bjoernager/rust
bjoernager/rust
1
Fork 0
Code Issues Pull requests Activity

Don't use kw::Empty in hir::Lifetime::ident.

Browse source 
`hir::Lifetime::ident` currently sometimes uses `kw::Empty` for elided
lifetimes and sometimes uses `kw::UnderscoreLifetime`, and the
distinction is used when creating some error suggestions, e.g. in
`Lifetime::suggestion` and `ImplicitLifetimeFinder::visit_ty`. I found
this *really* confusing, and it took me a while to understand what was
going on.

This commit replaces all uses of `kw::Empty` in `hir::Lifetime::ident`
with `kw::UnderscoreLifetime`. It adds a new field
`hir::Lifetime::is_path_anon` that mostly replaces the old
empty/underscore distinction and makes things much clearer.

Some other notable changes:

- Adds a big comment to `Lifetime` talking about permissable field
  values.

- Adds some assertions in `new_named_lifetime` about what ident values
  are permissible for the different `LifetimeRes` values.

- Adds a `Lifetime::new` constructor that does some checking to make
  sure the `is_elided` and `is_anonymous` states are valid.

- `add_static_impl_trait_suggestion` now looks at `Lifetime::res`
  instead of the ident when creating the suggestion. This is the one
  case where `is_path_anon` doesn't replace the old empty/underscore
  distinction.

- A couple of minor pretty-printing improvements.
This commit is contained in:
Nicholas Nethercote 2025-03-25 08:21:28 +11:00
parent cfd00f9c16
commit 8d2c63f514
9 changed files with 136 additions and 51 deletions
Download patch file Download diff file Expand all files Collapse all files

19
compiler/rustc_trait_selection/src/errors.rs
View file

@ -9,7 +9,7 @@ use rustc_errors::{
use rustc_hir::def::DefKind;
use rustc_hir::def_id::{DefId, LocalDefId};
use rustc_hir::intravisit::{Visitor, VisitorExt, walk_ty};
use rustc_hir::{self as hir, AmbigArg, FnRetTy, GenericParamKind, Node};
use rustc_hir::{self as hir, AmbigArg, FnRetTy, GenericParamKind, IsAnonInPath, Node};
use rustc_macros::{Diagnostic, Subdiagnostic};
use rustc_middle::ty::print::{PrintTraitRefExt as _, TraitRefPrintOnlyTraitPath};
use rustc_middle::ty::{self, Binder, ClosureKind, FnSig, Region, Ty, TyCtxt};
@ -567,10 +567,14 @@ impl Subdiagnostic for AddLifetimeParamsSuggestion<'_> {
impl<'v> Visitor<'v> for ImplicitLifetimeFinder {
fn visit_ty(&mut self, ty: &'v hir::Ty<'v, AmbigArg>) {
let make_suggestion = |ident: Ident| {
if ident.name == kw::Empty && ident.span.is_empty() {
let make_suggestion = |lifetime: &hir::Lifetime| {
if lifetime.is_anon_in_path == IsAnonInPath::Yes
&& lifetime.ident.span.is_empty()
{
format!("{}, ", self.suggestion_param_name)
} else if ident.name == kw::UnderscoreLifetime && ident.span.is_empty() {
} else if lifetime.ident.name == kw::UnderscoreLifetime
&& lifetime.ident.span.is_empty()
{
format!("{} ", self.suggestion_param_name)
} else {
self.suggestion_param_name.clone()
@ -584,7 +588,7 @@ impl Subdiagnostic for AddLifetimeParamsSuggestion<'_> {
matches!(
arg,
hir::GenericArg::Lifetime(lifetime)
if lifetime.ident.name == kw::Empty
if lifetime.is_anon_in_path == IsAnonInPath::Yes
)
}) {
self.suggestions.push((
@ -605,7 +609,7 @@ impl Subdiagnostic for AddLifetimeParamsSuggestion<'_> {
{
self.suggestions.push((
lifetime.ident.span,
make_suggestion(lifetime.ident),
make_suggestion(lifetime),
));
}
}
@ -614,8 +618,7 @@ impl Subdiagnostic for AddLifetimeParamsSuggestion<'_> {
}
}
hir::TyKind::Ref(lifetime, ..) if lifetime.is_anonymous() => {
self.suggestions
.push((lifetime.ident.span, make_suggestion(lifetime.ident)));
self.suggestions.push((lifetime.ident.span, make_suggestion(lifetime)));
}
_ => {}
}