This commit extends the logic used to determine what the expected
signature of a closure is so that it can also determine the expected
signature of a generator. This improves a diagnostic where the fn
signature was blamed instead of the generator body. It doesn't fix
fix the diagnostic for `async fn`.
This commit adds a test for the current behaviour of signature deduction
of generators when there is a type mismatch between the return type of
the function body and the signature.
Notably this nails down part of the behavior that MaybeUninit assumes,
e.g. that a Option<MaybeUninit<&u8>> does not take advantage of non-zero
optimization, and thus is a safe construct.
introduce unescape module
A WIP PR to gauge early feedback
Currently, we deal with escape sequences twice: once when we [lex](112f7e9ac5/src/libsyntax/parse/lexer/mod.rs (L928-L1065)) a string, and a second time when we [unescape](112f7e9ac5/src/libsyntax/parse/mod.rs (L313-L366)) literals. Note that we also produce different sets of diagnostics in these two cases.
This PR aims to remove this duplication, by introducing a new `unescape` module as a single source of truth for character escaping rules.
I think this would be a useful cleanup by itself, but I also need this for https://github.com/rust-lang/rust/pull/59706.
In the current state, the PR has `unescape` module which fully (modulo bugs) deals with string and char literals. I am quite happy about the state of this module
What this PR doesn't have yet are:
* [x] handling of byte and byte string literals (should be simple to add)
* [x] good diagnostics
* [x] actual removal of code from lexer (giant `scan_char_or_byte` should go away completely)
* [x] performance check
* [x] general cleanup of the new code
Diagnostics will be the most labor-consuming bit here, but they are mostly a question of just correctly adjusting spans to sub-tokens. The current setup for diagnostics is that `unescape` produces a plain old `enum` with various problems, and they are rendered into `Handler` separately. This bit is not actually required (it is possible to just pass the `Handler` in), but I like the separation between diagnostics and logic this approach imposes, and such separation should again be useful for #59706
cc @eddyb , @petrochenkov
rustc: collapse relevant DefPathData variants into {Type,Value,Macro,Lifetime}Ns.
`DefPathData` was meant to disambiguate within each namespace, but over the years, that purpose was overlooked, and it started to serve a double-role as a sort of `DefKind` (which #60462 properly adds).
Now, we can go back to *only* categorizing namespaces (at least for the variants with names in them).
r? @petrochenkov or @nikomatsakis cc @michaelwoerister
Fix async fn lowering ICE with APIT.
Fixes#60518.
This PR fixes an ICE where simple bindings (which aren't replaced with replacement arguments during async fn lowering) were not being visited in the def collector and thus caused an ICE during HIR lowering for types that use their `DefId` at that point - such as `impl Trait`.
r? @cramertj
Remove -Z borrowck=compare flag
This is the start of the work that needs to be done on #59193. It just removes the flag and updates
the tests.
r? @matthewjasper
Constrain all regions in the concrete type for an opaque type
`push_outlives_components` skips some regions in a type, notably the signature
of a closure is ignored. Most of the time this is OK, but for opaque types the
concrete type is used when checking auto-trait bounds in other functions.
cc @nikomatsakis @pnkfelix
Closes#57464Closes#60127
Account for paths in incorrect pub qualifier help
Handle case where incorrect pub qualifier with a mod path is used and provide the same help given for all other incorrect qualifiers by making the `pub(crate)` parse check more specific.
This commit fixes an ICE where simple bindings (which aren't replaced
with replacement arguments during async fn lowering) were not being
visited in the def collector and thus caused an ICE during HIR lowering
for types that use their `DefId` at that point - such as `impl Trait`.
Const prop refactoring
This is rebased on top of #60428 so only the top commit is new.
This is the refactoring to remove the `mir` field from `ConstPropagator` which is necessary before we can begin to actually propagate constants.
r? @oli-obk
Currently, we deal with escape sequences twice: once when we lex a
string, and a second time when we unescape literals. This PR aims to
remove this duplication, by introducing a new `unescape` mode as a
single source of truth for character escaping rules
Add const generics to infer (and transitive dependencies)
Split out from #53645. This work is a collaborative effort with @yodaldevoid.
There are a number of stubs. These are mainly to ensure we don't overlook them when completing the implementation, but are not necessary for the initial implementation. We plan to address these in follow up PRs.
r? @eddyb / @nikomatsakis
Ensure that drop order of `async fn` matches `fn` and that users cannot refer to generated arguments.
Fixes#60236 and fixes#60438.
This PR modifies the lowering of `async fn` arguments so that the
drop order matches the equivalent `fn`.
Previously, async function arguments were lowered as shown below:
async fn foo(<pattern>: <ty>) {
async move {
}
} // <-- dropped as you "exit" the fn
// ...becomes...
fn foo(__arg0: <ty>) {
async move {
let <pattern> = __arg0;
} // <-- dropped as you "exit" the async block
}
After this PR, async function arguments will be lowered as:
async fn foo(<pattern>: <ty>, <pattern>: <ty>, <pattern>: <ty>) {
async move {
}
} // <-- dropped as you "exit" the fn
// ...becomes...
fn foo(__arg0: <ty>, __arg1: <ty>, __arg2: <ty>) {
async move {
let __arg2 = __arg2;
let <pattern> = __arg2;
let __arg1 = __arg1;
let <pattern> = __arg1;
let __arg0 = __arg0;
let <pattern> = __arg0;
} // <-- dropped as you "exit" the async block
}
If `<pattern>` is a simple ident, then it is lowered to a single
`let <pattern> = <pattern>;` statement as an optimization.
This PR also stops users from referring to the generated `__argN`
identifiers.
r? @nikomatsakis
Added an explanation for the E0704 error.
# Description
Adds an explanation on the E0704 error. I tried to stick as closely to the message that the compiler generates. It's the first time I am fixing error messages here, so if there is something I did wrong or should improve, please let me know.
closes#55398
