nordic-dev.net/rust
nordic-dev.net/rust
2
0
Fork 0
mirror of https://github.com/rust-lang/rust.git synced 2025-05-05 14:37:37 +00:00
Code Issues Packages Projects Releases Wiki Activity

Auto merge of #135273 - dianne:argument-patterns-are-not-boring, r=lqd

Browse Source 
Remove special-casing for argument patterns in MIR typeck (attempt to fix perf regression of  #133858)

See [my comment](https://github.com/rust-lang/rust/pull/133858#issuecomment-2579029618) on #133858 for more information. This is just a guess as to what went wrong, and I haven't been able to get the profiler running locally, so I'll need a perf run to make sure this actually helps.

There's one test's stderr that suffers a bit, but this was just papering over the issue anyway. Making region errors point to the correct constraints in the presence of invariance/contravariance is a broader problem; the current way it's handled is mostly based on guesswork, luck, and hoping it works out. Properly handling that (somehow) would improve the test's stderr without the hack that this PR reverts.
This commit is contained in:
bors 2025-01-10 08:53:21 +00:00
commit b44e14f762
3 changed files with 9 additions and 20 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

13
compiler/rustc_borrowck/src/type_check/mod.rs
View File

@ -892,19 +892,6 @@ impl<'a, 'tcx> TypeChecker<'a, 'tcx> {
Some(l) if !body.local_decls[l].is_user_variable() => {
ConstraintCategory::Boring
}
Some(_)
if let Some(body_id) = tcx
.hir_node_by_def_id(body.source.def_id().expect_local())
.body_id()
&& let params = tcx.hir().body(body_id).params
&& params
.iter()
.any(|param| param.span.contains(stmt.source_info.span)) =>
{
// Assignments generated from lowering argument patterns shouldn't be called
// "assignments" in diagnostics and aren't interesting to blame for errors.
ConstraintCategory::Boring
}
_ => ConstraintCategory::Assignment,
};
debug!(

2
tests/ui/lifetimes/lifetime-errors/ex3-both-anon-regions-2.rs
View File

@ -1,6 +1,6 @@
fn foo(&mut (ref mut v, w): &mut (&u8, &u8), x: &u8) {
*v = x;
//~^ ERROR lifetime may not live long enough
*v = x;
}
fn main() { }

14
tests/ui/lifetimes/lifetime-errors/ex3-both-anon-regions-2.stderr
View File

@ -1,13 +1,15 @@
error: lifetime may not live long enough
--> $DIR/ex3-both-anon-regions-2.rs:2:5
--> $DIR/ex3-both-anon-regions-2.rs:1:14
|
LL | fn foo(&mut (ref mut v, w): &mut (&u8, &u8), x: &u8) {
| - - let's call the lifetime of this reference `'1`
| |
| let's call the lifetime of this reference `'2`
LL | *v = x;
| ^^^^^^ assignment requires that `'1` must outlive `'2`
| ^^^^^^^^^ - - let's call the lifetime of this reference `'1`
| | |
| | let's call the lifetime of this reference `'2`
| assignment requires that `'1` must outlive `'2`
|
= note: requirement occurs because of a mutable reference to `&u8`
= note: mutable references are invariant over their type parameter
= help: see <https://doc.rust-lang.org/nomicon/subtyping.html> for more information about variance
help: consider introducing a named lifetime parameter
|
LL | fn foo<'a>(&mut (ref mut v, w): &mut (&'a u8, &u8), x: &'a u8) {