src/test/ui/run-pass/issues/issue-43132.rs

   1 // Copyright 2017 The Rust Project Developers. See the COPYRIGHT
   2 // file at the top-level directory of this distribution and at
   3 // http://rust-lang.org/COPYRIGHT.
   4 //
   5 // Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
   6 // http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
   7 // <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
   8 // option. This file may not be copied, modified, or distributed
   9 // except according to those terms.
  10
  11 // run-pass
  12 #![allow(unused)]
  13
  14 fn main() {
  15 }
  16
  17 fn foo() {
  18     let b = mk::<
  19         Forward<(Box<Future<Error = u32>>,)>,
  20     >();
  21     b.map_err(|_| ()).join();
  22 }
  23
  24 fn mk<T>() -> T {
  25     loop {}
  26 }
  27
  28 impl<I: Future<Error = E>, E> Future for (I,) {
  29     type Error = E;
  30 }
  31
  32 struct Forward<T: Future> {
  33     _a: T,
  34 }
  35
  36 impl<T: Future> Future for Forward<T>
  37 where
  38     T::Error: From<u32>,
  39 {
  40     type Error = T::Error;
  41 }
  42
  43 trait Future {
  44     type Error;
  45
  46     fn map_err<F, E>(self, _: F) -> (Self, F)
  47     where
  48         F: FnOnce(Self::Error) -> E,
  49         Self: Sized,
  50     {
  51         loop {}
  52     }
  53
  54     fn join(self) -> (MaybeDone<Self>, ())
  55     where
  56         Self: Sized,
  57     {
  58         loop {}
  59     }
  60 }
  61
  62 impl<S: ?Sized + Future> Future for Box<S> {
  63     type Error = S::Error;
  64 }
  65
  66 enum MaybeDone<A: Future> {
  67     _Done(A::Error),
  68 }
  69
  70 impl<U, A: Future, F> Future for (A, F)
  71 where
  72     F: FnOnce(A::Error) -> U,
  73 {
  74     type Error = U;
  75 }