Trait upcasting coercion (part1)
This revives the first part of earlier PR #60900 .
It's not very clear to me which parts of that pr was design decisions, so i decide to cut it into pieces and land them incrementally. This allows more eyes on the details.
This is the first part, it adds feature gates, adds feature gates tests, and implemented the unsize conversion part.
(I hope i have dealt with the `ExistentialTraitRef` values correctly...)
The next part will be implementing the pointer casting.
Rollup of 9 pull requests
Successful merges:
- #86072 (Cross compiling rustc_llvm on Darwin requires zlib.)
- #87385 (Make `SEMICOLON_IN_EXPRESSIONS_FROM_MACROS` warn by default)
- #87547 (Add missing examples for NonNull)
- #87557 (Fix issue with autofix for ambiguous associated function from Rust 2021 prelude when struct is generic)
- #87559 (Tweak borrowing suggestion in `for` loop)
- #87596 (Add warning when whitespace is not skipped after an escaped newline)
- #87606 (Add some TAIT-related regression tests)
- #87609 (Add docs about performance and `Iterator::map` to `[T; N]::map`)
- #87616 (Fix missing word in rustdoc book)
Failed merges:
r? `@ghost`
`@rustbot` modify labels: rollup
Add warning when whitespace is not skipped after an escaped newline
Fixes issue #87318, also simplifies issue #87319.
* Add support to the lexer to emit warnings as well as errors.
* Emit a warning when a string literal contains an escaped newline, but when (some of) the whitespace on the next line is not skipped due to it being non-ASCII.
Fix issue with autofix for ambiguous associated function from Rust 2021 prelude when struct is generic
Fixes#86940
The test cases and associated issue should make it clear what specifically this is meant to fix. The fix is slightly hacky in that we check against the literal source code of the call site for the presence of `<` in order to determine if the user has included the generics for the struct (meaning we don't need to include them for them).
r? ``@nikomatsakis``
Make `SEMICOLON_IN_EXPRESSIONS_FROM_MACROS` warn by default
This PR makes the `SEMICOLON_IN_EXPRESSIONS_FROM_MACROS` lint warn by default.
To avoid showing a large number of un-actionable warnings to users, we only enable the lint for macros defined in the same crate. This ensures that users will be able to fix the warning by simply removing a semicolon.
In the future, I'd like to enable this lint unconditionally, and eventually make it into a hard error in a future edition. This PR is a step towards that goal.
Use more precise span for E0282 in cast expressions
This pull request fixes#85586. The example code given there:
```rust
fn main() {
let a = [1, 2, 3].iter().sum();
let b = (a + 1) as usize;
}
```
currently produces
```
error[E0282]: type annotations needed
--> issue-85586.rs:3:13
|
3 | let b = (a + 1) as usize;
| ^^^^^^^^^^^^^^^^ cannot infer type
|
= note: type must be known at this point
error: aborting due to previous error
```
even though the type of the entire cast expression quite clearly should be `usize`. The error is in the cast's left-hand side, which is made explicit by the changes in this PR:
```
error[E0282]: type annotations needed
--> issue-85586.rs:3:13
|
3 | let b = (a + 1) as usize;
| ^^^^^^^ cannot infer type
|
= note: type must be known at this point
error: aborting due to previous error
```
Add feature gates for `for` and `?` in consts
These operations seems *relatively* straightforward to support, and only seem to be blocked on `impl const Trait`.
I have included a working test for `const_try`, but `const_for` is currently unusable without reimplementing *every single* defaulted `Iterator` method, so I didn't do that.
(both features still need tracking issues before this is merged)
Rollup of 10 pull requests
Successful merges:
- #87052 (Optimize fmt::PadAdapter::wrap)
- #87522 (Fix assert in diy_float)
- #87553 (Fix typo in rustc_driver::version)
- #87554 (2229: Discr should be read when PatKind is Range)
- #87564 (min_type_alias_impl_trait is going to be removed in 1.56)
- #87574 (Update the examples in `String` and `VecDeque::retain`)
- #87583 (Refactor compression cache in v0 symbol mangler)
- #87585 (Add missing links for core::char types)
- #87594 (fs File get_path procfs usage for netbsd same as linux.)
- #87602 ([backtraces]: look for the `begin` symbol only after seeing `end`)
Failed merges:
r? `@ghost`
`@rustbot` modify labels: rollup
Refactor compression cache in v0 symbol mangler
* Remove redundant option around compression caches (they are always present).
* Flatten compression caches into symbol mangler to avoid dynamic memory allocation.
* Implement printer for `&mut SymbolMangler` instead of `SymbolMangler` to avoid passing now slightly larger symbol mangler by value.
min_type_alias_impl_trait is going to be removed in 1.56
#87501 removed `min_type_alias_impl_trait` but meanwhile that PR was approved in homu queue, a new beta was cut so we need to bump the version because it won't be removed in 1.55.
r? ```@oli-obk```
```@bors``` rollup=always
2229: Discr should be read when PatKind is Range
This PR fixes an issue related to pattern matching in closures when Edition 2021 is enabled.
- If any of the patterns the discr is being matched on is `PatKind::Range` then the discr should be read
r? ```@nikomatsakis```
Closes https://github.com/rust-lang/rust/issues/87426
Mir borrowck does not generate lifetime variables for 'static lifetimes during opaque type resolution
Fixes#87455
This situation was unreachable before #87287 as we used to just grab the resolved opaque type from typeck and replaced all regions with new inference vars. After #87287 we let the `InferCx` in mir borrowck figure out the opaque type all by itself (which it already did before, but it only used the result to sanity check with the typeck result).
The compression caches currently don't have any dedicated functionality
that would benefit from being separated. Incorporating caches directly
into the symbol manger also avoids dynamic memory allocation.
The symbol mangler, which is often passed by value, is now slightly
larger. This aspect will be addressed by a follow-up commit.
Make const panic!("..") work in Rust 2021.
During const eval, this replaces calls to core::panicking::panic_fmt and std::panicking::being_panic_fmt with a call to a new const fn: core::panicking::const_panic_fmt. That function uses fmt::Arguments::as_str() to get the str and calls panic_str with that instead.
panic!() invocations with formatting arguments are still not accepted, as the creation of such a fmt::Arguments cannot be done in constant functions right now.
r? `@RalfJung`
Create `QuerySideEffects` and use it for diagnostics
The code for saving and loading diagnostics during execution is generalized to handle a new `QuerySideEffects` struct. Currently, this struct just holds diagnostics - in a follow-up PR, I plan to add support for storing attriutes marked as used during query execution.
This is a pure refactor, with no intended behavior changes.
During const eval, this replaces calls to core::panicking::panic_fmt and
std::panicking::being_panic_fmt with a call to a new const fn:
core::panicking::const_panic_fmt. That function uses
fmt::Arguments::as_str() to get the str and calls panic_str with that
instead.
panic!() invocations with formatting arguments are still not accepted,
as the creation of such a fmt::Arguments cannot be done in constant
functions right now.
