Fixed accidental `undefined` omissions in union props sourced from index types under `noUncheckedIndexedAccess` by Andarist · Pull Request #61233 · microsoft/TypeScript

Andarist · 2025-02-20T08:55:06Z

…dex type under `noUncheckedIndexedAccess`

jakebailey · 2025-02-20T18:14:55Z

typescript-bot · 2025-02-20T18:15:00Z

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 · 2025-02-20T18:38:21Z

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

Everything looks the same!

You can check the log here.

typescript-bot · 2025-02-20T18:38:22Z

@jakebailey Here are the results of running the user tests with tsc comparing main and refs/pull/61233/merge:

Everything looks good!

typescript-bot · 2025-02-20T19:00:12Z

@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	₃₄	₃₄	_~	_~	_~	_{p=1.000 n=6}
_Symbols	_62,390	_62,390	_~	_~	_~	_{p=1.000 n=6}
_Types	_50,395	_50,395	_~	_~	_~	_{p=1.000 n=6}
_{Memory used}	_{193,518k (± 0.74%)}	_{193,673k (± 0.77%)}	_~	_192,905k	_196,685k	_{p=0.575 n=6}
_{Parse Time}	_{1.30s (± 0.90%)}	_{1.31s (± 0.75%)}	_~	_1.30s	_1.32s	_{p=0.157 n=6}
_{Bind Time}	_0.73s	_0.73s	_~	_~	_~	_{p=1.000 n=6}
_{Check Time}	_{9.73s (± 0.65%)}	_{9.75s (± 0.40%)}	_~	_9.69s	_9.79s	_{p=0.574 n=6}
_{Emit Time}	_{2.73s (± 0.56%)}	_{2.72s (± 0.66%)}	_~	_2.70s	_2.75s	_{p=0.570 n=6}
_{Total Time}	_{14.48s (± 0.52%)}	_{14.51s (± 0.39%)}	_~	_14.41s	_14.56s	_{p=0.629 n=6}
_{angular-1 - node (v18.15.0, x64)}
_Errors	₃₇	₃₇	_~	_~	_~	_{p=1.000 n=6}
_Symbols	_948,488	_948,488	_~	_~	_~	_{p=1.000 n=6}
_Types	_411,006	_411,006	_~	_~	_~	_{p=1.000 n=6}
_{Memory used}	_{1,224,187k (± 0.00%)}	_{1,224,188k (± 0.00%)}	_~	_1,224,105k	_1,224,273k	_{p=0.936 n=6}
_{Parse Time}	_{6.64s (± 0.49%)}	_{6.64s (± 0.98%)}	_~	_6.55s	_6.69s	_{p=0.809 n=6}
_{Bind Time}	_{1.88s (± 0.62%)}	_{1.89s (± 0.72%)}	_~	_1.87s	_1.90s	_{p=0.562 n=6}
_{Check Time}	_{31.76s (± 0.16%)}	_{31.81s (± 0.19%)}	_~	_31.71s	_31.89s	_{p=0.126 n=6}
_{Emit Time}	_{15.20s (± 0.43%)}	_{15.24s (± 0.53%)}	_~	_15.14s	_15.35s	_{p=0.521 n=6}
_{Total Time}	_{55.48s (± 0.09%)}	_{55.57s (± 0.24%)}	_~	_55.36s	_55.75s	_{p=0.172 n=6}
_{mui-docs - node (v18.15.0, x64)}
_Errors	₀	₀	_~	_~	_~	_{p=1.000 n=6}
_Symbols	_2,347,424	_2,347,424	_~	_~	_~	_{p=1.000 n=6}
_Types	_845,493	_845,493	_~	_~	_~	_{p=1.000 n=6}
_{Memory used}	_{2,120,429k (± 0.00%)}	_{2,120,394k (± 0.00%)}	_~	_2,120,319k	_2,120,543k	_{p=0.471 n=6}
_{Parse Time}	_{7.26s (± 0.19%)}	_{7.27s (± 0.17%)}	_~	_7.26s	_7.29s	_{p=1.000 n=6}
_{Bind Time}	_{2.46s (± 1.08%)}	_{2.46s (± 0.79%)}	_~	_2.44s	_2.49s	_{p=0.452 n=6}
_{Check Time}	_{72.42s (± 1.38%)}	_{72.67s (± 1.17%)}	_~	_70.96s	_73.20s	_{p=0.689 n=6}
_{Emit Time}	_{0.15s (± 5.07%)}	_{0.14s (± 3.60%)}	_~	_0.14s	_0.15s	_{p=0.247 n=6}
_{Total Time}	_{82.28s (± 1.17%)}	_{82.55s (± 0.99%)}	_~	_80.89s	_83.05s	_{p=0.689 n=6}
_{self-build-src - node (v18.15.0, x64)}
_Errors	₀	₀	_~	_~	_~	_{p=1.000 n=6}
_Symbols	_1,226,478	_1,226,480	_{+2 (+ 0.00%)}	_~	_~	_{p=0.001 n=6}
_Types	_266,963	_266,963	_~	_~	_~	_{p=1.000 n=6}
_{Memory used}	_{2,356,465k (± 0.01%)}	_{2,357,096k (± 0.03%)}	_~	_2,356,134k	_2,357,783k	_{p=0.093 n=6}
_{Parse Time}	_{5.22s (± 1.21%)}	_{5.22s (± 0.51%)}	_~	_5.18s	_5.25s	_{p=0.470 n=6}
_{Bind Time}	_{1.77s (± 0.83%)}	_{1.77s (± 1.45%)}	_~	_1.74s	_1.81s	_{p=1.000 n=6}
_{Check Time}	_{35.26s (± 0.23%)}	_{35.27s (± 0.27%)}	_~	_35.15s	_35.38s	_{p=0.810 n=6}
_{Emit Time}	_{2.98s (± 1.32%)}	_{2.95s (± 0.89%)}	_~	_2.91s	_2.99s	_{p=0.109 n=6}
_{Total Time}	_{45.23s (± 0.25%)}	_{45.24s (± 0.24%)}	_~	_45.07s	_45.35s	_{p=1.000 n=6}
_{self-build-src-public-api - node (v18.15.0, x64)}
_Errors	₀	₀	_~	_~	_~	_{p=1.000 n=6}
_Symbols	_1,226,478	_1,226,480	_{+2 (+ 0.00%)}	_~	_~	_{p=0.001 n=6}
_Types	_266,963	_266,963	_~	_~	_~	_{p=1.000 n=6}
_{Memory used}	_{3,032,329k (± 9.77%)}	_{3,152,667k (± 0.03%)}	_~	_3,151,674k	_3,154,442k	_{p=0.575 n=6}
_{Parse Time}	_{6.95s (± 0.98%)}	_{6.96s (± 0.87%)}	_~	_6.91s	_7.06s	_{p=0.936 n=6}
_{Bind Time}	_{2.14s (± 1.53%)}	_{2.16s (± 1.58%)}	_~	_2.12s	_2.22s	_{p=0.334 n=6}
_{Check Time}	_{42.92s (± 0.49%)}	_{42.91s (± 0.25%)}	_~	_42.80s	_43.06s	_{p=0.936 n=6}
_{Emit Time}	_{3.44s (± 1.79%)}	_{3.53s (± 2.04%)}	_{+0.09s (+ 2.52%)}	_3.41s	_3.62s	_{p=0.045 n=6}
_{Total Time}	_{55.45s (± 0.37%)}	_{55.56s (± 0.17%)}	_~	_55.41s	_55.69s	_{p=0.378 n=6}
_{self-compiler - node (v18.15.0, x64)}
_Errors	₀	₀	_~	_~	_~	_{p=1.000 n=6}
_Symbols	_262,584	_262,586	_{+2 (+ 0.00%)}	_~	_~	_{p=0.001 n=6}
_Types	_106,832	_106,832	_~	_~	_~	_{p=1.000 n=6}
_{Memory used}	_{440,369k (± 0.02%)}	_{440,361k (± 0.01%)}	_~	_440,286k	_440,423k	_{p=0.873 n=6}
_{Parse Time}	_{3.52s (± 0.75%)}	_{3.55s (± 1.09%)}	_~	_3.51s	_3.60s	_{p=0.377 n=6}
_{Bind Time}	_{1.32s (± 0.42%)}	_{1.32s (± 0.75%)}	_~	_1.31s	_1.33s	_{p=0.662 n=6}
_{Check Time}	_{18.91s (± 0.31%)}	_{18.87s (± 0.35%)}	_~	_18.80s	_18.97s	_{p=0.377 n=6}
_{Emit Time}	_{1.51s (± 0.90%)}	_{1.51s (± 2.17%)}	_~	_1.46s	_1.54s	_{p=1.000 n=6}
_{Total Time}	_{25.25s (± 0.20%)}	_{25.24s (± 0.46%)}	_~	_25.12s	_25.38s	_{p=0.682 n=6}
_{ts-pre-modules - node (v18.15.0, x64)}
_Errors	₇₀	₇₀	_~	_~	_~	_{p=1.000 n=6}
_Symbols	_226,113	_226,113	_~	_~	_~	_{p=1.000 n=6}
_Types	_94,488	_94,488	_~	_~	_~	_{p=1.000 n=6}
_{Memory used}	_{371,336k (± 0.05%)}	_{371,310k (± 0.02%)}	_~	_371,217k	_371,371k	_{p=0.688 n=6}
_{Parse Time}	_{2.86s (± 0.87%)}	_{2.89s (± 1.47%)}	_~	_2.82s	_2.95s	_{p=0.196 n=6}
_{Bind Time}	_{1.59s (± 1.77%)}	_{1.59s (± 1.80%)}	_~	_1.56s	_1.63s	_{p=0.572 n=6}
_{Check Time}	_{16.48s (± 0.42%)}	_{16.46s (± 0.45%)}	_~	_16.33s	_16.55s	_{p=0.520 n=6}
_{Emit Time}	_0.00s	_0.00s	_~	_~	_~	_{p=1.000 n=6}
_{Total Time}	_{20.93s (± 0.38%)}	_{20.95s (± 0.56%)}	_~	_20.72s	_21.02s	_{p=0.375 n=6}
_{vscode - node (v18.15.0, x64)}
_Errors	₁	₁	_~	_~	_~	_{p=1.000 n=6}
_Symbols	_3,227,811	_3,227,811	_~	_~	_~	_{p=1.000 n=6}
_Types	_1,094,612	_1,094,612	_~	_~	_~	_{p=1.000 n=6}
_{Memory used}	_{3,303,920k (± 0.01%)}	_{3,303,995k (± 0.03%)}	_~	_3,303,198k	_3,305,767k	_{p=0.810 n=6}
_{Parse Time}	_{14.35s (± 0.59%)}	_{14.22s (± 0.51%)}	_{-0.13s (- 0.91%)}	_14.08s	_14.27s	_{p=0.030 n=6}
_{Bind Time}	_{4.61s (± 0.73%)}	_{4.85s (±11.71%)}	_~	_4.56s	_6.01s	_{p=0.377 n=6}
_{Check Time}	_{89.98s (± 3.16%)}	_{88.74s (± 0.69%)}	_~	_88.36s	_89.95s	_{p=0.873 n=6}
_{Emit Time}	_{27.20s (± 7.38%)}	_{27.73s (± 8.54%)}	_~	_22.91s	_29.09s	_{p=0.230 n=6}
_{Total Time}	_{136.15s (± 0.96%)}	_{135.53s (± 0.94%)}	_~	_132.95s	_136.32s	_{p=0.936 n=6}
_{webpack - node (v18.15.0, x64)}
_Errors	₂	₂	_~	_~	_~	_{p=1.000 n=6}
_Symbols	_293,866	_293,866	_~	_~	_~	_{p=1.000 n=6}
_Types	_119,628	_119,628	_~	_~	_~	_{p=1.000 n=6}
_{Memory used}	_{447,126k (± 0.01%)}	_{447,178k (± 0.03%)}	_~	_446,981k	_447,383k	_{p=0.471 n=6}
_{Parse Time}	_{4.08s (± 1.19%)}	_{4.11s (± 0.97%)}	_~	_4.05s	_4.16s	_{p=0.377 n=6}
_{Bind Time}	_{1.77s (± 1.59%)}	_{1.77s (± 1.07%)}	_~	_1.75s	_1.79s	_{p=0.935 n=6}
_{Check Time}	_{18.74s (± 0.11%)}	_{18.83s (± 0.26%)}	_{+0.09s (+ 0.47%)}	_18.77s	_18.90s	_{p=0.005 n=6}
_{Emit Time}	_0.00s	_0.00s	_~	_~	_~	_{p=1.000 n=6}
_{Total Time}	_{24.58s (± 0.23%)}	_{24.71s (± 0.23%)}	_{+0.12s (+ 0.49%)}	_24.62s	_24.79s	_{p=0.013 n=6}
_{xstate-main - node (v18.15.0, x64)}
_Errors	₅	₅	_~	_~	_~	_{p=1.000 n=6}
_Symbols	_558,084	_558,084	_~	_~	_~	_{p=1.000 n=6}
_Types	_186,415	_186,415	_~	_~	_~	_{p=1.000 n=6}
_{Memory used}	_{495,085k (± 0.01%)}	_{495,050k (± 0.01%)}	_~	_495,016k	_495,079k	_{p=0.470 n=6}
_{Parse Time}	_{3.43s (± 0.63%)}	_{3.41s (± 0.80%)}	_~	_3.38s	_3.45s	_{p=0.254 n=6}
_{Bind Time}	_{1.19s (± 0.53%)}	_{1.19s (± 1.01%)}	_~	_1.18s	_1.21s	_{p=0.673 n=6}
_{Check Time}	_{19.58s (± 0.28%)}	_{19.58s (± 0.30%)}	_~	_19.49s	_19.65s	_{p=0.936 n=6}
_{Emit Time}	_0.00s	_0.00s	_~	_~	_~	_{p=1.000 n=6}
_{Total Time}	_{24.19s (± 0.25%)}	_{24.18s (± 0.28%)}	_~	_24.08s	_24.26s	_{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 · 2025-02-20T19:53:04Z

@jakebailey Here are the results of running the top 400 repos with tsc comparing main and refs/pull/61233/merge:

Everything looks good!

jakebailey · 2025-02-24T21:39:09Z

src/compiler/checker.ts

            propTypes.push(type);
        }
        addRange(propTypes, indexTypes);
+        if (indexTypes && compilerOptions.noUncheckedIndexedAccess) {


Maybe I'm just not familiar with this part of the code, but how can this get away with being unconditionally added when this flag is enabled? Are there code paths above this that are missing this too?

The preceding branch requires !indexTypes and this flag is only relevant to existing indexTypes.

…sion-union-prop

Fixed accidental undefined omissions in union props sourced from in…

464abcf

…dex type under `noUncheckedIndexedAccess`

Andarist force-pushed the fix/missing-type-omission-union-prop branch from 2964f64 to 464abcf Compare February 20, 2025 09:49

jakebailey reviewed Feb 24, 2025

View reviewed changes

typescript-bot added the For Backlog Bug PRs that fix a backlog bug label Dec 5, 2025

Merge remote-tracking branch 'origin/main' into fix/missing-type-omis…

04b9c70

…sion-union-prop

Andarist force-pushed the fix/missing-type-omission-union-prop branch from 1f21724 to 04b9c70 Compare December 5, 2025 17:46

Merge remote-tracking branch 'origin/main' into fix/missing-type-omis…

59ac314

…sion-union-prop

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Fixed accidental `undefined` omissions in union props sourced from index types under `noUncheckedIndexedAccess`#61233

Fixed accidental `undefined` omissions in union props sourced from index types under `noUncheckedIndexedAccess`#61233
Andarist wants to merge 3 commits intomicrosoft:mainfrom
Andarist:fix/missing-type-omission-union-prop

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