e9a0c429c5
Specifically, change `Ty` from this: ``` pub type Ty<'tcx> = &'tcx TyS<'tcx>; ``` to this ``` pub struct Ty<'tcx>(Interned<'tcx, TyS<'tcx>>); ``` There are two benefits to this. - It's now a first class type, so we can define methods on it. This means we can move a lot of methods away from `TyS`, leaving `TyS` as a barely-used type, which is appropriate given that it's not meant to be used directly. - The uniqueness requirement is now explicit, via the `Interned` type. E.g. the pointer-based `Eq` and `Hash` comes from `Interned`, rather than via `TyS`, which wasn't obvious at all. Much of this commit is boring churn. The interesting changes are in these files: - compiler/rustc_middle/src/arena.rs - compiler/rustc_middle/src/mir/visit.rs - compiler/rustc_middle/src/ty/context.rs - compiler/rustc_middle/src/ty/mod.rs Specifically: - Most mentions of `TyS` are removed. It's very much a dumb struct now; `Ty` has all the smarts. - `TyS` now has `crate` visibility instead of `pub`. - `TyS::make_for_test` is removed in favour of the static `BOOL_TY`, which just works better with the new structure. - The `Eq`/`Ord`/`Hash` impls are removed from `TyS`. `Interned`s impls of `Eq`/`Hash` now suffice. `Ord` is now partly on `Interned` (pointer-based, for the `Equal` case) and partly on `TyS` (contents-based, for the other cases). - There are many tedious sigil adjustments, i.e. adding or removing `*` or `&`. They seem to be unavoidable.
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};
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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 Ty<'_> {
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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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