This makes the error message in #28981 a bit shorter (152 to 115 lines).
Previous output (the local impl was always printed twice when it conflicted with an external impl):
```
test.rs:3:1: 3:23 error: conflicting implementations for trait `core::ops::Deref` [E0119]
test.rs:3 impl<T> Deref for T {}
^~~~~~~~~~~~~~~~~~~~~~
test.rs:3:1: 3:23 help: run `rustc --explain E0119` to see a detailed explanation
test.rs:3:1: 3:23 note: conflicting implementation in crate `std`
test.rs:3 impl<T> Deref for T {}
^~~~~~~~~~~~~~~~~~~~~~
```
Output after this patch:
```
test.rs:3:1: 3:23 error: conflicting implementations for trait `core::ops::Deref` [E0119]
test.rs:3 impl<T> Deref for T {}
^~~~~~~~~~~~~~~~~~~~~~
test.rs:3:1: 3:23 help: run `rustc --explain E0119` to see a detailed explanation
note: conflicting implementation in crate `std`
```
Closes#29314
The code from #29314:
```rust
fn main() {
if let Some(b) = None {
()
} else {
1
};
}
```
now prints this:
```
test.rs:2:5: 6:6 error: `if let` arms have incompatible types: expected `()`, found `_` (expected (), found integral variable) [E0308]
test.rs:2 if let Some(b) = None {
test.rs:3 ()
test.rs:4 } else {
test.rs:5 1
test.rs:6 };
test.rs:2:5: 6:6 help: run `rustc --explain E0308` to see a detailed explanation
test.rs:4:12: 6:6 note: `if let` arm with an incompatible type
test.rs:4 } else {
test.rs:5 1
test.rs:6 };
error: aborting due to previous error
```
this has the funky side-effect of also allowing constant evaluation of function calls to functions that are not `const fn` as long as `check_const` didn't mark that function `NOT_CONST`
It's still not possible to call a normal function from a `const fn`, but let statements' initialization value can get const evaluated (this caused the fallout in the overflowing tests)
we can now do this:
```rust
const fn add(x: usize, y: usize) -> usize { x + y }
const ARR: [i32; add(1, 2)] = [5, 6, 7];
```
also added a test for destructuring in const fn args
```rust
const fn i((a, b): (u32, u32)) -> u32 { a + b } //~ ERROR: E0022
```
This is a **[breaking change]**, since it turns some runtime panics into compile-time errors. This statement is true for ANY improvement to the const evaluator.
This commit stabilizes and deprecates library APIs whose FCP has closed in the
last cycle, specifically:
Stabilized APIs:
* `fs::canonicalize`
* `Path::{metadata, symlink_metadata, canonicalize, read_link, read_dir, exists,
is_file, is_dir}` - all moved to inherent methods from the `PathExt` trait.
* `Formatter::fill`
* `Formatter::width`
* `Formatter::precision`
* `Formatter::sign_plus`
* `Formatter::sign_minus`
* `Formatter::alternate`
* `Formatter::sign_aware_zero_pad`
* `string::ParseError`
* `Utf8Error::valid_up_to`
* `Iterator::{cmp, partial_cmp, eq, ne, lt, le, gt, ge}`
* `<[T]>::split_{first,last}{,_mut}`
* `Condvar::wait_timeout` - note that `wait_timeout_ms` is not yet deprecated
but will be once 1.5 is released.
* `str::{R,}MatchIndices`
* `str::{r,}match_indices`
* `char::from_u32_unchecked`
* `VecDeque::insert`
* `VecDeque::shrink_to_fit`
* `VecDeque::as_slices`
* `VecDeque::as_mut_slices`
* `VecDeque::swap_remove_front` - (renamed from `swap_front_remove`)
* `VecDeque::swap_remove_back` - (renamed from `swap_back_remove`)
* `Vec::resize`
* `str::slice_mut_unchecked`
* `FileTypeExt`
* `FileTypeExt::{is_block_device, is_char_device, is_fifo, is_socket}`
* `BinaryHeap::from` - `from_vec` deprecated in favor of this
* `BinaryHeap::into_vec` - plus a `Into` impl
* `BinaryHeap::into_sorted_vec`
Deprecated APIs
* `slice::ref_slice`
* `slice::mut_ref_slice`
* `iter::{range_inclusive, RangeInclusive}`
* `std::dynamic_lib`
Closes#27706Closes#27725
cc #27726 (align not stabilized yet)
Closes#27734Closes#27737Closes#27742Closes#27743Closes#27772Closes#27774Closes#27777Closes#27781
cc #27788 (a few remaining methods though)
Closes#27790Closes#27793Closes#27796Closes#27810
cc #28147 (not all parts stabilized)
This commit stabilizes and deprecates library APIs whose FCP has closed in the
last cycle, specifically:
Stabilized APIs:
* `fs::canonicalize`
* `Path::{metadata, symlink_metadata, canonicalize, read_link, read_dir, exists,
is_file, is_dir}` - all moved to inherent methods from the `PathExt` trait.
* `Formatter::fill`
* `Formatter::width`
* `Formatter::precision`
* `Formatter::sign_plus`
* `Formatter::sign_minus`
* `Formatter::alternate`
* `Formatter::sign_aware_zero_pad`
* `string::ParseError`
* `Utf8Error::valid_up_to`
* `Iterator::{cmp, partial_cmp, eq, ne, lt, le, gt, ge}`
* `<[T]>::split_{first,last}{,_mut}`
* `Condvar::wait_timeout` - note that `wait_timeout_ms` is not yet deprecated
but will be once 1.5 is released.
* `str::{R,}MatchIndices`
* `str::{r,}match_indices`
* `char::from_u32_unchecked`
* `VecDeque::insert`
* `VecDeque::shrink_to_fit`
* `VecDeque::as_slices`
* `VecDeque::as_mut_slices`
* `VecDeque::swap_remove_front` - (renamed from `swap_front_remove`)
* `VecDeque::swap_remove_back` - (renamed from `swap_back_remove`)
* `Vec::resize`
* `str::slice_mut_unchecked`
* `FileTypeExt`
* `FileTypeExt::{is_block_device, is_char_device, is_fifo, is_socket}`
* `BinaryHeap::from` - `from_vec` deprecated in favor of this
* `BinaryHeap::into_vec` - plus a `Into` impl
* `BinaryHeap::into_sorted_vec`
Deprecated APIs
* `slice::ref_slice`
* `slice::mut_ref_slice`
* `iter::{range_inclusive, RangeInclusive}`
* `std::dynamic_lib`
Closes#27706Closes#27725
cc #27726 (align not stabilized yet)
Closes#27734Closes#27737Closes#27742Closes#27743Closes#27772Closes#27774Closes#27777Closes#27781
cc #27788 (a few remaining methods though)
Closes#27790Closes#27793Closes#27796Closes#27810
cc #28147 (not all parts stabilized)
Fixes#29184
This adds an error message for the use of the reserved `typeof` keyword, instead of reporting an ICE.
Also adds a `compile-fail` test.
I chose to add a `span_err` instead of removing to parser code, as to preserve the reservation of `typeof`.
This rather crucial requirement was not checked. In most cases, that
didn't cause any trouble because the argument types are required to
outlive the call and are subtypes of a subformula of the callee type.
However, binary ops are taken by ref only indirectly, without it being
marked in the argument types, which led to the argument types not being
constrained anywhere causing spurious errors (as these are basically
unconstrainable, I don't think this change can break code). Of course,
the old way was also incorrent with contravariance, but that is still
unsound for other reasons.
This also improves rustc::front to get RUST_LOG to *somewhat* work.
Fixes#28999. That issue is one of the several regression introduced by #28669.
r? @pnkfelix
This rather crucial requirement was not checked. In most cases, that
didn't cause any trouble because the argument types are required to
outlive the call and are subtypes of a subformula of the callee type.
However, binary ops are taken by ref only indirectly, without it being
marked in the argument types, which led to the argument types not being
constrained anywhere causing spurious errors (as these are basically
unconstrainable, I don't think this change can break code). Of course,
the old way was also incorrent with contravariance, but that is still
unsound for other reasons.
This also improves rustc::front to get RUST_LOG to *somewhat* work.
Fixes#28999
I found these automatically, but fixed them manually to ensure the semantics are correct. I know things like these are hardly important, since they only marginally improve clarity. But at least for me typos and simple grammatical errors trigger an---unjustified---sense of unprofessionalism, despite the fact that I make them all the time and I understand that they're the sort of thing that is bound to slip through review.
Anyway, to find most of these I used:
* `ag '.*//.*(\b[A-Za-z]{2,}\b) \1\b'` for repeated words
* `ag '\b(the|this|those|these|a|it) (a|the|this|those|these|it)\b'` to find constructs like 'the this' etc. many false positives, but not too hard to scroll through them to actually find the mistakes.
* `cat ../../typos.txt | paste -d'|' - - - - - - - - - - - - - - - - - - - - - - | tr '\n' '\0' | xargs -0 -P4 -n1 ag`. Hacky way to find misspellings, but it works ok. I got `typos.txt` from [Wikipedia](https://en.wikipedia.org/wiki/Wikipedia:Lists_of_common_misspellings/For_machines)
* `ag '.*//.* a ([ae][a-z]|(o[^n])|(i[a-rt-z]))'` to find places where 'a' was followed by a vowel (requiring 'an' instead).
I also used a handful more one off regexes that are too boring to reproduce here.
Implement cannot-assume-parametricity (CAP) from RFC 1238, and add the
UGEH attribute.
----
Note that we check for the attribute attached to the dtor method, not
the Drop impl.
(This is just to match the specification of RFC and the tests; I am
not wedded to this approach.)
By RFC1214:
> Before calling a fn, we check that its argument and return types are WF.
The previous code only checked the trait-ref, which was not enough
in several cases.
As this is a soundness fix, it is a [breaking-change]. Some new annotations are needed, which I think are because of #18653 and the imperfection of `projection_must_outlive` (that can probably be worked around by moving the wf obligation later).
Fixes#28609
r? @nikomatsakis
libcore.rlib reduced from 19121 kiB to 15934 kiB - 20% win.
The librustc encoded AST is 9013500 bytes long - for the record, librustc consists of about 2254126 characters. Might be worth looking at.
r? @eddyb
