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Check that closures satisfy their where bounds

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This commit is contained in:
Oli Scherer 2022-05-10 14:19:19 +00:00
parent f001f9301c
commit 253408b409
16 changed files with 343 additions and 22 deletions
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24
compiler/rustc_trait_selection/src/traits/wf.rs
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@ -575,7 +575,7 @@ impl<'a, 'tcx> WfPredicates<'a, 'tcx> {
// generators don't take arguments.
}
ty::Closure(_, substs) => {
ty::Closure(did, substs) => {
// Only check the upvar types for WF, not the rest
// of the types within. This is needed because we
// capture the signature and it may not be WF
@ -596,18 +596,26 @@ impl<'a, 'tcx> WfPredicates<'a, 'tcx> {
// probably always be WF, because it should be
// shorthand for something like `where(T: 'a) {
// fn(&'a T) }`, as discussed in #25860.
//
// Note that we are also skipping the generic
// types. This is consistent with the `outlives`
// code, but anyway doesn't matter: within the fn
walker.skip_current_subtree(); // subtree handled below
// FIXME(eddyb) add the type to `walker` instead of recursing.
self.compute(substs.as_closure().tupled_upvars_ty().into());
// Note that we cannot skip the generic types
// types. Normally, within the fn
// body where they are created, the generics will
// always be WF, and outside of that fn body we
// are not directly inspecting closure types
// anyway, except via auto trait matching (which
// only inspects the upvar types).
walker.skip_current_subtree(); // subtree handled below
// FIXME(eddyb) add the type to `walker` instead of recursing.
self.compute(substs.as_closure().tupled_upvars_ty().into());
// But when a closure is part of a type-alias-impl-trait
// then the function that created the defining site may
// have had more bounds available than the type alias
// specifies. This may cause us to have a closure in the
// hidden type that is not actually well formed and
// can cause compiler crashes when the user abuses unsafe
// code to procure such a closure.
// See src/test/ui/type-alias-impl-trait/wf_check_closures.rs
let obligations = self.nominal_obligations(did, substs);
self.out.extend(obligations);
}
ty::FnPtr(_) => {