Fix support for intersections in template literal placeholder types by ahejlsberg · Pull Request #56434 · microsoft/TypeScript

Anders Hejlsberg (ahejlsberg) · 2023-11-16T17:37:05Z

Implements the changes discussed here and fixes#54177 according to our design meeting discussion.

Anders Hejlsberg (ahejlsberg) · 2023-11-16T17:41:50Z

TypeScript Bot (@typescript-bot) test top100
TypeScript Bot (@typescript-bot) user test this
TypeScript Bot (@typescript-bot) run dt
TypeScript Bot (@typescript-bot) perf test this faster

TypeScript Bot (typescript-bot) · 2023-11-16T17:41:52Z

Heya Anders Hejlsberg (@ahejlsberg), I've started to run the tsc-only perf test suite on this PR at ca7e9c4. You can monitor the build here.

Update: The results are in!

TypeScript Bot (typescript-bot) · 2023-11-16T17:41:52Z

Heya Anders Hejlsberg (@ahejlsberg), I've started to run the diff-based user code test suite on this PR at ca7e9c4. You can monitor the build here.

Update: The results are in!

TypeScript Bot (typescript-bot) · 2023-11-16T17:41:52Z

Heya Anders Hejlsberg (@ahejlsberg), I've started to run the diff-based top-repos suite on this PR at ca7e9c4. You can monitor the build here.

Update: The results are in!

TypeScript Bot (typescript-bot) · 2023-11-16T17:41:52Z

Heya Anders Hejlsberg (@ahejlsberg), I've started to run the parallelized Definitely Typed test suite on this PR at ca7e9c4. You can monitor the build here.

Update: The results are in!

TypeScript Bot (typescript-bot) · 2023-11-16T17:53:34Z

Anders Hejlsberg (@ahejlsberg)
The results of the perf run you requested are in!

Here they are:

Compiler

Comparison Report - baseline..pr

_Metric	_baseline	_pr	_Delta	_Best	_Worst	_p-value
_{Angular - node (v18.15.0, x64)}
_{Memory used}	_{295,199k (± 0.01%)}	_{295,206k (± 0.01%)}	_~	_295,164k	_295,243k	_{p=0.688 n=6}
_{Parse Time}	_{2.64s (± 0.20%)}	_{2.64s (± 0.24%)}	_~	_2.63s	_2.65s	_{p=0.386 n=6}
_{Bind Time}	_{0.83s (± 0.76%)}	_{0.82s (± 0.00%)}	_{-0.01s (- 1.20%)}	_0.82s	_0.82s	_{p=0.008 n=6}
_{Check Time}	_{8.04s (± 0.25%)}	_{8.04s (± 0.27%)}	_~	_8.01s	_8.07s	_{p=0.807 n=6}
_{Emit Time}	_{7.05s (± 0.07%)}	_{7.08s (± 0.18%)}	_{+0.03s (+ 0.38%)}	_7.06s	_7.09s	_{p=0.006 n=6}
_{Total Time}	_{18.57s (± 0.10%)}	_{18.58s (± 0.07%)}	_~	_18.56s	_18.60s	_{p=0.504 n=6}
_{Compiler-Unions - node (v18.15.0, x64)}
_{Memory used}	_{191,704k (± 1.28%)}	_{194,049k (± 1.47%)}	_~	_190,708k	_196,557k	_{p=0.128 n=6}
_{Parse Time}	_{1.35s (± 0.38%)}	_{1.37s (± 0.72%)}	_{+0.01s (+ 1.11%)}	_1.35s	_1.38s	_{p=0.022 n=6}
_{Bind Time}	_{0.72s (± 0.00%)}	_{0.72s (± 0.00%)}	_~	_0.72s	_0.72s	_{p=1.000 n=6}
_{Check Time}	_{9.17s (± 0.36%)}	_{9.17s (± 0.33%)}	_~	_9.11s	_9.20s	_{p=0.872 n=6}
_{Emit Time}	_{2.64s (± 0.29%)}	_{2.65s (± 0.57%)}	_~	_2.62s	_2.66s	_{p=0.316 n=6}
_{Total Time}	_{13.88s (± 0.28%)}	_{13.89s (± 0.20%)}	_~	_13.85s	_13.93s	_{p=0.747 n=6}
_{Monaco - node (v18.15.0, x64)}
_{Memory used}	_{347,341k (± 0.00%)}	_{347,353k (± 0.01%)}	_~	_347,315k	_347,383k	_{p=0.378 n=6}
_{Parse Time}	_{2.45s (± 0.80%)}	_{2.45s (± 0.49%)}	_~	_2.43s	_2.46s	_{p=1.000 n=6}
_{Bind Time}	_{0.93s (± 0.44%)}	_{0.93s (± 0.56%)}	_~	_0.92s	_0.93s	_{p=0.595 n=6}
_{Check Time}	_{6.92s (± 0.45%)}	_{6.91s (± 0.11%)}	_~	_6.90s	_6.92s	_{p=0.464 n=6}
_{Emit Time}	_{4.04s (± 0.56%)}	_{4.05s (± 0.25%)}	_~	_4.04s	_4.06s	_{p=0.360 n=6}
_{Total Time}	_{14.34s (± 0.31%)}	_{14.34s (± 0.20%)}	_~	_14.30s	_14.38s	_{p=0.871 n=6}
_{TFS - node (v18.15.0, x64)}
_{Memory used}	_{302,631k (± 0.01%)}	_{302,622k (± 0.01%)}	_~	_302,604k	_302,646k	_{p=1.000 n=6}
_{Parse Time}	_{1.99s (± 1.13%)}	_{1.98s (± 1.27%)}	_~	_1.94s	_2.01s	_{p=0.220 n=6}
_{Bind Time}	_{1.00s (± 1.22%)}	_{1.00s (± 0.52%)}	_~	_0.99s	_1.00s	_{p=0.241 n=6}
_{Check Time}	_{6.27s (± 0.56%)}	_{6.29s (± 0.70%)}	_~	_6.21s	_6.33s	_{p=0.374 n=6}
_{Emit Time}	_{3.58s (± 0.42%)}	_{3.58s (± 0.46%)}	_~	_3.56s	_3.60s	_{p=0.510 n=6}
_{Total Time}	_{12.85s (± 0.43%)}	_{12.84s (± 0.43%)}	_~	_12.74s	_12.89s	_{p=0.936 n=6}
_{material-ui - node (v18.15.0, x64)}
_{Memory used}	_{470,572k (± 0.01%)}	_{470,544k (± 0.01%)}	_~	_470,514k	_470,582k	_{p=0.173 n=6}
_{Parse Time}	_{2.57s (± 0.67%)}	_{2.57s (± 0.52%)}	_~	_2.55s	_2.58s	_{p=0.739 n=6}
_{Bind Time}	_{0.99s (± 1.23%)}	_{0.99s (± 0.52%)}	_~	_0.98s	_0.99s	_{p=1.000 n=6}
_{Check Time}	_{16.62s (± 0.38%)}	_{16.61s (± 0.16%)}	_~	_16.56s	_16.63s	_{p=0.936 n=6}
_{Emit Time}	_{0.00s (± 0.00%)}	_{0.00s (± 0.00%)}	_~	_0.00s	_0.00s	_{p=1.000 n=6}
_{Total Time}	_{20.18s (± 0.37%)}	_{20.17s (± 0.13%)}	_~	_20.12s	_20.19s	_{p=0.935 n=6}
_{xstate - node (v18.15.0, x64)}
_{Memory used}	_{512,872k (± 0.01%)}	_{512,819k (± 0.01%)}	_~	_512,760k	_512,872k	_{p=0.199 n=6}
_{Parse Time}	_{3.27s (± 0.49%)}	_{3.27s (± 0.30%)}	_~	_3.26s	_3.28s	_{p=0.720 n=6}
_{Bind Time}	_{1.54s (± 0.49%)}	_{1.54s (± 0.53%)}	_~	_1.53s	_1.55s	_{p=0.729 n=6}
_{Check Time}	_{2.85s (± 0.34%)}	_{2.86s (± 0.60%)}	_~	_2.83s	_2.88s	_{p=0.250 n=6}
_{Emit Time}	_{0.08s (± 0.00%)}	_{0.08s (± 0.00%)}	_~	_0.08s	_0.08s	_{p=1.000 n=6}
_{Total Time}	_{7.73s (± 0.29%)}	_{7.75s (± 0.32%)}	_~	_7.72s	_7.78s	_{p=0.145 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)
xstate - node (v18.15.0, x64)

_Benchmark	_Name	_Iterations
_Current	_pr	₆
_Baseline	_baseline	₆

Developer Information:

Download Benchmarks

TypeScript Bot (typescript-bot) · 2023-11-16T17:59:59Z

Anders Hejlsberg (@ahejlsberg) Here are the results of running the user test suite comparing main and refs/pull/56434/merge:

There were infrastructure failures potentially unrelated to your change:

2 instances of "Package install failed"

Otherwise...

Something interesting changed - please have a look.

Details

puppeteer

packages/browsers/test/src/tsconfig.json

[MISSING] error TS2307: Cannot find module '@pptr/testserver' or its corresponding type declarations.
- packages/browsers/test/src/utils.ts#L23 in packages/browsers/test/src/tsconfig.json

TypeScript Bot (typescript-bot) · 2023-11-16T18:30:56Z

Hey Anders Hejlsberg (@ahejlsberg), the results of running the DT tests are ready.
Everything looks the same!
You can check the log here.

TypeScript Bot (typescript-bot) · 2023-11-16T18:55:28Z

Anders Hejlsberg (@ahejlsberg) Here are the results of running the top-repos suite comparing main and refs/pull/56434/merge:

Everything looks good!

Daniel Rosenwasser (DanielRosenwasser) · 2023-11-17T20:13:06Z

TypeScript Bot (@typescript-bot) pack this

TypeScript Bot (typescript-bot) · 2023-11-17T20:13:09Z

Heya Daniel Rosenwasser (@DanielRosenwasser), I've started to run the tarball bundle task on this PR at b464619. You can monitor the build here.

TypeScript Bot (typescript-bot) · 2023-11-17T20:15:15Z

Hey Daniel Rosenwasser (@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/158671/artifacts?artifactName=tgz&fileId=DBC66C962627F09CAB1254DBD4AC2876AD0FE6754317E0AF108CDAF61D2D957D02&fileName=/typescript-5.4.0-insiders.20231117.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@5.4.0-pr-56434-11".;

Anders Hejlsberg (ahejlsberg) · 2023-11-17T20:27:38Z

Jake Bailey (@jakebailey)Daniel Rosenwasser (@DanielRosenwasser) So, there's this beauty:

typeGoo<T>={[key: `abc${"def"&{tag: T}}`]: string;}typeT0=Goo<void>;// Index signature key type not instantiated so type parameter leaks

By design we don't instantiate index signature key types (that's what mapped types are for), but that in turn means we really can't permit anything generic in tag types. But we have no guaranteed way of detecting whether an object type contains something generic. I should say that there's nothing particularly dangerous about the leaked type parameter (it's just a type that isn't compatible with anything but itself), but it's certainly esthetically displeasing.

Starting to seem like we just want to strip tags in template literal placeholders.

Anders Hejlsberg (ahejlsberg) · 2023-11-18T16:32:34Z

Hmm, the leaking type parameter issue isn't actually anything new:

typeLeak<T>={[key: string&{tag: T}]: string;}typeT0=Leak<void>;// Index signature key type not instantiated so type parameter leaks

I seem to recall us discussing this at some point in the past but can't find anything. As I said above, it's harmless, but certainly doesn't look right.

Daniel Rosenwasser (DanielRosenwasser) · 2023-11-21T19:53:11Z

TypeScript Bot (@typescript-bot) cherry-pick this to release-5.3

TypeScript Bot (typescript-bot) · 2023-11-21T19:53:15Z

Heya Daniel Rosenwasser (@DanielRosenwasser), I've started to run the task to cherry-pick this into release-5.3 on this PR at b464619. You can monitor the build here.

TypeScript Bot (typescript-bot) · 2023-11-21T20:01:18Z

Hey Daniel Rosenwasser (@DanielRosenwasser), I've opened #56491 for you.

Component commits: 7fa9179 Fix support for intersections in template literal placeholder types f45b6dd Accept new baselines 2cf8379 Update test ca7e9c4 Accept new baselines 8ab01eb Update fourslash test b464619 Add more tests per code review

…e-5.3 (#56491) Co-authored-by: Anders Hejlsberg <andersh@microsoft.com>

Anders Hejlsberg (ahejlsberg) added 4 commits November 16, 2023 09:27

Fix support for intersections in template literal placeholder types
7fa9179

Accept new baselines
f45b6dd

Update test
2cf8379

Accept new baselines
ca7e9c4

TypeScript Bot (typescript-bot) assigned Anders Hejlsberg (ahejlsberg)Nov 16, 2023

TypeScript Bot (typescript-bot) added Author: Team For Milestone Bug PRs that fix a bug with a specific milestone labels Nov 16, 2023

Anders Hejlsberg (ahejlsberg) requested review from Daniel Rosenwasser (DanielRosenwasser), Ryan Cavanaugh (RyanCavanaugh) and Jake Bailey (jakebailey)November 16, 2023 17:37

Update fourslash test
8ab01eb

Mateusz Burzyński (Andarist) reviewed Nov 16, 2023
View reviewed changes

Comment threadtests/cases/conformance/types/literal/templateLiteralTypesPatterns.ts

Add more tests per code review
b464619

Jake Bailey (jakebailey) approved these changes Nov 17, 2023
View reviewed changes

Daniel Rosenwasser (DanielRosenwasser) mentioned this pull request Nov 17, 2023
Design Meeting Notes, 11/17/2023 #56450
Closed

Anders Hejlsberg (ahejlsberg) mentioned this pull request Nov 19, 2023
Strip tags in placeholders #56458
Closed

Anders Hejlsberg (ahejlsberg) merged commit c266e47 into mainNov 21, 2023

Anders Hejlsberg (ahejlsberg) deleted the fixPlaceholderIntersections branch November 21, 2023 01:09

TypeScript Bot (typescript-bot) mentioned this pull request Nov 21, 2023
🤖 Pick PR #56434 (Fix support for intersections in te...) into release-5.3 #56491
Merged

Daniel Rosenwasser (DanielRosenwasser) pushed a commit that referenced this pull request Nov 30, 2023
🤖 Pick PR#56434(Fix support for intersections in te...) into releas…
ba3d2b0
…e-5.3 (#56491) Co-authored-by: Anders Hejlsberg <andersh@microsoft.com>

Mateusz Burzyński (Andarist) mentioned this pull request Mar 22, 2024
autocomplete workaround for string literal inside template literal stopped working since v5.3.3#57902
Closed

Jake Bailey (jakebailey) mentioned this pull request Mar 19, 2025
Fix #61098 #61113
Merged

Microsoft (microsoft) locked as resolved and limited conversation to collaborators Oct 16, 2025

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puppeteer

packages/browsers/test/src/tsconfig.json

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