Avoid an attempt to contextually type static property declaration using itself to avoid spurious circularity by Andarist · Pull Request #62554 · microsoft/TypeScript

Andarist · 2025-10-06T19:40:02Z

…ng itself to avoid spurious circularity

RyanCavanaugh · 2025-10-06T19:49:34Z

How does this affect this sample?

function id<T extends { foo : 0 | 1 }>(x: T): T {
  return x
}
const Foo = id(class {
  static readonly foo = 0
});

Andarist · 2025-10-06T21:27:27Z

It has no effect on this sample. This one works before and after this PR. The more interesting case would be a similar one with a mutable property:

function id<T extends { foo : 0 | 1 }>(x: T): T {
  return x
}
const Foo = id(class {
  static foo = 0
});

This one errors before and after this PR as 0 widens to number. In general, the contextual typing for those static properties is very limited in inference contexts. The problem is that those properties are not checked from within the scope of checkExpressionWithContextualType so when the constraint assignability check in getInferredType does its thing the contextual type used for those static properties is any (coming from getContextualTypeForArgumentAtIndex as signature === resolvingSignature).

When there is no constraint (like in the reported issue) the class expression is checked in a deferred fashion (outside of the inference context) and then the contextual type becomes the class expression itself (coming from the already inferred and resolved signature).

RyanCavanaugh · 2025-10-07T23:05:07Z

@typescript-bot test it
@typescript-bot pack this

typescript-bot · 2025-10-07T23:05:13Z

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

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

typescript-bot · 2025-10-07T23:09:26Z

Hey @RyanCavanaugh, I've packed this into an installable tgz. You can install it for testing by referencing it in your package.json like so:

{
    "devDependencies": {
        "typescript": "https://typescript.visualstudio.com/cf7ac146-d525-443c-b23c-0d58337efebc/_apis/build/builds/166262/artifacts?artifactName=tgz&fileId=B82884C27B8AD7A8182024E39A7D7192BD30C516EAAAF81B0D4567A311FE29E002&fileName=/typescript-6.0.0-insiders.20251007.tgz"
    }
}

and then running npm install.

There is also a playground for this build and an npm module you can use via "typescript": "npm:@typescript-deploys/pr-build@6.0.0-pr-62554-4".;

typescript-bot · 2025-10-07T23:27:19Z

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

Everything looks the same!

You can check the log here.

typescript-bot · 2025-10-07T23:32:58Z

@RyanCavanaugh Here are the results of running the user tests with tsc comparing main and refs/pull/62554/merge:

There were infrastructure failures potentially unrelated to your change:

1 instance of "Git clone failed"

Otherwise...

Everything looks good!

typescript-bot · 2025-10-07T23:54:35Z

@RyanCavanaugh
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	_62,370	_62,370	_~	_~	_~	_{p=1.000 n=6}
_Types	_50,386	_50,386	_~	_~	_~	_{p=1.000 n=6}
_{Memory used}	_{196,235k (± 0.11%)}	_{195,208k (± 0.94%)}	_~	_192,824k	_196,548k	_{p=0.936 n=6}
_{Parse Time}	_{1.60s (± 1.66%)}	_{1.59s (± 0.84%)}	_~	_1.57s	_1.61s	_{p=0.366 n=6}
_{Bind Time}	_{0.87s (± 0.93%)}	_{0.88s (± 2.21%)}	_~	_0.86s	_0.91s	_{p=0.932 n=6}
_{Check Time}	_{11.74s (± 0.72%)}	_{11.74s (± 0.64%)}	_~	_11.65s	_11.87s	_{p=0.936 n=6}
_{Emit Time}	_{3.40s (± 4.80%)}	_{3.35s (± 4.60%)}	_~	_3.26s	_3.66s	_{p=0.935 n=6}
_{Total Time}	_{17.61s (± 1.05%)}	_{17.55s (± 0.74%)}	_~	_17.40s	_17.76s	_{p=0.688 n=6}
_{angular-1 - node (v18.15.0, x64)}
_Errors	₂	₂	_~	_~	_~	_{p=1.000 n=6}
_Symbols	_955,117	_955,117	_~	_~	_~	_{p=1.000 n=6}
_Types	_415,619	_415,619	_~	_~	_~	_{p=1.000 n=6}
_{Memory used}	_{1,254,550k (± 0.00%)}	_{1,254,556k (± 0.00%)}	_~	_1,254,470k	_1,254,666k	_{p=1.000 n=6}
_{Parse Time}	_{6.53s (± 0.76%)}	_{6.52s (± 0.62%)}	_~	_6.48s	_6.59s	_{p=0.936 n=6}
_{Bind Time}	_{1.88s (± 0.27%)}	_{1.88s (± 0.34%)}	_~	_1.87s	_1.89s	_{p=0.386 n=6}
_{Check Time}	_{32.14s (± 0.32%)}	_{32.16s (± 0.51%)}	_~	_31.99s	_32.42s	_{p=1.000 n=6}
_{Emit Time}	_{14.86s (± 0.59%)}	_{14.89s (± 0.35%)}	_~	_14.82s	_14.96s	_{p=0.936 n=6}
_{Total Time}	_{55.41s (± 0.23%)}	_{55.45s (± 0.36%)}	_~	_55.26s	_55.79s	_{p=0.936 n=6}
_{mui-docs - node (v18.15.0, x64)}
_Errors	₀	₀	_~	_~	_~	_{p=1.000 n=6}
_Symbols	_2,657,229	_2,657,229	_~	_~	_~	_{p=1.000 n=6}
_Types	_920,898	_920,898	_~	_~	_~	_{p=1.000 n=6}
_{Memory used}	_{2,969,852k (± 0.00%)}	_{2,969,894k (± 0.00%)}	_~	_2,969,844k	_2,969,915k	_{p=0.173 n=6}
_{Parse Time}	_{8.63s (± 0.35%)}	_{8.65s (± 0.38%)}	_~	_8.60s	_8.70s	_{p=0.572 n=6}
_{Bind Time}	_{2.20s (± 0.47%)}	_{2.19s (± 0.25%)}	_~	_2.19s	_2.20s	_{p=0.663 n=6}
_{Check Time}	_{90.08s (± 0.19%)}	_{90.49s (± 0.56%)}	_~	_89.86s	_91.17s	_{p=0.128 n=6}
_{Emit Time}	_{0.30s (± 1.79%)}	_{0.31s (± 1.68%)}	_~	_0.30s	_0.31s	_{p=0.640 n=6}
_{Total Time}	_{101.22s (± 0.17%)}	_{101.64s (± 0.50%)}	_~	_101.04s	_102.29s	_{p=0.149 n=6}
_{self-build-src - node (v18.15.0, x64)}
_Errors	₀	₀	_~	_~	_~	_{p=1.000 n=6}
_Symbols	_1,237,230	_1,237,231	_{+1 (+ 0.00%)}	_~	_~	_{p=0.001 n=6}
_Types	_259,856	_259,856	_~	_~	_~	_{p=1.000 n=6}
_{Memory used}	_{2,425,534k (± 6.12%)}	_{2,546,594k (±11.94%)}	_~	_2,364,294k	_3,092,754k	_{p=0.575 n=6}
_{Parse Time}	_{5.13s (± 1.23%)}	_{5.15s (± 1.69%)}	_~	_5.05s	_5.30s	_{p=0.936 n=6}
_{Bind Time}	_{1.77s (± 0.97%)}	_{1.76s (± 0.51%)}	_~	_1.75s	_1.77s	_{p=0.452 n=6}
_{Check Time}	_{35.01s (± 0.81%)}	_{35.04s (± 0.77%)}	_~	_34.67s	_35.49s	_{p=0.810 n=6}
_{Emit Time}	_{3.01s (± 0.94%)}	_{3.01s (± 1.22%)}	_~	_2.96s	_3.05s	_{p=0.872 n=6}
_{Total Time}	_{44.92s (± 0.54%)}	_{44.97s (± 0.71%)}	_~	_44.65s	_45.58s	_{p=0.689 n=6}
_{self-build-src-public-api - node (v18.15.0, x64)}
_Errors	₀	₀	_~	_~	_~	_{p=1.000 n=6}
_Symbols	_1,237,230	_1,237,231	_{+1 (+ 0.00%)}	_~	_~	_{p=0.001 n=6}
_Types	_259,856	_259,856	_~	_~	_~	_{p=1.000 n=6}
_{Memory used}	_{2,431,508k (± 0.02%)}	_{2,672,970k (±13.98%)}	_~	_2,431,050k	_3,156,118k	_{p=0.575 n=6}
_{Parse Time}	_{5.38s (± 0.20%)}	_{5.41s (± 1.56%)}	_~	_5.32s	_5.52s	_{p=0.573 n=6}
_{Bind Time}	_{1.80s (± 1.47%)}	_{1.79s (± 1.10%)}	_~	_1.77s	_1.82s	_{p=0.806 n=6}
_{Check Time}	_{35.09s (± 0.32%)}	_{35.27s (± 0.71%)}	_~	_34.94s	_35.61s	_{p=0.173 n=6}
_{Emit Time}	_{3.06s (± 1.04%)}	_{3.04s (± 0.80%)}	_~	_3.02s	_3.09s	_{p=0.469 n=6}
_{Total Time}	_{45.31s (± 0.34%)}	_{45.52s (± 0.71%)}	_~	_45.15s	_45.99s	_{p=0.298 n=6}
_{self-compiler - node (v18.15.0, x64)}
_Errors	₀	₀	_~	_~	_~	_{p=1.000 n=6}
_Symbols	_262,534	_262,535	_{+1 (+ 0.00%)}	_~	_~	_{p=0.001 n=6}
_Types	_104,035	_104,035	_~	_~	_~	_{p=1.000 n=6}
_{Memory used}	_{440,666k (± 0.01%)}	_{440,664k (± 0.01%)}	_~	_440,626k	_440,736k	_{p=0.810 n=6}
_{Parse Time}	_{3.50s (± 0.77%)}	_{3.52s (± 0.31%)}	_~	_3.50s	_3.53s	_{p=0.241 n=6}
_{Bind Time}	_{1.33s (± 1.30%)}	_{1.32s (± 1.11%)}	_~	_1.30s	_1.34s	_{p=0.512 n=6}
_{Check Time}	_{19.01s (± 0.36%)}	_{18.93s (± 0.24%)}	_~	_18.89s	_18.98s	_{p=0.064 n=6}
_{Emit Time}	_{1.54s (± 1.59%)}	_{1.54s (± 0.90%)}	_~	_1.52s	_1.55s	_{p=0.935 n=6}
_{Total Time}	_{25.37s (± 0.33%)}	_{25.31s (± 0.17%)}	_~	_25.25s	_25.36s	_{p=0.171 n=6}
_{ts-pre-modules - node (v18.15.0, x64)}
_Errors	₇₂	₇₂	_~	_~	_~	_{p=1.000 n=6}
_Symbols	_225,367	_225,367	_~	_~	_~	_{p=1.000 n=6}
_Types	_94,290	_94,290	_~	_~	_~	_{p=1.000 n=6}
_{Memory used}	_{370,083k (± 0.05%)}	_{370,144k (± 0.07%)}	_~	_369,911k	_370,467k	_{p=0.810 n=6}
_{Parse Time}	_{2.85s (± 0.96%)}	_{2.79s (± 0.95%)}	_{-0.05s (- 1.76%)}	_2.76s	_2.83s	_{p=0.016 n=6}
_{Bind Time}	_{1.61s (± 1.47%)}	_{1.60s (± 1.23%)}	_~	_1.57s	_1.62s	_{p=0.333 n=6}
_{Check Time}	_{16.46s (± 0.39%)}	_{16.44s (± 0.41%)}	_~	_16.36s	_16.54s	_{p=0.572 n=6}
_{Emit Time}	_0.00s	_{0.00s (±244.70%)}	_~	_0.00s	_0.01s	_{p=0.405 n=6}
_{Total Time}	_{20.92s (± 0.38%)}	_{20.83s (± 0.33%)}	_~	_20.75s	_20.93s	_{p=0.092 n=6}
_{vscode - node (v18.15.0, x64)}
_Errors	₆	₆	_~	_~	_~	_{p=1.000 n=6}
_Symbols	_3,910,861	_3,910,861	_~	_~	_~	_{p=1.000 n=6}
_Types	_1,229,620	_1,229,620	_~	_~	_~	_{p=1.000 n=6}
_{Memory used}	_{3,717,289k (± 0.00%)}	_{3,717,151k (± 0.00%)}	_~	_3,716,914k	_3,717,353k	_{p=0.173 n=6}
_{Parse Time}	_{15.25s (± 0.77%)}	_{15.18s (± 0.27%)}	_~	_15.13s	_15.24s	_{p=0.225 n=6}
_{Bind Time}	_{4.95s (± 0.49%)}	_{4.95s (± 0.24%)}	_~	_4.94s	_4.97s	_{p=0.806 n=6}
_{Check Time}	_{103.56s (± 3.21%)}	_{102.97s (± 2.49%)}	_~	_100.64s	_107.38s	_{p=0.689 n=6}
_{Emit Time}	_{31.92s (± 8.65%)}	_{36.50s (±16.65%)}	_{🔻+4.58s (+14.33%)}	_30.98s	_47.27s	_{p=0.030 n=6}
_{Total Time}	_{155.68s (± 2.13%)}	_{159.60s (± 3.92%)}	_~	_152.08s	_168.37s	_{p=0.173 n=6}
_{webpack - node (v18.15.0, x64)}
_Errors	₃₉	₃₉	_~	_~	_~	_{p=1.000 n=6}
_Symbols	_371,242	_371,242	_~	_~	_~	_{p=1.000 n=6}
_Types	_162,546	_162,546	_~	_~	_~	_{p=1.000 n=6}
_{Memory used}	_{526,506k (± 0.02%)}	_{526,515k (± 0.01%)}	_~	_526,422k	_526,611k	_{p=0.936 n=6}
_{Parse Time}	_{4.45s (± 0.53%)}	_{4.45s (± 0.77%)}	_~	_4.43s	_4.52s	_{p=1.000 n=6}
_{Bind Time}	_{1.91s (± 1.98%)}	_{1.93s (± 1.88%)}	_~	_1.89s	_1.97s	_{p=0.257 n=6}
_{Check Time}	_{21.99s (± 0.45%)}	_{22.02s (± 0.24%)}	_~	_21.95s	_22.09s	_{p=0.689 n=6}
_{Emit Time}	_{0.00s (±244.70%)}	_{0.00s (±244.70%)}	_~	_0.00s	_0.01s	_{p=1.000 n=6}
_{Total Time}	_{28.34s (± 0.48%)}	_{28.39s (± 0.22%)}	_~	_28.31s	_28.46s	_{p=0.423 n=6}
_{xstate-main - node (v18.15.0, x64)}
_Errors	₃₀	₃₀	_~	_~	_~	_{p=1.000 n=6}
_Symbols	_673,808	_673,808	_~	_~	_~	_{p=1.000 n=6}
_Types	_202,123	_202,123	_~	_~	_~	_{p=1.000 n=6}
_{Memory used}	_{576,322k (± 0.03%)}	_{576,458k (± 0.03%)}	_~	_576,167k	_576,579k	_{p=0.298 n=6}
_{Parse Time}	_{4.18s (± 0.77%)}	_{4.19s (± 0.73%)}	_~	_4.14s	_4.22s	_{p=0.686 n=6}
_{Bind Time}	_{1.34s (± 1.13%)}	_{1.34s (± 1.21%)}	_~	_1.32s	_1.37s	_{p=0.934 n=6}
_{Check Time}	_{20.78s (± 1.62%)}	_{20.47s (± 1.48%)}	_~	_20.14s	_21.05s	_{p=0.471 n=6}
_{Emit Time}	_0.00s	_0.00s	_~	_~	_~	_{p=1.000 n=6}
_{Total Time}	_{26.31s (± 1.31%)}	_{26.01s (± 1.17%)}	_~	_25.68s	_26.59s	_{p=0.471 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 · 2025-10-08T00:18:47Z

@RyanCavanaugh Here are the results of running the top 400 repos with tsc comparing main and refs/pull/62554/merge:

Everything looks good!

…rop-circularity

typescript-bot · 2026-03-24T21:22:40Z

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

Avoid an attempt to contextually type static property declaration usi…

e797862

…ng itself to avoid spurious circularity

github-project-automation bot added this to PR Backlog Oct 6, 2025

github-project-automation bot moved this to Not started in PR Backlog Oct 6, 2025

typescript-bot added the For Uncommitted Bug PR for untriaged, rejected, closed or missing bug label Oct 6, 2025

typescript-bot added For Backlog Bug PRs that fix a backlog bug and removed For Uncommitted Bug PR for untriaged, rejected, closed or missing bug labels Oct 7, 2025

RyanCavanaugh requested a review from ahejlsberg October 7, 2025 23:04

Andarist added 2 commits October 23, 2025 08:57

add extra test case

33ca003

Merge remote-tracking branch 'origin/main' into fix/spurious-static-p…

525b8d6

…rop-circularity

Andarist mentioned this pull request Oct 23, 2025

bug: const type parameter does not work with anonymous classes #62662

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typescript-bot closed this Mar 24, 2026

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Avoid an attempt to contextually type static property declaration using itself to avoid spurious circularity#62554

Avoid an attempt to contextually type static property declaration using itself to avoid spurious circularity#62554
Andarist wants to merge 3 commits intomicrosoft:mainfrom
Andarist:fix/spurious-static-prop-circularity

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