There are now two queries: crate and item. The crate one computes the
variance of all items in the crate; it is sort of an implementation
detail, and not meant to be used. The item one reads from the crate one,
synthesizing correct deps in lieu of the red-green algorithm.
At the same time, remove the `variance_computed` flag, which was a
horrible hack used to force invariance early on (e.g. when type-checking
constants). This is only needed because of trait applications, and
traits are always invariant anyway. Therefore, we now change to take
advantage of the query system:
- When asked to compute variances for a trait, just return a vector
saying 'all invariant'.
- Remove the corresponding "inferreds" from traits, and tweak the
constraint generation code to understand that traits are always
inferred.
This is a more principled version of the `RefCell` we were using
before. We now allocate a `Steal<Mir<'tcx>>` for each intermediate MIR
pass; when the next pass steals the entry, any later attempts to use it
will panic (there is no way to *test* if MIR is stolen, you're just
supposed to *know*).
The new setup is as follows. There is a pipeline of MIR passes that each
run **per def-id** to optimize a particular function. You are intended
to request MIR at whatever stage you need it. At the moment, there is
only one stage you can request:
- `optimized_mir(def_id)`
This yields the final product. Internally, it pulls the MIR for the
given def-id through a series of steps. Right now, these are still using
an "interned ref-cell" but they are intended to "steal" from one
another:
- `mir_build` -- performs the initial construction for local MIR
- `mir_pass_set` -- performs a suite of optimizations and transformations
- `mir_pass` -- an individual optimization within a suite
So, to construct the optimized MIR, we invoke:
mir_pass_set((MIR_OPTIMIZED, def_id))
which will build up the final MIR.
Overall goal: reduce the amount of context a mir pass needs so that it
resembles a query.
- The hooks are no longer "threaded down" to the pass, but rather run
automatically from the top-level (we also thread down the current pass
number, so that the files are sorted better).
- The hook now receives a *single* callback, rather than a callback per-MIR.
- The traits are no longer lifetime parameters, which moved to the
methods -- given that we required
`for<'tcx>` objecs, there wasn't much point to that.
- Several passes now store a `String` instead of a `&'l str` (again, no
point).
Removal pass for anonymous parameters
Removes occurences of anonymous parameters from the
rustc codebase, as they are to be deprecated.
See issue #41686 and RFC 1685.
r? @frewsxcv
Add a lint to disallow anonymous parameters
Adds a (allow by default) lint to disallow anonymous parameters, like it was decided in RFC 1685 (rust-lang/rfcs#1685).
cc tracking issue #41686
On demandify region mapping
This is an adaptation of @cramertj's PR. I am sort of tempted to keep simplifying it, but also tempted to land it so and we can refactor more in follow-up PRs. As is, it does the following things:
- makes the region-maps an on-demand query, per function `tcx.region_maps(def_id)`
- interns code extents instead of of having them be integers
- remove the "root region extent" and (to some extent) item extents; instead we use `Option<CodeExtent<'tcx>>` in a few places (no space inefficiency since `CodeExtent<'tcx>` is now a pointer).
I'm not entirely happy with the way I have it setup though. Here are some of the changes I was considering (I'm not sure if they would work out well):
1. Removing `item_extents` entirely -- they are rarely used now, because most of the relevant places now accept an `Option<Region<'tcx>>` or an `Option<CodeExtent<'tcx>>`, but I think still used in a few places.
2. Merging `RegionMaps` into the typeck tables, instead of having it be its own query.
3. Change `CodeExtent<'tcx>` to store the parent pointer. This would mean that fewer places in the code actually *need* a `RegionMaps` anyhow, since most of them just want to be able to walk "up the tree". On the other hand, you wouldn't be able to intern a `CodeExtent<'tcx>` for some random node-id, you'd need to look it up in the table (since there'd be more information).
Most of this code is semi-temporary -- I expect it to largely go away as we move to NLL -- so I'm also not *that* concerned with making it perfect.
r? @eddyb
Under MinGW, x.py fails to run with UnboundLocalError.
Under MinGW, `x.py` will fail with the following errors:
```bash
$ ./x.py
Traceback (most recent call last):
File "./x.py", line 20, in <module>
bootstrap.main()
File "C:/src/rust/src/bootstrap/bootstrap.py", line 620, in main
bootstrap()
File "C:/src/rust/src/bootstrap/bootstrap.py", line 601, in bootstrap
rb.build = rb.build_triple()
File "C:/src/rust/src/bootstrap/bootstrap.py", line 459, in build_triple
if os.environ.get('MSYSTEM') == 'MINGW64':
UnboundLocalError: local variable 'os' referenced before assignment
```
The reason is due to the `build_triple` function in `src/bootstrap/bootstrap.py` (Line 416):
```python
if ostype == 'Linux':
os = subprocess.check_output(['uname', '-o']).strip().decode(default_encoding)
```
Here, the assignment to `os` is causing the `os` module to be shadowed.
Then, in (Line 459):
```python
if os.environ.get('MSYSTEM') == 'MINGW64':
cputype = 'x86_64'
```
`os` now refers to the uninitialized local variable, not the `os` module.
Easiest fix is to simply rename the `os` variable to something like `os_from_sp`.
Also, there is a small typo fix in `x.py` referencing the wrong file name.
Clean up callable type mismatch errors
```rust
error[E0593]: closure takes 1 argument but 2 arguments are required here
--> ../../src/test/ui/mismatched_types/closure-arg-count.rs:13:15
|
13 | [1, 2, 3].sort_by(|(tuple, tuple2)| panic!());
| ^^^^^^^ -------------------------- takes 1 argument
| |
| expected closure that takes 2 arguments
```
instead of
```rust
error[E0281]: type mismatch: the type `[closure@../../src/test/ui/mismatched_types/closure-arg-count.rs:13:23: 13:49]` implements the trait `for<'r> std::ops::FnMut<(&'r {integer},)>`, but the trait `for<'r, 'r> std::ops::FnMut<(&'r {integer}, &'r {integer})>` is required (expected a tuple with 2 elements, found one with 1 elements)
--> ../../src/test/ui/mismatched_types/closure-arg-count.rs:13:15
|
13 | [1, 2, 3].sort_by(|(tuple, tuple2)| panic!());
| ^^^^^^^
```
Fix#21857, re #24680.
