Fix #61429: Fast arithmetic type check for type-parameters upper-bounded by `bigint` fixed by CurtisFenner · Pull Request #61571 · microsoft/TypeScript

CurtisFenner · 2025-04-13T03:50:13Z

The maybeTypeOfKind function is a simpler version of full type-checking which is used by arithmetic. Previously it was used to determine whether arithmetic operations such as +, <<, and ~ were acting on number types or bigint types.

Note that these type checks are somewhat complicated by a desire to preserve unsoundness: any * any should be number, rather than the (sound but exceedingly impractical) number | bigint.

Previously, the maybeTypeOfKind function did not return true when an operand has a type T, regardless of the bounds of T. This meant that when maybeTypeOfKind is passed T extends bigint and bigint, it returned false.

This caused expressions like a & b to be assigned the "default" type number instead of bigint.

To fix this issue, I updated the checks to instead use maybeTypeOfKindConsideringBaseConstraint. I suspect that some of the other uses of maybeTypeOfKind have similar issues, but if so they seem much more subtle and I wasn't able to construct any suspicious tests for them.

I added the bigintSubtypingTypeParameter test which includes a variety of unary and binary operators acting on such T extends bigint values.

This is my first PR, so apologies if I'm missing something important.

CurtisFenner · 2025-04-13T03:51:33Z

@microsoft-github-policy-service agree

src/compiler/checker.ts

…straint

CurtisFenner · 2025-04-27T03:19:45Z

@jakebailey Hi, I'm not sure if you missed the new approach I took. I found a more appropriate maybeTypeOfKindConsideringBaseConstraint and audited all the existing callers of maybeTypeOfKind to see which obviously should be using it. (I also did an extraction of getBinaryArithmeticResultType into a function since it was a large code block in a large chain of alternatives, to be more similar to the getUnaryResultType)

Apologies if you were already aware, I'm sure you have more important tasks to attend to for TypeScript!

jakebailey · 2025-05-09T19:34:45Z

@typescript-bot test it

typescript-bot · 2025-05-09T19:34:50Z

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 · 2025-05-09T19:56:10Z

@jakebailey Here are the results of running the user tests with tsc comparing main and refs/pull/61571/merge:

Everything looks good!

typescript-bot · 2025-05-09T19:58:10Z

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

Everything looks the same!

You can check the log here.

typescript-bot · 2025-05-09T20:21:53Z

@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}	_{193,034k (± 0.07%)}	_{194,151k (± 0.95%)}	_~	_192,930k	_196,581k	_{p=1.000 n=6}
_{Parse Time}	_{1.31s (± 0.62%)}	_{1.31s (± 0.62%)}	_~	_1.29s	_1.31s	_{p=1.000 n=6}
_{Bind Time}	_0.73s	_0.73s	_~	_~	_~	_{p=1.000 n=6}
_{Check Time}	_{9.76s (± 0.45%)}	_{9.69s (± 0.36%)}	_{-0.08s (- 0.80%)}	_9.64s	_9.73s	_{p=0.020 n=6}
_{Emit Time}	_{2.73s (± 0.68%)}	_{2.75s (± 0.84%)}	_~	_2.73s	_2.78s	_{p=0.292 n=6}
_{Total Time}	_{14.54s (± 0.42%)}	_{14.48s (± 0.30%)}	_~	_14.42s	_14.55s	_{p=0.106 n=6}
_{angular-1 - node (v18.15.0, x64)}
_Errors	₅₆	₅₆	_~	_~	_~	_{p=1.000 n=6}
_Symbols	_949,240	_949,240	_~	_~	_~	_{p=1.000 n=6}
_Types	_411,065	_411,065	_~	_~	_~	_{p=1.000 n=6}
_{Memory used}	_{1,225,135k (± 0.01%)}	_{1,225,081k (± 0.00%)}	_~	_1,225,051k	_1,225,130k	_{p=0.093 n=6}
_{Parse Time}	_{6.66s (± 0.61%)}	_{6.63s (± 1.13%)}	_~	_6.53s	_6.69s	_{p=0.627 n=6}
_{Bind Time}	_{1.88s (± 0.22%)}	_{1.88s (± 0.22%)}	_~	_1.88s	_1.89s	_{p=1.000 n=6}
_{Check Time}	_{31.88s (± 0.19%)}	_{31.95s (± 0.27%)}	_~	_31.89s	_32.12s	_{p=0.196 n=6}
_{Emit Time}	_{15.20s (± 0.63%)}	_{15.15s (± 0.29%)}	_~	_15.09s	_15.21s	_{p=0.686 n=6}
_{Total Time}	_{55.62s (± 0.28%)}	_{55.61s (± 0.29%)}	_~	_55.45s	_55.88s	_{p=0.810 n=6}
_{mui-docs - node (v18.15.0, x64)}
_Errors	₀	₀	_~	_~	_~	_{p=1.000 n=6}
_Symbols	_2,439,920	_2,439,920	_~	_~	_~	_{p=1.000 n=6}
_Types	_872,553	_872,553	_~	_~	_~	_{p=1.000 n=6}
_{Memory used}	_{2,448,513k (± 0.00%)}	_{2,448,450k (± 0.00%)}	_~	_2,448,361k	_2,448,501k	_{p=0.066 n=6}
_{Parse Time}	_{10.51s (± 0.57%)}	_{10.53s (± 0.37%)}	_~	_10.46s	_10.57s	_{p=0.470 n=6}
_{Bind Time}	_{2.67s (± 1.03%)}	_{2.68s (± 0.41%)}	_~	_2.67s	_2.69s	_{p=0.498 n=6}
_{Check Time}	_{87.44s (± 1.55%)}	_{87.35s (± 1.56%)}	_~	_86.20s	_89.50s	_{p=0.689 n=6}
_{Emit Time}	_{0.37s (± 1.71%)}	_{0.37s (± 2.04%)}	_~	_0.36s	_0.38s	_{p=0.718 n=6}
_{Total Time}	_{100.99s (± 1.34%)}	_{100.93s (± 1.36%)}	_~	_99.72s	_103.10s	_{p=0.748 n=6}
_{self-build-src - node (v18.15.0, x64)}
_Errors	₀	₀	_~	_~	_~	_{p=1.000 n=6}
_Symbols	_1,228,052	_1,228,055	_{+3 (+ 0.00%)}	_~	_~	_{p=0.001 n=6}
_Types	_267,262	_267,261	_{-1 (- 0.00%)}	_~	_~	_{p=0.001 n=6}
_{Memory used}	_{2,360,628k (± 0.02%)}	_{2,361,074k (± 0.03%)}	_~	_2,360,348k	_2,361,978k	_{p=0.173 n=6}
_{Parse Time}	_{5.24s (± 0.79%)}	_{5.20s (± 0.35%)}	_~	_5.18s	_5.22s	_{p=0.109 n=6}
_{Bind Time}	_{1.80s (± 0.65%)}	_{1.80s (± 0.61%)}	_~	_1.78s	_1.81s	_{p=0.557 n=6}
_{Check Time}	_{35.36s (± 0.43%)}	_{35.24s (± 0.24%)}	_~	_35.10s	_35.33s	_{p=0.173 n=6}
_{Emit Time}	_{3.03s (± 3.16%)}	_{2.95s (± 1.92%)}	_~	_2.87s	_3.03s	_{p=0.128 n=6}
_{Total Time}	_{45.43s (± 0.43%)}	_{45.20s (± 0.27%)}	_~	_45.00s	_45.34s	_{p=0.054 n=6}
_{self-build-src-public-api - node (v18.15.0, x64)}
_Errors	₀	₀	_~	_~	_~	_{p=1.000 n=6}
_Symbols	_1,228,052	_1,228,055	_{+3 (+ 0.00%)}	_~	_~	_{p=0.001 n=6}
_Types	_267,262	_267,261	_{-1 (- 0.00%)}	_~	_~	_{p=0.001 n=6}
_{Memory used}	_{2,427,516k (± 0.03%)}	_{2,427,798k (± 0.02%)}	_~	_2,427,085k	_2,428,457k	_{p=0.575 n=6}
_{Parse Time}	_{5.46s (± 1.25%)}	_{5.42s (± 0.23%)}	_~	_5.41s	_5.44s	_{p=1.000 n=6}
_{Bind Time}	_{1.82s (± 0.92%)}	_{1.82s (± 0.69%)}	_~	_1.80s	_1.83s	_{p=1.000 n=6}
_{Check Time}	_{35.48s (± 0.78%)}	_{35.25s (± 0.20%)}	_~	_35.17s	_35.37s	_{p=0.261 n=6}
_{Emit Time}	_{3.10s (± 1.89%)}	_{3.02s (± 1.56%)}	_~	_2.94s	_3.06s	_{p=0.076 n=6}
_{Total Time}	_{45.85s (± 0.71%)}	_{45.52s (± 0.16%)}	_~	_45.44s	_45.65s	_{p=0.093 n=6}
_{self-compiler - node (v18.15.0, x64)}
_Errors	₀	₀	_~	_~	_~	_{p=1.000 n=6}
_Symbols	_263,419	_263,422	_{+3 (+ 0.00%)}	_~	_~	_{p=0.001 n=6}
_Types	_107,098	_107,097	_{-1 (- 0.00%)}	_~	_~	_{p=0.001 n=6}
_{Memory used}	_{441,781k (± 0.02%)}	_{441,837k (± 0.02%)}	_~	_441,767k	_441,915k	_{p=0.298 n=6}
_{Parse Time}	_{3.55s (± 0.99%)}	_{3.55s (± 1.09%)}	_~	_3.50s	_3.59s	_{p=0.935 n=6}
_{Bind Time}	_{1.32s (± 0.63%)}	_{1.33s (± 1.11%)}	_~	_1.31s	_1.35s	_{p=0.797 n=6}
_{Check Time}	_{19.06s (± 0.38%)}	_{18.96s (± 0.46%)}	_~	_18.84s	_19.06s	_{p=0.078 n=6}
_{Emit Time}	_{1.53s (± 1.41%)}	_{1.51s (± 0.97%)}	_~	_1.50s	_1.54s	_{p=0.217 n=6}
_{Total Time}	_{25.46s (± 0.25%)}	_{25.35s (± 0.38%)}	_{-0.11s (- 0.45%)}	_25.20s	_25.45s	_{p=0.036 n=6}
_{ts-pre-modules - node (v18.15.0, x64)}
_Errors	₇₁	₇₁	_~	_~	_~	_{p=1.000 n=6}
_Symbols	_225,981	_225,981	_~	_~	_~	_{p=1.000 n=6}
_Types	_94,356	_94,356	_~	_~	_~	_{p=1.000 n=6}
_{Memory used}	_{371,258k (± 0.01%)}	_{371,331k (± 0.04%)}	_~	_371,173k	_371,570k	_{p=0.471 n=6}
_{Parse Time}	_{2.92s (± 0.73%)}	_{2.90s (± 1.23%)}	_~	_2.86s	_2.94s	_{p=0.256 n=6}
_{Bind Time}	_{1.60s (± 1.00%)}	_{1.61s (± 1.14%)}	_~	_1.59s	_1.64s	_{p=0.324 n=6}
_{Check Time}	_{16.50s (± 0.37%)}	_{16.44s (± 0.36%)}	_~	_16.38s	_16.52s	_{p=0.172 n=6}
_{Emit Time}	_{0.00s (±244.70%)}	_0.00s	_~	_~	_~	_{p=0.405 n=6}
_{Total Time}	_{21.02s (± 0.41%)}	_{20.95s (± 0.40%)}	_~	_20.85s	_21.08s	_{p=0.228 n=6}
_{vscode - node (v18.15.0, x64)}
_Errors	₅₁	₅₁	_~	_~	_~	_{p=1.000 n=6}
_Symbols	_3,427,986	_3,427,986	_~	_~	_~	_{p=1.000 n=6}
_Types	_1,156,177	_1,156,177	_~	_~	_~	_{p=1.000 n=6}
_{Memory used}	_{3,477,216k (± 0.01%)}	_{3,477,330k (± 0.00%)}	_~	_3,477,123k	_3,477,494k	_{p=0.298 n=6}
_{Parse Time}	_{14.66s (± 0.32%)}	_{14.74s (± 1.03%)}	_~	_14.62s	_15.04s	_{p=0.293 n=6}
_{Bind Time}	_{4.80s (± 1.06%)}	_{4.76s (± 0.54%)}	_~	_4.74s	_4.80s	_{p=0.122 n=6}
_{Check Time}	_{94.61s (± 2.47%)}	_{94.94s (± 2.81%)}	_~	_93.40s	_100.35s	_{p=0.575 n=6}
_{Emit Time}	_{30.48s (± 2.29%)}	_{30.11s (± 2.20%)}	_~	_29.58s	_31.43s	_{p=0.108 n=6}
_{Total Time}	_{144.56s (± 2.07%)}	_{144.55s (± 2.29%)}	_~	_142.86s	_151.31s	_{p=0.936 n=6}
_{webpack - node (v18.15.0, x64)}
_Errors	₂	₂	_~	_~	_~	_{p=1.000 n=6}
_Symbols	_317,848	_317,848	_~	_~	_~	_{p=1.000 n=6}
_Types	_140,485	_140,485	_~	_~	_~	_{p=1.000 n=6}
_{Memory used}	_{473,035k (± 0.01%)}	_{473,047k (± 0.04%)}	_~	_472,896k	_473,370k	_{p=0.471 n=6}
_{Parse Time}	_{5.17s (± 0.50%)}	_{5.17s (± 0.87%)}	_~	_5.12s	_5.25s	_{p=1.000 n=6}
_{Bind Time}	_{2.26s (± 2.29%)}	_{2.27s (± 1.16%)}	_~	_2.23s	_2.31s	_{p=1.000 n=6}
_{Check Time}	_{25.99s (± 0.29%)}	_{25.93s (± 0.36%)}	_~	_25.80s	_26.03s	_{p=0.378 n=6}
_{Emit Time}	_{0.00s (±244.70%)}	_0.00s	_~	_~	_~	_{p=0.405 n=6}
_{Total Time}	_{33.42s (± 0.28%)}	_{33.37s (± 0.37%)}	_~	_33.21s	_33.56s	_{p=0.471 n=6}
_{xstate-main - node (v18.15.0, x64)}
_Errors	₅	₅	_~	_~	_~	_{p=1.000 n=6}
_Symbols	_570,733	_570,733	_~	_~	_~	_{p=1.000 n=6}
_Types	_191,446	_191,446	_~	_~	_~	_{p=1.000 n=6}
_{Memory used}	_{501,157k (± 0.04%)}	_{501,292k (± 0.01%)}	_~	_501,189k	_501,350k	_{p=0.298 n=6}
_{Parse Time}	_{4.31s (± 0.41%)}	_{4.31s (± 0.32%)}	_~	_4.30s	_4.34s	_{p=0.934 n=6}
_{Bind Time}	_{1.53s (± 0.96%)}	_{1.54s (± 0.71%)}	_~	_1.53s	_1.56s	_{p=0.452 n=6}
_{Check Time}	_{25.74s (± 3.60%)}	_{24.85s (± 0.26%)}	_~	_24.78s	_24.95s	_{p=0.065 n=6}
_{Emit Time}	_0.00s	_0.00s	_~	_~	_~	_{p=1.000 n=6}
_{Total Time}	_{31.58s (± 2.87%)}	_{30.71s (± 0.18%)}	_{-0.88s (- 2.78%)}	_30.66s	_30.81s	_{p=0.037 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 · 2025-05-09T21:19:28Z

@jakebailey Here are the results of running the top 400 repos with tsc comparing main and refs/pull/61571/merge:

Everything looks good!

Add failing test for microsoft#61429

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github-project-automation bot added this to PR Backlog Apr 13, 2025

github-project-automation bot moved this to Not started in PR Backlog Apr 13, 2025

typescript-bot added the For Backlog Bug PRs that fix a backlog bug label Apr 13, 2025

jakebailey reviewed Apr 14, 2025

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src/compiler/checker.ts Outdated Show resolved Hide resolved

CurtisFenner force-pushed the fix-61429-bigint-type-parameter-maybeTypeOfKind-bug branch from ae470a1 to 1390f5f Compare April 18, 2025 00:44

Fix 61429: Update arithmetic to use maybeTypeOfKindConsideringBaseCon…

71d535a

…straint

CurtisFenner force-pushed the fix-61429-bigint-type-parameter-maybeTypeOfKind-bug branch from 1390f5f to 71d535a Compare April 18, 2025 00:47

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Fix #61429: Fast arithmetic type check for type-parameters upper-bounded by `bigint` fixed#61571

Fix #61429: Fast arithmetic type check for type-parameters upper-bounded by `bigint` fixed#61571
CurtisFenner wants to merge 2 commits intomicrosoft:mainfrom
CurtisFenner:fix-61429-bigint-type-parameter-maybeTypeOfKind-bug

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