fix DFS for region error reporting
This was causing terrible error reports, because the algorithm was incorrectly identifying the constraints.
r? @eddyb
borrowck: do not suggest to change "&mut self" to "&mut mut self"
Matching the snippet string might not be the cleanest, but matching
the AST node instead seems to end in a lot of nested `if let`s, so I
don't know what's better.
Of course it's entirely possible that there is another API altogether
that I just don't know of?
Fixes#31424.
resolve: do not modify span of non-importable name
This span modification is probably leftover from a time when import spans were assigned differently.
With this change, error spans for the following are properly reported:
```
use abc::one_el;
use abc::{a, bbb, cccccc};
use a_very_long_name::{el, el2};
```
before (spans only):
```
x.rs:3 use abc::one_el;
^~~
x.rs:4 use abc::{a, bbb, cccccc};
^~~
x.rs:4 use abc::{a, bbb, cccccc};
^~~
x.rs:4 use abc::{a, bbb, cccccc};
^~~
(internal compiler error: unprintable span)
(internal compiler error: unprintable span)
```
after:
```
x.rs:3 use abc::one_el;
^~~~~~~~~~~
x.rs:4 use abc::{a, bbb, cccccc};
^
x.rs:4 use abc::{a, bbb, cccccc};
^~~
x.rs:4 use abc::{a, bbb, cccccc};
^~~~~~
x.rs:5 use a_very_long_name::{el, el2};
^~
x.rs:5 use a_very_long_name::{el, el2};
^~~
```
Fixes: #33464
This span modification is probably leftover from a time when
import spans were assigned differently.
With this change, error spans for the following are properly reported:
```
use abc::one_el;
use abc::{a, bbb, cccccc};
use a_very_long_name::{el, el2};
```
before (spans only):
```
x.rs:3 use abc::one_el;
^~~
x.rs:4 use abc::{a, bbb, cccccc};
^~~
x.rs:4 use abc::{a, bbb, cccccc};
^~~
x.rs:4 use abc::{a, bbb, cccccc};
^~~
(internal compiler error: unprintable span)
(internal compiler error: unprintable span)
```
after:
```
x.rs:3 use abc::one_el;
^~~~~~~~~~~
x.rs:4 use abc::{a, bbb, cccccc};
^
x.rs:4 use abc::{a, bbb, cccccc};
^~~
x.rs:4 use abc::{a, bbb, cccccc};
^~~~~~
x.rs:5 use a_very_long_name::{el, el2};
^~
x.rs:5 use a_very_long_name::{el, el2};
^~~
```
Fixes: #33464
Perform name resolution before and during ast->hir lowering
This PR performs name resolution before and during ast->hir lowering instead of in phase 3.
r? @nrc
This commit is an implementation of [RFC 1513] which allows applications to
alter the behavior of panics at compile time. A new compiler flag, `-C panic`,
is added and accepts the values `unwind` or `panic`, with the default being
`unwind`. This model affects how code is generated for the local crate, skipping
generation of landing pads with `-C panic=abort`.
[RFC 1513]: https://github.com/rust-lang/rfcs/blob/master/text/1513-less-unwinding.md
Panic implementations are then provided by crates tagged with
`#![panic_runtime]` and lazily required by crates with
`#![needs_panic_runtime]`. The panic strategy (`-C panic` value) of the panic
runtime must match the final product, and if the panic strategy is not `abort`
then the entire DAG must have the same panic strategy.
With the `-C panic=abort` strategy, users can expect a stable method to disable
generation of landing pads, improving optimization in niche scenarios,
decreasing compile time, and decreasing output binary size. With the `-C
panic=unwind` strategy users can expect the existing ability to isolate failure
in Rust code from the outside world.
Organizationally, this commit dismantles the `sys_common::unwind` module in
favor of some bits moving part of it to `libpanic_unwind` and the rest into the
`panicking` module in libstd. The custom panic runtime support is pretty similar
to the custom allocator support with the only major difference being how the
panic runtime is injected (takes the `-C panic` flag into account).
Improve diagnostics for constants being used in irrefutable patterns
It's pretty confusing and this error triggers in resolve only when "shadowing" a const, so let's make that clearer.
r? @steveklabnik
Instead of finding aux-build files in `auxiliary`, we now search for an
`aux` directory relative to the test. So if your test is
`compile-fail/foo.rs`, we would look in `compile-fail/aux`. Similarly,
we ignore the `aux` directory when searching for tets.
Short-cut `T: Sized` trait selection for ADTs
Basically avoids all nested obligations when checking whether an ADT is sized - this speeds up typeck by ~15%
The refactoring fixed#32963, but I also want to make `Copy` not object-safe (will commit that soon).
Fixes#33201
r? @nikomatsakis
This requirement appears to be missing from RFC1214, but is clearly
necessary for translation. The last field of a tuple/enum remains in
a state of limbo, compiling but causing an ICE when it is used - we
should eventually fix that somehow.
this is a [breaking-change] - a soundness fix - and requires a
crater run.
resolve: print location of static for "static in pattern" error
The implementation mirrors the one for "constant defined here" annotation used for constant patterns in the irrefutable-pattern case.
Fixes: #23716
fix various const eval errors
These were found after const_evaluating arbitrary expressions and linting if the const evaluator failed
fixes#33275 (int -> float casts for negative ints)
fixes#33291 (int -> char casts (new! wasn't allowed in constants until this PR))
r? @eddyb
cc @bluss @japaric
typeck: remove confusing suggestion for calling a fn type
* It is not clear what a "base function" is.
* The suggestion just adds parens, so suggests calling without args.
The second point could be fixed with e.g. `(...)` instead of `()`,
but the preceding "note: X is a function, perhaps you wish to call it"
should already be clear enough.
Fixes: #31341
match check: note "catchall" patterns in unreachable error
Caught as catchall patterns are:
* unconditional name bindings
* references to them
* tuple bindings with catchall elements
Fixes#31221.
resolve: improve diagnostics and lay groundwork for resolving before ast->hir
This PR improves diagnostics in `resolve` and lays some groundwork for resolving before ast->hir.
More specifically,
- It removes an API in `resolve` intended for external refactoring tools (see #27493) that appears not to be in active use. The API is incompatible with resolving before ast->hir, but could be rewritten in a more compatible and less intrusive way.
- It improves the diagnostics for pattern bindings that conflict with `const`s.
- It improves the diagnostics for modules used as expressions (fixes#33186).
- It refactors away some uses of the hir map, which is unavavailable before ast->hir lowering.
r? @eddyb
* It is not clear what a "base function" is.
* The suggestion just adds parens, so suggests calling without args.
The second point could be fixed with e.g. `(...)` instead of `()`,
but the preceding "note: X is a function, perhaps you wish to call it"
should already be clear enough.
Fixes: #31341
Feature gate clean
This PR does a bit of cleaning in the feature-gate-handling code of libsyntax. It also fixes two bugs (#32782 and #32648). Changes include:
* Change the way the existing features are declared in `feature_gate.rs`. The array of features and the `Features` struct are now defined together by a single macro. `featureck.py` has been updated accordingly. Note: there are now three different arrays for active, removed and accepted features instead of a single one with a `Status` item to tell wether a feature is active, removed, or accepted. This is mainly due to the way I implemented my macro in the first time and I can switch back to a single array if needed. But an advantage of the way it is now is that when an active feature is used, the parser only searches through the list of active features. It goes through the other arrays only if the feature is not found. I like to think that error checking (in this case, checking that an used feature is active) does not slow down compilation of valid code. :) But this is not very important...
* Feature-gate checking pass now use the `Features` structure instead of looking through a string vector. This should speed them up a bit. The construction of the `Features` struct should be faster too since it is build directly when parsing features instead of calling `has_feature` dozens of times.
* The MacroVisitor pass has been removed, it was mostly useless since the `#[cfg]-stripping` phase happens before (fixes#32648). The features that must actually be checked before expansion are now checked at the time they are used. This also allows us to check attributes that are generated by macro expansion and not visible to MacroVisitor, but are also removed by macro expansion and thus not visible to PostExpansionVisitor either. This fixes#32782. Note that in order for `#[derive_*]` to be feature-gated but still accepted when generated by `#[derive(Trait)]`, I had to do a little bit of trickery with spans that I'm not totally confident into. Please review that part carefully. (It's in `libsyntax_ext/deriving/mod.rs`.)::
Note: this is a [breaking change], since programs with feature-gated attributes on macro-generated macro invocations were not rejected before. For example:
```rust
macro_rules! bar (
() => ()
);
macro_rules! foo (
() => (
#[allow_internal_unstable] //~ ERROR allow_internal_unstable side-steps
bar!();
);
);
```
foo!();
report `const_err` on all expressions that can fail
also a drive-by fix for reporting an "overflow in shift *left*" when shifting an `i64` *right*
This increases the warning noise for shifting by more than the bitwidth and for `-T::MIN`. I can silence the bitwidth warnings explicitly and fix the const evaluator to make sure `--$expr` is treated exactly like `$expr` (which is kinda wrong, but mathematically right).
r? @eddyb
