bjoernager/rust
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Leave promoteds untainted by errors when borrowck fails

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Previously, when borrowck failed it would taint all promoteds within the MIR
body. An attempt to evaluated the promoteds would subsequently fail with
spurious "note: erroneous constant used". For example:

```console
...
note: erroneous constant used
 --> tests/ui/borrowck/tainted-promoteds.rs:7:9
  |
7 |     a = &0 * &1 * &2 * &3;
  |         ^^

note: erroneous constant used
 --> tests/ui/borrowck/tainted-promoteds.rs:7:14
  |
7 |     a = &0 * &1 * &2 * &3;
  |              ^^

note: erroneous constant used
 --> tests/ui/borrowck/tainted-promoteds.rs:7:19
  |
7 |     a = &0 * &1 * &2 * &3;
  |                   ^^

note: erroneous constant used
 --> tests/ui/borrowck/tainted-promoteds.rs:7:24
  |
7 |     a = &0 * &1 * &2 * &3;
  |                        ^^
```

Borrowck failure doesn't indicate that there is anything wrong with
promoteds. Leave them untainted.
This commit is contained in:
Tomasz Miąsko 2023-04-30 00:00:00 +00:00
parent f2eb9f85b9
commit c678acd3a2
3 changed files with 27 additions and 4 deletions
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5
compiler/rustc_mir_transform/src/lib.rs
View file

@ -616,13 +616,10 @@ fn promoted_mir(tcx: TyCtxt<'_>, def: LocalDefId) -> &IndexVec<Promoted, Body<'_
return tcx.arena.alloc(IndexVec::new());
}
let tainted_by_errors = tcx.mir_borrowck(def).tainted_by_errors;
tcx.ensure_with_value().mir_borrowck(def);
let mut promoted = tcx.mir_promoted(def).1.steal();
for body in &mut promoted {
if let Some(error_reported) = tainted_by_errors {
body.tainted_by_errors = Some(error_reported);
}
run_analysis_to_runtime_passes(tcx, body);
}