bjoernager/rust
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don't get trapped inside of expansions when trimming labels

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This commit is contained in:
dianne 2025-02-19 00:50:31 -08:00
parent ef6df3b713
commit 51a2ee3252
2 changed files with 16 additions and 19 deletions
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26
compiler/rustc_hir_typeck/src/pat.rs
View file

@ -835,20 +835,20 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
self.add_rust_2024_migration_desugared_pat(
pat_info.top_info.hir_id,
pat,
ident.span,
't',
def_br_mutbl,
);
BindingMode(ByRef::No, Mutability::Mut)
}
}
BindingMode(ByRef::No, mutbl) => BindingMode(def_br, mutbl),
BindingMode(ByRef::Yes(_), _) => {
BindingMode(ByRef::Yes(user_br_mutbl), _) => {
if let ByRef::Yes(def_br_mutbl) = def_br {
// `ref`/`ref mut` overrides the binding mode on edition <= 2021
self.add_rust_2024_migration_desugared_pat(
pat_info.top_info.hir_id,
pat,
ident.span,
if user_br_mutbl.is_mut() { 't' } else { 'f' },
def_br_mutbl,
);
}
@ -2387,7 +2387,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
self.add_rust_2024_migration_desugared_pat(
pat_info.top_info.hir_id,
pat,
inner.span,
if pat_mutbl.is_mut() { 't' } else { '&' },
inh_mut,
)
}
@ -2779,18 +2779,19 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
&self,
pat_id: HirId,
subpat: &'tcx Pat<'tcx>,
cutoff_span: Span,
final_char: char,
def_br_mutbl: Mutability,
) {
// Try to trim the span we're labeling to just the `&` or binding mode that's an issue.
// If the subpattern's span is is from an expansion, the emitted label will not be trimmed.
let source_map = self.tcx.sess.source_map();
let cutoff_span = source_map
.span_extend_prev_while(cutoff_span, |c| c.is_whitespace() || c == '(')
.unwrap_or(cutoff_span);
// Ensure we use the syntax context and thus edition of `subpat.span`; this will be a hard
// error if the subpattern is of edition >= 2024.
let trimmed_span = subpat.span.until(cutoff_span).with_ctxt(subpat.span.ctxt());
// Importantly, the edition of the trimmed span should be the same as `subpat.span`; this
// will be a hard error if the subpattern is of edition >= 2024.
let from_expansion = subpat.span.from_expansion();
let trimmed_span = if from_expansion {
subpat.span
} else {
self.tcx.sess.source_map().span_through_char(subpat.span, final_char)
};
let mut typeck_results = self.typeck_results.borrow_mut();
let mut table = typeck_results.rust_2024_migration_desugared_pats_mut();
@ -2824,7 +2825,6 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
};
// Only provide a detailed label if the problematic subpattern isn't from an expansion.
// In the case that it's from a macro, we'll add a more detailed note in the emitter.
let from_expansion = subpat.span.from_expansion();
let primary_label = if from_expansion {
// We can't suggest eliding modifiers within expansions.
info.suggest_eliding_modes = false;

9
tests/ui/pattern/rfc-3627-match-ergonomics-2024/migration_lint.stderr
View file

@ -581,12 +581,10 @@ LL | let &[migration_lint_macros::bind_ref!(a)] = &[0];
| +
error: reference patterns may only be written when the default binding mode is `move` in Rust 2024
--> $DIR/auxiliary/migration_lint_macros.rs:15:22
--> $DIR/migration_lint.rs:249:10
|
LL | ($foo:ident) => {
| ______________________^
LL | | ref $foo
| |________________^ reference pattern not allowed under `ref` default binding mode
LL | let [&migration_lint_macros::bind_ref!(a)] = &[&0];
| ^ reference pattern not allowed under `ref` default binding mode
|
= warning: this changes meaning in Rust 2024
= note: for more information, see <https://doc.rust-lang.org/nightly/edition-guide/rust-2024/match-ergonomics.html>
@ -596,7 +594,6 @@ note: matching on a reference type with a non-reference pattern changes the defa
LL | let [&migration_lint_macros::bind_ref!(a)] = &[&0];
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ this matches on type `&_`
help: make the implied reference pattern explicit
--> $DIR/migration_lint.rs:249:9
|
LL | let &[&migration_lint_macros::bind_ref!(a)] = &[&0];
| +