[benchamrk] Remove DispatchRule

[hildebrandmw]

Remove the module diskann_benchmark_runner::dispatcher and all its associated items except for MatchScore and FailureScore, which get moved to diskann_benchmark_runner::benchmark.

The current users of DispatchRule are almost universally focused on matching against DataType. This PR introduces a much simpler AsDataType trait as a replacement, removing the need for the Type auxiliary struct altogether.

PR #865 changed how benchmark matching worked and rendered DispatchRule obsolete, this continues that clean up in an effort to make the benchmark API friendlier.

Suggested Review Order

• diskann_benchmark_runner:
  • src/benchmark.rs: New home for MatchScore/FailureScore.
  • src/utils/datatype.rs: New AsDataType trait for matching against the DataType enum. Importantly, matching only returns true/false, not a MatchScore or FailureScore. This moves the ranking of matches to the caller rather than baking it in internally.
  • src/any.rs: Remove DispatchRule related inherent methods of Any as these are not longer useful. The type-erasure infrastructure in benchmark.rs has been responsible for proper downcasting and reporting since Cleanup diskann-benchmark-runner and friends. #865.
• diskann_benchmark:
  • src/utils/mod.rs: Since type-based matching is now the caller's responsibility, a small match_data_type helper is added to replace the current uses of Type<T>: DispatchRule<DataType>.
  • Everything Else: Adapting type level assignment to AsDataType.
• diskann_benchmark_simd: Mainly updating to AsDataType. Architecture dispatch gets a similar treatment to AsDataType, which is simpler now that AsArch is a local trait allowing us to skip the Identity new-type wrapper.

[Copilot]

Pull request overview

This PR removes the obsolete diskann_benchmark_runner::dispatcher module and replaces most type-matching usage with a simpler AsDataType trait, while relocating MatchScore/FailureScore into diskann_benchmark_runner::benchmark and updating downstream crates accordingly. It continues the cleanup started in PR #865 to make benchmark matching and diagnostics simpler and more caller-driven.

Changes:

• Remove dispatcher / DispatchRule infrastructure and migrate MatchScore/FailureScore into benchmark.
• Introduce AsDataType (+ Describe) for boolean type matching and human-readable mismatch descriptions.
• Update diskann-benchmark and diskann-benchmark-simd to use AsDataType (and a new local AsArch in SIMD) instead of dispatch rules.

Reviewed changes

Copilot reviewed 20 out of 20 changed files in this pull request and generated 3 comments.

Show a summary per file

File	Description
diskann-benchmark/src/utils/mod.rs	Adds match_data_type helper; updates imports to new benchmark::{MatchScore, FailureScore} path.
diskann-benchmark/src/backend/index/spherical.rs	Replaces DispatchRule/Type<T> matching with AsDataType::is_match checks.
diskann-benchmark/src/backend/index/scalar.rs	Migrates type matching + description formatting to AsDataType constants/descriptions.
diskann-benchmark/src/backend/index/product.rs	Uses utils::match_data_type and AsDataType::describe for matching/diagnostics.
diskann-benchmark/src/backend/index/benchmarks.rs	Updates full-precision benchmarks to new data type matching + description logic.
diskann-benchmark/src/backend/filters/benchmark.rs	Updates imports to use benchmark::{MatchScore, FailureScore}.
diskann-benchmark/src/backend/exhaustive/spherical.rs	Updates imports to use benchmark::{MatchScore, FailureScore}.
diskann-benchmark/src/backend/exhaustive/product.rs	Updates imports to use benchmark::{MatchScore, FailureScore}.
diskann-benchmark/src/backend/exhaustive/minmax.rs	Updates imports to use benchmark::{MatchScore, FailureScore}.
diskann-benchmark/src/backend/disk_index/benchmarks.rs	Replaces Type<T>: DispatchRule<DataType> constraints with T: AsDataType and new matching/description logic.
diskann-benchmark-simd/src/lib.rs	Replaces DispatchRule for data types + arch dispatch with AsDataType and new local AsArch.
diskann-benchmark-runner/src/utils/datatype.rs	Removes Type<T>/DispatchRule matching and introduces AsDataType + Describe.
diskann-benchmark-runner/src/test/typed.rs	Updates test benchmarks to match on AsDataType and use new description formatting.
diskann-benchmark-runner/src/test/dim.rs	Updates imports to new benchmark::{MatchScore, FailureScore} path.
diskann-benchmark-runner/src/registry.rs	Updates imports to new benchmark::{MatchScore, FailureScore} path.
diskann-benchmark-runner/src/lib.rs	Stops exporting the removed dispatcher module (left as a commented line).
diskann-benchmark-runner/src/dispatcher/mod.rs	Deleted (obsolete module removed).
diskann-benchmark-runner/src/dispatcher/api.rs	Deleted (obsolete module removed).
diskann-benchmark-runner/src/benchmark.rs	Adds MatchScore/FailureScore types directly to benchmark module.
diskann-benchmark-runner/src/any.rs	Removes DispatchRule-based matching/conversion helpers from Any.

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[codecov-commenter]

Codecov Report

❌ Patch coverage is 61.40351% with 44 lines in your changes missing coverage. Please review.
✅ Project coverage is 89.51%. Comparing base (d00cac0) to head (77540ba).

Files with missing lines	Patch %	Lines
diskann-benchmark-simd/src/lib.rs	38.29%	29 Missing ⚠️
diskann-benchmark/src/backend/index/benchmarks.rs	11.11%	8 Missing ⚠️
diskann-benchmark-runner/src/benchmark.rs	0.00%	6 Missing ⚠️
diskann-benchmark-runner/src/test/typed.rs	92.85%	1 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #1064      +/-   ##
==========================================
- Coverage   89.51%   89.51%   -0.01%     
==========================================
  Files         461      459       -2     
  Lines       85920    85642     -278     
==========================================
- Hits        76914    76659     -255     
+ Misses       9006     8983      -23     

Flag	Coverage Δ
miri	89.51% <61.40%> (-0.01%)	⬇️
unittests	89.13% <61.40%> (-0.01%)	⬇️

Flags with carried forward coverage won't be shown. Click here to find out more.

Files with missing lines	Coverage Δ
diskann-benchmark-runner/src/any.rs	100.00% <ø> (ø)
diskann-benchmark-runner/src/registry.rs	88.26% <ø> (ø)
diskann-benchmark-runner/src/test/dim.rs	89.21% <ø> (ø)
diskann-benchmark-runner/src/utils/datatype.rs	100.00% <100.00%> (+1.01%)	⬆️
diskann-benchmark/src/backend/exhaustive/minmax.rs	100.00% <ø> (ø)
...iskann-benchmark/src/backend/exhaustive/product.rs	100.00% <ø> (ø)
...kann-benchmark/src/backend/exhaustive/spherical.rs	100.00% <ø> (ø)
diskann-benchmark/src/backend/filters/benchmark.rs	86.14% <ø> (ø)
diskann-benchmark/src/backend/index/product.rs	100.00% <ø> (ø)
diskann-benchmark/src/backend/index/scalar.rs	100.00% <ø> (ø)
... and 6 more

... and 1 file with indirect coverage changes

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