[NLL] Fix various unused mut errors
Closes#51801Closes#50897Closes#51830Closes#51904
cc #51918 - keeping this one open in case there are any more issues
This PR contains multiple changes. List of changes with examples of what they fix:
* Change mir generation so that the parameter variable doesn't get a name when a `ref` pattern is used as an argument
```rust
fn f(ref y: i32) {} // doesn't trigger lint
```
* Change mir generation so that by-move closure captures don't get first moved into a temporary.
```rust
let mut x = 0; // doesn't trigger lint
move || {
x = 1;
};
```
* Treat generator upvars the same as closure upvars
```rust
let mut x = 0; // This mut is now necessary and is not linted against.
move || {
x = 1;
yield;
};
```
r? @nikomatsakis
This removes the `usize` argument to `inc_step_counter`. Now, the step
counter increments by exactly one for every terminator evaluated. After
`STEPS_UNTIL_DETECTOR_ENABLED` steps elapse, the detector is run every
`DETECTOR_SNAPSHOT_PERIOD` steps. The step counter is only kept modulo
this period.
This test relies on the fact that restrictions on expressions in `const
fn` do not apply when computing array lengths. It is more difficult to
statically analyze than the simple `loop{}` mentioned in #50637.
This test should be updated to ignore the warning after #49980 is resolved.
The detector runs every `DETECTOR_SNAPSHOT_PERIOD` steps. Since the
number of steps can increase by more than 1 (I'd like to remove this),
the detector may fail if the step counter is incremented past the
scheduled detection point during the loop.
This reverts commit 59d21c526c036d7097d05edd6dffdad9c5b1cb62, and uses
tuple to store the mutable parts of an EvalContext (which now includes
`Machine`). This requires that `Machine` be `Clone`.
Use the approach suggested by @oli-obk, a table holding `EvalState`
hashes and a table holding full `EvalState` objects. When a hash
collision is observed, the state is cloned and put into the full
table. If the collision was not spurious, it will be detected during the
next iteration of the infinite loop.
I use a pattern binding in each custom impl, so that adding fields to
`Memory` or `Frame` will cause a compiler error instead of causing e.g.
`PartialEq` to become invalid. This may be too cute.
This adds several requirements to `Machine::MemoryData`. These can be
removed if we don't want this associated type to be part of the equality
of `Memory`.
rustdoc codeblock hash escape
So that docstring text such as the following (in a code block) can be created ergonomically:
```rust
let s = "
foo
# bar
baz
";
```
Such code in a docstring hide the <code> # bar</code> line.
Previously, using two consecutive hashes <code> ## bar</code> would turn the line into _shown_ `# bar`, losing the leading whitespace. A line of code like <code> # bar</code> (such as in the example above) **could not be represented** in the docstring text.
This commit makes the two consecutive hashes not also trim the leading whitespace — the two hashes simply **escape** into a single hash and do not hide the line, leaving the rest of that line unaffected. The new docstring text to achieve the above code block is:
```rust
/// ```
/// let s = "
/// foo
/// ## bar
/// baz
/// ";
/// ```
```
rustdoc: import cross-crate macros alongside everything else
The thrilling conclusion of the cross-crate macro saga in rustdoc! After https://github.com/rust-lang/rust/pull/51425 made sure we saw all the namespaces of an import (and prevented us from losing the `vec!` macro in std's documentation), here is the PR to handle cross-crate macro re-exports at the same time as everything else. This way, attributes like `#[doc(hidden)]` and `#[doc(no_inline)]` can be used to control how the documentation for these macros is seen, rather than rustdoc inlining every macro every time.
Fixes https://github.com/rust-lang/rust/issues/50647
Reuse the `DefsUsesVisitor` in `simulate_block()`.
This avoids a bunch of allocations for the bitsets within it,
speeding up a number of NLL benchmarks, the best by 1%.
r? @nikomatsakis
Unpin references
I also considered adding an impl for raw pointers as well, but that makes it easy to accidentally have unsound owning-collections that might otherwise be able to project pinned-ness (e.g. `Box`).
cc @RalfJung
r? @withoutboats
Move self trait predicate to items
This is a "reimagination" of @tmandry's PR #50183. The main effect is described in this comment from one of the commits:
---
Before we had the following results for `predicates_of`:
```rust
trait Foo { // predicates_of: Self: Foo
fn bar(); // predicates_of: Self: Foo (inherited from trait)
}
```
Now we have removed the `Self: Foo` from the trait. However, we still
add it to the trait ITEM. This is because when people do things like
`<T as Foo>::bar()`, they still need to prove that `T: Foo`, and
having it in the `predicates_of` seems to be the cleanest way to
ensure that happens right now (otherwise, we'd need special case code
in various places):
```rust
trait Foo { // predicates_of: []
fn bar(); // predicates_of: Self: Foo
}
```
However, we sometimes want to get the list of *just* the predicates
truly defined on a trait item (e.g., for chalk, but also for a few
other bits of code). For that, we define `predicates_defined_on`,
which does not contain the `Self: Foo` predicate yet, and we plumb
that through metadata and so forth.
---
I'm assigning @eddyb as the main reviewer, but I thought I might delegate to scalexm for this one in any case. I also want to post an alternative that I'll leave in the comments; it occurred to me as I was writing. =)
r? @eddyb
cc @scalexm @tmandry @leodasvacas
This commit updates the stage0 build of tools to use the libraries of the stage0
compiler instead of the compiled libraries by the stage0 compiler. This should
enable us to avoid any stage0 hacks (like missing SIMD).
[NLL] Use better span for initializing a variable twice
Closes#51217
When assigning to a (projection from a) local immutable local which starts initialised (everything except `let PATTERN;`):
* Point to the declaration of that local
* Make the error message refer to the local, rather than the projection.
r? @nikomatsakis
introduce dirty list to dataflow
@nikomatsakis my naive implementation never worked, So, I decided to implement using `work_queue` data structure. This PR also includes your commits from `nll-liveness-dirty-list` branch. Those commits should not visible once your branch is merged.
r? @nikomatsakis
Benjamin Peterson