Rewrite Iterator::position default impl
Storing the accumulating value outside the fold in an attempt to improve code generation has shown speedups on various handwritten benchmarks, see discussion at #119551.
Avoid specialization in the metadata serialization code
With the exception of a perf-only specialization for byte slices and byte vectors.
This uses the same trick of introducing a new trait and having the Encodable and Decodable derives add a bound to it as used for TyEncoder/TyDecoder. The new code is clearer about which encoder/decoder uses which impl and it reduces the dependency of rustc on specialization, making it easier to remove support for specialization entirely or turn it into a construct that is only allowed for perf optimizations if we decide to do this.
Exhaustiveness: Statically enforce revealing of opaques
In https://github.com/rust-lang/rust/pull/116821 it was decided that exhaustiveness should operate on the hidden type of an opaque type when relevant. This PR makes sure we consistently reveal opaques within exhaustiveness. This makes it possible to remove `reveal_opaque_ty` from the `TypeCx` trait which was an unfortunate implementation detail.
r? `@compiler-errors`
Replace a number of FxHashMaps/Sets with stable-iteration-order alternatives
This PR replaces almost all of the remaining `FxHashMap`s in query results with either `FxIndexMap` or `UnordMap`. The only case that is missing is the `EffectiveVisibilities` struct which turned out to not be straightforward to transform. Once that is done too, we can remove the `HashStable` implementation from `HashMap`.
The first commit adds the `StableCompare` trait which is a companion trait to `StableOrd`. Some types like `Symbol` can be compared in a cross-session stable way, but their `Ord` implementation is not stable. In such cases, a `StableCompare` implementation can be provided to offer a lightweight way for stable sorting. The more heavyweight option is to sort via `ToStableHashKey`, but then sorting needs to have access to a stable hashing context and `ToStableHashKey` can also be expensive as in the case of `Symbol` where it has to allocate a `String`.
The rest of the commits are rather mechanical and don't overlap, so they are best reviewed individually.
Part of [MCP 533](https://github.com/rust-lang/compiler-team/issues/533).
Separate immediate and in-memory ScalarPair representation
Currently, we assume that ScalarPair is always represented using a two-element struct, both as an immediate value and when stored in memory.
This currently works fairly well, but runs into problems with https://github.com/rust-lang/rust/pull/116672, where a ScalarPair involving an i128 type can no longer be represented as a two-element struct in memory. For example, the tuple `(i32, i128)` needs to be represented in-memory as `{ i32, [3 x i32], i128 }` to satisfy alignment requirements. Using `{ i32, i128 }` instead will result in the second element being stored at the wrong offset (prior to LLVM 18).
Resolve this issue by no longer requiring that the immediate and in-memory type for ScalarPair are the same. The in-memory type will now look the same as for normal struct types (and will include padding filler and similar), while the immediate type stays a simple two-element struct type. This also means that booleans in immediate ScalarPair are now represented as i1 rather than i8, just like we do everywhere else.
The core change here is to llvm_type (which now treats ScalarPair as a normal struct) and immediate_llvm_type (which returns the two-element struct that llvm_type used to produce). The rest is fixing things up to no longer assume these are the same. In particular, this switches places that try to get pointers to the ScalarPair elements to use byte-geps instead of struct-geps.
internal: Only compare relevant parts in `ide::{runnables,inlay_hints}` tests
This PR limits the data being compared. Therefore the tests should be more readable, as well as being more robust to changes to the data structure.
Part of https://github.com/rust-lang/rust-analyzer/issues/14268.
internal: clean and enhance readability for `generate_delegate_trait`
Continue from #16112
This PR primarily involves some cleanup and simple refactoring work, including:
- Adding numerous comments to layer the code and explain the behavior of each step.
- Renaming some variables to make them more sensible.
- Simplify certain operations using a more elegant approach.
The goal is to make this intricate implementation clearer and facilitate future maintenance.
In addition to this, the PR also removes redundant `path_transform` operations for `type_gen_args`.
Taking the example of `impl Trait<T1> for S<S1>`, where `S1` is considered. The struct `S` must be in the file where the user triggers code actions, so there's no need for the `path_transform`. Furthermore, before performing the transform, we've already renamed `S1`, ensuring it won't clash with existing generics parameters. Therefore, there's no need to transform it.
internal: Speed up import searching some more
Pushes the sorting to the caller, meaning additional filtering can be done pre-sorting. Similarly a collect call was pushed to the caller for allowing some other filters to run pre-collecting.
Remove completion limit for trait importing method completions
Fixes https://github.com/rust-lang/rust-analyzer/issues/16075
The < 3 char limit never applied to methods and the amount of completions generated due this is not absolutely massive as not all traits in a project are ever applicable so there is little reason to employ the limit here. Especially as it limits the number of traits we consider, not items (after my changes yesterday), and the number of traits is not the slowing factor here. Tested this in r-a where we have ~800 traits project wide and even when ~260 are applicable there was no noticable slow down from it.
Further tuning of the Gentoo installation instructions.
Based on feedback from the Gentoo repository maintainer, addition of the possibility to install rust-analyzer via rustup.
