diff options
Diffstat (limited to 'compiler/rustc_query_impl/src/values.rs')
-rw-r--r-- | compiler/rustc_query_impl/src/values.rs | 45 |
1 files changed, 45 insertions, 0 deletions
diff --git a/compiler/rustc_query_impl/src/values.rs b/compiler/rustc_query_impl/src/values.rs new file mode 100644 index 000000000..718a2971c --- /dev/null +++ b/compiler/rustc_query_impl/src/values.rs @@ -0,0 +1,45 @@ +use super::QueryCtxt; +use rustc_middle::ty::{self, AdtSizedConstraint, Ty}; + +pub(super) trait Value<'tcx>: Sized { + fn from_cycle_error(tcx: QueryCtxt<'tcx>) -> Self; +} + +impl<'tcx, T> Value<'tcx> for T { + default fn from_cycle_error(tcx: QueryCtxt<'tcx>) -> T { + tcx.sess.abort_if_errors(); + bug!("Value::from_cycle_error called without errors"); + } +} + +impl<'tcx> Value<'tcx> for Ty<'_> { + fn from_cycle_error(tcx: QueryCtxt<'tcx>) -> Self { + // SAFETY: This is never called when `Self` is not `Ty<'tcx>`. + // FIXME: Represent the above fact in the trait system somehow. + unsafe { std::mem::transmute::<Ty<'tcx>, Ty<'_>>(tcx.ty_error()) } + } +} + +impl<'tcx> Value<'tcx> for ty::SymbolName<'_> { + fn from_cycle_error(tcx: QueryCtxt<'tcx>) -> Self { + // SAFETY: This is never called when `Self` is not `SymbolName<'tcx>`. + // FIXME: Represent the above fact in the trait system somehow. + unsafe { + std::mem::transmute::<ty::SymbolName<'tcx>, ty::SymbolName<'_>>(ty::SymbolName::new( + *tcx, "<error>", + )) + } + } +} + +impl<'tcx> Value<'tcx> for AdtSizedConstraint<'_> { + fn from_cycle_error(tcx: QueryCtxt<'tcx>) -> Self { + // SAFETY: This is never called when `Self` is not `AdtSizedConstraint<'tcx>`. + // FIXME: Represent the above fact in the trait system somehow. + unsafe { + std::mem::transmute::<AdtSizedConstraint<'tcx>, AdtSizedConstraint<'_>>( + AdtSizedConstraint(tcx.intern_type_list(&[tcx.ty_error()])), + ) + } + } +} |