diff --git a/src/Type/Constant/ConstantArrayType.php b/src/Type/Constant/ConstantArrayType.php
index 7fc1b6e86ed..1a237f61794 100644
--- a/src/Type/Constant/ConstantArrayType.php
+++ b/src/Type/Constant/ConstantArrayType.php
@@ -540,13 +540,16 @@ public function getOffsetType(Type $offsetValueType): Type
 				return $traverse($type);
 			}
 
+			$offsetType = new NeverType();
 			foreach ($this->valueTypes as $i => $valueType) {
-				if ($valueType->equals($type)) {
-					return $this->keyTypes[$i];
+				if (!$type->isSuperTypeOf($valueType)->yes()) {
+					continue;
 				}
+
+				$offsetType = TypeCombinator::union($offsetType, $this->keyTypes[$i]);
 			}
 
-			return new ErrorType(); // undefined offset value
+			return $offsetType instanceof NeverType ? new ErrorType() : $offsetType;
 		});
 	}