Replace replaceable indexed accesses early to reuse cache entries by Andarist · Pull Request #62822 · microsoft/TypeScript

Andarist · 2025-12-02T11:32:57Z

replaceIndexedAccess was introduced in #42485 . While I was investigating some other things, it occurred to me that it could possibly be used earlier. Everything stated in this comment should still apply to the creation of the reverse-mapped type object itself

typescript-bot · 2025-12-02T11:33:01Z

This PR doesn't have any linked issues. Please open an issue that references this PR. From there we can discuss and prioritise.

jakebailey · 2025-12-02T13:52:29Z

@typescript-bot test it

typescript-bot · 2025-12-02T13:52:33Z

Starting jobs; this comment will be updated as builds start and complete.

Command	Status	Results
`test top400`	✅ Started	✅ Results
`user test this`	✅ Started	✅ Results
`run dt`	✅ Started	✅ Results
`perf test this faster`	✅ Started	👀 Results

typescript-bot · 2025-12-02T14:16:47Z

Hey @jakebailey, the results of running the DT tests are ready.

Everything looks the same!

You can check the log here.

typescript-bot · 2025-12-02T14:22:06Z

@jakebailey Here are the results of running the user tests with tsc comparing main and refs/pull/62822/merge:

There were infrastructure failures potentially unrelated to your change:

1 instance of "Git clone failed"

Otherwise...

Everything looks good!

typescript-bot · 2025-12-02T14:44:58Z

@jakebailey
The results of the perf run you requested are in!

Here they are:

tsc

Comparison Report - baseline..pr

_Metric	_baseline	_pr	_Delta	_Best	_Worst	_p-value
_{Compiler-Unions - node (v18.15.0, x64)}
_Errors	₁	₁	_~	_~	_~	_{p=1.000 n=6}
_Symbols	_62,370	_62,370	_~	_~	_~	_{p=1.000 n=6}
_Types	_50,386	_50,386	_~	_~	_~	_{p=1.000 n=6}
_{Memory used}	_{194,966k (± 0.93%)}	_{193,290k (± 0.74%)}	_~	_192,601k	_196,208k	_{p=0.093 n=6}
_{Parse Time}	_{1.30s (± 0.64%)}	_{1.31s (± 0.39%)}	_~	_1.30s	_1.31s	_{p=0.923 n=6}
_{Bind Time}	_0.75s	_0.75s	_~	_~	_~	_{p=1.000 n=6}
_{Check Time}	_{9.93s (± 0.45%)}	_{9.91s (± 0.23%)}	_~	_9.89s	_9.95s	_{p=0.808 n=6}
_{Emit Time}	_{2.73s (± 0.44%)}	_{2.74s (± 0.64%)}	_~	_2.71s	_2.76s	_{p=0.933 n=6}
_{Total Time}	_{14.72s (± 0.30%)}	_{14.71s (± 0.17%)}	_~	_14.68s	_14.75s	_{p=0.746 n=6}
_{angular-1 - node (v18.15.0, x64)}
_Errors	₂	₂	_~	_~	_~	_{p=1.000 n=6}
_Symbols	_956,047	_956,082	_{+35 (+ 0.00%)}	_~	_~	_{p=0.001 n=6}
_Types	_415,881	_415,888	_{+7 (+ 0.00%)}	_~	_~	_{p=0.001 n=6}
_{Memory used}	_{1,255,064k (± 0.00%)}	_{1,255,048k (± 0.00%)}	_~	_1,254,989k	_1,255,109k	_{p=0.810 n=6}
_{Parse Time}	_{6.55s (± 0.76%)}	_{6.55s (± 0.41%)}	_~	_6.50s	_6.58s	_{p=1.000 n=6}
_{Bind Time}	_{1.96s (± 0.32%)}	_{1.96s (± 0.21%)}	_~	_1.95s	_1.96s	_{p=0.673 n=6}
_{Check Time}	_{32.34s (± 0.19%)}	_{32.39s (± 0.44%)}	_~	_32.18s	_32.60s	_{p=0.378 n=6}
_{Emit Time}	_{14.86s (± 0.19%)}	_{14.85s (± 0.23%)}	_~	_14.79s	_14.88s	_{p=0.686 n=6}
_{Total Time}	_{55.70s (± 0.15%)}	_{55.74s (± 0.23%)}	_~	_55.60s	_55.93s	_{p=0.936 n=6}
_{mui-docs - node (v18.15.0, x64)}
_Errors	₀	₀	_~	_~	_~	_{p=1.000 n=6}
_Symbols	_2,722,079	_2,722,079	_~	_~	_~	_{p=1.000 n=6}
_Types	_937,469	_937,469	_~	_~	_~	_{p=1.000 n=6}
_{Memory used}	_{3,050,885k (± 0.00%)}	_{3,050,838k (± 0.00%)}	_~	_3,050,761k	_3,050,883k	_{p=0.173 n=6}
_{Parse Time}	_{8.54s (± 0.16%)}	_{8.54s (± 0.18%)}	_~	_8.51s	_8.55s	_{p=0.805 n=6}
_{Bind Time}	_{2.32s (± 0.59%)}	_{2.32s (± 0.71%)}	_~	_2.30s	_2.34s	_{p=0.934 n=6}
_{Check Time}	_{93.15s (± 0.53%)}	_{92.79s (± 0.42%)}	_~	_92.38s	_93.26s	_{p=0.230 n=6}
_{Emit Time}	_{0.31s (± 1.32%)}	_{0.31s (± 1.68%)}	_~	_0.30s	_0.31s	_{p=0.595 n=6}
_{Total Time}	_{104.32s (± 0.48%)}	_{103.96s (± 0.38%)}	_~	_103.57s	_104.45s	_{p=0.296 n=6}
_{self-build-src - node (v18.15.0, x64)}
_Errors	₀	₀	_~	_~	_~	_{p=1.000 n=6}
_Symbols	_1,251,545	_1,251,544	_{-1 (- 0.00%)}	_~	_~	_{p=0.001 n=6}
_Types	_259,756	_259,756	_~	_~	_~	_{p=1.000 n=6}
_{Memory used}	_{2,574,799k (±11.81%)}	_{2,392,915k (± 0.02%)}	_~	_2,392,323k	_2,393,622k	_{p=0.378 n=6}
_{Parse Time}	_{5.20s (± 1.52%)}	_{5.16s (± 0.74%)}	_~	_5.12s	_5.22s	_{p=0.423 n=6}
_{Bind Time}	_{1.82s (± 1.68%)}	_{1.84s (± 1.27%)}	_~	_1.81s	_1.87s	_{p=0.256 n=6}
_{Check Time}	_{35.45s (± 0.64%)}	_{35.46s (± 0.30%)}	_~	_35.34s	_35.60s	_{p=0.936 n=6}
_{Emit Time}	_{3.01s (± 2.37%)}	_{3.01s (± 2.33%)}	_~	_2.92s	_3.10s	_{p=0.936 n=6}
_{Total Time}	_{45.49s (± 0.48%)}	_{45.47s (± 0.38%)}	_~	_45.23s	_45.70s	_{p=0.936 n=6}
_{self-build-src-public-api - node (v18.15.0, x64)}
_Errors	₀	₀	_~	_~	_~	_{p=1.000 n=6}
_Symbols	_1,251,545	_1,251,544	_{-1 (- 0.00%)}	_~	_~	_{p=0.001 n=6}
_Types	_259,756	_259,756	_~	_~	_~	_{p=1.000 n=6}
_{Memory used}	_{3,187,454k (± 0.02%)}	_{3,187,815k (± 0.01%)}	_~	_3,187,064k	_3,188,201k	_{p=0.471 n=6}
_{Parse Time}	_{6.82s (± 0.79%)}	_{6.82s (± 1.06%)}	_~	_6.69s	_6.87s	_{p=0.748 n=6}
_{Bind Time}	_{2.26s (± 0.91%)}	_{2.25s (± 1.36%)}	_~	_2.21s	_2.29s	_{p=0.471 n=6}
_{Check Time}	_{43.16s (± 0.40%)}	_{43.12s (± 0.27%)}	_~	_42.92s	_43.23s	_{p=0.936 n=6}
_{Emit Time}	_{3.51s (± 3.09%)}	_{3.51s (± 2.00%)}	_~	_3.38s	_3.57s	_{p=0.936 n=6}
_{Total Time}	_{55.76s (± 0.40%)}	_{55.69s (± 0.11%)}	_~	_55.62s	_55.78s	_{p=0.378 n=6}
_{self-compiler - node (v18.15.0, x64)}
_Errors	₀	₀	_~	_~	_~	_{p=1.000 n=6}
_Symbols	_264,177	_264,176	_{-1 (- 0.00%)}	_~	_~	_{p=0.001 n=6}
_Types	_103,979	_103,979	_~	_~	_~	_{p=1.000 n=6}
_{Memory used}	_{443,204k (± 0.01%)}	_{443,241k (± 0.02%)}	_~	_443,150k	_443,347k	_{p=0.378 n=6}
_{Parse Time}	_{3.52s (± 0.53%)}	_{3.52s (± 0.73%)}	_~	_3.49s	_3.55s	_{p=0.871 n=6}
_{Bind Time}	_{1.38s (± 1.29%)}	_{1.37s (± 1.19%)}	_~	_1.35s	_1.39s	_{p=0.512 n=6}
_{Check Time}	_{19.15s (± 0.44%)}	_{19.16s (± 0.48%)}	_~	_19.00s	_19.28s	_{p=0.872 n=6}
_{Emit Time}	_{1.54s (± 1.36%)}	_{1.53s (± 0.58%)}	_~	_1.52s	_1.54s	_{p=0.563 n=6}
_{Total Time}	_{25.59s (± 0.32%)}	_{25.58s (± 0.34%)}	_~	_25.41s	_25.64s	_{p=1.000 n=6}
_{ts-pre-modules - node (v18.15.0, x64)}
_Errors	₇₂	₇₂	_~	_~	_~	_{p=1.000 n=6}
_Symbols	_225,386	_225,386	_~	_~	_~	_{p=1.000 n=6}
_Types	_94,304	_94,304	_~	_~	_~	_{p=1.000 n=6}
_{Memory used}	_{370,098k (± 0.04%)}	_{370,074k (± 0.04%)}	_~	_369,939k	_370,374k	_{p=0.936 n=6}
_{Parse Time}	_{2.83s (± 1.17%)}	_{2.85s (± 0.75%)}	_~	_2.81s	_2.87s	_{p=0.466 n=6}
_{Bind Time}	_{1.63s (± 0.51%)}	_{1.65s (± 1.38%)}	_~	_1.63s	_1.69s	_{p=0.277 n=6}
_{Check Time}	_{16.61s (± 0.15%)}	_{16.60s (± 0.68%)}	_~	_16.39s	_16.72s	_{p=0.688 n=6}
_{Emit Time}	_0.00s	_{0.00s (±154.76%)}	_~	_0.00s	_0.01s	_{p=0.174 n=6}
_{Total Time}	_{21.08s (± 0.11%)}	_{21.10s (± 0.58%)}	_~	_20.89s	_21.23s	_{p=0.378 n=6}
_{vscode - node (v18.15.0, x64)}
_Errors	₁₁	₁₁	_~	_~	_~	_{p=1.000 n=6}
_Symbols	_4,072,930	_4,072,930	_~	_~	_~	_{p=1.000 n=6}
_Types	_1,282,754	_1,282,754	_~	_~	_~	_{p=1.000 n=6}
_{Memory used}	_{3,858,265k (± 0.00%)}	_{3,858,428k (± 0.00%)}	_{+164k (+ 0.00%)}	_3,858,310k	_3,858,683k	_{p=0.008 n=6}
_{Parse Time}	_{15.70s (± 0.65%)}	_{15.67s (± 0.58%)}	_~	_15.58s	_15.79s	_{p=0.748 n=6}
_{Bind Time}	_{5.39s (± 3.24%)}	_{5.34s (± 2.31%)}	_~	_5.19s	_5.56s	_{p=0.936 n=6}
_{Check Time}	_{112.41s (± 2.56%)}	_{111.48s (± 0.95%)}	_~	_110.36s	_113.46s	_{p=0.748 n=6}
_{Emit Time}	_{40.19s (± 5.78%)}	_{41.32s (±11.12%)}	_~	_38.72s	_50.52s	_{p=1.000 n=6}
_{Total Time}	_{173.70s (± 2.92%)}	_{173.82s (± 2.47%)}	_~	_171.02s	_182.30s	_{p=0.936 n=6}
_{webpack - node (v18.15.0, x64)}
_Errors	₄₀	₄₀	_~	_~	_~	_{p=1.000 n=6}
_Symbols	_380,455	_380,455	_~	_~	_~	_{p=1.000 n=6}
_Types	_166,708	_166,708	_~	_~	_~	_{p=1.000 n=6}
_{Memory used}	_{540,348k (± 0.03%)}	_{540,380k (± 0.01%)}	_~	_540,323k	_540,441k	_{p=0.575 n=6}
_{Parse Time}	_{4.67s (± 0.35%)}	_{4.68s (± 0.39%)}	_~	_4.66s	_4.71s	_{p=0.563 n=6}
_{Bind Time}	_{2.03s (± 1.83%)}	_{2.04s (± 1.26%)}	_~	_2.02s	_2.08s	_{p=0.627 n=6}
_{Check Time}	_{22.91s (± 0.33%)}	_{22.92s (± 0.43%)}	_~	_22.73s	_23.01s	_{p=0.518 n=6}
_{Emit Time}	_0.00s	_0.00s	_~	_~	_~	_{p=1.000 n=6}
_{Total Time}	_{29.62s (± 0.36%)}	_{29.65s (± 0.36%)}	_~	_29.45s	_29.74s	_{p=0.574 n=6}
_{xstate-main - node (v18.15.0, x64)}
_Errors	₃₀	₃₀	_~	_~	_~	_{p=1.000 n=6}
_Symbols	_690,447	_690,447	_~	_~	_~	_{p=1.000 n=6}
_Types	_208,639	_208,639	_~	_~	_~	_{p=1.000 n=6}
_{Memory used}	_{586,405k (± 0.03%)}	_{586,454k (± 0.02%)}	_~	_586,240k	_586,626k	_{p=0.748 n=6}
_{Parse Time}	_{4.17s (± 0.53%)}	_{4.17s (± 0.86%)}	_~	_4.13s	_4.21s	_{p=0.935 n=6}
_{Bind Time}	_{1.41s (± 1.76%)}	_{1.41s (± 1.15%)}	_~	_1.39s	_1.44s	_{p=0.624 n=6}
_{Check Time}	_{20.85s (± 1.67%)}	_{20.73s (± 1.25%)}	_~	_20.55s	_21.25s	_{p=0.748 n=6}
_{Emit Time}	_0.00s	_0.00s	_~	_~	_~	_{p=1.000 n=6}
_{Total Time}	_{26.43s (± 1.39%)}	_{26.31s (± 0.95%)}	_~	_26.17s	_26.81s	_{p=0.872 n=6}

System info unknown

Hosts

node (v18.15.0, x64)

Scenarios

Compiler-Unions - node (v18.15.0, x64)
angular-1 - node (v18.15.0, x64)
mui-docs - node (v18.15.0, x64)
self-build-src - node (v18.15.0, x64)
self-build-src-public-api - node (v18.15.0, x64)
self-compiler - node (v18.15.0, x64)
ts-pre-modules - node (v18.15.0, x64)
vscode - node (v18.15.0, x64)
webpack - node (v18.15.0, x64)
xstate-main - node (v18.15.0, x64)

_Benchmark	_Name	_Iterations
_Current	_pr	₆
_Baseline	_baseline	₆

Developer Information:

Download Benchmarks

typescript-bot · 2025-12-02T15:18:15Z

@jakebailey Here are the results of running the top 400 repos with tsc comparing main and refs/pull/62822/merge:

Everything looks good!

typescript-bot · 2026-03-24T21:23:02Z

With 6.0 out as the final release vehicle for this codebase, we're closing all PRs that don't fit the merge criteria for post-6.0 patches. If you think this was a mistake and this PR fits the post-6.0 patch criteria, please post to the 6.0 iteration issue with details (specifically, which PR and which patch criteria it satisfies).

Next steps for PRs:

For crash bugfixes or language service improvements, PRs are currently accepted at the typescript-go repo
Changes to type system behavior should wait until after 7.0, at which point mainline TypeScript development will resume in this repository with the Go codebase
Library file updates (lib.d.ts etc) continue to live in this repo or the DOM Generator repo as appropriate

Replace replaceable indexed accesses early to reuse cache entries

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typescript-bot closed this Mar 24, 2026

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Replace replaceable indexed accesses early to reuse cache entries#62822

Replace replaceable indexed accesses early to reuse cache entries#62822
Andarist wants to merge 1 commit intomicrosoft:mainfrom
Andarist:cache-replaced-indexes-early

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