Widen reverse mapped type properties to fix them being treated as EPC-valid sources #62722

Andarist · 2025-11-05T17:51:58Z

…-valid sources

jakebailey · 2025-11-05T17:54:43Z

typescript-bot · 2025-11-05T17:54:49Z

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

Andarist · 2025-11-05T17:58:41Z

src/compiler/checker.ts

        const inference = createInferenceInfo(typeParameter);
        inferTypes([inference], sourceType, templateType);
-        return getTypeFromInference(inference) || unknownType;
+        return getWidenedType(getTypeFromInference(inference) || unknownType);


note for reviewers: this is what getCovariantInference already does

typescript-bot · 2025-11-05T18:17:05Z

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

Everything looks the same!

You can check the log here.

typescript-bot · 2025-11-05T18:24:21Z

@jakebailey Here are the results of running the user tests with tsc comparing main and refs/pull/62722/merge:

There were infrastructure failures potentially unrelated to your change:

1 instance of "Git clone failed"

Otherwise...

Everything looks good!

typescript-bot · 2025-11-05T18:47:30Z

@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}	_{193,880k (± 0.95%)}	_{195,057k (± 0.95%)}	_~	_192,645k	_196,350k	_{p=0.689 n=6}
_{Parse Time}	_{1.30s (± 0.80%)}	_{1.30s (± 0.63%)}	_~	_1.29s	_1.31s	_{p=0.181 n=6}
_{Bind Time}	_0.72s	_{0.72s (± 0.57%)}	_~	_0.72s	_0.73s	_{p=0.405 n=6}
_{Check Time}	_{9.87s (± 0.31%)}	_{9.88s (± 0.33%)}	_~	_9.83s	_9.92s	_{p=0.628 n=6}
_{Emit Time}	_{2.73s (± 0.60%)}	_{2.74s (± 0.61%)}	_~	_2.72s	_2.76s	_{p=0.615 n=6}
_{Total Time}	_{14.63s (± 0.25%)}	_{14.65s (± 0.25%)}	_~	_14.60s	_14.69s	_{p=0.572 n=6}
_{angular-1 - node (v18.15.0, x64)}
_Errors	₂	₂	_~	_~	_~	_{p=1.000 n=6}
_Symbols	_956,047	_956,049	_{+2 (+ 0.00%)}	_~	_~	_{p=0.001 n=6}
_Types	_415,881	_415,885	_{+4 (+ 0.00%)}	_~	_~	_{p=0.001 n=6}
_{Memory used}	_{1,255,044k (± 0.00%)}	_{1,255,067k (± 0.00%)}	_~	_1,254,996k	_1,255,125k	_{p=0.336 n=6}
_{Parse Time}	_{6.54s (± 0.70%)}	_{6.52s (± 0.44%)}	_~	_6.47s	_6.55s	_{p=0.624 n=6}
_{Bind Time}	_{1.88s (± 0.22%)}	_{1.88s (± 0.34%)}	_~	_1.87s	_1.89s	_{p=0.673 n=6}
_{Check Time}	_{32.22s (± 0.25%)}	_{32.16s (± 0.29%)}	_~	_32.01s	_32.29s	_{p=0.378 n=6}
_{Emit Time}	_{14.91s (± 0.26%)}	_{14.92s (± 0.23%)}	_~	_14.87s	_14.97s	_{p=0.627 n=6}
_{Total Time}	_{55.55s (± 0.19%)}	_{55.49s (± 0.16%)}	_~	_55.34s	_55.61s	_{p=0.261 n=6}
_{mui-docs - node (v18.15.0, x64)}
_Errors	₁	₁	_~	_~	_~	_{p=1.000 n=6}
_Symbols	_552,568	_552,568	_~	_~	_~	_{p=1.000 n=6}
_Types	₈₉	₈₉	_~	_~	_~	_{p=1.000 n=6}
_{Memory used}	_{827,063k (± 0.00%)}	_{827,078k (± 0.00%)}	_~	_827,056k	_827,112k	_{p=0.423 n=6}
_{Parse Time}	_{8.39s (± 0.51%)}	_{8.37s (± 0.19%)}	_~	_8.34s	_8.38s	_{p=0.198 n=6}
_{Bind Time}	_{2.18s (± 0.54%)}	_{2.19s (± 0.29%)}	_~	_2.18s	_2.20s	_{p=0.177 n=6}
_{Check Time}	_0.00s	_0.00s	_~	_~	_~	_{p=1.000 n=6}
_{Emit Time}	_0.28s	_0.28s	_~	_~	_~	_{p=1.000 n=6}
_{Total Time}	_{10.85s (± 0.43%)}	_{10.83s (± 0.08%)}	_~	_10.82s	_10.84s	_{p=0.568 n=6}
_{self-build-src - node (v18.15.0, x64)}
_Errors	₀	₀	_~	_~	_~	_{p=1.000 n=6}
_Symbols	_1,237,277	_1,237,673	_{+396 (+ 0.03%)}	_~	_~	_{p=0.001 n=6}
_Types	_259,883	_259,883	_~	_~	_~	_{p=1.000 n=6}
_{Memory used}	_{2,547,232k (±11.94%)}	_{2,365,472k (± 0.01%)}	_~	_2,365,139k	_2,366,028k	_{p=0.471 n=6}
_{Parse Time}	_{5.14s (± 1.53%)}	_{5.12s (± 0.45%)}	_~	_5.09s	_5.16s	_{p=1.000 n=6}
_{Bind Time}	_{1.76s (± 0.77%)}	_{1.78s (± 1.30%)}	_~	_1.76s	_1.82s	_{p=0.361 n=6}
_{Check Time}	_{35.30s (± 0.84%)}	_{35.20s (± 0.38%)}	_~	_34.98s	_35.36s	_{p=0.173 n=6}
_{Emit Time}	_{3.01s (± 1.20%)}	_{2.99s (± 0.66%)}	_~	_2.98s	_3.03s	_{p=0.254 n=6}
_{Total Time}	_{45.22s (± 0.62%)}	_{45.12s (± 0.31%)}	_~	_44.91s	_45.32s	_{p=0.378 n=6}
_{self-build-src-public-api - node (v18.15.0, x64)}
_Errors	₀	₀	_~	_~	_~	_{p=1.000 n=6}
_Symbols	_1,237,277	_1,237,673	_{+396 (+ 0.03%)}	_~	_~	_{p=0.001 n=6}
_Types	_259,883	_259,883	_~	_~	_~	_{p=1.000 n=6}
_{Memory used}	_{3,159,604k (± 0.02%)}	_{3,159,135k (± 0.02%)}	_~	_3,158,123k	_3,160,230k	_{p=0.378 n=6}
_{Parse Time}	_{6.86s (± 0.85%)}	_{6.87s (± 0.89%)}	_~	_6.79s	_6.95s	_{p=0.689 n=6}
_{Bind Time}	_{2.14s (± 1.31%)}	_{2.13s (± 0.46%)}	_~	_2.12s	_2.15s	_{p=0.171 n=6}
_{Check Time}	_{42.78s (± 0.20%)}	_{42.86s (± 0.29%)}	_~	_42.68s	_43.02s	_{p=0.298 n=6}
_{Emit Time}	_{3.51s (± 3.34%)}	_{3.56s (± 1.60%)}	_~	_3.52s	_3.67s	_{p=0.688 n=6}
_{Total Time}	_{55.30s (± 0.27%)}	_{55.41s (± 0.34%)}	_~	_55.11s	_55.58s	_{p=0.298 n=6}
_{self-compiler - node (v18.15.0, x64)}
_Errors	₀	₀	_~	_~	_~	_{p=1.000 n=6}
_Symbols	_262,522	_262,918	_{+396 (+ 0.15%)}	_~	_~	_{p=0.001 n=6}
_Types	_104,048	_104,048	_~	_~	_~	_{p=1.000 n=6}
_{Memory used}	_{440,693k (± 0.01%)}	_{440,815k (± 0.01%)}	_{+122k (+ 0.03%)}	_440,751k	_440,892k	_{p=0.008 n=6}
_{Parse Time}	_{3.49s (± 0.93%)}	_{3.51s (± 0.59%)}	_~	_3.48s	_3.54s	_{p=0.196 n=6}
_{Bind Time}	_{1.33s (± 1.20%)}	_{1.32s (± 0.57%)}	_~	_1.31s	_1.33s	_{p=0.457 n=6}
_{Check Time}	_{19.06s (± 0.33%)}	_{19.03s (± 0.47%)}	_~	_18.87s	_19.13s	_{p=0.518 n=6}
_{Emit Time}	_{1.53s (± 1.52%)}	_{1.52s (± 0.54%)}	_~	_1.51s	_1.53s	_{p=0.100 n=6}
_{Total Time}	_{25.42s (± 0.31%)}	_{25.38s (± 0.29%)}	_~	_25.26s	_25.49s	_{p=0.520 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}	_{370,088k (± 0.04%)}	_{370,083k (± 0.03%)}	_~	_369,994k	_370,285k	_{p=0.810 n=6}
_{Parse Time}	_{2.83s (± 1.38%)}	_{2.81s (± 1.44%)}	_~	_2.75s	_2.85s	_{p=0.687 n=6}
_{Bind Time}	_{1.60s (± 1.02%)}	_{1.60s (± 1.08%)}	_~	_1.58s	_1.63s	_{p=0.452 n=6}
_{Check Time}	_{16.53s (± 0.23%)}	_{16.56s (± 0.44%)}	_~	_16.48s	_16.69s	_{p=0.630 n=6}
_{Emit Time}	_{0.00s (±244.70%)}	_0.00s	_~	_~	_~	_{p=0.405 n=6}
_{Total Time}	_{20.96s (± 0.26%)}	_{20.97s (± 0.17%)}	_~	_20.92s	_21.02s	_{p=1.000 n=6}
_{vscode - node (v18.15.0, x64)}
_Errors	₅	₅	_~	_~	_~	_{p=1.000 n=6}
_Symbols	_4,016,547	_4,016,547	_~	_~	_~	_{p=1.000 n=6}
_Types	_1,260,033	_1,260,033	_~	_~	_~	_{p=1.000 n=6}
_{Memory used}	_{3,797,947k (± 0.00%)}	_{3,797,813k (± 0.00%)}	_~	_3,797,541k	_3,798,009k	_{p=0.471 n=6}
_{Parse Time}	_{15.56s (± 0.54%)}	_{15.54s (± 0.49%)}	_~	_15.45s	_15.65s	_{p=0.809 n=6}
_{Bind Time}	_{5.02s (± 0.63%)}	_{5.05s (± 0.78%)}	_~	_4.99s	_5.09s	_{p=0.172 n=6}
_{Check Time}	_{104.91s (± 3.93%)}	_{105.54s (± 3.66%)}	_~	_101.88s	_110.75s	_{p=1.000 n=6}
_{Emit Time}	_{41.64s (±27.71%)}	_{40.49s (±15.53%)}	_~	_31.40s	_48.95s	_{p=0.936 n=6}
_{Total Time}	_{167.13s (± 5.84%)}	_{166.62s (± 5.11%)}	_~	_160.21s	_177.82s	_{p=0.810 n=6}
_{webpack - node (v18.15.0, x64)}
_Errors	₄₀	₄₀	_~	_~	_~	_{p=1.000 n=6}
_Symbols	_379,091	_379,091	_~	_~	_~	_{p=1.000 n=6}
_Types	_166,343	_166,343	_~	_~	_~	_{p=1.000 n=6}
_{Memory used}	_{538,010k (± 0.01%)}	_{538,010k (± 0.02%)}	_~	_537,882k	_538,162k	_{p=0.873 n=6}
_{Parse Time}	_{4.60s (± 0.53%)}	_{4.61s (± 0.57%)}	_~	_4.57s	_4.65s	_{p=0.935 n=6}
_{Bind Time}	_{1.95s (± 0.39%)}	_{1.92s (± 0.97%)}	_{-0.02s (- 1.28%)}	_1.90s	_1.95s	_{p=0.032 n=6}
_{Check Time}	_{22.63s (± 0.27%)}	_{22.63s (± 0.36%)}	_~	_22.49s	_22.70s	_{p=0.686 n=6}
_{Emit Time}	_0.00s	_0.00s	_~	_~	_~	_{p=1.000 n=6}
_{Total Time}	_{29.18s (± 0.21%)}	_{29.16s (± 0.26%)}	_~	_29.03s	_29.24s	_{p=0.683 n=6}
_{xstate-main - node (v18.15.0, x64)}
_Errors	₃₀	₃₀	_~	_~	_~	_{p=1.000 n=6}
_Symbols	_690,485	_690,485	_~	_~	_~	_{p=1.000 n=6}
_Types	_208,757	_208,757	_~	_~	_~	_{p=1.000 n=6}
_{Memory used}	_{586,574k (± 0.03%)}	_{586,541k (± 0.02%)}	_~	_586,413k	_586,768k	_{p=0.810 n=6}
_{Parse Time}	_{4.18s (± 0.89%)}	_{4.18s (± 0.49%)}	_~	_4.15s	_4.21s	_{p=1.000 n=6}
_{Bind Time}	_{1.34s (± 1.28%)}	_{1.35s (± 1.28%)}	_~	_1.32s	_1.37s	_{p=0.625 n=6}
_{Check Time}	_{20.69s (± 2.08%)}	_{20.87s (± 2.05%)}	_~	_20.29s	_21.24s	_{p=0.229 n=6}
_{Emit Time}	_0.00s	_{0.00s (±154.76%)}	_~	_0.00s	_0.01s	_{p=0.174 n=6}
_{Total Time}	_{26.21s (± 1.74%)}	_{26.40s (± 1.68%)}	_~	_25.83s	_26.80s	_{p=0.377 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 · 2025-11-05T19:24:08Z

@jakebailey Here are the results of running the top 400 repos with tsc comparing main and refs/pull/62722/merge:

Everything looks good!

Widen reverse mapped type properties to fix them being treated as EPC…

97a061d

…-valid sources

github-project-automation bot moved this to Not started in PR Backlog Nov 5, 2025

github-project-automation bot added this to PR Backlog Nov 5, 2025

typescript-bot added the For Uncommitted Bug PR for untriaged, rejected, closed or missing bug label Nov 5, 2025

move the fix to inferReverseMappedTypeWorker

6fd5860

Andarist commented Nov 5, 2025

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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 Nov 5, 2025

RyanCavanaugh requested a review from ahejlsberg November 5, 2025 19:31

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