Rework doc-test attribute documentation example
This PR change the doc-test attribute documentation example to prefer a more neutral example `deny(dead_code)`, instead of `deny(warnings)`, which is less susceptible to breakage across Rust version.
r? ```@GuillaumeGomez```
Fix duplicated attributes on nonterminal expressions
This PR fixes a long-standing bug (#86055) whereby expression attributes can be duplicated when expanded through declarative macros.
First, consider how items are parsed in declarative macros:
```
Items:
- parse_nonterminal
- parse_item(ForceCollect::Yes)
- parse_item_
- attrs = parse_outer_attributes
- parse_item_common(attrs)
- maybe_whole!
- collect_tokens_trailing_token
```
The important thing is that the parsing of outer attributes is outside token collection, so the item's tokens don't include the attributes. This is how it's supposed to be.
Now consider how expression are parsed in declarative macros:
```
Exprs:
- parse_nonterminal
- parse_expr_force_collect
- collect_tokens_no_attrs
- collect_tokens_trailing_token
- parse_expr
- parse_expr_res(None)
- parse_expr_assoc_with
- parse_expr_prefix
- parse_or_use_outer_attributes
- parse_expr_dot_or_call
```
The important thing is that the parsing of outer attributes is inside token collection, so the the expr's tokens do include the attributes, i.e. in `AttributesData::tokens`.
This PR fixes the bug by rearranging expression parsing to that outer attribute parsing happens outside of token collection. This requires a number of small refactorings because expression parsing is somewhat complicated. While doing so the PR makes the code a bit cleaner and simpler, by eliminating `parse_or_use_outer_attributes` and `Option<AttrWrapper>` arguments (in favour of the simpler `parse_outer_attributes` and `AttrWrapper` arguments), and simplifying `LhsExpr`.
r? `@petrochenkov`
local_def_path_hash_to_def_id is used by Debug impl for DepNode and it
looks for DefPathHash inside the current compilation. During incremental
compilation we are going through nodes that belong to a previous
compilation and might not be present and a simple attempt to print such
node with tracing::debug (try_mark_parent_green does it for example)
results in a otherwise avoidable panic
Panic was added in https://github.com/rust-lang/rust/pull/82183,
specifically in 2b60338ee9, with a comment "We only use this mapping for
cases where we know that it must succeed.", but I'm not sure if this
property holds when we traverse nodes from the old compilation in order
to figure out if they are valid or not
The way it is implemented currently try_force_from_dep_node returns true
as long as there's a function to force the query. It wasn't this way
from the beginning, earlier version was producing forcing result and it
was changed in https://github.com/rust-lang/rust/pull/89978, I couldn't
find any comments addressing this change.
One way it can fail is by failing to recover the query in
DepNodeParams::recover - when we are trying to query something that no
longer exists in the current environment
Rollup of 6 pull requests
Successful merges:
- #125447 (Allow constraining opaque types during subtyping in the trait system)
- #125766 (MCDC Coverage: instrument last boolean RHS operands from condition coverage)
- #125880 (Remove `src/tools/rust-demangler`)
- #126154 (StorageLive: refresh storage (instead of UB) when local is already live)
- #126572 (override user defined channel when using precompiled rustc)
- #126662 (Unconditionally warn on usage of `wasm32-wasi`)
r? `@ghost`
`@rustbot` modify labels: rollup
Unconditionally warn on usage of `wasm32-wasi`
This commit is a continuation of the work originally proposed in rust-lang/compiler-team#607 and later amended in
rust-lang/compiler-team#695. The end goal is to rename `wasm32-wasi` to `wasm32-wasip1` to reflect WASI's development and distinguish the preexisting target from the `wasm32-wasip2` target that WASI is now developing. Work for this transition began in #120468 which landed in Rust 1.78 which became stable on 2024-05-02.
This implements the next phase of the transition plan to warn on usage of `wasm32-wasi`. This is intended to help alert users that a removal is pending and all release channels have the replacement available as well. This will reach stable on 2024-09-05. The next stage of the plan is to remove the `wasm32-wasi` target some time in October 2024 which means that the removal will reach stable on 2025-01-09. For reference a full schedule of this transition is listed [here].
Currently this implementation is a simple unconditional warning whenever `rustc --target wasm32-wasi` is invoked. As-implemented there's no way to turn off the warning other than to switch to the `wasm32-wasip1` target.
[here]: https://github.com/rust-lang/rust/pull/120468#issuecomment-1977878747
override user defined channel when using precompiled rustc
We need to override `rust.channel` if it's manually specified when using the CI rustc. This is because if the compiler uses a different channel than the one specified in config.toml, tests may fail due to using a different channel than the one used by the compiler during tests.
For more context, see https://github.com/rust-lang/rust/pull/122709#issuecomment-2165246281.
Remove `src/tools/rust-demangler`
`rust-demangler` is a small binary that reads a list of mangled symbols from stdin, demangles them (using the `rustc-demangle` library crate), and prints the demangled symbols to stdout.
It was added as part of the initial implementation of coverage instrumentation in 2020/2021, so that coverage tests could pass it to `llvm-cov --Xdemangler` when generating coverage reports. It has been largely untouched since then.
As of #125816 it is no longer used by coverage tests, and has no remaining in-tree uses.
There is code in bootstrap to build and package the demangler, but it's unclear where the resulting binaries actually end up, or whether there's any reasonable way for `rustup` users to obtain them.
---
For users needing a command-line demangler, `rustfilt` exists and is more actively maintained. It's also quite easy to use the `rustc-demangle` library to build a custom command-line demangler if necessary, with only a few lines of code.
The tool's name (`rust-demangler`) is easily confused with the name of the library crate `rustc-demangle`, so removing the tool will eliminate that confusion. There also doesn't appear to be much reason to use `rust-demangler` over `rustfilt`.
---
This PR therefore removes the tool, and removes all of its associated code from bootstrap.
MCP filed: https://github.com/rust-lang/compiler-team/issues/754
MCDC Coverage: instrument last boolean RHS operands from condition coverage
Fresh PR from #124652
--
This PR ensures that the top-level boolean expressions that are not part of the control flow are correctly instrumented thanks to condition coverage.
See discussion on https://github.com/rust-lang/rust/issues/124120.
Depends on `@Zalathar` 's condition coverage implementation #125756.
Allow constraining opaque types during subtyping in the trait system
Previous attempt: https://github.com/rust-lang/rust/pull/123979
Sometimes we don't immediately perform subtyping, but instead register a subtyping obligation and solve that obligation when its inference variables become resolved. Unlike immediate subtyping, we currently do not allow registering hidden types for opaque types. This PR also allows that.
It now parses outer attributes before collecting tokens. This avoids the
problem where the outer attribute tokens were being stored twice -- for
the attribute tokesn, and also for the expression tokens.
Fixes#86055.
Rollup of 7 pull requests
Successful merges:
- #123782 (Test that opaque types can't have themselves as a hidden type with incompatible lifetimes)
- #124580 (Suggest removing unused tuple fields if they are the last fields)
- #125787 (Migrate `bin-emit-no-symbols` `run-make` test to `rmake`)
- #126553 (match lowering: expand or-candidates mixed with candidates above)
- #126594 (Make async drop code more consistent with regular drop code)
- #126654 (Make pretty printing for `f16` and `f128` consistent)
- #126656 (rustc_type_ir: Omit some struct fields from Debug output)
r? `@ghost`
`@rustbot` modify labels: rollup
Combine `NotYetParsed` and `AttributesParsed` into a single variant,
because (a) that reflects the structure of the code that consumes
`LhsExpr`, and (b) because that variant will have the `Option` removed
in a later commit.
The `Option<AttrWrapper>` one maps to the first two variants, and the
`P<Expr>` one maps to the third. Weird. The code is shorter and clearer
without them.
The call in `parse_expr_prefix` for the `++` case passes an empty
`attrs`, but it doesn' need to. This commit changes it to pass the
parsed `attrs`, which doesn't change any behaviour. As a result,
`parse_expr_dot_or_call` no longer needs an `Option` argument, and no
longer needs to call `parse_or_use_outer_attributes`.
Make pretty printing for `f16` and `f128` consistent
Currently the docs show e.g.
{transmute(0xfffeffffffffffffffffffffffffffff): f128}
for f128 constants. This should fix that to instead use apfloat for printing, as is done for `f32` and `f64`.
match lowering: expand or-candidates mixed with candidates above
This PR tweaks match lowering of or-patterns. Consider this:
```rust
match (x, y) {
(1, true) => 1,
(2, false) => 2,
(1 | 2, true | false) => 3,
(3 | 4, true | false) => 4,
_ => 5,
}
```
One might hope that this can be compiled to a single `SwitchInt` on `x` followed by some boolean checks. Before this PR, we compile this to 3 `SwitchInt`s on `x`, because an arm that contains more than one or-pattern was compiled on its own. This PR groups branch `3` with the two branches above, getting us down to 2 `SwitchInt`s on `x`.
We can't in general expand or-patterns freely, because this interacts poorly with another optimization we do: or-pattern simplification. When an or-pattern doesn't involve bindings, we branch the success paths of all its alternatives to the same block. The drawback is that in a case like:
```rust
match (1, true) {
(1 | 2, false) => unreachable!(),
(2, _) => unreachable!(),
_ => {}
}
```
if we used a single `SwitchInt`, by the time we test `false` we don't know whether we came from the `1` case or the `2` case, so we don't know where to go if `false` doesn't match.
Hence the limitation: we can process or-pattern alternatives alongside candidates that precede it, but not candidates that follow it. (Unless the or-pattern is the only remaining match pair of its candidate, in which case we can process it alongside whatever).
This PR allows the processing of or-pattern alternatives alongside candidates that precede it. One benefit is that we now process or-patterns in a single place in `mod.rs`.
r? ``@matthewjasper``
Suggest removing unused tuple fields if they are the last fields
Fixes#124556
We now check if dead/unused fields are the last fields of the tuple and suggest their removal instead of suggesting them to be changed to `()`.
Test that opaque types can't have themselves as a hidden type with incompatible lifetimes
fixes#122876
This PR used to add extra logic to prevent those cases, but after https://github.com/rust-lang/rust/pull/113169 this is implicitly rejected, because such usages are not defining.
Condition coverage extends branch coverage to treat the specific case
of last operands of boolean decisions not involved in control flow.
This is ultimately made for MCDC to be exhaustive on all boolean expressions.
This patch adds a call to `visit_branch_coverage_operation` to track the
top-level operand of the said decisions, and changes
`visit_coverage_standalone_condition` so MCDC branch registration is called
when enabled on these _last RHS_ cases.
improve tip for inaccessible traits
Improve the tips when the candidate method is from an inaccessible trait.
For example:
```rs
mod m {
trait Trait {
fn f() {}
}
impl<T> Trait for T {}
}
fn main() {
struct S;
S::f();
}
```
The difference between before and now is:
```diff
error[E0599]: no function or associated item named `f` found for struct `S` in the current scope
--> ./src/main.rs:88:6
|
LL | struct S;
| -------- function or associated item `f` not found for this struct
LL | S::f();
| ^ function or associated item not found in `S`
|
= help: items from traits can only be used if the trait is implemented and in scope
- help: trait `Trait` which provides `f` is implemented but not in scope; perhaps you want to import it
+ help: trait `crate:Ⓜ️:Trait` which provides `f` is implemented but not reachable
|
- LL + use crate:Ⓜ️:Trait;
|
```
