00040-std-function-func-swift-constraints-solution-computesubstitutions.swift

// This source file is part of the Swift.org open source project
// Copyright (c) 2014 - 2017 Apple Inc. and the Swift project authors
// Licensed under Apache License v2.0 with Runtime Library Exception
//
// See https://swift.org/LICENSE.txt for license information
// See https://swift.org/CONTRIBUTORS.txt for the list of Swift project authors

// RUN: %target-swift-frontend %s -typecheck -verify -swift-version 3

// Test case submitted to project by https://github.com/tmu (Teemu Kurppa)
// rdar://18175202

func d<b: Sequence, e where Optional<e> == b.Iterator.Element>(c : b) -> e? {
  // expected-warning@-1 {{'where' clause next to generic parameters}}
  for mx : e? in c { // expected-warning {{immutable value 'mx' was never used}}
  }
}