Allow implicit `undefined` returns when the contextual union type contains it #57912

Andarist · 2024-03-22T20:17:09Z

@RyanCavanaugh triaged this as a bug here. I'm pretty sure that @ahejlsberg didn't want this to work this way though (as per the description of #53607 and the comment in tests that I had to touch here).

…tains it

jakebailey · 2024-03-22T20:27:54Z

@typescript-bot test top400
@typescript-bot user test this
@typescript-bot run dt

@typescript-bot perf test this faster
@typescript-bot pack this

typescript-bot · 2024-03-22T20:27:57Z

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
`pack this`	✅ Started	✅ Results

typescript-bot · 2024-03-22T20:33:05Z

Hey @jakebailey, 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/160694/artifacts?artifactName=tgz&fileId=976D886DEE8ACEEF241EF5A35B6FFC03FD3FAC6E83579B8581E469403D8E9E5002&fileName=/typescript-5.5.0-insiders.20240322.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@5.5.0-pr-57912-2".;

typescript-bot · 2024-03-22T20:47:38Z

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

There were interesting changes:

Branch only errors:

Package: nodes7
Error:

Error: 
/mnt/vss/_work/1/DefinitelyTyped/types/nodes7/nodes7-tests.ts
  62:1  error  TypeScript@local compile error: 
Unused '@ts-expect-error' directive  @definitelytyped/expect

✖ 1 problem (1 error, 0 warnings)

    at combineErrorsAndWarnings (/mnt/vss/_work/1/DefinitelyTyped/node_modules/.pnpm/@definitelytyped+dtslint@0.2.18_typescript@5.5.0-dev.20240322/node_modules/@definitelytyped/dtslint/dist/index.js:194:28)
    at runTests (/mnt/vss/_work/1/DefinitelyTyped/node_modules/.pnpm/@definitelytyped+dtslint@0.2.18_typescript@5.5.0-dev.20240322/node_modules/@definitelytyped/dtslint/dist/index.js:186:20)

You can check the log here.

typescript-bot · 2024-03-22T20:52:14Z

@jakebailey Here are the results of running the user tests comparing main and refs/pull/57912/merge:

Everything looks good!

typescript-bot · 2024-03-22T20:57:45Z

@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
_{Angular - node (v18.15.0, x64)}
_{Memory used}	_{295,514k (± 0.01%)}	_{295,515k (± 0.00%)}	_~	_295,503k	_295,530k	_{p=0.199 n=6}
_{Parse Time}	_{2.66s (± 0.61%)}	_{2.67s (± 0.39%)}	_~	_2.65s	_2.68s	_{p=0.358 n=6}
_{Bind Time}	_{0.83s (± 0.66%)}	_{0.83s (± 1.41%)}	_~	_0.82s	_0.85s	_{p=0.859 n=6}
_{Check Time}	_{8.19s (± 0.23%)}	_{8.21s (± 0.31%)}	_~	_8.18s	_8.25s	_{p=0.226 n=6}
_{Emit Time}	_{7.05s (± 0.20%)}	_{7.06s (± 0.45%)}	_~	_7.03s	_7.12s	_{p=1.000 n=6}
_{Total Time}	_{18.73s (± 0.14%)}	_{18.76s (± 0.27%)}	_~	_18.72s	_18.85s	_{p=0.198 n=6}
_{Compiler-Unions - node (v18.15.0, x64)}
_{Memory used}	_{193,094k (± 0.94%)}	_{193,656k (± 1.01%)}	_~	_191,845k	_195,576k	_{p=0.810 n=6}
_{Parse Time}	_{1.35s (± 2.64%)}	_{1.36s (± 1.30%)}	_~	_1.33s	_1.38s	_{p=0.870 n=6}
_{Bind Time}	_{0.72s (± 0.00%)}	_{0.72s (± 0.00%)}	_~	_0.72s	_0.72s	_{p=1.000 n=6}
_{Check Time}	_{9.47s (± 0.68%)}	_{9.46s (± 0.34%)}	_~	_9.41s	_9.50s	_{p=0.935 n=6}
_{Emit Time}	_{2.62s (± 0.51%)}	_{2.62s (± 0.68%)}	_~	_2.59s	_2.64s	_{p=0.743 n=6}
_{Total Time}	_{14.15s (± 0.62%)}	_{14.15s (± 0.23%)}	_~	_14.10s	_14.19s	_{p=1.000 n=6}
_{Monaco - node (v18.15.0, x64)}
_{Memory used}	_{347,377k (± 0.01%)}	_{347,380k (± 0.01%)}	_~	_347,359k	_347,417k	_{p=0.810 n=6}
_{Parse Time}	_{2.48s (± 0.34%)}	_{2.48s (± 0.59%)}	_~	_2.46s	_2.50s	_{p=0.867 n=6}
_{Bind Time}	_{0.92s (± 0.56%)}	_{0.92s (± 0.59%)}	_~	_0.92s	_0.93s	_{p=0.640 n=6}
_{Check Time}	_{7.01s (± 0.42%)}	_{7.00s (± 0.28%)}	_~	_6.98s	_7.03s	_{p=0.324 n=6}
_{Emit Time}	_{4.06s (± 0.43%)}	_{4.06s (± 0.34%)}	_~	_4.04s	_4.08s	_{p=0.871 n=6}
_{Total Time}	_{14.49s (± 0.18%)}	_{14.47s (± 0.19%)}	_~	_14.42s	_14.49s	_{p=0.681 n=6}
_{TFS - node (v18.15.0, x64)}
_{Memory used}	_{302,689k (± 0.01%)}	_{302,713k (± 0.01%)}	_~	_302,681k	_302,754k	_{p=0.093 n=6}
_{Parse Time}	_{2.44s (± 0.48%)}	_{2.42s (± 0.89%)}	_{-0.03s (- 1.02%)}	_2.39s	_2.44s	_{p=0.034 n=6}
_{Bind Time}	_{1.20s (± 0.46%)}	_{1.20s (± 1.47%)}	_~	_1.18s	_1.23s	_{p=0.322 n=6}
_{Check Time}	_{7.46s (± 0.30%)}	_{7.45s (± 0.37%)}	_~	_7.42s	_7.50s	_{p=0.742 n=6}
_{Emit Time}	_{4.28s (± 0.58%)}	_{4.29s (± 0.82%)}	_~	_4.24s	_4.33s	_{p=0.872 n=6}
_{Total Time}	_{15.37s (± 0.25%)}	_{15.35s (± 0.37%)}	_~	_15.26s	_15.43s	_{p=0.627 n=6}
_{material-ui - node (v18.15.0, x64)}
_{Memory used}	_{509,899k (± 0.00%)}	_{509,899k (± 0.00%)}	_~	_509,885k	_509,920k	_{p=1.000 n=6}
_{Parse Time}	_{2.64s (± 0.56%)}	_{2.65s (± 0.50%)}	_~	_2.63s	_2.66s	_{p=0.394 n=6}
_{Bind Time}	_{0.99s (± 0.76%)}	_{0.98s (± 1.19%)}	_~	_0.96s	_0.99s	_{p=0.383 n=6}
_{Check Time}	_{17.22s (± 0.45%)}	_{17.27s (± 0.71%)}	_~	_17.18s	_17.50s	_{p=0.520 n=6}
_{Emit Time}	_{0.00s (± 0.00%)}	_{0.00s (± 0.00%)}	_~	_0.00s	_0.00s	_{p=1.000 n=6}
_{Total Time}	_{20.85s (± 0.32%)}	_{20.90s (± 0.65%)}	_~	_20.78s	_21.15s	_{p=0.747 n=6}
_{mui-docs - node (v18.15.0, x64)}
_{Memory used}	_{1,737,546k (± 0.00%)}	_{1,737,562k (± 0.00%)}	_~	_1,737,506k	_1,737,594k	_{p=0.378 n=6}
_{Parse Time}	_{7.76s (± 0.29%)}	_{7.80s (± 0.59%)}	_~	_7.76s	_7.88s	_{p=0.122 n=6}
_{Bind Time}	_{2.79s (± 0.67%)}	_{2.81s (± 1.18%)}	_~	_2.76s	_2.86s	_{p=0.373 n=6}
_{Check Time}	_{66.65s (± 0.38%)}	_{66.61s (± 0.49%)}	_~	_66.14s	_66.99s	_{p=0.748 n=6}
_{Emit Time}	_{0.15s (± 3.53%)}	_{0.15s (± 2.69%)}	_~	_0.15s	_0.16s	_{p=0.282 n=6}
_{Total Time}	_{77.36s (± 0.34%)}	_{77.37s (± 0.39%)}	_~	_76.87s	_77.72s	_{p=1.000 n=6}
_{self-build-src - node (v18.15.0, x64)}
_{Memory used}	_{2,394,576k (± 0.03%)}	_{2,394,386k (± 0.02%)}	_~	_2,393,918k	_2,394,850k	_{p=0.378 n=6}
_{Parse Time}	_{6.05s (± 1.49%)}	_{6.05s (± 0.44%)}	_~	_6.02s	_6.08s	_{p=0.575 n=6}
_{Bind Time}	_{2.26s (± 0.97%)}	_{2.25s (± 0.96%)}	_~	_2.24s	_2.29s	_{p=0.931 n=6}
_{Check Time}	_{39.43s (± 0.22%)}	_{39.48s (± 0.39%)}	_~	_39.29s	_39.72s	_{p=0.689 n=6}
_{Emit Time}	_{3.14s (± 1.17%)}	_{3.13s (± 1.28%)}	_~	_3.09s	_3.19s	_{p=0.873 n=6}
_{Total Time}	_{50.89s (± 0.20%)}	_{50.92s (± 0.29%)}	_~	_50.70s	_51.13s	_{p=0.630 n=6}
_{self-compiler - node (v18.15.0, x64)}
_{Memory used}	_{415,193k (± 0.00%)}	_{415,235k (± 0.01%)}	_{+42k (+ 0.01%)}	_415,187k	_415,270k	_{p=0.031 n=6}
_{Parse Time}	_{3.41s (± 1.15%)}	_{3.40s (± 1.31%)}	_~	_3.34s	_3.46s	_{p=0.515 n=6}
_{Bind Time}	_{1.29s (± 0.94%)}	_{1.28s (± 0.77%)}	_~	_1.27s	_1.29s	_{p=0.507 n=6}
_{Check Time}	_{18.07s (± 0.36%)}	_{18.07s (± 0.34%)}	_~	_17.99s	_18.16s	_{p=0.936 n=6}
_{Emit Time}	_{1.34s (± 1.19%)}	_{1.31s (± 1.04%)}	_{-0.03s (- 2.11%)}	_1.29s	_1.33s	_{p=0.015 n=6}
_{Total Time}	_{24.11s (± 0.35%)}	_{24.07s (± 0.42%)}	_~	_23.97s	_24.23s	_{p=0.572 n=6}
_{vscode - node (v18.15.0, x64)}
_{Memory used}	_{2,890,201k (± 0.00%)}	_{2,890,195k (± 0.00%)}	_~	_2,890,082k	_2,890,313k	_{p=0.873 n=6}
_{Parse Time}	_{12.93s (± 0.52%)}	_{12.93s (± 0.27%)}	_~	_12.88s	_12.98s	_{p=0.810 n=6}
_{Bind Time}	_{4.12s (± 0.42%)}	_{4.12s (± 0.36%)}	_~	_4.11s	_4.14s	_{p=1.000 n=6}
_{Check Time}	_{71.71s (± 0.55%)}	_{71.52s (± 0.37%)}	_~	_71.21s	_71.86s	_{p=0.378 n=6}
_{Emit Time}	_{19.44s (± 0.36%)}	_{19.45s (± 0.52%)}	_~	_19.33s	_19.62s	_{p=1.000 n=6}
_{Total Time}	_{108.20s (± 0.44%)}	_{108.03s (± 0.30%)}	_~	_107.72s	_108.59s	_{p=0.689 n=6}
_{webpack - node (v18.15.0, x64)}
_{Memory used}	_{408,148k (± 0.01%)}	_{408,114k (± 0.01%)}	_~	_408,077k	_408,140k	_{p=0.092 n=6}
_{Parse Time}	_{3.91s (± 0.53%)}	_{3.90s (± 0.53%)}	_~	_3.87s	_3.93s	_{p=0.223 n=6}
_{Bind Time}	_{1.69s (± 0.61%)}	_{1.67s (± 1.05%)}	_~	_1.66s	_1.70s	_{p=0.249 n=6}
_{Check Time}	_{16.73s (± 0.43%)}	_{16.75s (± 0.41%)}	_~	_16.67s	_16.86s	_{p=0.748 n=6}
_{Emit Time}	_{0.00s (± 0.00%)}	_{0.00s (± 0.00%)}	_~	_0.00s	_0.00s	_{p=1.000 n=6}
_{Total Time}	_{22.34s (± 0.35%)}	_{22.33s (± 0.31%)}	_~	_22.25s	_22.43s	_{p=0.936 n=6}
_{xstate - node (v18.15.0, x64)}
_{Memory used}	_{513,082k (± 0.02%)}	_{512,993k (± 0.02%)}	_~	_512,925k	_513,136k	_{p=0.066 n=6}
_{Parse Time}	_{3.95s (± 0.41%)}	_{4.01s (± 4.24%)}	_~	_3.92s	_4.35s	_{p=0.746 n=6}
_{Bind Time}	_{1.86s (± 0.88%)}	_{1.84s (± 0.74%)}	_~	_1.82s	_1.86s	_{p=0.085 n=6}
_{Check Time}	_{3.39s (± 0.86%)}	_{3.36s (± 0.15%)}	_~	_3.36s	_3.37s	_{p=0.100 n=6}
_{Emit Time}	_{0.09s (± 4.62%)}	_{0.09s (± 6.44%)}	_~	_0.08s	_0.09s	_{p=0.282 n=6}
_{Total Time}	_{9.27s (± 0.38%)}	_{9.30s (± 1.74%)}	_~	_9.20s	_9.62s	_{p=0.336 n=6}

System info unknown

Hosts

node (v18.15.0, x64)

Scenarios

Angular - node (v18.15.0, x64)
Compiler-Unions - node (v18.15.0, x64)
Monaco - node (v18.15.0, x64)
TFS - node (v18.15.0, x64)
material-ui - node (v18.15.0, x64)
mui-docs - node (v18.15.0, x64)
self-build-src - node (v18.15.0, x64)
self-compiler - node (v18.15.0, x64)
vscode - node (v18.15.0, x64)
webpack - node (v18.15.0, x64)
xstate - node (v18.15.0, x64)

_Benchmark	_Name	_Iterations
_Current	_pr	₆
_Baseline	_baseline	₆

Developer Information:

Download Benchmarks

RyanCavanaugh · 2024-03-22T21:35:22Z

I think there's a possible parsing ambiguity in the referenced comment

Note that this does not apply to functions with union return types that include undefined

Foo | (() => undefined) vs () => (Foo | undefined)

typescript-bot · 2024-03-22T22:00:22Z

@jakebailey Here are the results of running the top 400 repos comparing main and refs/pull/57912/merge:

Everything looks good!

Andarist · 2024-03-23T14:55:25Z

The single reported failure here comes from those lines here. We can quickly verify on this TS playground that the contextual type of this function is (name: string) => string | undefined. So it makes sense that the error went away with this PR.

…turn-contextual-union # Conflicts: # tests/baselines/reference/functionsMissingReturnStatementsAndExpressionsStrictNullChecks.types # tests/baselines/reference/inferenceDoesNotAddUndefinedOrNull.types

Allow implicit undefined returns when the contextual union type con…

c309c6f

…tains it

typescript-bot added the For Backlog Bug PRs that fix a backlog bug label Mar 22, 2024

sandersn added this to Not started in PR Backlog Apr 2, 2024

Merge remote-tracking branch 'origin/main' into implicit-undefined-re…

4042168

…turn-contextual-union # Conflicts: # tests/baselines/reference/functionsMissingReturnStatementsAndExpressionsStrictNullChecks.types # tests/baselines/reference/inferenceDoesNotAddUndefinedOrNull.types

DanielRosenwasser mentioned this pull request May 2, 2024

Design Meeting Notes, 3/29/2024 #58412

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Allow implicit `undefined` returns when the contextual union type contains it #57912

Allow implicit `undefined` returns when the contextual union type contains it #57912

Andarist commented Mar 22, 2024

jakebailey commented Mar 22, 2024

typescript-bot commented Mar 22, 2024 •

edited

typescript-bot commented Mar 22, 2024 •

edited

typescript-bot commented Mar 22, 2024

typescript-bot commented Mar 22, 2024

typescript-bot commented Mar 22, 2024

tsc

RyanCavanaugh commented Mar 22, 2024

typescript-bot commented Mar 22, 2024

Andarist commented Mar 23, 2024

Allow implicit undefined returns when the contextual union type contains it #57912

Are you sure you want to change the base?

Allow implicit undefined returns when the contextual union type contains it #57912

Conversation

Andarist commented Mar 22, 2024

jakebailey commented Mar 22, 2024

typescript-bot commented Mar 22, 2024 • edited

typescript-bot commented Mar 22, 2024 • edited

typescript-bot commented Mar 22, 2024

typescript-bot commented Mar 22, 2024

typescript-bot commented Mar 22, 2024

tsc

RyanCavanaugh commented Mar 22, 2024

typescript-bot commented Mar 22, 2024

Andarist commented Mar 23, 2024

Allow implicit `undefined` returns when the contextual union type contains it #57912

Allow implicit `undefined` returns when the contextual union type contains it #57912

typescript-bot commented Mar 22, 2024 •

edited

typescript-bot commented Mar 22, 2024 •

edited