConstantArrayType(
-							[new ConstantIntegerType(0), new ConstantIntegerType(1)],
-							[$offset0ValueType, $offset1ValueType],
-							[2],
-							isList: TrinaryLogic::createYes(),
-						);
+						$types[$j] = $narrowed;
 						continue;
 					}
 
@@ -1841,6 +1827,27 @@ public static function removeTruthy(Type $type): Type
 		return self::remove($type, StaticTypeFactory::truthy());
 	}
 
+	private static function narrowArrayTypeWithCallable(ArrayType $arrayType): Type
+	{
+		if ($arrayType->getKeyType()->isSuperTypeOf(new IntegerType())->no()) {
+			return new NeverType();
+		}
+
+		$existingValueType = $arrayType->getItemType();
+		$offset0ValueType = self::intersect($existingValueType, new UnionType([new ClassStringType(), new ObjectWithoutClassType()]));
+		$offset1ValueType = self::intersect($existingValueType, new StringType());
+		if ($offset0ValueType instanceof NeverType || $offset1ValueType instanceof NeverType) {
+			return new NeverType();
+		}
+
+		return new ConstantArrayType(
+			[new ConstantIntegerType(0), new ConstantIntegerType(1)],
+			[$offset0ValueType, $offset1ValueType],
+			[2],
+			isList: TrinaryLogic::createYes(),
+		);
+	}
+
 	private static function narrowConstantArrayWithCallable(ConstantArrayType $constantArray): Type
 	{
 		$keyTypes = $constantArray->getKeyTypes();

tests/PHPStan/Analyser/nsrt/bug-14549.php

@@ -52,6 +52,14 @@ public function testTypedArrayNarrowing(array $task): void
 		}
 	}
 
+	/** @param array<string, mixed> $task */
+	public function testStringKeyedArrayNarrowing(array $task): void
+	{
+		if (\is_callable($task)) {
+			assertType('*NEVER*', $task);
+		}
+	}
+
 	/** @param callable-array $value */
 	public function testCallableArrayPhpDoc(array $value): void
 	{