The first PR for https://github.com/rust-lang/compiler-team/issues/606
This is just the move-and-rename, because it's plenty big-and-bitrotty already. Future PRs will start using `FieldIdx` more broadly, and concomitantly removing `FieldIdx::new`s.
Do not implement HashStable for HashSet (MCP 533)
This PR removes all occurrences of `HashSet` in query results, replacing it either with `FxIndexSet` or with `UnordSet`, and then removes the `HashStable` implementation of `HashSet`. This is part of implementing [MCP 533](https://github.com/rust-lang/compiler-team/issues/533), that is, removing the `HashStable` implementations of all collection types with unstable iteration order.
The changes are mostly mechanical. The only place where additional sorting is happening is in Miri's override implementation of the `exported_symbols` query.
rustc_middle: Remove trait `DefIdTree`
This trait was a way to generalize over both `TyCtxt` and `Resolver`, but now `Resolver` has access to `TyCtxt`, so this trait is no longer necessary.
(This is a large commit. The changes to
`compiler/rustc_middle/src/ty/context.rs` are the most important ones.)
The current naming scheme is a mess, with a mix of `_intern_`, `intern_`
and `mk_` prefixes, with little consistency. In particular, in many
cases it's easy to use an iterator interner when a (preferable) slice
interner is available.
The guiding principles of the new naming system:
- No `_intern_` prefixes.
- The `intern_` prefix is for internal operations.
- The `mk_` prefix is for external operations.
- For cases where there is a slice interner and an iterator interner,
the former is `mk_foo` and the latter is `mk_foo_from_iter`.
Also, `slice_interners!` and `direct_interners!` can now be `pub` or
non-`pub`, which helps enforce the internal/external operations
division.
It's not perfect, but I think it's a clear improvement.
The following lists show everything that was renamed.
slice_interners
- const_list
- mk_const_list -> mk_const_list_from_iter
- intern_const_list -> mk_const_list
- substs
- mk_substs -> mk_substs_from_iter
- intern_substs -> mk_substs
- check_substs -> check_and_mk_substs (this is a weird one)
- canonical_var_infos
- intern_canonical_var_infos -> mk_canonical_var_infos
- poly_existential_predicates
- mk_poly_existential_predicates -> mk_poly_existential_predicates_from_iter
- intern_poly_existential_predicates -> mk_poly_existential_predicates
- _intern_poly_existential_predicates -> intern_poly_existential_predicates
- predicates
- mk_predicates -> mk_predicates_from_iter
- intern_predicates -> mk_predicates
- _intern_predicates -> intern_predicates
- projs
- intern_projs -> mk_projs
- place_elems
- mk_place_elems -> mk_place_elems_from_iter
- intern_place_elems -> mk_place_elems
- bound_variable_kinds
- mk_bound_variable_kinds -> mk_bound_variable_kinds_from_iter
- intern_bound_variable_kinds -> mk_bound_variable_kinds
direct_interners
- region
- intern_region (unchanged)
- const
- mk_const_internal -> intern_const
- const_allocation
- intern_const_alloc -> mk_const_alloc
- layout
- intern_layout -> mk_layout
- adt_def
- intern_adt_def -> mk_adt_def_from_data (unusual case, hard to avoid)
- alloc_adt_def(!) -> mk_adt_def
- external_constraints
- intern_external_constraints -> mk_external_constraints
Other
- type_list
- mk_type_list -> mk_type_list_from_iter
- intern_type_list -> mk_type_list
- tup
- mk_tup -> mk_tup_from_iter
- intern_tup -> mk_tup
All the slice interners have a wrapper that handles the empty slice
case. We can instead handle this in the `slice_interners!` macro,
avoiding the need for most of the wrappers, and allowing the interner
functions to be renamed from `_intern_foos` to `intern_foos`.
The two exceptions:
- intern_predicates: I kept this wrapper because there's a FIXME
comment about a possible future change.
- intern_poly_existential_predicates: I kept this wrapper because it
asserts that the slice is empty and sorted.
Use `tcx.ty_error_with_guaranteed` in more places, rename variants
1. Use `ty_error_with_guaranteed` more so we don't delay so many span bugs
2. Rename `ty_error_with_guaranteed` to `ty_error`, `ty_error` to `ty_error_misc`. This is to incentivize using the former over the latter in cases where we already are witness to a `ErrorGuaranteed` token.
Second commit is just name replacement, so the first commit can be reviewed on its own with more scrutiny.
Use associated type bounds in some places in the compiler
Use associated type bounds for some nested `impl Trait<Assoc = impl Trait2>` cases. I'm generally keen to introduce new lang features that are more mature into the compiler, but maybe let's see what others think?
Side-note: I was surprised that the only use-cases of nested impl trait in the compiler are just iterator related?!
Use a lock-free datastructure for source_span
follow up to the perf regression in https://github.com/rust-lang/rust/pull/105462
The main regression is likely the CStore, but let's evaluate the perf impact of this on its own
Add rpitit queries
This is part of the changes we are making to lower RPITITs as an associated type. The rest of the stuff will follow under a `-Z` flag.
I still need to add comments to the code, explain stuff and also I'd need to avoid encoding in metadata when rpitit queries return `&[]`
r? `@compiler-errors`
There are two traits, `InternAs` and `InternIteratorElement`. I found
them confusing to use, particularly this:
```
pub fn mk_tup<I: InternAs<Ty<'tcx>, Ty<'tcx>>>(self, iter: I) -> I::Output {
iter.intern_with(|ts| self.intern_tup(ts))
}
```
where I thought there might have been two levels of interning going on
(there isn't) due to the `intern_with`/`InternAs` + `intern_tup` naming.
And then I found the actual traits and impls themselves *very*
confusing.
- `InternAs` has a single impl, for iterators, with four type variables.
- `InternAs` is only implemented for iterators because it wouldn't
really make sense to implement for any other type. And you can't
really understand the trait without seeing that single impl, which is
suspicious.
- `InternAs` is basically just a wrapper for `InternIteratorElement`
which does all the actual work.
- Neither trait actually does any interning. They just have `Intern` in
their name because they are used *by* interning code.
- There are no comments.
So this commit improves things.
- It removes `InternAs` completely. This makes the `mk_*` function
signatures slightly more verbose -- two trait bounds instead of one --
but much easier to read, because you only need to understand one trait
instead of two.
- It renames `InternIteratorElement` as `CollectAndApply`. Likewise, it
renames its method `intern_with` as `collect_and_apply`. These names
describe better what's going on: we collect the iterator elements into
a slice and then apply a function to the slice.
- It adds comments, making clear that all this is all there just to
provide an optimized version of `f(&iter.collect::<Vec<_>>())`.
It took me a couple of attempts to come up with this commit. My initial
attempt kept `InternAs` around, but renamed things and added comments,
and I wasn't happy with it. I think this version is much better. The
resulting code is shorter, despite the addition of the comments.
`InternIteratorElement` is a trait used to intern values produces by
iterators. There are three impls, corresponding to iterators that
produce different types:
- One for `T`, which operates straightforwardly.
- One for `Result<T, E>`, which is fallible, and will fail early with an
error result if any of the iterator elements are errors.
- One for `&'a T`, which clones the items as it iterates.
That last one is bad: it's extremely easy to use it without realizing
that it clones, which goes against Rust's normal "explicit is better"
approach to cloning.
So this commit just removes it. In practice, there weren't many use
sites. For all but one of them `into_iter()` could be used, which avoids
the need for cloning. And for the one remaining case `copied()` is
used.
There are several `mk_foo`/`intern_foo` pairs, where the former takes an
iterator and the latter takes a slice. (This naming convention is bad,
but that's a fix for another PR.)
This commit changes several `mk_foo` occurrences into `intern_foo`,
avoiding the need for some `.iter()`/`.into_iter()` calls. Affected
cases:
- mk_type_list
- mk_tup
- mk_substs
- mk_const_list
Switch to `EarlyBinder` for `type_of` query
Part of the work to finish #105779 and implement https://github.com/rust-lang/types-team/issues/78.
Several queries `X` have a `bound_X` variant that wraps the output in `EarlyBinder`. This adds `EarlyBinder` to the return type of the `type_of` query and removes `bound_type_of`.
r? `@lcnr`
