46 lines
1.6 KiB
Rust
46 lines
1.6 KiB
Rust
use super::QueryCtxt;
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use rustc_middle::ty::{self, AdtSizedConstraint, Ty, TyS};
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pub(super) trait Value<'tcx>: Sized {
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fn from_cycle_error(tcx: QueryCtxt<'tcx>) -> Self;
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}
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impl<'tcx, T> Value<'tcx> for T {
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default fn from_cycle_error(tcx: QueryCtxt<'tcx>) -> T {
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tcx.sess.abort_if_errors();
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bug!("Value::from_cycle_error called without errors");
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}
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}
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impl<'tcx> Value<'tcx> for &'_ TyS<'_> {
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fn from_cycle_error(tcx: QueryCtxt<'tcx>) -> Self {
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// SAFETY: This is never called when `Self` is not `Ty<'tcx>`.
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// FIXME: Represent the above fact in the trait system somehow.
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unsafe { std::mem::transmute::<Ty<'tcx>, Ty<'_>>(tcx.ty_error()) }
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}
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}
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impl<'tcx> Value<'tcx> for ty::SymbolName<'_> {
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fn from_cycle_error(tcx: QueryCtxt<'tcx>) -> Self {
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// SAFETY: This is never called when `Self` is not `SymbolName<'tcx>`.
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// FIXME: Represent the above fact in the trait system somehow.
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unsafe {
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std::mem::transmute::<ty::SymbolName<'tcx>, ty::SymbolName<'_>>(ty::SymbolName::new(
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*tcx, "<error>",
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))
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}
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}
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}
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impl<'tcx> Value<'tcx> for AdtSizedConstraint<'_> {
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fn from_cycle_error(tcx: QueryCtxt<'tcx>) -> Self {
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// SAFETY: This is never called when `Self` is not `AdtSizedConstraint<'tcx>`.
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// FIXME: Represent the above fact in the trait system somehow.
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unsafe {
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std::mem::transmute::<AdtSizedConstraint<'tcx>, AdtSizedConstraint<'_>>(
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AdtSizedConstraint(tcx.intern_type_list(&[tcx.ty_error()])),
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)
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}
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}
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}
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