compiler: Rename several types/traits for per-query vtables by Zalathar · Pull Request #151666 · rust-lang/rust

Zalathar · 2026-01-26T02:44:57Z

Follow-up to Rename DepKindStruct to DepKindVTable #151577

This is another round of renaming for some subtle types and traits used by the query system, to hopefully make them easier to understand.

Key renames:

struct DynamicQuery → QueryVTable (the actual vtable-like structure)
struct DynamicQueries → PerQueryVTables (holds a vtable for each query)
trait QueryConfig → QueryDispatcher
- (used by generic functions in rustc_query_system to interact with query vtables)
struct DynamicConfig → SemiDynamicQueryDispatcher
- (implements QueryDispatcher by combining a vtable with some compile-time boolean flags for improved perf)
trait QueryConfigRestored → UnerasedQueryDispatcher
- (provides a QueryDispatcher while also remembering the query's unerased value type; allows some per-query code to be moved out of macros and into generic functions)

This was trickier than DepKindVTable, because there are more types and traits involved, and it's harder to come up with distinctive and useful names for all of them.

There should be no change to compiler behaviour.

r? Kivooeo (or compiler)

Zalathar · 2026-01-27T03:02:07Z

As a follow-up PR, I might try getting rid of QueryConfigRestored/QueryDispatcherUnerased entirely, and just passing a dispatcher plus an unerase function.

That would sidestep the need to name and document the trait.

EDIT: This turns out to be a bit tricky; I would want to land a few other simplifications before trying again.

rustbot · 2026-01-27T11:02:33Z

This PR was rebased onto a different main commit. Here's a range-diff highlighting what actually changed.

Rebasing is a normal part of keeping PRs up to date, so no action is needed—this note is just to help reviewers.

Kivooeo

looks good, thanks!

View changes since this review

Kivooeo · 2026-01-27T17:40:45Z

@bors r+ rollup

rust-bors · 2026-01-27T17:40:48Z

📌 Commit 2c9175d has been approved by Kivooeo

It is now in the queue for this repository.

compiler: Rename several types/traits for per-query vtables - Follow-up to rust-lang#151577 --- This is another round of renaming for some subtle types and traits used by the query system, to hopefully make them easier to understand. Key renames: - struct `DynamicQuery` → `QueryVTable` (the actual vtable-like structure) - struct `DynamicQueries` → `PerQueryVTables` (holds a vtable for each query) - trait `QueryConfig` → `QueryDispatcher` - (used by generic functions in `rustc_query_system` to interact with query vtables) - struct `DynamicConfig` → `SemiDynamicQueryDispatcher` - (implements `QueryDispatcher` by combining a vtable with some compile-time boolean flags for improved perf) - trait `QueryConfigRestored` → `UnerasedQueryDispatcher` - (provides a `QueryDispatcher` while also remembering the query's unerased value type; allows some per-query code to be moved out of macros and into generic functions) This was trickier than `DepKindVTable`, because there are more types and traits involved, and it's harder to come up with distinctive and useful names for all of them. There should be no change to compiler behaviour. r? Kivooeo (or compiler)

Rollup of 6 pull requests Successful merges: - #151751 (`rust-analyzer` subtree update) - #150893 (offload: move (un)register lib into global_ctors) - #151013 (Add some clarifications and fixes for fmt syntax) - #151666 (compiler: Rename several types/traits for per-query vtables) - #151738 (Add `extern crate core` to diagnostic tests) - #151759 (Update `browser-ui-test` version to `0.23.3`)

compiler: Rename several types/traits for per-query vtables - Follow-up to rust-lang#151577 --- This is another round of renaming for some subtle types and traits used by the query system, to hopefully make them easier to understand. Key renames: - struct `DynamicQuery` → `QueryVTable` (the actual vtable-like structure) - struct `DynamicQueries` → `PerQueryVTables` (holds a vtable for each query) - trait `QueryConfig` → `QueryDispatcher` - (used by generic functions in `rustc_query_system` to interact with query vtables) - struct `DynamicConfig` → `SemiDynamicQueryDispatcher` - (implements `QueryDispatcher` by combining a vtable with some compile-time boolean flags for improved perf) - trait `QueryConfigRestored` → `UnerasedQueryDispatcher` - (provides a `QueryDispatcher` while also remembering the query's unerased value type; allows some per-query code to be moved out of macros and into generic functions) This was trickier than `DepKindVTable`, because there are more types and traits involved, and it's harder to come up with distinctive and useful names for all of them. There should be no change to compiler behaviour. r? Kivooeo (or compiler)

Rollup of 6 pull requests Successful merges: - #150893 (offload: move (un)register lib into global_ctors) - #151013 (Add some clarifications and fixes for fmt syntax) - #151449 ([rustdoc] Add regression test for #151411) - #151666 (compiler: Rename several types/traits for per-query vtables) - #151738 (Add `extern crate core` to diagnostic tests) - #151759 (Update `browser-ui-test` version to `0.23.3`)

compiler: Rename several types/traits for per-query vtables - Follow-up to rust-lang#151577 --- This is another round of renaming for some subtle types and traits used by the query system, to hopefully make them easier to understand. Key renames: - struct `DynamicQuery` → `QueryVTable` (the actual vtable-like structure) - struct `DynamicQueries` → `PerQueryVTables` (holds a vtable for each query) - trait `QueryConfig` → `QueryDispatcher` - (used by generic functions in `rustc_query_system` to interact with query vtables) - struct `DynamicConfig` → `SemiDynamicQueryDispatcher` - (implements `QueryDispatcher` by combining a vtable with some compile-time boolean flags for improved perf) - trait `QueryConfigRestored` → `UnerasedQueryDispatcher` - (provides a `QueryDispatcher` while also remembering the query's unerased value type; allows some per-query code to be moved out of macros and into generic functions) This was trickier than `DepKindVTable`, because there are more types and traits involved, and it's harder to come up with distinctive and useful names for all of them. There should be no change to compiler behaviour. r? Kivooeo (or compiler)

Rollup of 6 pull requests Successful merges: - #150893 (offload: move (un)register lib into global_ctors) - #151013 (Add some clarifications and fixes for fmt syntax) - #151449 ([rustdoc] Add regression test for #151411) - #151666 (compiler: Rename several types/traits for per-query vtables) - #151738 (Add `extern crate core` to diagnostic tests) - #151759 (Update `browser-ui-test` version to `0.23.3`)

Rollup of 9 pull requests Successful merges: - #151239 (Support trait objects in type info reflection) - #150893 (offload: move (un)register lib into global_ctors) - #151013 (Add some clarifications and fixes for fmt syntax) - #151666 (compiler: Rename several types/traits for per-query vtables) - #151738 (Add `extern crate core` to diagnostic tests) - #151747 (Update `askama` version to `0.15.2`) - #151759 (Update `browser-ui-test` version to `0.23.3`) - #151763 (Add FileCheck annotations to simplify_match.rs) - #151766 (Fix `x fix`, again)

Rollup merge of #151666 - Zalathar:query-vtable, r=Kivooeo compiler: Rename several types/traits for per-query vtables - Follow-up to #151577 --- This is another round of renaming for some subtle types and traits used by the query system, to hopefully make them easier to understand. Key renames: - struct `DynamicQuery` → `QueryVTable` (the actual vtable-like structure) - struct `DynamicQueries` → `PerQueryVTables` (holds a vtable for each query) - trait `QueryConfig` → `QueryDispatcher` - (used by generic functions in `rustc_query_system` to interact with query vtables) - struct `DynamicConfig` → `SemiDynamicQueryDispatcher` - (implements `QueryDispatcher` by combining a vtable with some compile-time boolean flags for improved perf) - trait `QueryConfigRestored` → `UnerasedQueryDispatcher` - (provides a `QueryDispatcher` while also remembering the query's unerased value type; allows some per-query code to be moved out of macros and into generic functions) This was trickier than `DepKindVTable`, because there are more types and traits involved, and it's harder to come up with distinctive and useful names for all of them. There should be no change to compiler behaviour. r? Kivooeo (or compiler)

rustbot assigned Kivooeo Jan 26, 2026

Zalathar force-pushed the query-vtable branch from 4f1952f to b0532b2 Compare January 27, 2026 03:02

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Zalathar mentioned this pull request Jan 27, 2026

[EXPERIMENT] Reduce short-backtrace overhead in some query plumbing call stacks #151719

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Zalathar added 2 commits January 27, 2026 21:57

Rename DynamicQuery to QueryVTable

89d7695

Rename trait QueryConfig to QueryDispatcher

2c9175d

Zalathar force-pushed the query-vtable branch from b0532b2 to 2c9175d Compare January 27, 2026 11:02

Kivooeo approved these changes Jan 27, 2026

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rust-bors bot added S-waiting-on-bors Status: Waiting on bors to run and complete tests. Bors will change the label on completion. and removed S-waiting-on-review Status: Awaiting review from the assignee but also interested parties. labels Jan 27, 2026

matthiaskrgr mentioned this pull request Jan 27, 2026

Rollup of 6 pull requests #151762

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matthiaskrgr mentioned this pull request Jan 27, 2026

Rollup of 6 pull requests #151765

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GuillaumeGomez mentioned this pull request Jan 27, 2026

Rollup of 6 pull requests #151767

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This was referenced Jan 28, 2026

Make some load-from-disk function pointers optional in query vtables #151736

Merged

Rollup of 9 pull requests #151778

Merged

Reduce generics use in the query system. #151777

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rust-bors bot merged commit 384a569 into rust-lang:main Jan 28, 2026
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rustbot added this to the 1.95.0 milestone Jan 28, 2026

Zalathar deleted the query-vtable branch January 28, 2026 22:36

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compiler: Rename several types/traits for per-query vtables#151666

compiler: Rename several types/traits for per-query vtables#151666
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