Fixes#75050
Previously, we would unconditionally suppress the panic hook during
proc-macro execution. This commit adds a new flag
-Z proc-macro-backtrace, which allows running the panic hook for
easier debugging.
Previous implementation used the `Parser::parse_expr` function in order
to extract the format expression. If the first comma following the
format expression was mistakenly replaced with a dot, then the next
format expression was eaten by the function, because it looked as a
syntactically valid expression, which resulted in incorrectly spanned
error messages.
The way the format expression is exctracted is changed: we first look at
the first available token in the first argument supplied to the
`format!` macro call. If it is a string literal, then it is promoted as
a format expression immediatly, otherwise we fall back to the original
`parse_expr`-related method.
This allows us to ensure that the parser won't consume too much tokens
when a typo is made.
A test has been created so that it is ensured that the issue is properly
fixed.
Fix another clashing_extern_declarations false positive.
Fixes#75739.
Fix another clashing_extern_declarations false positive, this time for transparent newtype with a non-zero member.
r? @lcnr
Abort when foreign exceptions are caught by catch_unwind
Prior to this PR, foreign exceptions were not caught by catch_unwind, and instead passed through invisibly. This represented a painful soundness hole in some libraries ([take_mut](https://github.com/Sgeo/take_mut/blob/master/src/lib.rs#L37)), which relied on `catch_unwind` to handle all possible exit paths from a closure.
With this PR, foreign exceptions are now caught by `catch_unwind` and will trigger an abort since catching foreign exceptions is currently UB according to the latest proposals by the FFI unwind project group.
cc @rust-lang/wg-ffi-unwind
Point to a move-related span when pointing to closure upvars
Fixes#75904
When emitting move/borrow errors, we may point into a closure to
indicate why an upvar is used in the closure. However, we use the
'upvar span', which is just an arbitrary usage of the upvar. If the
upvar is used in multiple places (e.g. a borrow and a move), we may end
up pointing to the borrow. If the overall error is a move error, this
can be confusing.
This PR tracks the span that caused an upvar to become captured by-value
instead of by-ref (assuming that it's not a `move` closure). We use this
span instead of the 'upvar' span when we need to point to an upvar usage
during borrow checking.
Await on mismatched future types
Closes#61076
This PR suggests to `await` on:
1. `async_fn().bar() => async_fn().await.bar()`
2. `async_fn().field => async_fn().await.field`
3. ` if let x = async() {} => if let x = async().await {}`
r? @tmandry @estebank
Fixes#75904
When emitting move/borrow errors, we may point into a closure to
indicate why an upvar is used in the closure. However, we use the
'upvar span', which is just an arbitrary usage of the upvar. If the
upvar is used in multiple places (e.g. a borrow and a move), we may end
up pointing to the borrow. If the overall error is a move error, this
can be confusing.
This PR tracks the span that caused an upvar to become captured by-value
instead of by-ref (assuming that it's not a `move` closure). We use this
span instead of the 'upvar' span when we need to point to an upvar usage
during borrow checking.
Be consistent when describing a move as a 'partial' in diagnostics
When an error occurs due to a partial move, we would use the world
"partial" in some parts of the error message, but not in others. This
commit ensures that we use the word 'partial' in either all or none of
the diagnostic messages.
Additionally, we no longer describe a move out of a `Box` via `*` as
a 'partial move'. This was a pre-existing issue, but became more
noticable when the word 'partial' is used in more places.
I would like to propose these two simple methods for stabilization:
- Knowing that a range is exhaused isn't otherwise trivial
- Clippy would like to suggest them, but had to do extra work to disable that path <https://github.com/rust-lang/rust-clippy/issues/3807> because they're unstable
- These work on `PartialOrd`, consistently with now-stable `contains`, and are thus more general than iterator-based approaches that need `Step`
- They've been unchanged for some time, and have picked up uses in the compiler
- Stabilizing them doesn't block any future iterator-based is_empty plans, as the inherent ones are preferred in name resolution
Provide better spans for the match arm without tail expression
Resolves#75418.
Applied the same logic in the `if`-`else` type mismatch case.
r? @estebank
stabilize ptr_offset_from
This stabilizes ptr::offset_from, and closes https://github.com/rust-lang/rust/issues/41079. It also removes the deprecated `wrapping_offset_from`. This function was deprecated 19 days ago and was never stable; given an FCP of 10 days and some waiting time until FCP starts, that leaves at least a month between deprecation and removal which I think is fine for a nightly-only API.
Regarding the open questions in https://github.com/rust-lang/rust/issues/41079:
* Should offset_from abort instead of panic on ZSTs? -- As far as I know, there is no precedent for such aborts. We could, however, declare this UB. Given that the size is always known statically and the check thus rather cheap, UB seems excessive.
* Should there be more methods like this with different restrictions (to allow nuw/nsw, perhaps) or that return usize (like how isize-taking offset is more conveniently done with usize-taking add these days)? -- No reason to block stabilization on that, we can always add such methods later.
Also nominating the lang team because this exposes an intrinsic.
The stabilized method is best described [by its doc-comment](56d4b2d69a/src/libcore/ptr/const_ptr.rs (L227)). The documentation forgot to mention the requirement that both pointers must "have the same provenance", aka "be derived from pointers to the same allocation", which I am adding in this PR. This is a precondition that [Miri already implements](https://play.rust-lang.org/?version=nightly&mode=debug&edition=2018&gist=a3b9d0a07a01321f5202cd99e9613480) and that, should LLVM ever obtain a `psub` operation to subtract pointers, will likely be required for that operation (following the semantics in [this paper](https://people.mpi-sws.org/~jung/twinsem/twinsem.pdf)).
Use smaller def span for functions
Currently, the def span of a function encompasses the entire function
signature and body. However, this is usually unnecessarily verbose - when we are
pointing at an entire function in a diagnostic, we almost always want to
point at the signature. The actual contents of the body tends to be
irrelevant to the diagnostic we are emitting, and just takes up
additional screen space.
This commit changes the `def_span` of all function items (freestanding
functions, `impl`-block methods, and `trait`-block methods) to be the
span of the signature. For example, the function
```rust
pub fn foo<T>(val: T) -> T { val }
```
now has a `def_span` corresponding to `pub fn foo<T>(val: T) -> T`
(everything before the opening curly brace).
Trait methods without a body have a `def_span` which includes the
trailing semicolon. For example:
```rust
trait Foo {
fn bar();
}
```
the function definition `Foo::bar` has a `def_span` of `fn bar();`
This makes our diagnostic output much shorter, and emphasizes
information that is relevant to whatever diagnostic we are reporting.
We continue to use the full span (including the body) in a few of
places:
* MIR building uses the full span when building source scopes.
* 'Outlives suggestions' use the full span to sort the diagnostics being
emitted.
* The `#[rustc_on_unimplemented(enclosing_scope="in this scope")]`
attribute points the entire scope body.
All of these cases work only with local items, so we don't need to
add anything extra to crate metadata.
Re-land PR #72388: Recursively expand `TokenKind::Interpolated` in `probably_equal_for_proc_macro`
PR #72388 allowed us to preserve the original `TokenStream` in more cases during proc-macro expansion, but had to be reverted due to a large number of regressions (See #72545 and #72622). These regressions fell into two categories
1. Missing handling for `Group`s with `Delimiter::None`, which are inserted during `macro_rules!` expansion (but are lost during stringification and re-parsing). A large number of these regressions were due to `syn` and `proc-macro-hack`, but several crates needed changes to their own proc-macro code.
2. Legitimate hygiene issues that were previously being masked by stringification. Some of these were relatively benign (e.g. [a compiliation error](https://github.com/paritytech/parity-scale-codec/pull/210) caused by misusing `quote_spanned!`). However, two crates had intentionally written unhygenic `macro_rules!` macros, which were able to access identifiers that were not passed as arguments (see https://github.com/rust-lang/rust/issues/72622#issuecomment-636402573).
All but one of the Crater regressions have now been fixed upstream (see https://hackmd.io/ItrXWRaSSquVwoJATPx3PQ?both). The remaining crate (which has a PR pending at https://github.com/sammhicks/face-generator/pull/1) is not on `crates.io`, and is a Yew application that seems unlikely to have any reverse dependencies.
As @petrochenkov mentioned in https://github.com/rust-lang/rust/issues/72545#issuecomment-638632434, not re-landing PR #72388 allows more crates to write unhygenic `macro_rules!` macros, which will eventually stop compiling. Since there is only one Crater regression remaining, since additional crates could write unhygenic `macro_rules!` macros in the time it takes that PR to be merged.
Currently, the def span of a funtion encompasses the entire function
signature and body. However, this is usually unnecessarily verbose - when we are
pointing at an entire function in a diagnostic, we almost always want to
point at the signature. The actual contents of the body tends to be
irrelevant to the diagnostic we are emitting, and just takes up
additional screen space.
This commit changes the `def_span` of all function items (freestanding
functions, `impl`-block methods, and `trait`-block methods) to be the
span of the signature. For example, the function
```rust
pub fn foo<T>(val: T) -> T { val }
```
now has a `def_span` corresponding to `pub fn foo<T>(val: T) -> T`
(everything before the opening curly brace).
Trait methods without a body have a `def_span` which includes the
trailing semicolon. For example:
```rust
trait Foo {
fn bar();
}```
the function definition `Foo::bar` has a `def_span` of `fn bar();`
This makes our diagnostic output much shorter, and emphasizes
information that is relevant to whatever diagnostic we are reporting.
We continue to use the full span (including the body) in a few of
places:
* MIR building uses the full span when building source scopes.
* 'Outlives suggestions' use the full span to sort the diagnostics being
emitted.
* The `#[rustc_on_unimplemented(enclosing_scope="in this scope")]`
attribute points the entire scope body.
* The 'unconditional recursion' lint uses the full span to show
additional context for the recursive call.
All of these cases work only with local items, so we don't need to
add anything extra to crate metadata.
Fixes#68430
This is a re-attempt of PR #72388, which was previously reverted due to
a large number of breakages. All of the known breakages should now be
patched upstream.
Fix RFC-1014 test
Use two printlns when testing that writing to a closed stdout does not
panic. Otherwise the test is ineffective, since the current implementation
silently ignores the error during first println regardless.
Capture tokens for Pat used in macro_rules! argument
This extends PR #73293 to handle patterns (Pat). Unlike expressions,
patterns do not support custom attributes, so we only need to capture
tokens during macro_rules! argument parsing.
Don't immediately error for cycles during normalization
#73452 meant some normalization cycles could be detected earlier, breaking some code.
This PR makes defers errors for normalization cycles to fulfillment, fixing said code.
Fixes#74868
r? @nikomatsakis
This extends PR #73293 to handle patterns (Pat). Unlike expressions,
patterns do not support custom attributes, so we only need to capture
tokens during macro_rules! argument parsing.
