dnrops
/
rust
mirror of https://github.com/rust-lang/rust.git
1
0
Fork 0
Code Issues Packages Projects Releases Wiki Activity

Fix liveness analysis in the presence of never patterns

This commit is contained in:
Nadrieril 2024-02-20 02:55:40 +01:00
parent 7168c13579
commit 5e0e5b1efb
2 changed files with 11 additions and 4 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

11
compiler/rustc_hir/src/pat_util.rs
View File

@ -71,14 +71,21 @@ impl hir::Pat<'_> {
/// Call `f` on every "binding" in a pattern, e.g., on `a` in
/// `match foo() { Some(a) => (), None => () }`.
///
/// When encountering an or-pattern `p_0 | ... | p_n` only `p_0` will be visited.
/// When encountering an or-pattern `p_0 | ... | p_n` only the first non-never pattern will be
/// visited. If they're all never patterns we visit nothing, which is ok since a never pattern
/// cannot have bindings.
pub fn each_binding_or_first(
&self,
f: &mut impl FnMut(hir::BindingAnnotation, HirId, Span, Ident),
) {
self.walk(|p| match &p.kind {
PatKind::Or(ps) => {
ps[0].each_binding_or_first(f);
for p in *ps {
if !p.is_never_pattern() {
p.each_binding_or_first(f);
break;
}
}
false
}
PatKind::Binding(bm, _, ident, _) => {

4
compiler/rustc_passes/src/liveness.rs
View File

@ -526,8 +526,8 @@ impl<'a, 'tcx> Liveness<'a, 'tcx> {
}
fn define_bindings_in_pat(&mut self, pat: &hir::Pat<'_>, mut succ: LiveNode) -> LiveNode {
// In an or-pattern, only consider the first pattern; any later patterns
// must have the same bindings, and we also consider the first pattern
// In an or-pattern, only consider the first non-never pattern; any later patterns
// must have the same bindings, and we also consider that pattern
// to be the "authoritative" set of ids.
pat.each_binding_or_first(&mut |_, hir_id, pat_sp, ident| {
let ln = self.live_node(hir_id, pat_sp);