[susitsm]

Adds DenseMap, DenseMapRef and DenseKey as alternatives for IndexVec, IndexSlice and Idx and replaces Idx with DensKey for SyntaxContext, LocalExpnId, LocalDefId, OwnerId

Motivation: IndexVec allows iteration, which should not be allowed for some index types, as it can result in nondeterminism.

[susitsm]

@aerooneqq this surfaced 2 places (1, 2), I think mostly for debugging output, where iteration order should be considered for LocalExpnId and SyntaxContext. Do you have an easy fix?

[rust-log-analyzer]

The job test-aarch64-gnu-llvm-22-2 failed! Check out the build log: (web) (plain enhanced) (plain)

Click to see the possible cause of the failure (guessed by this bot)

    |
note: required by a bound in `vec_cache::VecCache`
   --> compiler/rustc_data_structures/src/vec_cache.rs:225:24
    |
225 | pub struct VecCache<K: DenseKey, V, I> {
    |                        ^^^^^^^^ required by this bound in `VecCache`

error[E0599]: the method `lookup` exists for struct `vec_cache::VecCache<u32, u32, u32>`, but its trait bounds were not satisfied
   --> compiler/rustc_data_structures/src/vec_cache/tests.rs:44:23
    |
 44 |         assert!(cache.lookup(&key).is_none());
    |                       ^^^^^^ method cannot be called on `vec_cache::VecCache<u32, u32, u32>` due to unsatisfied trait bounds
    |
   ::: compiler/rustc_data_structures/src/vec_cache.rs:225:1
    |
225 | pub struct VecCache<K: DenseKey, V, I> {
    | -------------------------------------- method `lookup` not found for this struct
    |
note: trait bound `u32: DenseKey` was not satisfied
   --> compiler/rustc_data_structures/src/vec_cache.rs:307:13
    |
305 | impl<K, V, I> VecCache<K, V, I>
    |               -----------------
306 | where
307 |     K: Eq + DenseKey + Copy + Debug,
    |             ^^^^^^^^ unsatisfied trait bound introduced here

error[E0277]: the trait bound `u32: DenseKey` is not satisfied
   --> compiler/rustc_data_structures/src/vec_cache/tests.rs:50:16
    |
 50 |     let cache: VecCache<u32, u32, u32> = VecCache::default();
    |                ^^^^^^^^^^^^^^^^^^^^^^^ the trait `DenseKey` is not implemented for `u32`
    |
note: required by a bound in `vec_cache::VecCache`
   --> compiler/rustc_data_structures/src/vec_cache.rs:225:24
    |
225 | pub struct VecCache<K: DenseKey, V, I> {
    |                        ^^^^^^^^ required by this bound in `VecCache`

error[E0599]: the method `complete` exists for struct `vec_cache::VecCache<u32, u32, u32>`, but its trait bounds were not satisfied
   --> compiler/rustc_data_structures/src/vec_cache/tests.rs:51:11
    |
 51 |     cache.complete(0, 1, 2);
    |           ^^^^^^^^ method cannot be called on `vec_cache::VecCache<u32, u32, u32>` due to unsatisfied trait bounds
    |
   ::: compiler/rustc_data_structures/src/vec_cache.rs:225:1
    |
225 | pub struct VecCache<K: DenseKey, V, I> {
    | -------------------------------------- method `complete` not found for this struct
    |
note: trait bound `u32: DenseKey` was not satisfied
   --> compiler/rustc_data_structures/src/vec_cache.rs:307:13
    |
305 | impl<K, V, I> VecCache<K, V, I>
    |               -----------------
306 | where
307 |     K: Eq + DenseKey + Copy + Debug,
    |             ^^^^^^^^ unsatisfied trait bound introduced here

error[E0599]: the method `lookup` exists for struct `vec_cache::VecCache<u32, u32, u32>`, but its trait bounds were not satisfied
   --> compiler/rustc_data_structures/src/vec_cache/tests.rs:52:22
    |
 52 |     assert_eq!(cache.lookup(&0), Some((1, 2)));
    |                      ^^^^^^ method cannot be called on `vec_cache::VecCache<u32, u32, u32>` due to unsatisfied trait bounds
    |
   ::: compiler/rustc_data_structures/src/vec_cache.rs:225:1
    |
225 | pub struct VecCache<K: DenseKey, V, I> {
    | -------------------------------------- method `lookup` not found for this struct
    |
note: trait bound `u32: DenseKey` was not satisfied
   --> compiler/rustc_data_structures/src/vec_cache.rs:307:13
    |
305 | impl<K, V, I> VecCache<K, V, I>
    |               -----------------
306 | where
307 |     K: Eq + DenseKey + Copy + Debug,
    |             ^^^^^^^^ unsatisfied trait bound introduced here

error[E0277]: the trait bound `u32: DenseKey` is not satisfied
   --> compiler/rustc_data_structures/src/vec_cache/tests.rs:57:16
    |
 57 |     let cache: VecCache<u32, u8, u32> = VecCache::default();
    |                ^^^^^^^^^^^^^^^^^^^^^^ the trait `DenseKey` is not implemented for `u32`
    |
note: required by a bound in `vec_cache::VecCache`
   --> compiler/rustc_data_structures/src/vec_cache.rs:225:24
    |
225 | pub struct VecCache<K: DenseKey, V, I> {
    |                        ^^^^^^^^ required by this bound in `VecCache`

error[E0599]: the method `complete` exists for struct `vec_cache::VecCache<u32, u8, u32>`, but its trait bounds were not satisfied
   --> compiler/rustc_data_structures/src/vec_cache/tests.rs:73:15
    |
 73 |         cache.complete(key, shift, key);
    |               ^^^^^^^^ method cannot be called on `vec_cache::VecCache<u32, u8, u32>` due to unsatisfied trait bounds
    |
   ::: compiler/rustc_data_structures/src/vec_cache.rs:225:1
    |
225 | pub struct VecCache<K: DenseKey, V, I> {
    | -------------------------------------- method `complete` not found for this struct
    |
note: trait bound `u32: DenseKey` was not satisfied
   --> compiler/rustc_data_structures/src/vec_cache.rs:307:13
    |
305 | impl<K, V, I> VecCache<K, V, I>
    |               -----------------
306 | where
307 |     K: Eq + DenseKey + Copy + Debug,
    |             ^^^^^^^^ unsatisfied trait bound introduced here

error[E0599]: the method `lookup` exists for struct `vec_cache::VecCache<u32, u8, u32>`, but its trait bounds were not satisfied
   --> compiler/rustc_data_structures/src/vec_cache/tests.rs:74:26
    |
 74 |         assert_eq!(cache.lookup(&key), Some((shift, key)));
    |                          ^^^^^^ method cannot be called on `vec_cache::VecCache<u32, u8, u32>` due to unsatisfied trait bounds
    |
   ::: compiler/rustc_data_structures/src/vec_cache.rs:225:1
    |
225 | pub struct VecCache<K: DenseKey, V, I> {
    | -------------------------------------- method `lookup` not found for this struct
    |
note: trait bound `u32: DenseKey` was not satisfied
   --> compiler/rustc_data_structures/src/vec_cache.rs:307:13
    |
305 | impl<K, V, I> VecCache<K, V, I>
    |               -----------------
306 | where
307 |     K: Eq + DenseKey + Copy + Debug,
    |             ^^^^^^^^ unsatisfied trait bound introduced here

error[E0277]: the trait bound `u32: DenseKey` is not satisfied
   --> compiler/rustc_data_structures/src/vec_cache/tests.rs:80:16
    |
 80 |     let cache: VecCache<u32, u32, u32> = VecCache::default();
    |                ^^^^^^^^^^^^^^^^^^^^^^^ the trait `DenseKey` is not implemented for `u32`
    |
note: required by a bound in `vec_cache::VecCache`
   --> compiler/rustc_data_structures/src/vec_cache.rs:225:24
    |
225 | pub struct VecCache<K: DenseKey, V, I> {
    |                        ^^^^^^^^ required by this bound in `VecCache`

error[E0599]: the method `complete` exists for reference `&vec_cache::VecCache<u32, u32, u32>`, but its trait bounds were not satisfied
   --> compiler/rustc_data_structures/src/vec_cache/tests.rs:85:23
    |
 85 |                 cache.complete(idx, idx, idx);
    |                       ^^^^^^^^ method cannot be called on `&vec_cache::VecCache<u32, u32, u32>` due to unsatisfied trait bounds
    |
note: trait bound `u32: DenseKey` was not satisfied
   --> compiler/rustc_data_structures/src/vec_cache.rs:307:13
    |
305 | impl<K, V, I> VecCache<K, V, I>
    |               -----------------
306 | where
307 |     K: Eq + DenseKey + Copy + Debug,
    |             ^^^^^^^^ unsatisfied trait bound introduced here

error[E0599]: the method `lookup` exists for struct `vec_cache::VecCache<u32, u32, u32>`, but its trait bounds were not satisfied
   --> compiler/rustc_data_structures/src/vec_cache/tests.rs:91:26
    |
 91 |         assert_eq!(cache.lookup(&idx), Some((idx, idx)));
    |                          ^^^^^^ method cannot be called on `vec_cache::VecCache<u32, u32, u32>` due to unsatisfied trait bounds
    |
   ::: compiler/rustc_data_structures/src/vec_cache.rs:225:1
    |
225 | pub struct VecCache<K: DenseKey, V, I> {
    | -------------------------------------- method `lookup` not found for this struct
    |
note: trait bound `u32: DenseKey` was not satisfied
   --> compiler/rustc_data_structures/src/vec_cache.rs:307:13
    |
305 | impl<K, V, I> VecCache<K, V, I>
    |               -----------------
306 | where
307 |     K: Eq + DenseKey + Copy + Debug,
    |             ^^^^^^^^ unsatisfied trait bound introduced here

Some errors have detailed explanations: E0277, E0599.
For more information about an error, try `rustc --explain E0277`.
[RUSTC-TIMING] rustc_data_structures test:true 3.810

[aerooneqq]

Do you have an easy fix?

Sort by stable hashes maybe? Recently we merged (#163668) the remapping for syntax contexts and local expansions which sorts them by stable hash, as this is used in pretty print only this sort should not cause perf troubles.

[rust-bors]

☔ The latest upstream changes (presumably #164757) made this pull request unmergeable. Please resolve the merge conflicts by rebasing.