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Auto merge of #102787 - Dylan-DPC:rollup-fvbb4t9, r=Dylan-DPC
Rollup of 6 pull requests Successful merges: - #102300 (Use a macro to not have to copy-paste `ConstFnMutClosure::new(&mut fold, NeverShortCircuit::wrap_mut_2_imp)).0` everywhere) - #102475 (unsafe keyword: trait examples and unsafe_op_in_unsafe_fn update) - #102760 (Avoid repeated re-initialization of the BufReader buffer) - #102764 (Check `WhereClauseReferencesSelf` after all other object safety checks) - #102779 (Fix `type_of` ICE) - #102780 (run Miri CI when std::sys changes) Failed merges: r? `@ghost` `@rustbot` modify labels: rollup
This commit is contained in:
commit
2d3a85b4f8
@ -493,8 +493,10 @@ pub(super) fn type_of(tcx: TyCtxt<'_>, def_id: DefId) -> Ty<'_> {
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},
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def_id.to_def_id(),
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);
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if let Some(assoc_item) = assoc_item {
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tcx.type_of(tcx.generics_of(assoc_item.def_id).params[idx].def_id)
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if let Some(param)
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= assoc_item.map(|item| &tcx.generics_of(item.def_id).params[idx]).filter(|param| param.kind.is_ty_or_const())
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{
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tcx.type_of(param.def_id)
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} else {
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// FIXME(associated_const_equality): add a useful error message here.
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tcx.ty_error_with_message(
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|
@ -447,19 +447,6 @@ fn virtual_call_violation_for_method<'tcx>(
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return Some(MethodViolationCode::Generic);
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}
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if tcx
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.predicates_of(method.def_id)
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.predicates
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.iter()
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// A trait object can't claim to live more than the concrete type,
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// so outlives predicates will always hold.
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.cloned()
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.filter(|(p, _)| p.to_opt_type_outlives().is_none())
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.any(|pred| contains_illegal_self_type_reference(tcx, trait_def_id, pred))
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{
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return Some(MethodViolationCode::WhereClauseReferencesSelf);
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}
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let receiver_ty = tcx.liberate_late_bound_regions(method.def_id, sig.input(0));
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// Until `unsized_locals` is fully implemented, `self: Self` can't be dispatched on.
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@ -538,6 +525,21 @@ fn virtual_call_violation_for_method<'tcx>(
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}
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}
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// NOTE: This check happens last, because it results in a lint, and not a
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// hard error.
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if tcx
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.predicates_of(method.def_id)
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.predicates
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.iter()
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// A trait object can't claim to live more than the concrete type,
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// so outlives predicates will always hold.
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.cloned()
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.filter(|(p, _)| p.to_opt_type_outlives().is_none())
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.any(|pred| contains_illegal_self_type_reference(tcx, trait_def_id, pred))
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{
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return Some(MethodViolationCode::WhereClauseReferencesSelf);
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}
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None
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}
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|
@ -1,7 +1,6 @@
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use crate::array;
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use crate::const_closure::ConstFnMutClosure;
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use crate::iter::{ByRefSized, FusedIterator, Iterator};
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use crate::ops::{ControlFlow, NeverShortCircuit, Try};
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use crate::ops::{ControlFlow, Try};
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/// An iterator over `N` elements of the iterator at a time.
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///
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@ -83,13 +82,7 @@ where
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}
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}
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fn fold<B, F>(mut self, init: B, mut f: F) -> B
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where
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Self: Sized,
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F: FnMut(B, Self::Item) -> B,
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{
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self.try_fold(init, ConstFnMutClosure::new(&mut f, NeverShortCircuit::wrap_mut_2_imp)).0
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}
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impl_fold_via_try_fold! { fold -> try_fold }
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}
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#[unstable(feature = "iter_array_chunks", reason = "recently added", issue = "100450")]
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@ -127,13 +120,7 @@ where
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try { acc }
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}
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fn rfold<B, F>(mut self, init: B, mut f: F) -> B
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where
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Self: Sized,
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F: FnMut(B, Self::Item) -> B,
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{
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self.try_rfold(init, ConstFnMutClosure::new(&mut f, NeverShortCircuit::wrap_mut_2_imp)).0
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}
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impl_fold_via_try_fold! { rfold -> try_rfold }
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}
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impl<I, const N: usize> ArrayChunks<I, N>
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|
@ -64,19 +64,7 @@ where
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.into_try()
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}
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#[inline]
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fn fold<Acc, Fold>(mut self, init: Acc, fold: Fold) -> Acc
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where
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Self: Sized,
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Fold: FnMut(Acc, Self::Item) -> Acc,
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{
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#[inline]
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fn ok<B, T>(mut f: impl FnMut(B, T) -> B) -> impl FnMut(B, T) -> Result<B, !> {
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move |acc, x| Ok(f(acc, x))
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}
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self.try_fold(init, ok(fold)).unwrap()
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}
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impl_fold_via_try_fold! { fold -> try_fold }
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}
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#[unstable(issue = "none", feature = "inplace_iteration")]
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|
@ -1,6 +1,5 @@
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use crate::const_closure::ConstFnMutClosure;
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use crate::iter::{InPlaceIterable, Iterator};
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use crate::ops::{ChangeOutputType, ControlFlow, FromResidual, NeverShortCircuit, Residual, Try};
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use crate::ops::{ChangeOutputType, ControlFlow, FromResidual, Residual, Try};
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mod array_chunks;
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mod by_ref_sized;
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@ -204,13 +203,7 @@ where
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.into_try()
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}
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fn fold<B, F>(mut self, init: B, mut fold: F) -> B
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where
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Self: Sized,
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F: FnMut(B, Self::Item) -> B,
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{
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self.try_fold(init, ConstFnMutClosure::new(&mut fold, NeverShortCircuit::wrap_mut_2_imp)).0
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}
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impl_fold_via_try_fold! { fold -> try_fold }
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}
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#[unstable(issue = "none", feature = "inplace_iteration")]
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|
@ -74,19 +74,7 @@ where
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self.iter.try_fold(init, scan(state, f, fold)).into_try()
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}
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#[inline]
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fn fold<Acc, Fold>(mut self, init: Acc, fold: Fold) -> Acc
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where
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Self: Sized,
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Fold: FnMut(Acc, Self::Item) -> Acc,
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{
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#[inline]
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fn ok<B, T>(mut f: impl FnMut(B, T) -> B) -> impl FnMut(B, T) -> Result<B, !> {
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move |acc, x| Ok(f(acc, x))
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}
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self.try_fold(init, ok(fold)).unwrap()
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}
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impl_fold_via_try_fold! { fold -> try_fold }
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}
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#[unstable(issue = "none", feature = "inplace_iteration")]
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|
@ -206,17 +206,7 @@ where
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if n == 0 { try { init } } else { self.iter.try_rfold(init, check(n, fold)).into_try() }
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}
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fn rfold<Acc, Fold>(mut self, init: Acc, fold: Fold) -> Acc
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where
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Fold: FnMut(Acc, Self::Item) -> Acc,
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{
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#[inline]
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fn ok<Acc, T>(mut f: impl FnMut(Acc, T) -> Acc) -> impl FnMut(Acc, T) -> Result<Acc, !> {
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move |acc, x| Ok(f(acc, x))
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}
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self.try_rfold(init, ok(fold)).unwrap()
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}
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impl_fold_via_try_fold! { rfold -> try_rfold }
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#[inline]
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fn advance_back_by(&mut self, n: usize) -> Result<(), usize> {
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|
@ -98,19 +98,7 @@ where
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||||
}
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}
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#[inline]
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fn fold<Acc, Fold>(mut self, init: Acc, fold: Fold) -> Acc
|
||||
where
|
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Self: Sized,
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Fold: FnMut(Acc, Self::Item) -> Acc,
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{
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#[inline]
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fn ok<B, T>(mut f: impl FnMut(B, T) -> B) -> impl FnMut(B, T) -> Result<B, !> {
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move |acc, x| Ok(f(acc, x))
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||||
}
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|
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self.try_fold(init, ok(fold)).unwrap()
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}
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impl_fold_via_try_fold! { fold -> try_fold }
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|
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#[inline]
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#[rustc_inherit_overflow_checks]
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|
@ -94,19 +94,7 @@ where
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||||
}
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}
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|
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#[inline]
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fn fold<Acc, Fold>(mut self, init: Acc, fold: Fold) -> Acc
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where
|
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Self: Sized,
|
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Fold: FnMut(Acc, Self::Item) -> Acc,
|
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{
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#[inline]
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fn ok<B, T>(mut f: impl FnMut(B, T) -> B) -> impl FnMut(B, T) -> Result<B, !> {
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move |acc, x| Ok(f(acc, x))
|
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}
|
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|
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self.try_fold(init, ok(fold)).unwrap()
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}
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impl_fold_via_try_fold! { fold -> try_fold }
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}
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#[stable(feature = "fused", since = "1.26.0")]
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|
@ -352,6 +352,29 @@
|
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#![stable(feature = "rust1", since = "1.0.0")]
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|
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// This needs to be up here in order to be usable in the child modules
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macro_rules! impl_fold_via_try_fold {
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(fold -> try_fold) => {
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impl_fold_via_try_fold! { @internal fold -> try_fold }
|
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};
|
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(rfold -> try_rfold) => {
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impl_fold_via_try_fold! { @internal rfold -> try_rfold }
|
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};
|
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(@internal $fold:ident -> $try_fold:ident) => {
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#[inline]
|
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fn $fold<AAA, FFF>(mut self, init: AAA, mut fold: FFF) -> AAA
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where
|
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FFF: FnMut(AAA, Self::Item) -> AAA,
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{
|
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use crate::const_closure::ConstFnMutClosure;
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use crate::ops::NeverShortCircuit;
|
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|
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let fold = ConstFnMutClosure::new(&mut fold, NeverShortCircuit::wrap_mut_2_imp);
|
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self.$try_fold(init, fold).0
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}
|
||||
};
|
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}
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#[stable(feature = "rust1", since = "1.0.0")]
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pub use self::traits::Iterator;
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|
@ -1150,19 +1150,7 @@ impl<A: Step> Iterator for ops::RangeInclusive<A> {
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self.spec_try_fold(init, f)
|
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}
|
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|
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#[inline]
|
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fn fold<B, F>(mut self, init: B, f: F) -> B
|
||||
where
|
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Self: Sized,
|
||||
F: FnMut(B, Self::Item) -> B,
|
||||
{
|
||||
#[inline]
|
||||
fn ok<B, T>(mut f: impl FnMut(B, T) -> B) -> impl FnMut(B, T) -> Result<B, !> {
|
||||
move |acc, x| Ok(f(acc, x))
|
||||
}
|
||||
|
||||
self.try_fold(init, ok(f)).unwrap()
|
||||
}
|
||||
impl_fold_via_try_fold! { fold -> try_fold }
|
||||
|
||||
#[inline]
|
||||
fn last(mut self) -> Option<A> {
|
||||
@ -1230,19 +1218,7 @@ impl<A: Step> DoubleEndedIterator for ops::RangeInclusive<A> {
|
||||
self.spec_try_rfold(init, f)
|
||||
}
|
||||
|
||||
#[inline]
|
||||
fn rfold<B, F>(mut self, init: B, f: F) -> B
|
||||
where
|
||||
Self: Sized,
|
||||
F: FnMut(B, Self::Item) -> B,
|
||||
{
|
||||
#[inline]
|
||||
fn ok<B, T>(mut f: impl FnMut(B, T) -> B) -> impl FnMut(B, T) -> Result<B, !> {
|
||||
move |acc, x| Ok(f(acc, x))
|
||||
}
|
||||
|
||||
self.try_rfold(init, ok(f)).unwrap()
|
||||
}
|
||||
impl_fold_via_try_fold! { rfold -> try_rfold }
|
||||
}
|
||||
|
||||
// Safety: See above implementation for `ops::Range<A>`
|
||||
|
@ -224,6 +224,14 @@ impl<R> BufReader<R> {
|
||||
}
|
||||
}
|
||||
|
||||
// This is only used by a test which asserts that the initialization-tracking is correct.
|
||||
#[cfg(test)]
|
||||
impl<R> BufReader<R> {
|
||||
pub fn initialized(&self) -> usize {
|
||||
self.buf.initialized()
|
||||
}
|
||||
}
|
||||
|
||||
impl<R: Seek> BufReader<R> {
|
||||
/// Seeks relative to the current position. If the new position lies within the buffer,
|
||||
/// the buffer will not be flushed, allowing for more efficient seeks.
|
||||
|
@ -20,13 +20,19 @@ pub struct Buffer {
|
||||
// Each call to `fill_buf` sets `filled` to indicate how many bytes at the start of `buf` are
|
||||
// initialized with bytes from a read.
|
||||
filled: usize,
|
||||
// This is the max number of bytes returned across all `fill_buf` calls. We track this so that we
|
||||
// can accurately tell `read_buf` how many bytes of buf are initialized, to bypass as much of its
|
||||
// defensive initialization as possible. Note that while this often the same as `filled`, it
|
||||
// doesn't need to be. Calls to `fill_buf` are not required to actually fill the buffer, and
|
||||
// omitting this is a huge perf regression for `Read` impls that do not.
|
||||
initialized: usize,
|
||||
}
|
||||
|
||||
impl Buffer {
|
||||
#[inline]
|
||||
pub fn with_capacity(capacity: usize) -> Self {
|
||||
let buf = Box::new_uninit_slice(capacity);
|
||||
Self { buf, pos: 0, filled: 0 }
|
||||
Self { buf, pos: 0, filled: 0, initialized: 0 }
|
||||
}
|
||||
|
||||
#[inline]
|
||||
@ -51,6 +57,12 @@ impl Buffer {
|
||||
self.pos
|
||||
}
|
||||
|
||||
// This is only used by a test which asserts that the initialization-tracking is correct.
|
||||
#[cfg(test)]
|
||||
pub fn initialized(&self) -> usize {
|
||||
self.initialized
|
||||
}
|
||||
|
||||
#[inline]
|
||||
pub fn discard_buffer(&mut self) {
|
||||
self.pos = 0;
|
||||
@ -96,13 +108,14 @@ impl Buffer {
|
||||
let mut buf = BorrowedBuf::from(&mut *self.buf);
|
||||
// SAFETY: `self.filled` bytes will always have been initialized.
|
||||
unsafe {
|
||||
buf.set_init(self.filled);
|
||||
buf.set_init(self.initialized);
|
||||
}
|
||||
|
||||
reader.read_buf(buf.unfilled())?;
|
||||
|
||||
self.filled = buf.len();
|
||||
self.pos = 0;
|
||||
self.filled = buf.len();
|
||||
self.initialized = buf.init_len();
|
||||
}
|
||||
Ok(self.buffer())
|
||||
}
|
||||
|
@ -1039,3 +1039,27 @@ fn single_formatted_write() {
|
||||
writeln!(&mut writer, "{}, {}!", "hello", "world").unwrap();
|
||||
assert_eq!(writer.get_ref().events, [RecordedEvent::Write("hello, world!\n".to_string())]);
|
||||
}
|
||||
|
||||
#[test]
|
||||
fn bufreader_full_initialize() {
|
||||
struct OneByteReader;
|
||||
impl Read for OneByteReader {
|
||||
fn read(&mut self, buf: &mut [u8]) -> crate::io::Result<usize> {
|
||||
if buf.len() > 0 {
|
||||
buf[0] = 0;
|
||||
Ok(1)
|
||||
} else {
|
||||
Ok(0)
|
||||
}
|
||||
}
|
||||
}
|
||||
let mut reader = BufReader::new(OneByteReader);
|
||||
// Nothing is initialized yet.
|
||||
assert_eq!(reader.initialized(), 0);
|
||||
|
||||
let buf = reader.fill_buf().unwrap();
|
||||
// We read one byte...
|
||||
assert_eq!(buf.len(), 1);
|
||||
// But we initialized the whole buffer!
|
||||
assert_eq!(reader.initialized(), reader.capacity());
|
||||
}
|
||||
|
@ -1867,11 +1867,15 @@ mod type_keyword {}
|
||||
/// Code or interfaces whose [memory safety] cannot be verified by the type
|
||||
/// system.
|
||||
///
|
||||
/// The `unsafe` keyword has two uses: to declare the existence of contracts the
|
||||
/// compiler can't check (`unsafe fn` and `unsafe trait`), and to declare that a
|
||||
/// programmer has checked that these contracts have been upheld (`unsafe {}`
|
||||
/// and `unsafe impl`, but also `unsafe fn` -- see below). They are not mutually
|
||||
/// exclusive, as can be seen in `unsafe fn`.
|
||||
/// The `unsafe` keyword has two uses:
|
||||
/// - to declare the existence of contracts the compiler can't check (`unsafe fn` and `unsafe
|
||||
/// trait`),
|
||||
/// - and to declare that a programmer has checked that these contracts have been upheld (`unsafe
|
||||
/// {}` and `unsafe impl`, but also `unsafe fn` -- see below).
|
||||
///
|
||||
/// They are not mutually exclusive, as can be seen in `unsafe fn`: the body of an `unsafe fn` is,
|
||||
/// by default, treated like an unsafe block. The `unsafe_op_in_unsafe_fn` lint can be enabled to
|
||||
/// change that.
|
||||
///
|
||||
/// # Unsafe abilities
|
||||
///
|
||||
@ -1914,12 +1918,12 @@ mod type_keyword {}
|
||||
/// - `unsafe impl`: the contract necessary to implement the trait has been
|
||||
/// checked by the programmer and is guaranteed to be respected.
|
||||
///
|
||||
/// `unsafe fn` also acts like an `unsafe {}` block
|
||||
/// By default, `unsafe fn` also acts like an `unsafe {}` block
|
||||
/// around the code inside the function. This means it is not just a signal to
|
||||
/// the caller, but also promises that the preconditions for the operations
|
||||
/// inside the function are upheld. Mixing these two meanings can be confusing
|
||||
/// and [proposal]s exist to use `unsafe {}` blocks inside such functions when
|
||||
/// making `unsafe` operations.
|
||||
/// inside the function are upheld. Mixing these two meanings can be confusing, so the
|
||||
/// `unsafe_op_in_unsafe_fn` lint can be enabled to warn against that and require explicit unsafe
|
||||
/// blocks even inside `unsafe fn`.
|
||||
///
|
||||
/// See the [Rustnomicon] and the [Reference] for more information.
|
||||
///
|
||||
@ -1987,13 +1991,16 @@ mod type_keyword {}
|
||||
///
|
||||
/// ```rust
|
||||
/// # #![allow(dead_code)]
|
||||
/// #![deny(unsafe_op_in_unsafe_fn)]
|
||||
///
|
||||
/// /// Dereference the given pointer.
|
||||
/// ///
|
||||
/// /// # Safety
|
||||
/// ///
|
||||
/// /// `ptr` must be aligned and must not be dangling.
|
||||
/// unsafe fn deref_unchecked(ptr: *const i32) -> i32 {
|
||||
/// *ptr
|
||||
/// // SAFETY: the caller is required to ensure that `ptr` is aligned and dereferenceable.
|
||||
/// unsafe { *ptr }
|
||||
/// }
|
||||
///
|
||||
/// let a = 3;
|
||||
@ -2003,35 +2010,118 @@ mod type_keyword {}
|
||||
/// unsafe { assert_eq!(*b, deref_unchecked(b)); };
|
||||
/// ```
|
||||
///
|
||||
/// Traits marked as `unsafe` must be [`impl`]emented using `unsafe impl`. This
|
||||
/// makes a guarantee to other `unsafe` code that the implementation satisfies
|
||||
/// the trait's safety contract. The [Send] and [Sync] traits are examples of
|
||||
/// this behaviour in the standard library.
|
||||
/// ## `unsafe` and traits
|
||||
///
|
||||
/// The interactions of `unsafe` and traits can be surprising, so let us contrast the
|
||||
/// two combinations of safe `fn` in `unsafe trait` and `unsafe fn` in safe trait using two
|
||||
/// examples:
|
||||
///
|
||||
/// ```rust
|
||||
/// /// Implementors of this trait must guarantee an element is always
|
||||
/// /// accessible with index 3.
|
||||
/// unsafe trait ThreeIndexable<T> {
|
||||
/// /// Returns a reference to the element with index 3 in `&self`.
|
||||
/// fn three(&self) -> &T;
|
||||
/// /// # Safety
|
||||
/// ///
|
||||
/// /// `make_even` must return an even number.
|
||||
/// unsafe trait MakeEven {
|
||||
/// fn make_even(&self) -> i32;
|
||||
/// }
|
||||
///
|
||||
/// // The implementation of `ThreeIndexable` for `[T; 4]` is `unsafe`
|
||||
/// // because the implementor must abide by a contract the compiler cannot
|
||||
/// // check but as a programmer we know there will always be a valid element
|
||||
/// // at index 3 to access.
|
||||
/// unsafe impl<T> ThreeIndexable<T> for [T; 4] {
|
||||
/// fn three(&self) -> &T {
|
||||
/// // SAFETY: implementing the trait means there always is an element
|
||||
/// // with index 3 accessible.
|
||||
/// unsafe { self.get_unchecked(3) }
|
||||
/// // SAFETY: Our `make_even` always returns something even.
|
||||
/// unsafe impl MakeEven for i32 {
|
||||
/// fn make_even(&self) -> i32 {
|
||||
/// self << 1
|
||||
/// }
|
||||
/// }
|
||||
///
|
||||
/// let a = [1, 2, 4, 8];
|
||||
/// assert_eq!(a.three(), &8);
|
||||
/// fn use_make_even(x: impl MakeEven) {
|
||||
/// if x.make_even() % 2 == 1 {
|
||||
/// // SAFETY: this can never happen, because all `MakeEven` implementations
|
||||
/// // ensure that `make_even` returns something even.
|
||||
/// unsafe { std::hint::unreachable_unchecked() };
|
||||
/// }
|
||||
/// }
|
||||
/// ```
|
||||
///
|
||||
/// Note how the safety contract of the trait is upheld by the implementation, and is itself used to
|
||||
/// uphold the safety contract of the unsafe function `unreachable_unchecked` called by
|
||||
/// `use_make_even`. `make_even` itself is a safe function because its *callers* do not have to
|
||||
/// worry about any contract, only the *implementation* of `MakeEven` is required to uphold a
|
||||
/// certain contract. `use_make_even` is safe because it can use the promise made by `MakeEven`
|
||||
/// implementations to uphold the safety contract of the `unsafe fn unreachable_unchecked` it calls.
|
||||
///
|
||||
/// It is also possible to have `unsafe fn` in a regular safe `trait`:
|
||||
///
|
||||
/// ```rust
|
||||
/// # #![feature(never_type)]
|
||||
/// #![deny(unsafe_op_in_unsafe_fn)]
|
||||
///
|
||||
/// trait Indexable {
|
||||
/// const LEN: usize;
|
||||
///
|
||||
/// /// # Safety
|
||||
/// ///
|
||||
/// /// The caller must ensure that `idx < LEN`.
|
||||
/// unsafe fn idx_unchecked(&self, idx: usize) -> i32;
|
||||
/// }
|
||||
///
|
||||
/// // The implementation for `i32` doesn't need to do any contract reasoning.
|
||||
/// impl Indexable for i32 {
|
||||
/// const LEN: usize = 1;
|
||||
///
|
||||
/// unsafe fn idx_unchecked(&self, idx: usize) -> i32 {
|
||||
/// debug_assert_eq!(idx, 0);
|
||||
/// *self
|
||||
/// }
|
||||
/// }
|
||||
///
|
||||
/// // The implementation for arrays exploits the function contract to
|
||||
/// // make use of `get_unchecked` on slices and avoid a run-time check.
|
||||
/// impl Indexable for [i32; 42] {
|
||||
/// const LEN: usize = 42;
|
||||
///
|
||||
/// unsafe fn idx_unchecked(&self, idx: usize) -> i32 {
|
||||
/// // SAFETY: As per this trait's documentation, the caller ensures
|
||||
/// // that `idx < 42`.
|
||||
/// unsafe { *self.get_unchecked(idx) }
|
||||
/// }
|
||||
/// }
|
||||
///
|
||||
/// // The implementation for the never type declares a length of 0,
|
||||
/// // which means `idx_unchecked` can never be called.
|
||||
/// impl Indexable for ! {
|
||||
/// const LEN: usize = 0;
|
||||
///
|
||||
/// unsafe fn idx_unchecked(&self, idx: usize) -> i32 {
|
||||
/// // SAFETY: As per this trait's documentation, the caller ensures
|
||||
/// // that `idx < 0`, which is impossible, so this is dead code.
|
||||
/// unsafe { std::hint::unreachable_unchecked() }
|
||||
/// }
|
||||
/// }
|
||||
///
|
||||
/// fn use_indexable<I: Indexable>(x: I, idx: usize) -> i32 {
|
||||
/// if idx < I::LEN {
|
||||
/// // SAFETY: We have checked that `idx < I::LEN`.
|
||||
/// unsafe { x.idx_unchecked(idx) }
|
||||
/// } else {
|
||||
/// panic!("index out-of-bounds")
|
||||
/// }
|
||||
/// }
|
||||
/// ```
|
||||
///
|
||||
/// This time, `use_indexable` is safe because it uses a run-time check to discharge the safety
|
||||
/// contract of `idx_unchecked`. Implementing `Indexable` is safe because when writing
|
||||
/// `idx_unchecked`, we don't have to worry: our *callers* need to discharge a proof obligation
|
||||
/// (like `use_indexable` does), but the *implementation* of `get_unchecked` has no proof obligation
|
||||
/// to contend with. Of course, the implementation of `Indexable` may choose to call other unsafe
|
||||
/// operations, and then it needs an `unsafe` *block* to indicate it discharged the proof
|
||||
/// obligations of its callees. (We enabled `unsafe_op_in_unsafe_fn`, so the body of `idx_unchecked`
|
||||
/// is not implicitly an unsafe block.) For that purpose it can make use of the contract that all
|
||||
/// its callers must uphold -- the fact that `idx < LEN`.
|
||||
///
|
||||
/// Formally speaking, an `unsafe fn` in a trait is a function with *preconditions* that go beyond
|
||||
/// those encoded by the argument types (such as `idx < LEN`), whereas an `unsafe trait` can declare
|
||||
/// that some of its functions have *postconditions* that go beyond those encoded in the return type
|
||||
/// (such as returning an even integer). If a trait needs a function with both extra precondition
|
||||
/// and extra postcondition, then it needs an `unsafe fn` in an `unsafe trait`.
|
||||
///
|
||||
/// [`extern`]: keyword.extern.html
|
||||
/// [`trait`]: keyword.trait.html
|
||||
/// [`static`]: keyword.static.html
|
||||
@ -2043,7 +2133,6 @@ mod type_keyword {}
|
||||
/// [nomicon-soundness]: ../nomicon/safe-unsafe-meaning.html
|
||||
/// [soundness]: https://rust-lang.github.io/unsafe-code-guidelines/glossary.html#soundness-of-code--of-a-library
|
||||
/// [Reference]: ../reference/unsafety.html
|
||||
/// [proposal]: https://github.com/rust-lang/rfcs/pull/2585
|
||||
/// [discussion on Rust Internals]: https://internals.rust-lang.org/t/what-does-unsafe-mean/6696
|
||||
mod unsafe_keyword {}
|
||||
|
||||
|
@ -19,9 +19,12 @@ if [[ -n "${CI_ONLY_WHEN_SUBMODULES_CHANGED-}" ]]; then
|
||||
# those files are present in the diff a submodule was updated.
|
||||
echo "Submodules were updated"
|
||||
elif ! (git diff --quiet "$BASE_COMMIT" -- \
|
||||
src/tools/clippy src/tools/rustfmt src/tools/miri); then
|
||||
src/tools/clippy src/tools/rustfmt src/tools/miri
|
||||
library/std/src/sys); then
|
||||
# There is not an easy blanket search for subtrees. For now, manually list
|
||||
# the subtrees.
|
||||
# Also run this when the platform-specific parts of std change, in case
|
||||
# that breaks Miri.
|
||||
echo "Tool subtrees were updated"
|
||||
elif ! (git diff --quiet "$BASE_COMMIT" -- \
|
||||
src/test/rustdoc-gui \
|
||||
|
@ -0,0 +1,14 @@
|
||||
#![feature(generic_const_exprs)]
|
||||
#![allow(incomplete_features)]
|
||||
|
||||
trait X {
|
||||
type Y<'a>;
|
||||
}
|
||||
|
||||
const _: () = {
|
||||
fn f2<'a>(arg: Box<dyn X<Y<1> = &'a ()>>) {}
|
||||
//~^ ERROR this associated type takes 1 lifetime argument but 0 lifetime arguments
|
||||
//~| ERROR this associated type takes 0 generic arguments but 1 generic argument
|
||||
};
|
||||
|
||||
fn main() {}
|
@ -0,0 +1,33 @@
|
||||
error[E0107]: this associated type takes 1 lifetime argument but 0 lifetime arguments were supplied
|
||||
--> $DIR/issue-102768.rs:9:30
|
||||
|
|
||||
LL | fn f2<'a>(arg: Box<dyn X<Y<1> = &'a ()>>) {}
|
||||
| ^ expected 1 lifetime argument
|
||||
|
|
||||
note: associated type defined here, with 1 lifetime parameter: `'a`
|
||||
--> $DIR/issue-102768.rs:5:10
|
||||
|
|
||||
LL | type Y<'a>;
|
||||
| ^ --
|
||||
help: add missing lifetime argument
|
||||
|
|
||||
LL | fn f2<'a>(arg: Box<dyn X<Y<'a, 1> = &'a ()>>) {}
|
||||
| +++
|
||||
|
||||
error[E0107]: this associated type takes 0 generic arguments but 1 generic argument was supplied
|
||||
--> $DIR/issue-102768.rs:9:30
|
||||
|
|
||||
LL | fn f2<'a>(arg: Box<dyn X<Y<1> = &'a ()>>) {}
|
||||
| ^--- help: remove these generics
|
||||
| |
|
||||
| expected 0 generic arguments
|
||||
|
|
||||
note: associated type defined here, with 0 generic parameters
|
||||
--> $DIR/issue-102768.rs:5:10
|
||||
|
|
||||
LL | type Y<'a>;
|
||||
| ^
|
||||
|
||||
error: aborting due to 2 previous errors
|
||||
|
||||
For more information about this error, try `rustc --explain E0107`.
|
26
src/test/ui/object-safety/issue-102762.rs
Normal file
26
src/test/ui/object-safety/issue-102762.rs
Normal file
@ -0,0 +1,26 @@
|
||||
// compile-flags: --crate-type=lib
|
||||
// This test checks that the `where_clauses_object_safety` lint does not cause
|
||||
// other object safety *hard errors* to be suppressed, because we currently
|
||||
// only emit one object safety error per trait...
|
||||
|
||||
use std::future::Future;
|
||||
use std::pin::Pin;
|
||||
|
||||
pub trait Fetcher: Send + Sync {
|
||||
fn get<'a>(self: &'a Box<Self>) -> Pin<Box<dyn Future<Output = Vec<u8>> + 'a>>
|
||||
where
|
||||
Self: Sync,
|
||||
{
|
||||
todo!()
|
||||
}
|
||||
}
|
||||
|
||||
fn fetcher() -> Box<dyn Fetcher> {
|
||||
//~^ ERROR the trait `Fetcher` cannot be made into an object
|
||||
todo!()
|
||||
}
|
||||
|
||||
pub fn foo() {
|
||||
let fetcher = fetcher();
|
||||
let _ = fetcher.get();
|
||||
}
|
20
src/test/ui/object-safety/issue-102762.stderr
Normal file
20
src/test/ui/object-safety/issue-102762.stderr
Normal file
@ -0,0 +1,20 @@
|
||||
error[E0038]: the trait `Fetcher` cannot be made into an object
|
||||
--> $DIR/issue-102762.rs:18:21
|
||||
|
|
||||
LL | fn get<'a>(self: &'a Box<Self>) -> Pin<Box<dyn Future<Output = Vec<u8>> + 'a>>
|
||||
| ------------- help: consider changing method `get`'s `self` parameter to be `&self`: `&Self`
|
||||
...
|
||||
LL | fn fetcher() -> Box<dyn Fetcher> {
|
||||
| ^^^^^^^^^^^ `Fetcher` cannot be made into an object
|
||||
|
|
||||
note: for a trait to be "object safe" it needs to allow building a vtable to allow the call to be resolvable dynamically; for more information visit <https://doc.rust-lang.org/reference/items/traits.html#object-safety>
|
||||
--> $DIR/issue-102762.rs:10:22
|
||||
|
|
||||
LL | pub trait Fetcher: Send + Sync {
|
||||
| ------- this trait cannot be made into an object...
|
||||
LL | fn get<'a>(self: &'a Box<Self>) -> Pin<Box<dyn Future<Output = Vec<u8>> + 'a>>
|
||||
| ^^^^^^^^^^^^^ ...because method `get`'s `self` parameter cannot be dispatched on
|
||||
|
||||
error: aborting due to previous error
|
||||
|
||||
For more information about this error, try `rustc --explain E0038`.
|
Loading…
Reference in New Issue
Block a user