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Rollup merge of #130712 - compiler-errors:const-eval-error-reporting, r=BoxyUwU

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Don't call `ty::Const::normalize` in error reporting

We do this to ensure that trait refs with unevaluated consts have those consts simplified to their evaluated forms. Instead, use `try_normalize_erasing_regions`.

**NOTE:** This has the side-effect of erasing regions from all of our trait refs. If this is too much to review or you think it's too opinionated of a diagnostics change, then I could split out the effective change (i.e. erasing regions from this impl suggestion) into another PR and have someone else review it.
This commit is contained in:
Matthias Krüger 2024-09-23 06:45:34 +02:00 • committed by GitHub
commit 82060368e6
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31 changed files with 178 additions and 179 deletions
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39
compiler/rustc_trait_selection/src/error_reporting/traits/fulfillment_errors.rs
View file

@ -17,7 +17,7 @@ use rustc_middle::traits::SignatureMismatchData;
use rustc_middle::traits::select::OverflowError;
use rustc_middle::ty::abstract_const::NotConstEvaluatable;
use rustc_middle::ty::error::{ExpectedFound, TypeError};
use rustc_middle::ty::fold::{BottomUpFolder, TypeFolder, TypeSuperFoldable};
use rustc_middle::ty::fold::{TypeFolder, TypeSuperFoldable};
use rustc_middle::ty::print::{
FmtPrinter, Print, PrintTraitPredicateExt as _, PrintTraitRefExt as _,
with_forced_trimmed_paths,
@ -1788,22 +1788,18 @@ impl<'a, 'tcx> TypeErrCtxt<'a, 'tcx> {
return false;
}
let cand = self.resolve_vars_if_possible(impl_trait_ref).fold_with(
&mut BottomUpFolder {
tcx: self.tcx,
ty_op: |ty| ty,
lt_op: |lt| lt,
ct_op: |ct| ct.normalize(self.tcx, ty::ParamEnv::empty()),
},
);
if cand.references_error() {
let impl_trait_ref = self.resolve_vars_if_possible(impl_trait_ref);
if impl_trait_ref.references_error() {
return false;
}
err.highlighted_help(vec![
StringPart::normal(format!("the trait `{}` ", cand.print_trait_sugared())),
StringPart::normal(format!(
"the trait `{}` ",
impl_trait_ref.print_trait_sugared()
)),
StringPart::highlighted("is"),
StringPart::normal(" implemented for `"),
StringPart::highlighted(cand.self_ty().to_string()),
StringPart::highlighted(impl_trait_ref.self_ty().to_string()),
StringPart::normal("`"),
]);
@ -1915,15 +1911,18 @@ impl<'a, 'tcx> TypeErrCtxt<'a, 'tcx> {
let mut impl_candidates: Vec<_> = impl_candidates
.iter()
.cloned()
.filter(|cand| !cand.trait_ref.references_error())
.map(|mut cand| {
// Fold the consts so that they shows up as, e.g., `10`
// instead of `core::::array::{impl#30}::{constant#0}`.
cand.trait_ref = cand.trait_ref.fold_with(&mut BottomUpFolder {
tcx: self.tcx,
ty_op: |ty| ty,
lt_op: |lt| lt,
ct_op: |ct| ct.normalize(self.tcx, ty::ParamEnv::empty()),
});
// Normalize the trait ref in its *own* param-env so
// that consts are folded and any trivial projections
// are normalized.
cand.trait_ref = self
.tcx
.try_normalize_erasing_regions(
self.tcx.param_env(cand.impl_def_id),
cand.trait_ref,
)
.unwrap_or(cand.trait_ref);
cand
})
.collect();

2
compiler/rustc_trait_selection/src/error_reporting/traits/suggestions.rs
View file

@ -4620,7 +4620,7 @@ impl<'a, 'tcx> TypeErrCtxt<'a, 'tcx> {
format!("&{}{ty}", mutability.prefix_str())
}
}
ty::Array(ty, len) if let Some(len) = len.try_eval_target_usize(tcx, param_env) => {
ty::Array(ty, len) if let Some(len) = len.try_to_target_usize(tcx) => {
if len == 0 {
"[]".to_string()
} else if self.type_is_copy_modulo_regions(param_env, ty) || len == 1 {