mirror of https://github.com/rust-lang/rust
50 lines
1022 B
Rust
50 lines
1022 B
Rust
// This doesn't work, because we don't flow information from opaque types
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// into function arguments via the function's generic parameters
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// FIXME(oli-obk): make `expected_inputs_for_expected_output` support this
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//@ revisions: default next
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//@[next] compile-flags: -Znext-solver
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#![feature(type_alias_impl_trait)]
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fn reify_as() -> Thunk<impl FnOnce(Continuation) -> Continuation> {
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Thunk::new(|mut cont| {
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//~^ ERROR type annotations needed
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cont.reify_as();
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cont
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})
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}
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type Tait = impl FnOnce(Continuation) -> Continuation;
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fn reify_as_tait() -> Thunk<Tait> {
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Thunk::new(|mut cont| {
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//~^ ERROR type annotations needed
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cont.reify_as();
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cont
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})
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}
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#[must_use]
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struct Thunk<F>(F);
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impl<F> Thunk<F> {
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fn new(f: F) -> Self
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where
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F: ContFn,
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{
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Thunk(f)
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}
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}
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trait ContFn {}
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impl<F: FnOnce(Continuation) -> Continuation> ContFn for F {}
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struct Continuation;
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impl Continuation {
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fn reify_as(&mut self) {}
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}
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fn main() {}
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