Avoid subtype reduction when creating a union result in `discriminateTypeByDiscriminableItems` #54052

Andarist · 2023-04-28T10:04:01Z

fixes #54048 (which is a recent regression from https://github.com/microsoft/TypeScript/pull/53709/files , cc @ahejlsberg )

…TypeByDiscriminableItems`

jakebailey · 2023-04-28T17:48:49Z

@typescript-bot test this
@typescript-bot test top100
@typescript-bot user test this
@typescript-bot run dt
@typescript-bot perf test this faster
@typescript-bot pack this

typescript-bot · 2023-04-28T17:49:09Z

Heya @jakebailey, I've started to run the extended test suite on this PR at 1ef6b24. You can monitor the build here.

typescript-bot · 2023-04-28T17:49:09Z

Heya @jakebailey, I've started to run the abridged perf test suite on this PR at 1ef6b24. You can monitor the build here.

Update: The results are in!

typescript-bot · 2023-04-28T17:49:09Z

Heya @jakebailey, I've started to run the tarball bundle task on this PR at 1ef6b24. You can monitor the build here.

typescript-bot · 2023-04-28T17:49:09Z

Heya @jakebailey, I've started to run the diff-based user code test suite on this PR at 1ef6b24. You can monitor the build here.

Update: The results are in!

typescript-bot · 2023-04-28T17:49:09Z

Heya @jakebailey, I've started to run the parallelized Definitely Typed test suite on this PR at 1ef6b24. You can monitor the build here.

Update: The results are in!

typescript-bot · 2023-04-28T17:49:09Z

Heya @jakebailey, I've started to run the diff-based top-repos suite on this PR at 1ef6b24. You can monitor the build here.

Update: The results are in!

typescript-bot · 2023-04-28T17:51:13Z

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/153488/artifacts?artifactName=tgz&fileId=58624324DE8EC1191EA9F435313E02981A83B8D982B7E34D31A749096E3A7DCE02&fileName=/typescript-5.1.0-insiders.20230428.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@5.1.0-pr-54052-7".;

typescript-bot · 2023-04-28T18:01:10Z

@jakebailey Here are the results of running the user test suite comparing main and refs/pull/54052/merge:

There were infrastructure failures potentially unrelated to your change:

1 instance of "Package install failed"

Otherwise...

Everything looks good!

typescript-bot · 2023-04-28T18:26:25Z

@jakebailey
The results of the perf run you requested are in!

Here they are:

Comparison Report - main..54052

_Metric	_main	₅₄₀₅₂	_Delta	_Best	_Worst	_p-value
_{Angular - node (v16.17.1, x64)}
_{Memory used}	_{365,294k (± 0.01%)}	_{365,345k (± 0.01%)}	_{+51k (+ 0.01%)}	_365,270k	_365,399k	_{p=0.045 n=6}
_{Parse Time}	_{3.55s (± 0.48%)}	_{3.54s (± 0.46%)}	_~	_3.52s	_3.56s	_{p=0.684 n=6}
_{Bind Time}	_{1.17s (± 0.47%)}	_{1.17s (± 0.35%)}	_~	_1.17s	_1.18s	_{p=0.282 n=6}
_{Check Time}	_{9.56s (± 0.33%)}	_{9.59s (± 0.50%)}	_~	_9.51s	_9.65s	_{p=0.295 n=6}
_{Emit Time}	_{7.89s (± 0.41%)}	_{7.96s (± 0.78%)}	_{+0.08s (+ 0.95%)}	_7.85s	_8.03s	_{p=0.045 n=6}
_{Total Time}	_{22.18s (± 0.22%)}	_{22.27s (± 0.50%)}	_~	_22.06s	_22.40s	_{p=0.065 n=6}
_{Compiler-Unions - node (v16.17.1, x64)}
_{Memory used}	_{193,803k (± 0.90%)}	_{192,728k (± 0.03%)}	_~	_192,639k	_192,812k	_{p=1.000 n=6}
_{Parse Time}	_{1.60s (± 0.51%)}	_{1.60s (± 0.86%)}	_~	_1.57s	_1.61s	_{p=1.000 n=6}
_{Bind Time}	_{0.82s (± 0.63%)}	_{0.82s (± 0.00%)}	_~	_0.82s	_0.82s	_{p=0.174 n=6}
_{Check Time}	_{10.22s (± 0.49%)}	_{10.30s (± 0.63%)}	_~	_10.22s	_10.38s	_{p=0.065 n=6}
_{Emit Time}	_{3.00s (± 1.32%)}	_{3.04s (± 1.64%)}	_~	_2.99s	_3.12s	_{p=0.147 n=6}
_{Total Time}	_{15.64s (± 0.30%)}	_{15.76s (± 0.61%)}	_{+0.11s (+ 0.71%)}	_15.61s	_15.88s	_{p=0.045 n=6}
_{Monaco - node (v16.17.1, x64)}
_{Memory used}	_{345,853k (± 0.00%)}	_{345,864k (± 0.01%)}	_~	_345,842k	_345,897k	_{p=0.422 n=6}
_{Parse Time}	_{2.72s (± 0.43%)}	_{2.72s (± 0.23%)}	_~	_2.71s	_2.73s	_{p=1.000 n=6}
_{Bind Time}	_{1.09s (± 0.75%)}	_{1.08s (± 0.38%)}	_{-0.01s (- 0.77%)}	_1.07s	_1.08s	_{p=0.038 n=6}
_{Check Time}	_{7.89s (± 0.57%)}	_{7.90s (± 0.62%)}	_~	_7.83s	_7.97s	_{p=0.686 n=6}
_{Emit Time}	_{4.49s (± 0.81%)}	_{4.50s (± 0.71%)}	_~	_4.46s	_4.55s	_{p=0.517 n=6}
_{Total Time}	_{16.18s (± 0.54%)}	_{16.21s (± 0.43%)}	_~	_16.09s	_16.28s	_{p=0.575 n=6}
_{TFS - node (v16.17.1, x64)}
_{Memory used}	_{300,100k (± 0.01%)}	_{300,101k (± 0.01%)}	_~	_300,062k	_300,136k	_{p=1.000 n=6}
_{Parse Time}	_{2.15s (± 0.54%)}	_{2.15s (± 0.54%)}	_~	_2.14s	_2.17s	_{p=1.000 n=6}
_{Bind Time}	_{1.23s (± 0.61%)}	_{1.24s (± 0.33%)}	_~	_1.23s	_1.24s	_{p=0.100 n=6}
_{Check Time}	_{7.29s (± 0.27%)}	_{7.30s (± 0.23%)}	_~	_7.27s	_7.32s	_{p=0.195 n=6}
_{Emit Time}	_{4.39s (± 0.81%)}	_{4.38s (± 0.89%)}	_~	_4.33s	_4.43s	_{p=0.468 n=6}
_{Total Time}	_{15.06s (± 0.30%)}	_{15.06s (± 0.42%)}	_~	_14.97s	_15.14s	_{p=1.000 n=6}
_{material-ui - node (v16.17.1, x64)}
_{Memory used}	_{481,600k (± 0.00%)}	_{481,692k (± 0.01%)}	_{+92k (+ 0.02%)}	_481,654k	_481,753k	_{p=0.005 n=6}
_{Parse Time}	_{3.22s (± 0.25%)}	_{3.24s (± 0.30%)}	_{+0.02s (+ 0.47%)}	_3.23s	_3.25s	_{p=0.026 n=6}
_{Bind Time}	_{0.94s (± 0.80%)}	_{0.93s (± 0.55%)}	_~	_0.93s	_0.94s	_{p=0.247 n=6}
_{Check Time}	_{17.90s (± 0.49%)}	_{18.41s (± 1.24%)}	_{+0.51s (+ 2.83%)}	_18.17s	_18.83s	_{p=0.005 n=6}
_{Emit Time}	_{0.00s (± 0.00%)}	_{0.00s (± 0.00%)}	_~	_0.00s	_0.00s	_{p=1.000 n=6}
_{Total Time}	_{22.06s (± 0.39%)}	_{22.58s (± 0.97%)}	_{+0.52s (+ 2.35%)}	_22.36s	_22.98s	_{p=0.005 n=6}
_{xstate - node (v16.17.1, x64)}
_{Memory used}	_{560,694k (± 0.02%)}	_{560,660k (± 0.02%)}	_~	_560,538k	_560,879k	_{p=0.471 n=6}
_{Parse Time}	_{3.97s (± 0.35%)}	_{3.99s (± 0.47%)}	_~	_3.97s	_4.02s	_{p=0.243 n=6}
_{Bind Time}	_{1.76s (± 0.56%)}	_{1.76s (± 0.47%)}	_~	_1.76s	_1.78s	_{p=0.273 n=6}
_{Check Time}	_{3.05s (± 0.13%)}	_{3.06s (± 0.27%)}	_{+0.01s (+ 0.49%)}	_3.05s	_3.07s	_{p=0.010 n=6}
_{Emit Time}	_{0.09s (± 0.00%)}	_{0.09s (± 0.00%)}	_~	_0.09s	_0.09s	_{p=1.000 n=6}
_{Total Time}	_{8.88s (± 0.22%)}	_{8.90s (± 0.15%)}	_{+0.03s (+ 0.30%)}	_8.88s	_8.92s	_{p=0.042 n=6}

System

_{Machine Name}	_ts-ci-ubuntu
_Platform	_{linux 5.4.0-148-generic}
_Architecture	_x64
_{Available Memory}	_{16 GB}
_{Available Memory}	_{15 GB}
_CPUs	_{4 × Intel(R) Core(TM) i7-4770 CPU @ 3.40GHz}

Hosts

node (v16.17.1, x64)

Scenarios

Angular - node (v16.17.1, x64)
Compiler-Unions - node (v16.17.1, x64)
Monaco - node (v16.17.1, x64)
TFS - node (v16.17.1, x64)
material-ui - node (v16.17.1, x64)
xstate - node (v16.17.1, x64)

_Benchmark	_Name	_Iterations
_Current	₅₄₀₅₂	₆
_Baseline	_main	₆

Developer Information:

Download Benchmark

jakebailey · 2023-04-28T18:57:58Z

@typescript-bot perf test this faster

typescript-bot · 2023-04-28T18:58:01Z

Heya @jakebailey, I've started to run the abridged perf test suite on this PR at 1ef6b24. You can monitor the build here.

Update: The results are in!

typescript-bot · 2023-04-28T19:13:30Z

@jakebailey
The results of the perf run you requested are in!

Here they are:

Comparison Report - main..54052

_Metric	_main	₅₄₀₅₂	_Delta	_Best	_Worst	_p-value
_{Angular - node (v16.17.1, x64)}
_{Memory used}	_{365,294k (± 0.01%)}	_{365,333k (± 0.00%)}	_{+39k (+ 0.01%)}	_365,315k	_365,350k	_{p=0.016 n=6}
_{Parse Time}	_{3.55s (± 0.48%)}	_{3.53s (± 0.76%)}	_~	_3.51s	_3.58s	_{p=0.145 n=6}
_{Bind Time}	_{1.17s (± 0.47%)}	_{1.17s (± 0.44%)}	_~	_1.17s	_1.18s	_{p=0.640 n=6}
_{Check Time}	_{9.56s (± 0.33%)}	_{9.59s (± 0.29%)}	_~	_9.57s	_9.64s	_{p=0.293 n=6}
_{Emit Time}	_{7.89s (± 0.41%)}	_{7.96s (± 0.84%)}	_~	_7.87s	_8.04s	_{p=0.108 n=6}
_{Total Time}	_{22.18s (± 0.22%)}	_{22.25s (± 0.24%)}	_{+0.07s (+ 0.33%)}	_22.16s	_22.30s	_{p=0.037 n=6}
_{Compiler-Unions - node (v16.17.1, x64)}
_{Memory used}	_{193,803k (± 0.90%)}	_{192,698k (± 0.02%)}	_~	_192,645k	_192,774k	_{p=0.689 n=6}
_{Parse Time}	_{1.60s (± 0.51%)}	_{1.59s (± 0.95%)}	_~	_1.57s	_1.60s	_{p=0.213 n=6}
_{Bind Time}	_{0.82s (± 0.63%)}	_{0.82s (± 0.66%)}	_~	_0.82s	_0.83s	_{p=0.640 n=6}
_{Check Time}	_{10.22s (± 0.49%)}	_{10.33s (± 0.58%)}	_{+0.11s (+ 1.06%)}	_10.25s	_10.40s	_{p=0.013 n=6}
_{Emit Time}	_{3.00s (± 1.32%)}	_{3.02s (± 1.35%)}	_~	_2.98s	_3.08s	_{p=0.423 n=6}
_{Total Time}	_{15.64s (± 0.30%)}	_{15.77s (± 0.58%)}	_{+0.12s (+ 0.78%)}	_15.62s	_15.88s	_{p=0.045 n=6}
_{Monaco - node (v16.17.1, x64)}
_{Memory used}	_{345,853k (± 0.00%)}	_{345,856k (± 0.00%)}	_~	_345,844k	_345,871k	_{p=0.936 n=6}
_{Parse Time}	_{2.72s (± 0.43%)}	_{2.73s (± 0.61%)}	_~	_2.71s	_2.75s	_{p=0.410 n=6}
_{Bind Time}	_{1.09s (± 0.75%)}	_{1.08s (± 0.59%)}	_~	_1.07s	_1.09s	_{p=0.097 n=6}
_{Check Time}	_{7.89s (± 0.57%)}	_{7.91s (± 0.37%)}	_~	_7.87s	_7.94s	_{p=0.373 n=6}
_{Emit Time}	_{4.49s (± 0.81%)}	_{4.50s (± 0.54%)}	_~	_4.47s	_4.53s	_{p=1.000 n=6}
_{Total Time}	_{16.18s (± 0.54%)}	_{16.22s (± 0.35%)}	_~	_16.15s	_16.31s	_{p=0.469 n=6}
_{TFS - node (v16.17.1, x64)}
_{Memory used}	_{300,100k (± 0.01%)}	_{300,113k (± 0.01%)}	_~	_300,089k	_300,132k	_{p=0.378 n=6}
_{Parse Time}	_{2.15s (± 0.54%)}	_{2.16s (± 0.63%)}	_~	_2.14s	_2.17s	_{p=0.562 n=6}
_{Bind Time}	_{1.23s (± 0.61%)}	_{1.24s (± 0.83%)}	_~	_1.22s	_1.25s	_{p=0.351 n=6}
_{Check Time}	_{7.29s (± 0.27%)}	_{7.26s (± 0.54%)}	_~	_7.23s	_7.32s	_{p=0.259 n=6}
_{Emit Time}	_{4.39s (± 0.81%)}	_{4.39s (± 1.01%)}	_~	_4.34s	_4.44s	_{p=0.936 n=6}
_{Total Time}	_{15.06s (± 0.30%)}	_{15.05s (± 0.56%)}	_~	_14.96s	_15.17s	_{p=0.872 n=6}
_{material-ui - node (v16.17.1, x64)}
_{Memory used}	_{481,600k (± 0.00%)}	_{481,688k (± 0.02%)}	_{+88k (+ 0.02%)}	_481,629k	_481,870k	_{p=0.008 n=6}
_{Parse Time}	_{3.22s (± 0.25%)}	_{3.24s (± 0.23%)}	_{+0.02s (+ 0.47%)}	_3.23s	_3.25s	_{p=0.015 n=6}
_{Bind Time}	_{0.94s (± 0.80%)}	_{0.93s (± 0.81%)}	_~	_0.92s	_0.94s	_{p=0.195 n=6}
_{Check Time}	_{17.90s (± 0.49%)}	_{18.15s (± 0.56%)}	_{+0.25s (+ 1.40%)}	_18.05s	_18.29s	_{p=0.005 n=6}
_{Emit Time}	_{0.00s (± 0.00%)}	_{0.00s (± 0.00%)}	_~	_0.00s	_0.00s	_{p=1.000 n=6}
_{Total Time}	_{22.06s (± 0.39%)}	_{22.32s (± 0.46%)}	_{+0.26s (+ 1.19%)}	_22.22s	_22.47s	_{p=0.005 n=6}
_{xstate - node (v16.17.1, x64)}
_{Memory used}	_{560,694k (± 0.02%)}	_{560,739k (± 0.02%)}	_~	_560,598k	_560,867k	_{p=0.575 n=6}
_{Parse Time}	_{3.97s (± 0.35%)}	_{3.97s (± 0.19%)}	_~	_3.96s	_3.98s	_{p=0.389 n=6}
_{Bind Time}	_{1.76s (± 0.56%)}	_{1.76s (± 0.43%)}	_~	_1.75s	_1.77s	_{p=0.554 n=6}
_{Check Time}	_{3.05s (± 0.13%)}	_{3.07s (± 0.39%)}	_{+0.02s (+ 0.60%)}	_3.05s	_3.08s	_{p=0.010 n=6}
_{Emit Time}	_{0.09s (± 0.00%)}	_{0.09s (± 0.00%)}	_~	_0.09s	_0.09s	_{p=1.000 n=6}
_{Total Time}	_{8.88s (± 0.22%)}	_{8.89s (± 0.20%)}	_~	_8.86s	_8.91s	_{p=0.258 n=6}

System

_{Machine Name}	_ts-ci-ubuntu
_Platform	_{linux 5.4.0-148-generic}
_Architecture	_x64
_{Available Memory}	_{16 GB}
_{Available Memory}	_{15 GB}
_CPUs	_{4 × Intel(R) Core(TM) i7-4770 CPU @ 3.40GHz}

Hosts

node (v16.17.1, x64)

Scenarios

Angular - node (v16.17.1, x64)
Compiler-Unions - node (v16.17.1, x64)
Monaco - node (v16.17.1, x64)
TFS - node (v16.17.1, x64)
material-ui - node (v16.17.1, x64)
xstate - node (v16.17.1, x64)

_Benchmark	_Name	_Iterations
_Current	₅₄₀₅₂	₆
_Baseline	_main	₆

Developer Information:

Download Benchmark

typescript-bot · 2023-04-28T19:55:11Z

Hey @jakebailey, the results of running the DT tests are ready.
Everything looks the same!
You can check the log here.

typescript-bot · 2023-04-28T20:07:03Z

@jakebailey Here are the results of running the top-repos suite comparing main and refs/pull/54052/merge:

Everything looks good!

Andarist · 2023-05-26T21:32:56Z

this is for 5.1 regression, is there any chance to get some eyes on it before the stable release?

DanielRosenwasser · 2023-05-26T22:17:04Z

@typescript-bot test this
@typescript-bot test top100
@typescript-bot user test this
@typescript-bot run dt
@typescript-bot perf test this faster
@typescript-bot pack this

typescript-bot · 2023-05-26T22:17:07Z

Heya @DanielRosenwasser, I've started to run the parallelized Definitely Typed test suite on this PR at 1ef6b24. You can monitor the build here.

Update: The results are in!

typescript-bot · 2023-05-26T22:17:07Z

Heya @DanielRosenwasser, I've started to run the diff-based top-repos suite on this PR at 1ef6b24. You can monitor the build here.

Update: The results are in!

typescript-bot · 2023-05-26T22:17:07Z

Heya @DanielRosenwasser, I've started to run the tarball bundle task on this PR at 1ef6b24. You can monitor the build here.

typescript-bot · 2023-05-26T22:17:07Z

Heya @DanielRosenwasser, I've started to run the extended test suite on this PR at 1ef6b24. You can monitor the build here.

typescript-bot · 2023-05-26T22:17:07Z

Heya @DanielRosenwasser, I've started to run the abridged perf test suite on this PR at 1ef6b24. You can monitor the build here.

Update: The results are in!

typescript-bot · 2023-05-26T22:17:07Z

Heya @DanielRosenwasser, I've started to run the diff-based user code test suite on this PR at 1ef6b24. You can monitor the build here.

Update: The results are in!

typescript-bot · 2023-05-26T22:18:56Z

Hey @DanielRosenwasser, 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/155020/artifacts?artifactName=tgz&fileId=371BFA1AE731F4CD85C993428125E1F040D1F3F411588EDE7261519EA824D12602&fileName=/typescript-5.2.0-insiders.20230526.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@5.2.0-pr-54052-23".;

ahejlsberg · 2023-05-26T22:24:18Z

In general I think this is a good change, we really shouldn't be subtype reducing contextual types (elsewhere we specifically avoid it). Seems like there's a slight performance regression in material-ui, but may just be that we're giving back the slight gain we got in #53709. Plus, TBH I'm not sure what we're really measuring with that old snapshot at this point.

typescript-bot · 2023-05-26T22:32:55Z

@DanielRosenwasser
The results of the perf run you requested are in!

Here they are:

Comparison Report - main..54052

_Metric	_main	₅₄₀₅₂	_Delta	_Best	_Worst	_p-value
_{Angular - node (v16.17.1, x64)}
_{Memory used}	_{365,242k (± 0.01%)}	_{365,247k (± 0.01%)}	_~	_365,187k	_365,303k	_{p=0.936 n=6}
_{Parse Time}	_{3.56s (± 0.49%)}	_{3.57s (± 0.46%)}	_~	_3.54s	_3.58s	_{p=0.744 n=6}
_{Bind Time}	_{1.18s (± 1.15%)}	_{1.19s (± 0.34%)}	_~	_1.19s	_1.20s	_{p=0.275 n=6}
_{Check Time}	_{9.55s (± 0.58%)}	_{9.62s (± 0.80%)}	_~	_9.52s	_9.71s	_{p=0.108 n=6}
_{Emit Time}	_{7.88s (± 0.46%)}	_{7.96s (± 1.01%)}	_~	_7.86s	_8.07s	_{p=0.064 n=6}
_{Total Time}	_{22.18s (± 0.41%)}	_{22.34s (± 0.63%)}	_~	_22.15s	_22.47s	_{p=0.053 n=6}
_{Compiler-Unions - node (v16.17.1, x64)}
_{Memory used}	_{193,524k (± 0.71%)}	_{192,919k (± 0.03%)}	_~	_192,836k	_192,986k	_{p=0.375 n=6}
_{Parse Time}	_{1.59s (± 1.52%)}	_{1.60s (± 1.16%)}	_~	_1.57s	_1.62s	_{p=0.511 n=6}
_{Bind Time}	_{0.82s (± 0.50%)}	_{0.83s (± 0.49%)}	_{+0.01s (+ 1.22%)}	_0.83s	_0.84s	_{p=0.008 n=6}
_{Check Time}	_{10.13s (± 0.70%)}	_{10.22s (± 0.62%)}	_{+0.09s (+ 0.90%)}	_10.13s	_10.30s	_{p=0.045 n=6}
_{Emit Time}	_{3.00s (± 0.88%)}	_{3.01s (± 0.66%)}	_~	_2.98s	_3.03s	_{p=0.406 n=6}
_{Total Time}	_{15.55s (± 0.53%)}	_{15.67s (± 0.43%)}	_{+0.12s (+ 0.75%)}	_15.56s	_15.75s	_{p=0.030 n=6}
_{Monaco - node (v16.17.1, x64)}
_{Memory used}	_{345,891k (± 0.00%)}	_{345,891k (± 0.00%)}	_~	_345,876k	_345,916k	_{p=0.935 n=6}
_{Parse Time}	_{2.73s (± 0.97%)}	_{2.74s (± 0.43%)}	_~	_2.73s	_2.76s	_{p=0.370 n=6}
_{Bind Time}	_{1.08s (± 0.48%)}	_{1.09s (± 0.37%)}	_~	_1.08s	_1.09s	_{p=0.112 n=6}
_{Check Time}	_{7.85s (± 0.23%)}	_{7.87s (± 0.36%)}	_~	_7.84s	_7.90s	_{p=0.368 n=6}
_{Emit Time}	_{4.46s (± 0.93%)}	_{4.49s (± 0.64%)}	_~	_4.46s	_4.53s	_{p=0.261 n=6}
_{Total Time}	_{16.12s (± 0.47%)}	_{16.19s (± 0.30%)}	_~	_16.14s	_16.25s	_{p=0.170 n=6}
_{TFS - node (v16.17.1, x64)}
_{Memory used}	_{299,951k (± 0.01%)}	_{299,965k (± 0.01%)}	_~	_299,947k	_299,994k	_{p=0.423 n=6}
_{Parse Time}	_{2.16s (± 0.35%)}	_{2.18s (± 0.84%)}	_~	_2.16s	_2.21s	_{p=0.063 n=6}
_{Bind Time}	_{1.24s (± 0.42%)}	_{1.24s (± 0.61%)}	_~	_1.23s	_1.25s	_{p=0.241 n=6}
_{Check Time}	_{7.27s (± 0.20%)}	_{7.28s (± 0.45%)}	_~	_7.24s	_7.32s	_{p=0.872 n=6}
_{Emit Time}	_{4.33s (± 0.72%)}	_{4.34s (± 0.56%)}	_~	_4.30s	_4.37s	_{p=0.413 n=6}
_{Total Time}	_{15.00s (± 0.28%)}	_{15.04s (± 0.23%)}	_~	_15.02s	_15.11s	_{p=0.089 n=6}
_{material-ui - node (v16.17.1, x64)}
_{Memory used}	_{480,988k (± 0.00%)}	_{481,071k (± 0.01%)}	_{+83k (+ 0.02%)}	_481,010k	_481,179k	_{p=0.013 n=6}
_{Parse Time}	_{3.25s (± 0.34%)}	_{3.26s (± 0.32%)}	_~	_3.24s	_3.27s	_{p=0.281 n=6}
_{Bind Time}	_{0.94s (± 0.55%)}	_{0.94s (± 0.43%)}	_~	_0.94s	_0.95s	_{p=0.114 n=6}
_{Check Time}	_{17.80s (± 0.30%)}	_{18.35s (± 0.60%)}	_{+0.55s (+ 3.10%)}	_18.16s	_18.45s	_{p=0.005 n=6}
_{Emit Time}	_{0.00s (± 0.00%)}	_{0.00s (± 0.00%)}	_~	_0.00s	_0.00s	_{p=1.000 n=6}
_{Total Time}	_{21.98s (± 0.23%)}	_{22.55s (± 0.48%)}	_{+0.57s (+ 2.58%)}	_22.37s	_22.67s	_{p=0.005 n=6}
_{xstate - node (v16.17.1, x64)}
_{Memory used}	_{560,637k (± 0.01%)}	_{560,571k (± 0.02%)}	_~	_560,488k	_560,710k	_{p=0.173 n=6}
_{Parse Time}	_{4.00s (± 0.44%)}	_{4.01s (± 0.60%)}	_~	_3.99s	_4.06s	_{p=0.732 n=6}
_{Bind Time}	_{1.77s (± 0.29%)}	_{1.76s (± 0.59%)}	_~	_1.75s	_1.78s	_{p=0.437 n=6}
_{Check Time}	_{3.06s (± 0.74%)}	_{3.08s (± 0.70%)}	_~	_3.04s	_3.09s	_{p=0.249 n=6}
_{Emit Time}	_{0.09s (± 0.00%)}	_{0.09s (± 0.00%)}	_~	_0.09s	_0.09s	_{p=1.000 n=6}
_{Total Time}	_{8.91s (± 0.38%)}	_{8.94s (± 0.41%)}	_~	_8.91s	_9.01s	_{p=0.125 n=6}

System

_{Machine Name}	_ts-ci-ubuntu
_Platform	_{linux 5.4.0-148-generic}
_Architecture	_x64
_{Available Memory}	_{16 GB}
_{Available Memory}	_{15 GB}
_CPUs	_{4 × Intel(R) Core(TM) i7-4770 CPU @ 3.40GHz}

Hosts

node (v16.17.1, x64)

Scenarios

Angular - node (v16.17.1, x64)
Compiler-Unions - node (v16.17.1, x64)
Monaco - node (v16.17.1, x64)
TFS - node (v16.17.1, x64)
material-ui - node (v16.17.1, x64)
xstate - node (v16.17.1, x64)

_Benchmark	_Name	_Iterations
_Current	₅₄₀₅₂	₆
_Baseline	_main	₆

Developer Information:

Download Benchmark

typescript-bot · 2023-05-26T22:44:32Z

@DanielRosenwasser Here are the results of running the user test suite comparing main and refs/pull/54052/merge:

There were infrastructure failures potentially unrelated to your change:

1 instance of "Unknown failure"
1 instance of "Package install failed"

Otherwise...

Everything looks good!

typescript-bot · 2023-05-26T23:52:32Z

Hey @DanielRosenwasser, the results of running the DT tests are ready.
Everything looks the same!
You can check the log here.

typescript-bot · 2023-05-27T00:10:58Z

@DanielRosenwasser Here are the results of running the top-repos suite comparing main and refs/pull/54052/merge:

Everything looks good!

Andarist · 2023-05-31T09:10:30Z

It seems that this PR got preliminary approval from @ahejlsberg . I wonder if it could land before 5.1 (and be cherry-picked into it) since its due date was supposed to be... yesterday 😅 (according to the 5.1 iteration plan)

…on-on-discriminated-items

DanielRosenwasser · 2023-06-27T18:48:25Z

It seems that this PR got preliminary approval from @ahejlsberg .

Sorry, can you link back to where? @weswigham can you take a look?

Andarist · 2023-06-27T18:52:02Z

@DanielRosenwasser here:

In general I think this is a good change, we really shouldn't be subtype reducing contextual types (elsewhere we specifically avoid it)

I called it preliminary since it didnt come with a more formal ✅ :P

DanielRosenwasser · 2023-07-18T21:40:50Z

Just documenting this one as a consistent 0.3-0.4 second regression.

jakebailey · 2023-07-18T21:42:32Z

Original PR which this PR fixes up shows an improvement, so it may be a wash maybe but not entirely :\

Avoid subtype reduction when creating a union result in `discriminate…

1ef6b24

…TypeByDiscriminableItems`

typescript-bot added the For Uncommitted Bug PR for untriaged, rejected, closed or missing bug label Apr 28, 2023

sandersn added this to Not started in PR Backlog May 8, 2023

sandersn requested review from weswigham and ahejlsberg May 24, 2023 22:17

sandersn assigned ahejlsberg May 24, 2023

sandersn moved this from Not started to Waiting on reviewers in PR Backlog May 24, 2023

jakebailey added this to the TypeScript 5.1.4 milestone Jun 6, 2023

typescript-bot added For Milestone Bug PRs that fix a bug with a specific milestone and removed For Uncommitted Bug PR for untriaged, rejected, closed or missing bug labels Jun 6, 2023

Merge remote-tracking branch 'origin/main' into avoid-subtype-reducti…

ab02254

…on-on-discriminated-items

DanielRosenwasser merged commit a3773ec into microsoft:main Jun 27, 2023
17 checks passed

PR Backlog automation moved this from Waiting on reviewers to Done Jun 27, 2023

Andarist deleted the avoid-subtype-reduction-on-discriminated-items branch June 27, 2023 19:04

This was referenced Dec 17, 2023

chore: set noPropertyAccessFromIndexSignature to true in tsconfig (on next-branch) trpc/trpc#5175

Closed

bug: TRPCClientError.ts compilation error due to typescript 5.1.3 type narrowing regression trpc/trpc#5176

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Avoid subtype reduction when creating a union result in `discriminateTypeByDiscriminableItems` #54052

Avoid subtype reduction when creating a union result in `discriminateTypeByDiscriminableItems` #54052

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Avoid subtype reduction when creating a union result in discriminateTypeByDiscriminableItems #54052

Avoid subtype reduction when creating a union result in discriminateTypeByDiscriminableItems #54052

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Avoid subtype reduction when creating a union result in `discriminateTypeByDiscriminableItems` #54052

Avoid subtype reduction when creating a union result in `discriminateTypeByDiscriminableItems` #54052

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