1902 Commits

Author SHA1 Message Date
Dylan DPC
df8b0dfc27
Rollup merge of #111612 - ChayimFriedman2:collect-into-slice-ref, r=petrochenkov
Give better error when collecting into `&[T]`

The detection of slice reference of `{integral}` in `rustc_on_unimplemented` is hacky, but a proper solution requires changing `FmtPrinter` to add a parameter to print integers as `{integral}` and I didn't want to change it just for `rustc_on_unimplemented`. I can do that if requested, though.

I'm open to better wording; this is the best I could come up with.
2023-05-23 00:32:18 +05:30
bors
cfcde247cd Auto merge of #111754 - lcnr:recursion-depth, r=matthewjasper
fix recursion depth handling after confirmation

fixes #111729

I think having to use `Obligation::with_depth` correctly everywhere is very hard because e.g. the nested obligations from `eq` currently do not have the correct obligation depth.

The new solver [completely removes `recursion_depth` from obligations](https://doc.rust-lang.org/nightly/nightly-rustc/rustc_middle/traits/solve/struct.Goal.html) and instead tracks the depth in the solver itself which is far easier to get right. Moving the old solver towards this shouldn't be that hard but is probably somewhat annoying.

r? `@matthewjasper`
2023-05-22 17:56:26 +00:00
Matthew Jasper
72d41f3bd3 Run AST validation on match guards correctly 2023-05-22 14:52:52 +01:00
Scott McMurray
57c5ac7894 Tweak the post-order for multi-successor blocks 2023-05-21 17:48:36 -07:00
bors
9d871b0617 Auto merge of #111731 - MU001999:fix/issue-111727, r=cjgillot
Keep only the trait when emitting the error for `MyTrait + 'a`

Fixes #111727
2023-05-21 19:19:49 +00:00
Matthias Krüger
cb5dd1d598
Rollup merge of #111745 - Badel2:emitter-add-overflow, r=compiler-errors
Fix overflow in error emitter

Fix #109854
Close #94171 (was already fixed before but missing test)

This bug happens when a multipart suggestion spans more than one line.

The fix is to update the `acc` variable, which didn't handle the case when the text to remove spans multiple lines but the text to add spans only one line.

Also, use `usize::try_from` instead of  `as usize` to detect overflows earlier in the future, and point to the source of the overflow (the original issue points to a different place where this value is used, not where the overflow had happened).

And finally add an `if start != end` check to avoid doing any extra work in case of empty ranges.

Long explanation:

Given this test case:

```rust
fn generate_setter() {
    String::with_capacity(
    //~^ ERROR this function takes 1 argument but 3 arguments were supplied
    generate_setter,
    r#"
pub(crate) struct Person<T: Clone> {}
"#,
     r#""#,
    );
}
```

The compiler will try to convert that code into the following:

```rust
fn generate_setter() {
    String::with_capacity(
    //~^ ERROR this function takes 1 argument but 3 arguments were supplied
    /* usize */,
    );
}
```

So it creates a suggestion with 3 separate parts:

```
// Replace "generate_setter" with "/* usize */"
SubstitutionPart { span: fuzz_input.rs:4:5: 4:20 (#0), snippet: "/* usize */" }
// Remove second arg (multiline string)
SubstitutionPart { span: fuzz_input.rs:4:20: 7:3 (#0), snippet: "" }
// Remove third arg (r#""#)
SubstitutionPart { span: fuzz_input.rs:7:3: 8:11 (#0), snippet: "" }
```

Each of this parts gets a separate `SubstitutionHighlight` (this marks the relevant text green in a terminal, the values are 0-indexed so `start: 4` means column 5):

```
SubstitutionHighlight { start: 4, end: 15 }
SubstitutionHighlight { start: 15, end: 15 }
SubstitutionHighlight { start: 18446744073709551614, end: 18446744073709551614 }
```

The 2nd and 3rd suggestion are empty (start = end) because they only remove text, so there are no additions to highlight. But the 3rd span has overflowed because the compiler assumes that the 3rd suggestion is on the same line as the first suggestion. The 2nd span starts at column 20 and the highlight starts at column 16 (15+1), so that suggestion is good. But since the 3rd span starts at column 3, the result is `3 - 4`, or column -1, which turns into -2 with 0-indexed, and that's equivalent to `18446744073709551614 as isize`.

With this fix, the resulting `SubstitutionHighlight` are:

```
SubstitutionHighlight { start: 4, end: 15 }
SubstitutionHighlight { start: 15, end: 15 }
SubstitutionHighlight { start: 15, end: 15 }
```

As expected. I guess ideally we shouldn't emit empty highlights when removing text, but I am too scared to change that.
2023-05-21 16:02:59 +02:00
Urgau
6b08a745a4 Rename forget_ref lint to forgetting_references 2023-05-21 14:28:09 +02:00
Urgau
c93d9c1794 Rename drop_ref lint to dropping_references 2023-05-21 14:16:41 +02:00
Urgau
85a1828943 Rename forget_copy lint to forgetting_copy_types 2023-05-21 14:09:03 +02:00
Urgau
1c7ab18c08 Rename drop_copy lint to dropping_copy_types 2023-05-21 13:37:32 +02:00
Lukas Markeffsky
7cdb23b98a don't skip inference for type in offset_of! 2023-05-20 15:20:27 +02:00
Dylan DPC
94ca44a50a
Rollup merge of #111762 - bvanjoi:fix-111749, r=compiler-errors
fix: emit error when fragment is `MethodReceiverExpr` and items is empty

Fixes https://github.com/rust-lang/rust/issues/111749
2023-05-20 12:21:02 +05:30
Dylan DPC
e892e32df4
Rollup merge of #111665 - est31:offset_of_tests, r=WaffleLapkin
Add more tests for the offset_of macro

Implements what I [suggested in the tracking issue](https://github.com/rust-lang/rust/issues/106655#issuecomment-1535007205), plus some further improvements:

* ensuring that offset_of!(Self, ...) works iff inside an impl block
* ensuring that the output type is usize and doesn't coerce. this can be changed in the future, but if it is done, it should be a conscious decision
* improving the privacy checking test
* ensuring that generics don't let you escape the unsized check

r? `````@WaffleLapkin`````
2023-05-20 12:21:00 +05:30
Dylan DPC
13f3585dc6
Rollup merge of #111652 - clubby789:self-import-improvement, r=compiler-errors
Better diagnostic for `use Self::..`

Fixes #111627

cc `@petrochenkov,` you might have thoughts on a better way to handle this (https://github.com/rust-lang/rust/issues/63720#issuecomment-591597466)
2023-05-20 12:21:00 +05:30
Dylan DPC
2294d81fb3
Rollup merge of #111491 - compiler-errors:nested-fut-must-use, r=wesleywiser
Dont check `must_use` on nested `impl Future` from fn

Fixes (but does not close, per beta policy) #111484

Also fixes a `FIXME` left in the code about (presumably) false-positives on non-async `#[must_use] fn() -> impl Future` cases, though if that's not desirable to include in the beta backport then I can certainly revert it.

Beta nominating as it fixes a beta ICE.
2023-05-20 12:20:58 +05:30
Badel2
cbb41008fd Fix overflow in error emitter 2023-05-19 20:58:06 +02:00
Mu001999
a9528a28f2 Keep only the trait when emitting the error for MyTrait + 'a 2023-05-19 22:11:54 +08:00
bohan
990b2899ad fix: emit error when fragment is MethodReceiverExpr and items is empty 2023-05-19 21:21:05 +08:00
bors
17a681000b Auto merge of #111641 - michaelwoerister:debugger-visualizer-fixes, r=cjgillot
Fix dependency tracking for debugger visualizers

This PR fixes dependency tracking for debugger visualizer files by changing the `debugger_visualizers` query to an `eval_always` query that scans the AST while it is still available. This way the set of visualizer files is already available when dep-info is emitted. Since the query is turned into an `eval_always` query, dependency tracking will now reliably detect changes to the visualizer script files themselves.

TODO:
 - [x] perf.rlo
 - [x] Needs a bit more documentation in some places
 - [x] Needs regression test for the incr. comp. case

Fixes https://github.com/rust-lang/rust/issues/111226
Fixes https://github.com/rust-lang/rust/issues/111227
Fixes https://github.com/rust-lang/rust/issues/111295

r? `@wesleywiser`
cc `@gibbyfree`
2023-05-19 11:30:44 +00:00
Ryo Yoshida
3a03587836
Consider lint check attributes on match arms in match checks 2023-05-19 19:04:15 +09:00
Ryo Yoshida
ddafe23401
Consider lint check attributes on match arms in late lints
Additionally add analogous test for early lints.
2023-05-19 19:04:10 +09:00
lcnr
c5ec1b8bc5 add test 2023-05-19 10:44:38 +02:00
bors
2d17294d18 Auto merge of #111590 - dtolnay:panictemporaries, r=bjorn3
Shorten even more panic temporary lifetimes

Followup to #104134. As pointed out by `@bjorn3` in https://github.com/rust-lang/rust/pull/104134#pullrequestreview-1425585948, there are other cases in the panic macros which would also benefit from dropping their non-Send temporaries as soon as possible, avoiding pointlessly holding them across an await point.

For the tests added in this PR, here are the failures you get today on master without the macro changes in this PR:

<details>
<summary>tests/ui/macros/panic-temporaries-2018.rs</summary>

```console
error: future cannot be sent between threads safely
  --> tests/ui/macros/panic-temporaries-2018.rs:52:18
   |
LL |     require_send(panic_display());
   |                  ^^^^^^^^^^^^^^^ future returned by `panic_display` is not `Send`
   |
   = help: within `impl Future<Output = ()>`, the trait `Send` is not implemented for `*const u8`
note: future is not `Send` as this value is used across an await
  --> tests/ui/macros/panic-temporaries-2018.rs:35:31
   |
LL |     f(panic!("{}", NOT_SEND)).await;
   |                    --------   ^^^^^- `NOT_SEND` is later dropped here
   |                    |          |
   |                    |          await occurs here, with `NOT_SEND` maybe used later
   |                    has type `NotSend` which is not `Send`
note: required by a bound in `require_send`
  --> tests/ui/macros/panic-temporaries-2018.rs:48:25
   |
LL | fn require_send(_: impl Send) {}
   |                         ^^^^ required by this bound in `require_send`

error: future cannot be sent between threads safely
  --> tests/ui/macros/panic-temporaries-2018.rs:52:18
   |
LL |     require_send(panic_display());
   |                  ^^^^^^^^^^^^^^^ future returned by `panic_display` is not `Send`
   |
   = help: within `NotSend`, the trait `Sync` is not implemented for `*const u8`
note: future is not `Send` as this value is used across an await
  --> tests/ui/macros/panic-temporaries-2018.rs:35:31
   |
LL |     f(panic!("{}", NOT_SEND)).await;
   |       ----------------------  ^^^^^- the value is later dropped here
   |       |                       |
   |       |                       await occurs here, with the value maybe used later
   |       has type `&NotSend` which is not `Send`
note: required by a bound in `require_send`
  --> tests/ui/macros/panic-temporaries-2018.rs:48:25
   |
LL | fn require_send(_: impl Send) {}
   |                         ^^^^ required by this bound in `require_send`

error: future cannot be sent between threads safely
  --> tests/ui/macros/panic-temporaries-2018.rs:53:18
   |
LL |     require_send(panic_str());
   |                  ^^^^^^^^^^^ future returned by `panic_str` is not `Send`
   |
   = help: within `impl Future<Output = ()>`, the trait `Send` is not implemented for `*const u8`
note: future is not `Send` as this value is used across an await
  --> tests/ui/macros/panic-temporaries-2018.rs:40:36
   |
LL |     f(panic!((NOT_SEND, "...").1)).await;
   |               --------             ^^^^^- `NOT_SEND` is later dropped here
   |               |                    |
   |               |                    await occurs here, with `NOT_SEND` maybe used later
   |               has type `NotSend` which is not `Send`
note: required by a bound in `require_send`
  --> tests/ui/macros/panic-temporaries-2018.rs:48:25
   |
LL | fn require_send(_: impl Send) {}
   |                         ^^^^ required by this bound in `require_send`

error: future cannot be sent between threads safely
  --> tests/ui/macros/panic-temporaries-2018.rs:54:18
   |
LL |     require_send(unreachable_display());
   |                  ^^^^^^^^^^^^^^^^^^^^^ future returned by `unreachable_display` is not `Send`
   |
   = help: within `impl Future<Output = ()>`, the trait `Send` is not implemented for `*const u8`
note: future is not `Send` as this value is used across an await
  --> tests/ui/macros/panic-temporaries-2018.rs:45:31
   |
LL |     f(unreachable!(NOT_SEND)).await;
   |                    --------   ^^^^^- `NOT_SEND` is later dropped here
   |                    |          |
   |                    |          await occurs here, with `NOT_SEND` maybe used later
   |                    has type `NotSend` which is not `Send`
note: required by a bound in `require_send`
  --> tests/ui/macros/panic-temporaries-2018.rs:48:25
   |
LL | fn require_send(_: impl Send) {}
   |                         ^^^^ required by this bound in `require_send`

error: future cannot be sent between threads safely
  --> tests/ui/macros/panic-temporaries-2018.rs:54:18
   |
LL |     require_send(unreachable_display());
   |                  ^^^^^^^^^^^^^^^^^^^^^ future returned by `unreachable_display` is not `Send`
   |
   = help: within `NotSend`, the trait `Sync` is not implemented for `*const u8`
note: future is not `Send` as this value is used across an await
  --> tests/ui/macros/panic-temporaries-2018.rs:45:31
   |
LL |     f(unreachable!(NOT_SEND)).await;
   |       ----------------------  ^^^^^- the value is later dropped here
   |       |                       |
   |       |                       await occurs here, with the value maybe used later
   |       has type `&NotSend` which is not `Send`
note: required by a bound in `require_send`
  --> tests/ui/macros/panic-temporaries-2018.rs:48:25
   |
LL | fn require_send(_: impl Send) {}
   |                         ^^^^ required by this bound in `require_send`

error: aborting due to 5 previous errors
```
</details>

<details>
<summary>tests/ui/macros/panic-temporaries.rs</summary>

```console
error: future cannot be sent between threads safely
  --> tests/ui/macros/panic-temporaries.rs:42:18
   |
LL |     require_send(panic_display());
   |                  ^^^^^^^^^^^^^^^ future returned by `panic_display` is not `Send`
   |
   = help: within `impl Future<Output = ()>`, the trait `Send` is not implemented for `*const u8`
note: future is not `Send` as this value is used across an await
  --> tests/ui/macros/panic-temporaries.rs:35:31
   |
LL |     f(panic!("{}", NOT_SEND)).await;
   |                    --------   ^^^^^- `NOT_SEND` is later dropped here
   |                    |          |
   |                    |          await occurs here, with `NOT_SEND` maybe used later
   |                    has type `NotSend` which is not `Send`
note: required by a bound in `require_send`
  --> tests/ui/macros/panic-temporaries.rs:38:25
   |
LL | fn require_send(_: impl Send) {}
   |                         ^^^^ required by this bound in `require_send`

error: future cannot be sent between threads safely
  --> tests/ui/macros/panic-temporaries.rs:42:18
   |
LL |     require_send(panic_display());
   |                  ^^^^^^^^^^^^^^^ future returned by `panic_display` is not `Send`
   |
   = help: within `NotSend`, the trait `Sync` is not implemented for `*const u8`
note: future is not `Send` as this value is used across an await
  --> tests/ui/macros/panic-temporaries.rs:35:31
   |
LL |     f(panic!("{}", NOT_SEND)).await;
   |       ----------------------  ^^^^^- the value is later dropped here
   |       |                       |
   |       |                       await occurs here, with the value maybe used later
   |       has type `&NotSend` which is not `Send`
note: required by a bound in `require_send`
  --> tests/ui/macros/panic-temporaries.rs:38:25
   |
LL | fn require_send(_: impl Send) {}
   |                         ^^^^ required by this bound in `require_send`

error: aborting due to 2 previous errors
```
</details>

r? bjorn3
2023-05-19 07:15:38 +00:00
bors
19ca5692f6 Auto merge of #110100 - compiler-errors:no-infer-pred-must-hold, r=jackh726
do not allow inference in `predicate_must_hold` (alternative approach)

See the FCP description for more info, but tl;dr is that we should not return `EvaluatedToOkModuloRegions` if an obligation may hold only with some choice of inference vars being constrained.

Attempts to solve this in the approach laid out by lcnr here: https://github.com/rust-lang/rust/pull/109558#discussion_r1147318134, rather than by eagerly replacing infer vars with placeholders which is a bit too restrictive.

r? `@ghost`
2023-05-19 03:36:37 +00:00
bors
92f5dea0eb Auto merge of #109602 - bvanjoi:fix-issue-109343, r=petrochenkov
fix(resolve): replace bindings to dummy for unresolved imports

close #109343

In #109343, `f` in `pub use f as g` points to:

|namespace| binding|
|-|-|
|type| `external crate f`|
|value| `None` |
|macro| `None` |

When resolve `value_ns` during `resolve_doc_links`, the value of the binding of single_import `pub use f as g` goes to `pub use inner::f`, and since it does not satisfy [!self.is_accessible_from(binding.vis, single_import.parent_scope.module)](https://github.com/rust-lang/rust/blob/master/compiler/rustc_resolve/src/ident.rs#L971) and returns `Err(Undetermined)`, which eventually goes to `PathResult::Indeterminate => unreachable!`.

This PR replace all namespace binding to `dummy_binding` for indeterminate import, so, the bindings of `pub use f as g` had been changed to followings after finalize:

|namespace| binding|
|-|-|
|type| `dummy`|
|value| `dummy` |
|macro| `dummy` |

r?`@petrochenkov`
2023-05-19 00:41:32 +00:00
bors
d3f416dc06 Auto merge of #110493 - bvanjoi:new_disambiguated_key, r=petrochenkov
fix(resolve): only disambiguate binding key during define

- close https://github.com/rust-lang/rust/issues/110164
- discussion: https://github.com/rust-lang/rust/pull/110264#discussion_r1168895468

r? `@petrochenkov`
2023-05-18 18:53:49 +00:00
Dylan DPC
ee26abdafb
Rollup merge of #111054 - cjgillot:cfg-eval-recover, r=b-naber
Do not recover when parsing stmt in cfg-eval.

`parse_stmt` does recovery on its own. When parsing the statement fails, we always get `Ok(None)` instead of an `Err` variant with the diagnostic that we can emit.

To avoid this behaviour, we need to opt-out of recovery for cfg_eval.

Fixes https://github.com/rust-lang/rust/issues/105228
2023-05-18 17:37:08 +05:30
est31
30c0e4e72b Add more tests for the offset_of!() macro
* ensuring that offset_of!(Self, ...) works iff inside an impl block
* ensuring that the output type is usize and doesn't coerce. this can be
  changed in the future, but if it is done, it should be a conscious descision
* improving the privacy checking test
* ensuring that generics don't let you escape the unsized check
2023-05-18 13:16:17 +02:00
Camille GILLOT
f52db3ecaa Stop confusing specification levels when computing expectations. 2023-05-18 08:52:54 +00:00
bors
77c836e1ae Auto merge of #108938 - chenyukang:yukang/fix-107910-shorten-ice, r=cjgillot
Shorten backtraces for queries in ICEs

r? `@jyn514`
Fixes #107910
2023-05-18 04:21:15 +00:00
Michael Goulet
3db2bcf4eb Remove return type sized check hack from hir typeck 2023-05-18 01:53:01 +00:00
Michael Goulet
795fdf7d61 Simplify suggestion when returning bare dyn trait 2023-05-18 01:47:55 +00:00
bohan
5b09810976 fix(resolve): only disambiguate binding key during define 2023-05-18 09:29:48 +08:00
bohan
f34678c097 fix(resolve): replace bindings to dummy for unresolved imports 2023-05-18 09:22:29 +08:00
Dylan DPC
291ced5e9a
Rollup merge of #111588 - MU001999:diag/improve-e0782, r=fee1-dead
Emits E0599 when meeting `MyTrait::missing_method`

Fixes #111312
2023-05-17 19:11:55 +05:30
Dylan DPC
ff364b0082
Rollup merge of #111557 - cjgillot:revert-111020, r=petrochenkov
Revert "Validate resolution for SelfCtor too."

This reverts commit 83453408a0ce91b9e3d3ae6e7f117b1fd28b487d.

That PR introduced a breaking change.

Fixes https://github.com/rust-lang/rust/issues/111541
Reopens https://github.com/rust-lang/rust/issues/89868

r? `@petrochenkov`
2023-05-17 19:11:54 +05:30
Dylan DPC
828caa80a9
Rollup merge of #110930 - b-naber:normalize-elaborate-drops, r=cjgillot
Don't expect normalization to succeed in elaborate_drops

Fixes https://github.com/rust-lang/rust/issues/110682

This was exposed through the changes in https://github.com/rust-lang/rust/pull/109247, which causes more things to be inlined. Inlining can happen before monomorphization, so we can't expect normalization to succeed. In the elaborate_drops analysis we currently have [this call](033aa092ab/compiler/rustc_mir_dataflow/src/elaborate_drops.rs (L278)) to `normalize_erasing_regions`, which ICEs when normalization fails. The types are used to infer [whether the type needs a drop](033aa092ab/compiler/rustc_mir_dataflow/src/elaborate_drops.rs (L374)), where `needs_drop` itself [uses `try_normalize_erasing_regions`](033aa092ab/compiler/rustc_middle/src/ty/util.rs (L1121)).

~[`instance_mir`](https://doc.rust-lang.org/stable/nightly-rustc/rustc_middle/ty/context/struct.TyCtxt.html#method.instance_mir) isn't explicit about whether it expects the instances corresponding to the `InstanceDef`s to be monomorphized (though I think in all other contexts the function is used post-monomorphization), so the use of `instance_mir` in inlining doesn't necessarily seem wrong to me.~
2023-05-17 19:11:53 +05:30
yukang
c3394b3eaa Fix #107910, Shorten backtraces in ICEs 2023-05-17 17:56:26 +08:00
mu001999
db64512422 Emits E0599 when meeting MyTrait::missing_method 2023-05-17 16:59:39 +08:00
Dylan DPC
0720743836
Rollup merge of #111661 - clubby789:offset-of-erase-regions, r=compiler-errors
Erase regions of type in `offset_of!`

Fixes #111657
2023-05-17 11:13:58 +05:30
Dylan DPC
bc3b94a486
Rollup merge of #111649 - Nilstrieb:derive-const-param-ty, r=BoxyUwU
Add derive for `core::marker::ConstParamTy`

This makes it easier to implement it for a type, just like `Copy`.

`@BoxyUwU` half asked me to add it
2023-05-17 11:13:57 +05:30
clubby789
35cf5726e3 Erase regions of type in offset_of! 2023-05-16 21:36:42 +00:00
clubby789
eaf47a30cb Better diagnostic for use Self::.. 2023-05-16 20:30:48 +00:00
Matthias Krüger
d2e52ea127
Rollup merge of #111610 - bvanjoi:fix-99597, r=compiler-errors
fix(diagnostic): wrap parens for ref impl trait param

Fixes https://github.com/rust-lang/rust/issues/99597

When parameters are an `impl_trait` which it needed to add trait, and it is a reference, add parentheses to the type of the parameter in the suggestion
2023-05-16 20:12:18 +02:00
Matthias Krüger
6dc365003b
Rollup merge of #111573 - compiler-errors:erase-re-error, r=WaffleLapkin
Erase `ReError` properly

Fixes #111341

Since we check whether a type has free regions before erasing (to short circuit unnecesary folding), we need to consider `ReError` as a free region, or else we'll skip it when erasing a type that only mentions `ReError`.

cc `@nnethercote`
2023-05-16 20:12:17 +02:00
Matthias Krüger
426dbcdf92
Rollup merge of #111533 - clubby789:drop-tracking-error, r=oli-obk
Handle error body in generator layout

Fixes #111468

I feel like making this query return `Option<GeneratorLayout>` might be better but had some issues with that approach
2023-05-16 20:12:16 +02:00
Nilstrieb
0336dd132b Add derive for core::marker::ConstParamTy
This makes it easier to implement it for a type, just like `Copy`.
2023-05-16 20:09:25 +02:00
Michael Woerister
7f01893900 Fix dependency tracking for debugger visualizers 2023-05-16 18:50:26 +02:00
Michael Goulet
8921391a12 Use error term if missing associated item in new solver 2023-05-16 16:02:17 +00:00
bors
9239760da8 Auto merge of #105750 - oli-obk:valtrees, r=lcnr
Always fall back to PartialEq when a constant in a pattern is not recursively structural-eq

Right now we destructure the constant as far as we can, but with this PR we just don't take it apart anymore. This is preparatory work for moving to always using valtrees, as these will just do a single conversion of the constant to a valtree at the start, and if that fails, fall back to `PartialEq`.

This removes a few cases where we emitted the `unreachable pattern` lint, because we stop looking into the constant deeply enough to detect that a constant is already covered by another pattern.

Previous work: https://github.com/rust-lang/rust/pull/70743

This is groundwork towards fixing https://github.com/rust-lang/rust/issues/83085 and https://github.com/rust-lang/rust/issues/105047
2023-05-16 13:10:24 +00:00