Fix

Author: VincentLanglet

src/Rules/Arrays/InvalidKeyInArrayDimFetchRule.php

@@ -10,7 +10,6 @@
 use PHPStan\Rules\RuleErrorBuilder;
 use PHPStan\Rules\RuleLevelHelper;
 use PHPStan\Type\ErrorType;
-use PHPStan\Type\MixedType;
 use PHPStan\Type\Type;
 use PHPStan\Type\VerbosityLevel;
 use function sprintf;
@@ -60,7 +59,7 @@ public function processNode(Node $node, Scope $scope): array
 			'',
 			static fn (Type $dimType): bool => AllowedArrayKeysTypes::getType($reportArrayKeyCast)->isSuperTypeOf($dimType)->yes(),
 		)->getType();
-		if ($dimensionType instanceof MixedType) {
+		if ($dimensionType instanceof ErrorType) {
 			return [];
 		}