// RUN: %target-swift-frontend -c -verify -primary-file %s %S/Inputs/other_file_protocol_default_implementation_witness.swift

// SR-13455: Test missing protocol requirement `@differentiable` attribute
// errors for protocol witnesses declared in a different file than the protocol
// conformance.
//
// This test case specifically tests protocol extension method witnesses.

import _Differentiation

// expected-error @+1 {{type 'ConformingStruct' does not conform to protocol 'P1'}}
struct ConformingStruct: P2 {}