adjust desugaring for async fn to correct drop order
Old desugaring, given a user function body `{ $stmts; $expr }`
```
{
let $param_pattern0 = $raw_param0;
...
let $param_patternN = $raw_paramN;
$stmts;
$expr
}
```
New desugaring:
```
{
let $param_pattern0 = $raw_param0;
...
let $param_patternN = $raw_paramN;
drop-temps {
$stmts;
$expr
}
}
```
The drop-temps is an internal bit of HIR that drops temporaries from the resulting expression, but it should be equivalent to `return { $stmts; $expr }`.
Fixes#64512Fixes#64391
Various refactorings to clean up nll diagnostics
- Create ErrorReportingCtx and ErrorConstraintInfo, vasting reducing the
number of arguments passed around everywhere in the error reporting code
- Create RegionErrorNamingCtx, making a given lifetime have consistent
numbering thoughout all error messages for that MIR def.
- Make the error reporting code return the DiagnosticBuilder rather than
directly buffer the Diagnostic. This makes it easier to modify the
diagnostic later, e.g. to add suggestions.
r? @estebank
Split out from https://github.com/rust-lang/rust/pull/58281
Make sure interned constants are immutable
This makes sure that interning for constants (not statics) creates only immutable allocations.
Previously, the "main" allocation of `const FOO: Cell<i32> = Cell::new(0);` was marked as mutable, but I don't think we want that. It can be only copied, not written to.
Also, "leftover" allocations (behind raw pointers etc) were left mutable. I don't think we want to support that. I tried asserting that these are all already immutable (to double-check our static checks), but that failed in this one:
```rust
const NON_NULL_PTR2: NonNull<u8> = unsafe { mem::transmute(&0) };
```
Seems like maybe we want more precise mutability annotation inside Miri for locals (like `&0` here) so that this would actually become immutable to begin with?
I also factored `intern_shallow` out of the visitor so that we don't have to construct a visitor when we do not plan to visit anything. That confused me at first.
Rollup of 3 pull requests
Successful merges:
- #63872 (Document platform-specific behavior of the iterator returned by std::fs::read_dir)
- #64250 (save-analysis: Nest typeck tables when processing functions/methods)
- #64472 (Don't mark expression with attributes as not needing parentheses)
Failed merges:
r? @ghost
Don't mark expression with attributes as not needing parentheses
This is not perfectly correct as `#[attr] (5)` will still not lint, but it does seem good enough, in particular as the parentheses in that case are not unambiguously incorrect; I might personally prefer to see them for clarity.
Fixes https://github.com/rust-lang/rust/issues/43279.
save-analysis: Nest typeck tables when processing functions/methods
Fixes an issue where we did not nest tables correctly when resolving
associated types in formal argument/return type positions.
This was the minimized reproduction case that I tested the fix on:
```rust
pub trait Trait {
type Assoc;
}
pub struct A;
pub fn func() {
fn _inner1<U: Trait>(_: U::Assoc) {}
fn _inner2<U: Trait>() -> U::Assoc { unimplemented!() }
impl A {
fn _inner1<U: Trait>(self, _: U::Assoc) {}
fn _inner2<U: Trait>(self) -> U::Assoc { unimplemented!() }
}
}
```
using `debug_assertions`-enabled rustc and by additionally passing `-Zsave-analysis`.
Unfortunately the original assertion fired is a *debug* one and from what I can tell we don't run the tests with these on, so I'm not adding a test here. If I missed it and there is a way to run tests with these on, I'd love to add a test case for this.
Closes#63663Closes#50328Closes#43982
Cleanup handling of hygiene for built-in macros
This makes most identifiers generated by built-in macros use def-site hygiene, not only the ones that previously used gensyms.
* `ExtCtxt::ident_of` now takes a `Span` and is preferred to `Ident::{from_str, from_str_and_span}`
* Remove `Span::with_legacy_ctxt`
* `assert` now uses call-site hygiene because it needs to resolve `panic` unhygienically.
* `concat_idents` now uses call-site hygiene because it wouldn't be very useful with def-site hygiene.
* everything else is moved to def-site hygiene
r? @petrochenkov
Warn on no_start, crate_id attribute use
These attributes are now deprecated; they don't have any use anymore.
`no_start` stopped being applicable in 3ee916e50b as part of #18967. Ideally we would've removed it pre-1.0, but since that didn't happen let's at least mark it deprecated.
`crate_id` was renamed to `crate_name` in 50ee1ec1b4 as part of #15319. Ideally we would've followed that up with a removal of crate_id itself as well, but that didn't happen; this PR finally marks it as deprecated at least.
Fixes https://github.com/rust-lang/rust/issues/43142 and resolves https://github.com/rust-lang/rust/issues/43144.
def_collector: Do not ICE on attributes on unnamed fields
The primary issue here is that the expansion infra needs to visit a field in isolation, and fields don't know their own indices during expansion, so they have to be kept in some other place (e.g. `struct Definitions`).
Fixes https://github.com/rust-lang/rust/issues/64385
Use `panic::set_hook` to print the ICE message
This allows custom frontends and backends to override the hook with their own, for example to point people to a different issue tracker.
ICE messages are printed in a slightly different order now. Nightly prints:
```
thread 'rustc' panicked at 'called `Option::unwrap()` on a `None` value', src/libcore/option.rs:347:21
note: Run with `RUST_BACKTRACE=1` environment variable to display a backtrace.
error: aborting due to 2 previous errors
Some errors have detailed explanations: E0277, E0658.
For more information about an error, try `rustc --explain E0277`.
error: internal compiler error: unexpected panic
note: the compiler unexpectedly panicked. this is a bug.
note: we would appreciate a bug report: https://github.com/rust-lang/rust/blob/master/CONTRIBUTING.md#bug-reports
note: rustc 1.36.0-nightly (08bfe1612 2019-05-02) running on x86_64-unknown-linux-gnu
```
After this PR, rustc prints:
```
thread 'rustc' panicked at 'called `Option::unwrap()` on a `None` value', src/libcore/option.rs:347:21
note: Run with `RUST_BACKTRACE=1` environment variable to display a backtrace.
error: internal compiler error: unexpected panic
note: the compiler unexpectedly panicked. this is a bug.
note: we would appreciate a bug report: https://github.com/rust-lang/rust/blob/master/CONTRIBUTING.md#bug-reports
note: rustc 1.36.0-dev running on x86_64-unknown-linux-gnu
error: aborting due to 2 previous errors
Some errors have detailed explanations: E0277, E0658.
For more information about an error, try `rustc --explain E0277`.
```
This is not perfectly correct as `#[attr] (5)` will still not lint, but
it does seem good enough, in particular as the parentheses in that case
are not unambiguously incorrect.
feature_gate: Remove dead code from attribute checking
https://github.com/rust-lang/rust/pull/63468 is merged, so all attributes go through name resolution now, so we can remove code that previously performed some checks for attributes not going through resolution.
Provide a span if main function is not present in crate
Unfortunately, the diagnostic machinery does not cope well with an empty
span which can happen if the crate is empty, in which case we merely set
a spanless note.
Tests are already updated for this change, so a dedicated test is not added.
Resolves#36561.
Unfortunately, the diagnotic machinery does not cope well with an empty
span which can happen if the crate is empty, in which case we merely set
a spanless note.
codegen: use "_N" (like for other locals) instead of "argN", for argument names.
Based on #64408 (second commit is new), fixing something I mentioned in #64408 (which turned to be an immediate blocker for unifying relevant codepaths).
Closes#64408 (by containing it).
r? @rkruppe
