diff --git a/src/Type/IterableType.php b/src/Type/IterableType.php
index 46e004ae23..804fe27c7f 100644
--- a/src/Type/IterableType.php
+++ b/src/Type/IterableType.php
@@ -241,13 +241,7 @@ public function toCoercedArgumentType(bool $strictTypes): Type
 		return TypeCombinator::union(
 			$this,
 			new ArrayType(
-				TypeCombinator::intersect(
-					$this->keyType->toArrayKey(),
-					new UnionType([
-						new IntegerType(),
-						new StringType(),
-					]),
-				),
+				$this->keyType->toArrayKey(),
 				$this->itemType,
 			),
 			new GenericObjectType(Traversable::class, [