Last nits · rust-lang/rust@9a75603 (original) (raw)
`@@ -13,6 +13,7 @@ use rustc_span::{ErrorGuaranteed, Span};
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`use std::collections::VecDeque;
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`use std::fmt::Write;
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use std::ops::ControlFlow;
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`impl<'tcx> Value<TyCtxt<'tcx>> for Ty<'_> {
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`fn from_cycle_error(tcx: TyCtxt<'tcx>, _: &CycleError, guar: ErrorGuaranteed) -> Self {
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`@@ -130,16 +131,34 @@ impl<'tcx> Value<TyCtxt<'tcx>> for ty::EarlyBinder<ty::Binder<'_, ty::FnSig<'_>>
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`}
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`}
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// Take a cycle of Q and try try_cycle on every permutation, falling back to otherwise.
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fn search_for_cycle_permutation<Q, T>(
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cycle: &[Q],
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try_cycle: impl Fn(&mut VecDeque<&Q>) -> ControlFlow<T, ()>,
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otherwise: impl FnOnce() -> T,
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) -> T {
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let mut cycle: VecDeque<_> = cycle.iter().collect();
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for _ in 0..cycle.len() {
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match try_cycle(&mut cycle) {
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ControlFlow::Continue(_) => {
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cycle.rotate_left(1);
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}
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ControlFlow::Break(t) => return t,
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}
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}
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otherwise()
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}
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`impl<'tcx, T> Value<TyCtxt<'tcx>> for Result<T, &'_ ty::layout::LayoutError<'_>> {
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`fn from_cycle_error(
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`tcx: TyCtxt<'tcx>,
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`cycle_error: &CycleError,
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`_guar: ErrorGuaranteed,
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`) -> Self {
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let mut cycle: VecDeque<_> = cycle_error.cycle.iter().collect();
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let guar = 'search: {
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for _ in 0..cycle.len() {
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let diag = search_for_cycle_permutation(
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&cycle_error.cycle,
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|cycle| {
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`if cycle[0].query.dep_kind == dep_kinds::layout_of
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` && let Some(def_id) = cycle[0].query.ty_def_id
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` && let Some(def_id) = def_id.as_local()
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`@@ -204,13 +223,16 @@ impl<'tcx, T> Value<TyCtxt<'tcx>> for Result<T, &'_ ty::layout::LayoutError<'_>>
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`) {
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`` diag.note("a recursive async fn call must introduce indirection such as Box::pin to avoid an infinitely sized future");
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`}
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break 'search diag.emit();
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ControlFlow::Break(diag)
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`} else {
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cycle.rotate_left(1);
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ControlFlow::Continue(())
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`}
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}
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report_cycle(tcx.sess, cycle_error).emit()
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};
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},
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|| report_cycle(tcx.sess, cycle_error),
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);
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let guar = diag.emit();
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`// tcx.arena.alloc cannot be used because we are not allowed to use &'tcx LayoutError under
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`// min_specialization. Since this is an error path anyways, leaking doesn't matter (and really,
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