Implement Copy/Clone for closures
#44551
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r? @pnkfelix (rust_highfive has picked a reviewer for you, use r? to override) |
aidanhs
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| @@ -2084,6 +2083,22 @@ impl<'cx, 'gcx, 'tcx> SelectionContext<'cx, 'gcx, 'tcx> { | |||
| Where(ty::Binder(tys.to_vec())) | |||
| } | |||
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| ty::TyClosure(def_id, substs) => { | |||
| let trait_id = obligation.predicate.def_id(); | |||
| let copy_closures = | |||
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Don't you need to check the feature-gate status of the crate that defined the closure, to avoid ICEs?
Crate A:
#![feature(clone_closures)]
pub trait Generic {
fn foo<T: Clone>(self, t: T);
}
pub fn example<G: Generic>(g: G) {
g.foo(|| {});
}Crate B:
// no feature flags!
extern crate a;
struct S;
impl Generic for S {
fn foo<T: Clone>(self, t: T) { let _ = t.clone(); }
}
fn main() {
// trans will monomorphize this, and will try to evaluate `[closure]: Clone`, which
// will fail and cause an ICE.
foo::example(S);
}Another option would be to make all closures Copy & Clone in trans, but that would be visible through specialization etc. so I'm not sure it's the better idea.
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@arielb1 Yes you're right. I'm working on it.
src/librustc_mir/shim.rs
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| @@ -613,7 +619,12 @@ impl<'a, 'tcx> CloneShimBuilder<'a, 'tcx> { | |||
| self.block(vec![], TerminatorKind::Resume, true); | |||
| } | |||
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| fn tuple_shim(&mut self, tys: &ty::Slice<ty::Ty<'tcx>>) { | |||
| fn tuple_like_shim(&mut self, tys: &[ty::Ty<'tcx>], kind: AggregateKind<'tcx>) { | |||
| match kind { | |||
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Is there a reason for this assertion? This method works just as well for structs and univariant enums.
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Indeed, but it won't work for arrays. I guess the match can be extended in the future if needed.
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☔ The latest upstream changes (presumably #44634) made this pull request unmergeable. Please resolve the merge conflicts. |
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@bors r+ |
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📌 Commit 3fa3fe0 has been approved by |
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Implement `Copy`/`Clone` for closures Implement RFC [#2132](rust-lang/rfcs#2132) (tracking issue: #44490). NB: I'm not totally sure about the whole feature gates thing, that's my first PR of this kind...
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☀️ Test successful - status-appveyor, status-travis |
Implement RFC #2132 (tracking issue: #44490).
NB: I'm not totally sure about the whole feature gates thing, that's my first PR of this kind...