fix: deduplicate fields and types in completion
Fixes#15024
- `hir_ty::autoderef()` (which is only meant to be used outside `hir-ty`) now deduplicates types and completely resolves inference variables within.
- field completion now deduplicates fields of the same name and only picks such field of the first type in the deref chain.
Lower const params with a bad id
cc #7434
This PR adds an `InTypeConstId` which is a `DefWithBodyId` and lower const generic parameters into bodies using it, and evaluate them with the mir interpreter. I think this is the last unimplemented const generic feature relative to rustc stable.
But there is a problem: The id used in the `InTypeConstId` is the raw `FileAstId`, which changes frequently. So these ids and their bodies will be invalidated very frequently, which is bad for incremental analysis.
Due this problem, I disabled lowering for local crates (in library crate the id is stable since files won't be changed). This might be overreacting (const generic expressions are usually small, maybe it would be better enabled with bad performance than disabled) but it makes motivation for doing it in the correct way, and it splits the potential panic and breakages that usually comes with const generic PRs in two steps.
Other than the id, I think (at least I hope) other parts are in the right direction.
fix: implemeted lifetime transformation fot assits
A part of https://github.com/rust-lang/rust-analyzer/issues/13363
I expect to implement transformation of const params in a separate PR
Other assists and a completion affected:
- `generate_function` currently just ignores lifetimes and, consequently, is not affected
- `inline_call` and `replace_derive_with...` don't seem to need lifetime transformation
- `trait_impl` (a completion) is fixed and tested
MIR episode 5
This PR inits drop support (it is very broken at this stage, some things are dropped multiple time, drop scopes are wrong, ...) and adds stdout support (`println!` doesn't work since its expansion is dummy, but `stdout().write(b"hello world\n")` works if you use `RA_SYSROOT_HACK`) for interpreting. There is no useful unit test that it can interpret yet, but it is a good sign that it didn't hit a major road block yet.
In MIR lowering, it adds support for slice pattern and anonymous const blocks, and some fixes so that we can evaluate `SmolStr::new_inline` in const eval. With these changes, 57 failed mir body remains.
Introduce macro sub-namespaces and `macro_use` prelude
This PR implements two mechanisms needed for correct macro name resolution: macro sub-namespace and `macro_use` prelude.
- [macro sub-namespaces][subns-ref]
Macros have two sub-namespaces: one for function-like macro and the other for those in attributes (including custom derive macros). When we're resolving a macro name for function-like macro, we should ignore non-function-like macros, and vice versa.
This helps resolve single-segment macro names because we can (and should, as rustc does) fallback to names in preludes when the name in the current module scope is in different sub-namespace.
- [`macro_use` prelude][prelude-ref]
`#[macro_use]`'d extern crate declarations (including the standard library) bring their macros into scope, but they should not be prioritized over local macros (those defined in place and those explicitly imported).
We have been bringing them into legacy (textual) macro scope, which has the highest precedence in name resolution. This PR introduces the `macro_use` prelude in crate-level `DefMap`s, whose precedence is lower than local macros but higher than the standard library prelude.
The first 3 commits are drive-by fixes/refactors.
Fixes#8828 (prelude)
Fixes#12505 (prelude)
Fixes#12734 (prelude)
Fixes#13683 (prelude)
Fixes#13821 (prelude)
Fixes#13974 (prelude)
Fixes#14254 (namespace)
[subns-ref]: https://doc.rust-lang.org/reference/names/namespaces.html#sub-namespaces
[prelude-ref]: https://doc.rust-lang.org/reference/names/preludes.html#macro_use-prelude
