We have four macros for generating trivial traversal (fold/visit) and
lift impls.
- `rustc_ir::TrivialTypeTraversalImpls`
- `rustc_middle::TrivialTypeTraversalImpls`
- `rustc_middle::TrivialLiftImpls`
- `rustc_middle::TrivialTypeTraversalAndLiftImpls`
The first two are very similar. The last one just combines the second
and third one.
The macros themselves are ok, but their use is a mess. This commit does
the following.
- Removes types that no longer need a lift and/or traversal impl from
the macro calls.
- Consolidates the macro calls into the smallest number of calls
possible, with each one mentioning as many types as possible.
- Orders the types within those macro calls alphabetically, and makes
the module qualification more consistent.
- Eliminates `rustc_middle::mir::type_foldable`, because the macro calls
were merged and the manual `TypeFoldable` impls are better placed in
`structural_impls.rs`, alongside all the other ones.
This makes the code more concise. Moving forward, it also makes it more
obvious where new types should be added.
From `rustc_middle::infer` to `rustc_infer::infer`. Because everything
in it is only used within `rustc_infer`, and no longer needs to be
`pub`. Plus it's always good to make the huge `rustc_middle` crate
smaller.
This doesn't change behavior.
It should prevent unintentional resolution of inference variables
during canonicalization, which previously caused a soundness bug.
See PR description for more.
ParamEnv is canonicalized in *queries input* rather than query response.
In such case we don't "preserve universes" of canonical variable.
This means that `universe_map` always has the default value, which is
wasteful to store in the cache.
The `Debug` impl for `Ty` just calls the `Display` impl for `Ty`. This
is surprising and annoying. In particular, it means `Debug` doesn't show
as much information as `Debug` for `TyKind` does. And `Debug` is used in
some user-facing error messages, which seems bad.
This commit changes the `Debug` impl for `Ty` to call the `Debug` impl
for `TyKind`. It also does a number of follow-up changes to preserve
existing output, many of which involve inserting
`with_no_trimmed_paths!` calls. It also adds `Display` impls for
`UserType` and `Canonical`.
Some tests have changes to expected output:
- Those that use the `rustc_abi(debug)` attribute.
- Those that use the `EMIT_MIR` annotation.
In each case the output is slightly uglier than before. This isn't
ideal, but it's pretty weird (particularly for the attribute) that the
output is using `Debug` in the first place. They're fairly obscure
attributes (I hadn't heard of them) so I'm not worried by this.
For `async-is-unwindsafe.stderr`, there is one line that now lacks a
full path. This is a consistency improvement, because all the other
mentions of `Context` in this test lack a path.
