bjoernager/rust
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replace unnecessary folder impls with fold_region

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This commit is contained in:
lcnr 2023-11-15 17:40:54 +00:00
parent 00bfd6b273
commit 41cfb20abb
4 changed files with 15 additions and 51 deletions
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32
compiler/rustc_hir_analysis/src/hir_wf_check.rs
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@ -5,7 +5,7 @@ use rustc_hir::{ForeignItem, ForeignItemKind};
use rustc_infer::infer::TyCtxtInferExt;
use rustc_infer::traits::{ObligationCause, WellFormedLoc};
use rustc_middle::query::Providers;
use rustc_middle::ty::{self, Region, TyCtxt, TypeFoldable, TypeFolder};
use rustc_middle::ty::{self, TyCtxt};
use rustc_span::def_id::LocalDefId;
use rustc_trait_selection::traits::{self, ObligationCtxt};
@ -68,7 +68,13 @@ fn diagnostic_hir_wf_check<'tcx>(
let infcx = self.tcx.infer_ctxt().build();
let ocx = ObligationCtxt::new(&infcx);
let tcx_ty = self.icx.to_ty(ty).fold_with(&mut EraseAllBoundRegions { tcx: self.tcx });
let tcx_ty = self.icx.to_ty(ty);
// This visitor can walk into binders, resulting in the `tcx_ty` to
// potentially reference escaping bound variables. We simply erase
// those here.
let tcx_ty = self.tcx.fold_regions(tcx_ty, |r, _| {
if r.is_bound() { self.tcx.lifetimes.re_erased } else { r }
});
let cause = traits::ObligationCause::new(
ty.span,
self.def_id,
@ -178,25 +184,3 @@ fn diagnostic_hir_wf_check<'tcx>(
}
visitor.cause
}
struct EraseAllBoundRegions<'tcx> {
tcx: TyCtxt<'tcx>,
}
// Higher ranked regions are complicated.
// To make matters worse, the HIR WF check can instantiate them
// outside of a `Binder`, due to the way we (ab)use
// `ItemCtxt::to_ty`. To make things simpler, we just erase all
// of them, regardless of depth. At worse, this will give
// us an inaccurate span for an error message, but cannot
// lead to unsoundness (we call `delay_span_bug` at the start
// of `diagnostic_hir_wf_check`).
impl<'tcx> TypeFolder<TyCtxt<'tcx>> for EraseAllBoundRegions<'tcx> {
fn interner(&self) -> TyCtxt<'tcx> {
self.tcx
}
fn fold_region(&mut self, r: Region<'tcx>) -> Region<'tcx> {
// FIXME(@lcnr): only erase escaping bound regions!
if r.is_bound() { self.tcx.lifetimes.re_erased } else { r }
}
}