Add future incompatibility lint for `array.into_iter()`
This is for #65819. This lint warns when calling `into_iter` on an array directly. That's because today the method call resolves to `<&[T] as IntoIterator>::into_iter` but that would change when adding `IntoIterator` impls for arrays. This problem is discussed in detail in #65819.
We still haven't decided how to proceed exactly, but it seems like adding a lint is a good idea regardless?
Also: this is the first time I implement a lint, so there are probably a lot of things I can improve. I used a different strategy than @scottmcm describes [here](https://github.com/rust-lang/rust/pull/65819#issuecomment-548667847) since I already started implementing this before they commented.
### TODO
- [x] Decide if we want this lint -> apparently [we want](https://github.com/rust-lang/rust/pull/65819#issuecomment-548964818)
- [x] Open a lint-tracking-issue and add the correct issue number in the code -> https://github.com/rust-lang/rust/issues/66145
A scheme for more macro-matcher friendly pre-expansion gating
Pre-expansion gating will now avoid gating macro matchers that did not result in `Success(...)`. That is, the following is now OK despite `box 42` being a valid `expr` and that form being pre-expansion gated:
```rust
macro_rules! m {
($e:expr) => { 0 }; // This fails on the input below due to `, foo`.
(box $e:expr, foo) => { 1 }; // Successful matcher, we should get `2`.
}
fn main() {
assert_eq!(1, m!(box 42, foo));
}
```
Closes https://github.com/rust-lang/rust/issues/65846.
r? @petrochenkov
cc @Mark-Simulacrum
syntax: ABI-oblivious grammar
This PR has the following effects:
1. `extern $lit` is now legal where `$lit:literal` and `$lit` is substituted for a string literal.
2. `extern "abi_that_does_not_exist"` is now *syntactically* legal whereas before, the set of ABI strings was hard-coded into the grammar of the language. With this PR, the set of ABIs are instead validated and translated during lowering. That seems more appropriate.
3. `ast::FloatTy` is now distinct from `rustc_target::abi::FloatTy`. The former is used substantially more and the translation between them is only necessary in a single place.
4. As a result of 2-3, libsyntax no longer depends on librustc_target, which should improve pipe-lining somewhat.
cc @rust-lang/lang -- the points 1-2 slightly change the definition of the language but in a way which seems consistent with our general principles (in particular wrt. the discussions of turning things into semantic errors). I expect this to be uncontroversial but it's worth letting y'all know. :)
r? @varkor
Use structured suggestions for missing associated items
When encountering an `impl` that is missing associated items required by its `trait`, use structured suggestions at an appropriate place in the `impl`.
Miri: Refactor to_scalar_ptr out of existence
`to_scalar_ptr` is somewhat subtle as it just throws away the 2nd component of a `ScalarPair` if there is one -- without any check if this is truly a pointer or so. And indeed we used it wrong on two occasions!
So I fixed those two, and then refactored things such that everyone calls `ref_to_mplace` instead (which they did anyway, I just moved up the calls), which is the only place that should interpret a `ScalarPair` as a wide ptr -- and it checks the type first. Thus we can remove `to_scalar_ptr` and `to_meta`.
r? @oli-obk
Do not require extra LLVM backends for `x.py test` to pass
For long time our testing passed with a partially built LLVM
```
[llvm]
targets = "X86;ARM"
```
, a [recent PR](https://github.com/rust-lang/rust/pull/65809) changed that.
Improve uninit/zeroed lint
* Also warn when creating a raw pointer with a NULL vtable.
* Also identify `MaybeUninit::uninit().assume_init()` and `MaybeUninit::zeroed().assume_init()` as dangerous.
Optimize long-linker-command-line test
Replace O(n^3) text matching with inexpensive hash set lookups.
On my machine this reduces the total runtime of complete
run-make-fulldeps suite from roughly 75 seconds to 45 seconds.
gate rustc_on_unimplemented under rustc_attrs
Move `rustc_on_implemented` from the `on_implemented` gate to `rustc_attrs` as it is internal.
Closes#29628
r? @varkor
Fix promotion in a `const` when projections are present
Resolves#65727.
This marks the entire local as "needs promotion" when only a projection of that local appears in a promotable context. This should only affect promotion in a `const` or `static`, not in a `fn` or `const fn`, which is handled in `promote_consts.rs`.
r? @eddyb
Use ident.span instead of def_span in dead-code pass
Hello! First time contributor! :)
This should fix#58729.
According to @estebank in the duplicate #63064, def_span scans forward on the line until it finds a {,
and if it can't find one, falls back to the span for the whole item. This
was apparently written before the identifier span was explicitly tracked on
each node.
This means that if an unused function signature spans multiple lines, the
entire function (potentially hundreds of lines) gets flagged as dead code.
This could, for example, cause IDEs to add error squiggly's to the whole
function.
By using the span from the ident instead, we narrow the scope of this in
most cases. In a wider sense, it's probably safe to use ident.span
instead of def_span in most locations throughout the whole code base,
but since this is my first contribution, I kept it small.
Some interesting points that came up while I was working on this:
- I reorganized the tests a bit to bring some of the dead code ones all
into the same location
- A few tests were for things unrelated to dead code (like the
path-lookahead for parens), so I added #![allow(dead_code)] and
cleaned up the stderr file to reduce noise in the future
- The same fix doesn't apply to const and static declarations. I tried
adding these cases to the match expression, but that created a much
wider change to tests and error messages, so I left it off until I
could get some code review to validate the approach.
caller_location: point to macro invocation sites, like file!/line!, and use in core::panic!.
The main change here is to `core::panic!`, trying to fix this remaining regression: https://github.com/rust-lang/rust/pull/65927#issuecomment-547625147
However, in order for `caller_location` to be usable from macros the same way `file!()`/`line!()` are, it needs to have the same behavior (of extracting the macro invocation site `Span` and using that).
Arguably we would've had to do this at some point anyway, if we want to use `#[track_caller]` to replace the `file!()`/`line!()` uses from macros, but I'm not sure the RFC mentions this at all.
r? @petrochenkov cc @anp @nnethercote
rustc: remove "GlobalMetaData" dead code from hir::map::definitions.
Spotted while refactoring uses of `DefIndex` and/or `LocalDefId`.
r? @michaelwoerister
Tweak type mismatch caused by break on tail expr
When `break;` has a type mismatch because the `Destination` points at a tail
expression with an obligation flowing from a return type, point at the
return type.
Fix#39968.
syntax: Avoid span arithmetic for delimiter tokens
The +/-1 logic is from the time where the whole group had a single span and the delimiter spans had to be calculated from it.
Now the delimiters have their own spans which are constructed by lexer or proc macro API and can be used directly.
If those spans are not perfect, then it should be fixed by tweaking the corresponding lexer logic rather than by trying to add or substract `1` from the span boundaries.
Fixes https://github.com/rust-lang/rust/issues/62524
r? @estebank
When `break;` has a type mismatch because the `Destination` points at a tail
expression with an obligation flowing from a return type, point at the
return type.
Fix#39968.
If item.span is part of a macro invocation, this has several downstream
implications. To name two that were found while working on this:
- The dead-code error gets annotated with a "in this macro invocation"
- Some errors get canceled if they refer to remote crates
Ideally, we should annotate item.ident.span with the same macro info,
but this is a larger change (see: #66095), so for now we just fall
back to the old behavior if this item was generated by a macro.
I use span.macro_backtrace().len() to detect if it's part of a macro,
because that (among other things) is what is used by the code which
adds the "in this macro invocation" annotations mentioned above.
Add a failing UI test for multiple loops of all kinds in a `const`
This simply demonstrates the current behavior and ensures we don't allow anything by accident.
The new const checker will be able to improve the diagnostics here. While working on it, I didn't see very many tests with non-`while` loops in a `const`, and there were no tests with multiple loops.
Suggest correct code when encountering an incorrect trait bound referencing the current trait
Fixes#65985 and also improves the suggestion for code like this:
```
trait Grab {
type Value;
fn grab(&self) -> Grab::Value;
}
```
To suggest `<Self as Grab>::Value`.
I wasn't sure which of the syntax versions is better (`<Self as ..>::` vs `Self::`), so I used the former simply because it was less change to the existing code.
r? @estebank
Reduce amount of errors given unclosed delimiter
When in a file with a non-terminated item, catch the error and consume
the block instead of trying to recover it on a more granular way in order to
reduce the amount of unrelated errors that would be fixed after adding
the missing closing brace. Also point out the possible location of the
missing closing brace.
Fix#63690.
