Change vtable memory representation to use tcx allocated allocations.
This fixes https://github.com/rust-lang/rust/issues/86324. However i suspect there's more to change before it can land.
r? `@bjorn3`
cc `@rust-lang/miri`
One key observation while going over the closure size profile of rustc
was that we are disjointly capturing one or more fields starting at an
immutable reference.
Disjoint capture over immutable reference doesn't add too much value
because the fields can either be borrowed immutably or copied.
One possible edge case of the optimization is when a fields of a struct
have a longer lifetime than the structure, therefore we can't completely
get rid of all the accesses on top of sharef refs, only the rightmost
one. Here is a possible example:
```rust
struct MyStruct<'a> {
a: &'static A,
b: B,
c: C<'a>,
}
fn foo<'a, 'b>(m: &'a MyStruct<'b>) -> impl FnMut() + 'static {
let c = || drop(&*m.a.field_of_a);
// Here we really do want to capture `*m.a` because that outlives `'static`
// If we capture `m`, then the closure no longer outlives `'static'
// it is constrained to `'a`
}
```
Don't make `rustc_insignificant_dtor` feature gate
This isn't a feature gate, it's an attribute that is feature gated behind the `rustc_attrs` attribute. Closes#85680.
Fix garbled suggestion for missing lifetime specifier
This PR fixes#86667. The suggestion code currently checks whether there is a generic parameter that is not a synthetic `impl Trait` parameter and, if so, suggests to insert a new lifetime `'a` before that generic parameter. However, it does not make sense to insert `'a` in front of an elided lifetime parameter, since these are synthetic as well, which leads to the garbled suggestion in #86667.
Turn non_fmt_panic into a future_incompatible edition lint.
This turns the `non_fmt_panic` lint into a future_incompatible edition lint, so it becomes part of the `rust_2021_compatibility` group. See https://github.com/rust-lang/rust/issues/85894.
This lint produces both warnings about semantical changes (e.g. `panic!("{{")`) and things that will become hard errors (e.g. `panic!("{")`). So I added a `explain_reason: false` that supresses the default "this will become a hard error" or "the semantics will change" message, and instead added a note depending on the situation. (cc `@rylev)`
r? `@nikomatsakis`
Fix `future_prelude_collision` false positive
Fixes#86633
The lint for checking if method resolution of methods named `try_into` will fail in 2021 edition previously would fire on all inherent methods, however for inherent methods that consume `self`, this takes priority over `TryInto::try_into` due to being inherent, while trait method and methods that take `&self` or `&mut self` don't take priority, and thus aren't affected by this false positive.
This fix is rather simple: simply checking if the inherent method doesn't auto-deref or auto-ref (and thus takes `self`) and if so, prevents the lint from firing.
This prevents mistakes where the feature is in the list of incomplete
features but not actually a feature by making the incompleteness a part
of the declaration.
This creates a CSV with name "closure_profile_XXXXX.csv", where the
variable part is the process id of the compiler.
To profile a cargo project you can run one of the following depending on
if you're compiling a library or a binary:
```
cargo +stage1 rustc --lib -- -Zprofile-closures
cargo +stage1 rustc --bin -- -Zprofile-closures
```
Fix type checking of return expressions outside of function bodies
This pull request fixes#86188. The problem is that the current code for type-checking `return` expressions stops if the `return` occurs outside of a function body, while the correct behavior is to continue type-checking the return value expression (otherwise an ICE happens later on because variables declared in the return value expression don't have a type).
Also, I have noticed that it is sometimes not obvious why a `return` is outside of a function body; for instance, in the example from #86188 (which currently causes an ICE):
```rust
fn main() {
[(); return || {
let tx;
}]
}
```
I have changed the error message to also explain why the `return` is considered outside of the function body:
```
error[E0572]: return statement outside of function body
--> ice0.rs:2:10
|
1 | / fn main() {
2 | | [(); return || {
| |__________^
3 | || let tx;
4 | || }]
| ||_____^ the return is part of this body...
5 | | }
| |_- ...not the enclosing function body
```
Reserve prefixed identifiers and literals (RFC 3101)
This PR denies any identifiers immediately followed by one of three tokens `"`, `'` or `#`, which is stricter than the requirements of RFC 3101 but may be necessary according to the discussion at [Zulip].
[Zulip]: https://rust-lang.zulipchat.com/#narrow/stream/268952-edition-2021/topic/reserved.20prefixes/near/238470099
The tracking issue #84599 says we'll add a feature gate named `reserved_prefixes`, but I don't think I can do this because it is impossible for the lexer to know whether a feature is enabled or not. I guess determining the behavior by the edition information should be enough.
Fixes#84599
2229: Capture box completely in move closures
Even if the content from box is used in a sharef-ref context,
we capture the box entirerly.
This is motivated by:
1) We only capture data that is on the stack.
2) Capturing data from within the box might end up moving more data than
the user anticipated.
Closes https://github.com/rust-lang/project-rfc-2229/issues/50
r? `@nikomatsakis`
