Refactorings to borrowck region diagnostic reporting
This PR is a followup to #66886 and #67404
EDIT: updated
In this PR: Clean up how errors are collected from NLL: introduce `borrow_check::diagnostics::RegionErrors` to collect errors. This is later passed to `MirBorrowckCtx::report_region_errors` after the `MirBorrowckCtx` is created. This will allow us to refactor away some of the extra context structs floating around (but we don't do it in this PR). `borrow_check::region_infer` is now mostly free of diagnostic generating code. The signatures of most of the functions in `region_infer` lose somewhere between 4 and 7 arguments :)
Left for future (feedback appreciated):
- Merge `ErrorRegionCtx` with `MirBorrowckCtx`, as suggested by @matthewjasper in https://github.com/rust-lang/rust/pull/66886#issuecomment-559949499
- Maybe move the contents of `borrow_check::nll` into `borrow_check` and remove the `nll` submodule altogether.
- Find a way to make `borrow_check::diagnostics::region_errors` less of a strange appendage to `RegionInferenceContext`. I'm not really sure how to do this yet. Ideas welcome.
Show the actual value of constant values in the documentation
Fixes#66099, making rustdoc show evaluated constant scalar values.
where `main.rs` is
```
pub const VAL3: i32 = i32::max_value();
pub const VAL4: i32 = i32::max_value() - 1;
```
As a fallback, when a constant value is not evaluated (either because of an error or because it isn't a scalar), the original expression is used for consistency.
I mimicked the way min/max values of integers are [`pretty_print`ed](https://github.com/rust-lang/rust/blob/master/src/librustc/ty/print/pretty.rs#L900), to show both the value a the "hint". While a little goofy for `std`, in user crates I think it's actually rather helpful.
Rollup of 7 pull requests
Successful merges:
- #67337 (Ensure that evaluating or validating a constant never reads from a static)
- #67543 (Add regression tests for fixed ICEs)
- #67547 (Cleanup err codes)
- #67551 (Add long error code explanation message for E0627)
- #67561 (remove `description` from `Error` impls in docs)
- #67569 (Clean up unsafety in char::encode_utf8)
- #67572 (Use the chocolatey CDN directly to avoid the flaky API)
Failed merges:
r? @ghost
Clean up unsafety in char::encode_utf8
This originally started as an attempt to allow LLVM to optimize through
encode_utf8 to detect the try_encode_utf8 case (#52579, #52580), but due to a
typo my conclusion that my optimizations were successful was incorrect.
Furthermore, as far as I can tell, this optimization is probably just not
possible with LLVM today. This [code](https://rust.godbolt.org/z/JggRj4)
compiles down to a long series of compares, notably, two identical series of
compares. That essentially means that LLVM is today unable to see that these two
ifs are identical and as such can be merged and then realize that no value of
the if condition can result in a call to `please_delete`. As such, for now, we
do not attempt to specifically optimize for that case.
Add regression tests for fixed ICEs
Closes#61747 (fixed from 1.41.0-nightly (4007d4ef2 2019-12-01))
Closes#66205 (fixed from 1.41.0-nightly (4007d4ef2 2019-12-01))
Closes#66270 (fixed by #66246)
Closes#67424 (fixed by #67160)
Also picking a minor nit up from #67071 with 101dd7bad9
r? @Centril
Ensure that evaluating or validating a constant never reads from a static
r? @RalfJung
as per https://github.com/rust-lang/rust/pull/66302#issuecomment-554663387
This does not yet address the fact that evaluation of a constant can read from a static (under unleash-miri)
Initial implementation of `#![feature(bindings_after_at)]`
Following up on #16053, under the gate `#![feature(bindings_after_at)]`, `x @ Some(y)` is allowed subject to restrictions necessary for soundness.
The implementation and test suite should be fairly complete now.
One aspect that is not covered is the interaction with nested `#![feature(or_patterns)]`.
This is not possible to test at the moment in a good way because that feature has not progressed sufficiently and has fatal errors in MIR building. We should make sure to add such tests before we stabilize both features (but shipping one of them is fine).
r? @pnkfelix
cc @nikomatsakis @matthewjasper @pcwalton
cc https://github.com/rust-lang/rust/issues/65490
Rollup of 8 pull requests
Successful merges:
- #67233 (Add PartialEq and Eq to Cursor)
- #67466 (Require const stability attributes on intrinsics to be able to use them in constant contexts)
- #67507 (Remove mem::uninitalized from tests)
- #67527 (Results show too much)
- #67536 (Move `{hir::lowering -> hir}::is_range_literal`)
- #67538 (Improve diagnostics for invalid assignment)
- #67546 (Fix ICE in mir interpretation)
- #67559 (Document that calling Drop, even after it panics, is UB)
Failed merges:
r? @ghost
Improve diagnostics for invalid assignment
- Improve wording and span information for invalid assignment diagnostics.
- Link to https://github.com/rust-lang/rfcs/issues/372 when it appears the user is trying a destructuring assignment.
- Make the equality constraint in `where` clauses error consistent with the invalid assignment error.
Move `{hir::lowering -> hir}::is_range_literal`
The function is never used inside lowering, but only ever in external crates.
By moving it, we facilitate lowering as its own crate.
Best read commit-by-commit.
r? @Mark-Simulacrum
Results show too much
Fixes#67461.
To reproduce the current issue: search anything, then once the results appears, press escape. They should disappear then re-appear right away. This is because blurring an element triggers the "change" event.
r? @kinnison
Remove mem::uninitalized from tests
This purges uses of uninitialized where possible from test cases. Some
are merely moved over to the equally bad pattern of
MaybeUninit::uninit().assume_init() but with an annotation that this is
"the best we can do".
Fixes#62397
bors
