resolve: more declarative `fresh_binding`
Following up on https://github.com/rust-lang/rust/pull/64111, this PR redefines `fresh_binding` wrt. `already_bound_and` and `already_bound_or` in a more declarative and simplified fashion.
cc #54883
r? @petrochenkov
Handle statics in MIR as const pointers
This is the first PR towards the goal of removing `PlaceBase::Static`. In this PR:
* Statics are lowered to dereferencing a const pointer.
* The temporaries holding such pointers are tracked in MIR, for the most part this is only used for diagnostics. There are two exceptions:
* The borrow checker has some checks for thread-locals that directly use this data.
* Const checking will suppress "cannot dereference raw pointer" diagnostics for pointers to `static mut`/`extern static`. This is to maintain the current behaviour (12 tests fail otherwise).
The following are left to future PRs (I think that @spastorino will be working on the first 3):
* Applying the same treatments to promoted statics.
* Removing `PlaceBase::Static`.
* Replacing `PlaceBase` with `Local`.
* Moving the ever growing collection of metadata that we have for diagnostics in MIR passes somewhere more appropriate.
r? @oli-obk
Remove pretty printing of specific nodes in AST
The ability to print a specific item as identified by NodeId or path
seems not particularly useful, and certainly carries quite a bit of
complexity with it.
This is intended to simplify our CLI parsing a bit and remove a
non-uncomplicated piece of it; I largely did this to remove the
dependency on NodeId from librustc/session but it's not really
necessary to do so in this invasive a way. The alternative is
moving it to librustc_interface or driver, probably.
*Syntactically* permit visibilities on trait items & enum variants
Fixes#65041
Suppose we have `$vis trait_item` or `$vis enum_variant` and `$vis` is a `:vis` macro fragment. Before this PR, this would fail to parse. This is now instead allowed as per language team consensus in https://github.com/rust-lang/rust/issues/65041#issuecomment-538105286. (See added tests for elaboration.)
Moreover, we now also permit visibility modifiers on trait items & enum variants *syntactically* but reject them with semantic checks (in `ast_validation`):
```rust
#[cfg(FALSE)]
trait Foo { pub fn bar(); } // OK
#[cfg(FALSE)]
enum E { pub U } // OK
```
Add a proc-macro to derive HashStable in librustc dependencies
A second proc-macro is added to derive HashStable for crates librustc depends on.
This proc-macro HashStable_Generic (to bikeshed) allows to decouple code and some librustc's boilerplate.
Not everything is migrated, because `Span` and `TokenKind` require to be placed inside librustc.
Types using them stay there too.
Split out of #66279
r? @Zoxc
Move process_configure_mod to rustc_parse
This removes the hack in favor of perhaps a less principled, but less painful, approach.
This also supports my work to decouple `Session` from librustc, as `ParseSess` currently has `Attribute` as "part" of it but after this PR will no longer do so.
Delay an `is_local_ever_initialized` call.
This commit moves the call after a `return` that almost always runs. It
speeds up the `unicode_normalization` benchmark by about 2%.
r? @spastorino
Support multiple revisions in `compiletest`
The `//[X]~` syntax filters errors for tests that are run across multiple cfgs with `// revisions:`. This commit extends that syntax to accept `//[X,Y]~`, which will match multiple cfgs to the same error annotation. This is functionally the same as writing two comments, `//[X]~` and `//[Y]~`, but can fit on a single line.
While refactoring `compiletest` to support this, I also uncovered a small bug that was causing an incremental test to always pass, despite no errors being emitted.
r? @Centril
This creates a new test directory, `ui/consts/control-flow` to hold
tests related to control flow in a const context. It also blesses all
existing tests with the new error messages, and adds new tests for the
`const_if_match` feature.
[mir-opt] asking `?`s in a more optimized fashion
This PR works towards https://github.com/rust-lang/rust/issues/66234 by providing two optimization passes meant to run in sequence:
- `SimplifyArmIdentity` which transforms something like:
```rust
_LOCAL_TMP = ((_LOCAL_1 as Variant ).FIELD: TY );
((_LOCAL_0 as Variant).FIELD: TY) = move _LOCAL_TMP;
discriminant(_LOCAL_0) = VAR_IDX;
```
into:
```rust
_LOCAL_0 = move _LOCAL_1
```
- `SimplifyBranchSame` which transforms `SwitchInt`s to identical basic blocks into a `goto` to the first reachable target.
Together, these are meant to simplify the following into just `res`:
```rust
match res {
Ok(x) => Ok(x),
Err(x) => Err(x),
}
```
It should be noted however that the desugaring of `?` includes a function call and so the first pass in this PR relies on inlining to substitute that function call for identity on `x`. Inlining requires `mir-opt-level=2` so this might not have any effect in perf-bot but let's find out.
r? @oli-obk -- This is WIP, but I'd appreciate feedback. :)
These are generated when matching on enum variants to extract the value
within. We should have no problem evaluating these, but care should be
taken that we aren't accidentally allowing some other operation.
This test does not actually emit any warnings, since
`#![allow(warnings)]` was specified. `compiletest` was erroneously
ignoring `//~` tests and looking only for `//[X]~` ones. As a result of
the changes in the previous commit, we now look for `//~` comments in
incremental tests and expect them to appear in *all* revisions.
The `//[X]~` syntax filters errors for tests that are run across
multiple cfgs with `// revisions:`. This commit extends that syntax to
accept `//[X,Y]~`, which will match multiple cfgs to the same error
annotation. This is functionally the same as writing two comments,
`//[X]~` and `//[Y]~`, but can fit on a single line.
Aggregation of drive-by cosmetic changes for trait-upcasting PR
Cherry-picked from #60900.
As requested by @Centril (and @nikomatsakis, I believe).
r? @Centril
This optimization depends on inlining for the identity
conversions introduced by the lowering of the `?`.
To take advantage of `SimplifyArmIdentity`, `-Z mir-opt-level=2`
is required because that triggers the inlining MIR optimization.
