[experiment] Skip incompatible discriminants when inferring by Andarist · Pull Request #64695 · microsoft/TypeScript

Mateusz Burzyński (Andarist) · 2026-10-08T17:21:28Z

I was kinda always wondering if a logic like this could be used to cut down on inference work when dealing with discriminated unions and the referenced PR pushed me to try it out.

I'd still like to do more work on this and recheck things. That's why I'm opening this as a draft, I'd be curious what extended user tests etc would show for this

Jake Bailey (jakebailey) · 2026-10-08T17:24:26Z

TypeScript Bot (@typescript-bot) test it

typescript-automation · 2026-10-08T17:24:33Z

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

Copilot

🔵 Needs a closer look

The draft changes broad compiler inference semantics despite strong regression coverage and warrants human evaluation against extended user tests.

0 open findings

What changed in this PR

Adds discriminant-aware filtering to union-source inference, addressing #64690 while expanding compiler regression coverage.

Changes:

Skips source constituents with incompatible fixed discriminants.
Tests aliases, nesting, tag types, ordering, and optional-property semantics.
Adds diagnostics, type, and symbol baselines for both optional-property modes.

File	Description
`tsc/internal/checker/inference.go`	Implements discriminant-aware inference filtering.
`tsc/testdata/tests/cases/compiler/inferenceDiscriminatedUnionSource.ts`	Adds compiler regression cases.
`tsc/testdata/baselines/reference/compiler/inferenceDiscriminatedUnionSource(exactoptionalpropertytypes=true).types`	Records inferred types.
`tsc/testdata/baselines/reference/compiler/inferenceDiscriminatedUnionSource(exactoptionalpropertytypes=true).symbols`	Records symbols.
`tsc/testdata/baselines/reference/compiler/inferenceDiscriminatedUnionSource(exactoptionalpropertytypes=true).errors.txt`	Records diagnostics.
`tsc/testdata/baselines/reference/compiler/inferenceDiscriminatedUnionSource(exactoptionalpropertytypes=false).types`	Records inferred types.
`tsc/testdata/baselines/reference/compiler/inferenceDiscriminatedUnionSource(exactoptionalpropertytypes=false).symbols`	Records symbols.
`tsc/testdata/baselines/reference/compiler/inferenceDiscriminatedUnionSource(exactoptionalpropertytypes=false).errors.txt`	Records diagnostics.

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typescript-automation · 2026-10-08T17:48:44Z

Hey Jake Bailey (@jakebailey), the results of running the DT tests are ready.

Everything looks the same!

You can check the log here.

typescript-automation · 2026-10-08T17:55:44Z

Jake Bailey (@jakebailey) Here are the results of running the user tests with tsc comparing baseline and pr:

Everything looks good!

typescript-automation · 2026-10-08T17:55:47Z

Jake Bailey (@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 - native}
_Errors	₄₁	₄₁	_~	_~	_~	_{p=1.000 n=12}
_Symbols	_115,276	_115,344	_{+68 (+ 0.06%)}	_~	_~	_{p=0.000 n=12}
_Types	_79,613	_79,825	_{+212 (+ 0.27%)}	_~	_~	_{p=0.000 n=12}
_{Memory Used}	_{139,467k (± 0.05%)}	_{139,524k (± 0.07%)}	_~	_139,283k	_139,868k	_{p=0.291 n=12}
_{Memory Allocs}	_{2,190,609 (± 0.00%)}	_{2,191,450 (± 0.01%)}	_{+842 (+ 0.04%)}	_2,191,208	_2,191,918	_{p=0.000 n=12}
_{Config Time}	_0.000s	_0.000s	_~	_~	_~	_{p=1.000 n=12}
_{Parse Time}	_{0.041s (± 4.59%)}	_{0.042s (± 3.81%)}	_~	_0.037s	_0.046s	_{p=0.466 n=12}
_{Bind Time}	_{0.013s (±11.42%)}	_{0.013s (±15.40%)}	_~	_0.010s	_0.018s	_{p=0.651 n=12}
_{Check Time}	_{0.496s (± 0.81%)}	_{0.499s (± 0.88%)}	_~	_0.490s	_0.512s	_{p=0.324 n=12}
_{Emit Time}	_{0.271s (± 1.78%)}	_{0.271s (± 1.74%)}	_~	_0.263s	_0.291s	_{p=0.743 n=12}
_{Total Time}	_{0.827s (± 0.53%)}	_{0.831s (± 0.89%)}	_~	_0.815s	_0.856s	_{p=0.522 n=12}
_{angular-1 - native}
_Errors	₃	₃	_~	_~	_~	_{p=1.000 n=12}
_Symbols	_{845,646 (± 0.07%)}	_{846,217 (± 0.08%)}	_~	_844,344	_847,855	_{p=0.266 n=12}
_Types	_{248,123 (± 0.00%)}	_{251,330 (± 0.00%)}	_{+3,206 (+ 1.29%)}	_251,326	_251,340	_{p=0.000 n=12}
_{Memory Used}	_{788,084k (± 0.03%)}	_{789,200k (± 0.02%)}	_{+1,116k (+ 0.14%)}	_788,766k	_789,559k	_{p=0.000 n=12}
_{Memory Allocs}	_{12,920,468 (± 0.02%)}	_{12,931,329 (± 0.03%)}	_{+10,861 (+ 0.08%)}	_12,924,217	_12,946,521	_{p=0.000 n=12}
_{Config Time}	_{0.016s (± 1.97%)}	_{0.016s (± 1.75%)}	_~	_0.016s	_0.017s	_{p=0.667 n=12}
_{Parse Time}	_{0.263s (± 1.85%)}	_{0.253s (± 3.42%)}	_~	_0.225s	_0.271s	_{p=0.061 n=12}
_{Bind Time}	_{0.059s (± 2.22%)}	_{0.069s (±17.04%)}	_{🔻+0.011s (+18.07%)}	_0.059s	_0.119s	_{p=0.013 n=12}
_{Check Time}	_0s	_0s	_~	_~	_~	_{p=1.000 n=12}
_{Emit Time}	_{1.584s (± 0.76%)}	_{1.597s (± 1.43%)}	_~	_1.553s	_1.669s	_{p=0.523 n=12}
_{Total Time}	_{1.935s (± 0.72%)}	_{1.950s (± 1.46%)}	_~	_1.895s	_2.026s	_{p=0.580 n=12}
_{mui-docs - native}
_Errors	_11,405	_11,405	_~	_~	_~	_{p=1.000 n=12}
_Symbols	_4,359,614	_4,359,688	_{+74 (+ 0.00%)}	_~	_~	_{p=0.000 n=12}
_Types	_1,376,379	_1,382,217	_{+5,838 (+ 0.42%)}	_~	_~	_{p=0.000 n=12}
_{Memory Used}	_{2,954,247k (± 0.06%)}	_{2,955,020k (± 0.05%)}	_~	_2,951,708k	_2,960,703k	_{p=0.514 n=12}
_{Memory Allocs}	_{32,839,861 (± 0.07%)}	_{32,841,660 (± 0.04%)}	_~	_32,819,481	_32,866,395	_{p=0.977 n=12}
_{Config Time}	_{0.016s (± 1.97%)}	_{0.017s (± 1.45%)}	_~	_0.016s	_0.017s	_{p=0.089 n=12}
_{Parse Time}	_{0.502s (± 1.89%)}	_{0.492s (± 2.84%)}	_~	_0.452s	_0.516s	_{p=0.385 n=12}
_{Bind Time}	_{0.002s (±31.13%)}	_0.002s	_~	_~	_~	_{p=1.000 n=12}
_{Check Time}	_{8.681s (± 0.51%)}	_{8.637s (± 0.68%)}	_~	_8.528s	_8.788s	_{p=0.272 n=12}
_{Emit Time}	_{0.487s (±14.75%)}	_{0.528s (±14.10%)}	_~	_0.419s	_0.682s	_{p=0.172 n=12}
_{Total Time}	_{10.449s (± 0.31%)}	_{10.450s (± 0.52%)}	_~	_10.269s	_10.566s	_{p=0.767 n=12}
_{strada-build-src - native}
_Errors	₀	₀	_~	_~	_~	_{p=1.000 n=12}
_Symbols	_1,390,229	_1,394,216	_{+3,987 (+ 0.29%)}	_~	_~	_{p=0.000 n=12}
_Types	_441,498	_450,921	_{+9,423 (+ 2.13%)}	_~	_~	_{p=0.000 n=12}
_{Memory Used}	_{1,685,848k (± 0.99%)}	_{1,679,834k (± 0.85%)}	_~	_1,661,307k	_1,723,079k	_{p=0.590 n=12}
_{Memory Allocs}	_{92,117,106 (± 0.15%)}	_{92,360,812 (± 0.17%)}	_{+243,706 (+ 0.26%)}	_92,046,435	_92,717,754	_{p=0.020 n=12}
_{Config Time}	_{0.004s (±10.74%)}	_{0.003s (±18.62%)}	_{🟩-0.001s (-19.15%)}	_0.002s	_0.005s	_{p=0.048 n=12}
_{Parse Time}	_{0.199s (± 4.36%)}	_{0.193s (± 3.28%)}	_~	_0.179s	_0.214s	_{p=0.173 n=12}
_{Bind Time}	_{0.000s (±217.90%)}	_0.000s	_~	_~	_~	_{p=1.000 n=12}
_{Check Time}	_{1.813s (± 0.66%)}	_{1.820s (± 0.54%)}	_~	_1.801s	_1.849s	_{p=0.291 n=12}
_{Emit Time}	_{0.291s (± 6.21%)}	_{0.303s (± 2.82%)}	_~	_0.280s	_0.327s	_{p=0.417 n=12}
_{Total Time}	_{23.517s (± 0.73%)}	_{23.633s (± 0.69%)}	_~	_23.198s	_23.996s	_{p=0.347 n=12}
_{strada-compiler - native}
_Errors	₀	₀	_~	_~	_~	_{p=1.000 n=12}
_Symbols	_334,953	_336,259	_{+1,306 (+ 0.39%)}	_~	_~	_{p=0.000 n=12}
_Types	_197,616	_201,520	_{+3,904 (+ 1.98%)}	_~	_~	_{p=0.000 n=12}
_{Memory Used}	_{313,258k (± 0.02%)}	_{314,862k (± 0.03%)}	_{+1,604k (+ 0.51%)}	_314,659k	_315,126k	_{p=0.000 n=12}
_{Memory Allocs}	_{4,623,651 (± 0.01%)}	_{4,637,069 (± 0.01%)}	_{+13,418 (+ 0.29%)}	_4,634,924	_4,637,871	_{p=0.000 n=12}
_{Config Time}	_0.001s	_0.001s	_~	_~	_~	_{p=1.000 n=12}
_{Parse Time}	_{0.114s (± 4.63%)}	_{0.114s (± 5.00%)}	_~	_0.100s	_0.130s	_{p=0.966 n=12}
_{Bind Time}	_0.000s	_0.000s	_~	_~	_~	_{p=1.000 n=12}
_{Check Time}	_{1.050s (± 0.52%)}	_{1.055s (± 0.36%)}	_~	_1.045s	_1.066s	_{p=0.246 n=12}
_{Emit Time}	_{0.140s (±11.74%)}	_{0.126s (±12.55%)}	_~	_0.100s	_0.168s	_{p=0.325 n=12}
_{Total Time}	_{1.357s (± 1.26%)}	_{1.352s (± 0.95%)}	_~	_1.323s	_1.383s	_{p=0.560 n=12}
_{ts-pre-modules - native}
_Errors	₈₇	₈₇	_~	_~	_~	_{p=1.000 n=12}
_Symbols	_303,834	_305,049	_{+1,215 (+ 0.40%)}	_~	_~	_{p=0.000 n=12}
_Types	_181,663	_185,425	_{+3,762 (+ 2.07%)}	_~	_~	_{p=0.000 n=12}
_{Memory Used}	_{273,936k (± 0.02%)}	_{275,311k (± 0.02%)}	_{+1,374k (+ 0.50%)}	_275,201k	_275,543k	_{p=0.000 n=12}
_{Memory Allocs}	_{1,615,929 (± 0.01%)}	_{1,629,712 (± 0.02%)}	_{+13,783 (+ 0.85%)}	_1,629,137	_1,630,454	_{p=0.000 n=12}
_{Config Time}	_0.000s	_{0.000s (±146.91%)}	_~	_0.000s	_0.001s	_{p=0.478 n=12}
_{Parse Time}	_{0.100s (± 3.02%)}	_{0.101s (± 3.96%)}	_~	_0.091s	_0.114s	_{p=0.659 n=12}
_{Bind Time}	_{0.037s (±13.63%)}	_{0.036s (±10.94%)}	_~	_0.028s	_0.047s	_{p=0.987 n=12}
_{Check Time}	_{0.828s (± 0.56%)}	_{0.830s (± 0.64%)}	_~	_0.821s	_0.846s	_{p=0.876 n=12}
_{Emit Time}	_0.000s	_0.000s	_~	_~	_~	_{p=1.000 n=12}
_{Total Time}	_{0.980s (± 0.80%)}	_{0.983s (± 1.05%)}	_~	_0.963s	_1.009s	_{p=0.639 n=12}
_{vscode - native}
_Errors	₃₈₀	₃₈₀	_~	_~	_~	_{p=1.000 n=12}
_Symbols	_11,123,441	_11,130,334	_{+6,893 (+ 0.06%)}	_~	_~	_{p=0.000 n=12}
_Types	_3,686,393	_3,728,322	_{+41,929 (+ 1.14%)}	_~	_~	_{p=0.000 n=12}
_{Memory Used}	_{7,127,150k (± 0.01%)}	_{7,141,723k (± 0.02%)}	_{+14,573k (+ 0.20%)}	_7,138,568k	_7,144,118k	_{p=0.000 n=12}
_{Memory Allocs}	_{54,647,398 (± 0.01%)}	_{54,766,078 (± 0.01%)}	_{+118,680 (+ 0.22%)}	_54,756,768	_54,789,920	_{p=0.000 n=12}
_{Config Time}	_{0.074s (± 0.53%)}	_{0.074s (± 0.49%)}	_~	_0.073s	_0.075s	_{p=0.870 n=12}
_{Parse Time}	_{1.810s (± 5.75%)}	_{1.806s (± 3.36%)}	_~	_1.666s	_2.004s	_{p=0.523 n=12}
_{Bind Time}	_{0.662s (±18.88%)}	_{0.588s (±15.39%)}	_~	_0.447s	_0.876s	_{p=0.541 n=12}
_{Check Time}	_{14.180s (± 1.50%)}	_{14.367s (± 1.55%)}	_~	_13.918s	_14.775s	_{p=0.062 n=12}
_{Emit Time}	_{5.327s (± 9.71%)}	_{4.941s (±11.75%)}	_~	_4.096s	_6.160s	_{p=0.319 n=12}
_{Total Time}	_{22.140s (± 1.53%)}	_{21.863s (± 1.88%)}	_~	_21.244s	_22.766s	_{p=0.319 n=12}
_{webpack - native}
_Errors	₅₈₉	₅₈₉	_~	_~	_~	_{p=1.000 n=12}
_Symbols	_1,302,905	_1,303,729	_{+824 (+ 0.06%)}	_~	_~	_{p=0.000 n=12}
_Types	_618,533	_621,278	_{+2,745 (+ 0.44%)}	_~	_~	_{p=0.000 n=12}
_{Memory Used}	_{1,010,981k (± 0.02%)}	_{1,011,922k (± 0.01%)}	_{+941k (+ 0.09%)}	_1,011,664k	_1,012,089k	_{p=0.000 n=12}
_{Memory Allocs}	_{6,595,437 (± 0.02%)}	_{6,606,104 (± 0.05%)}	_{+10,668 (+ 0.16%)}	_6,602,158	_6,621,750	_{p=0.000 n=12}
_{Config Time}	_0.009s	_0.009s	_~	_~	_~	_{p=1.000 n=12}
_{Parse Time}	_{0.290s (± 3.50%)}	_{0.297s (± 2.46%)}	_~	_0.271s	_0.315s	_{p=0.247 n=12}
_{Bind Time}	_{0.082s (±16.47%)}	_{0.071s (± 9.16%)}	_~	_0.062s	_0.099s	_{p=0.504 n=12}
_{Check Time}	_{2.023s (± 0.61%)}	_{2.032s (± 0.79%)}	_~	_1.976s	_2.055s	_{p=0.091 n=12}
_{Emit Time}	_0.000s	_0.000s	_~	_~	_~	_{p=1.000 n=12}
_{Total Time}	_{2.439s (± 0.67%)}	_{2.445s (± 0.81%)}	_~	_2.382s	_2.499s	_{p=0.809 n=12}
_{xstate-main - native}
_Errors	₀	₀	_~	_~	_~	_{p=1.000 n=12}
_Symbols	_1,055,452	_1,060,768	_{+5,316 (+ 0.50%)}	_~	_~	_{p=0.000 n=12}
_Types	_386,738	_389,848	_{+3,110 (+ 0.80%)}	_~	_~	_{p=0.000 n=12}
_{Memory Used}	_{613,361k (± 0.03%)}	_{615,681k (± 0.03%)}	_{+2,320k (+ 0.38%)}	_615,295k	_616,271k	_{p=0.000 n=12}
_{Memory Allocs}	_{4,862,964 (± 0.04%)}	_{4,907,231 (± 0.11%)}	_{+44,267 (+ 0.91%)}	_4,896,581	_4,926,204	_{p=0.000 n=12}
_{Config Time}	_0.003s	_0.003s	_~	_~	_~	_{p=1.000 n=12}
_{Parse Time}	_{0.141s (± 3.53%)}	_{0.143s (± 2.59%)}	_~	_0.136s	_0.154s	_{p=0.485 n=12}
_{Bind Time}	_{0.047s (±18.37%)}	_{0.040s (±10.57%)}	_~	_0.032s	_0.051s	_{p=0.353 n=12}
_{Check Time}	_{1.138s (± 0.48%)}	_{1.157s (± 0.67%)}	_{+0.019s (+ 1.68%)}	_1.143s	_1.184s	_{p=0.000 n=12}
_{Emit Time}	_0.000s	_0.000s	_~	_~	_~	_{p=1.000 n=12}
_{Total Time}	_{1.339s (± 0.86%)}	_{1.355s (± 0.89%)}	_~	_1.335s	_1.397s	_{p=0.109 n=12}

System info unknown

Hosts

native

Scenarios

Compiler-Unions - native
angular-1 - native
mui-docs - native
strada-build-src - native
strada-compiler - native
ts-pre-modules - native
vscode - native
webpack - native
xstate-main - native

_Benchmark	_Name	_Iterations
_Current	_pr	₁₂
_Baseline	_baseline	₁₂

Developer Information:

Download Benchmarks

Wesley Wigham (weswigham) · 2026-10-08T18:19:11Z

Man, when we tried this in the JS codebase, the type comparison on every possible inference target ended up blowing up any savings we got from skipping deeper inferences on less appropriate members. But the perf suite shows it as good now, so I'm a fan. Maybe the optional prop fastpath and objecty type carve-outs are saving enough low-value comparisons it's at least perf neutral again? I'd be happier if we used discriminateTypeByDiscriminableItems (and maybe optimized it a bit to match), though, so "the method of discrimination" always matches. areTypesComparable is interesting, considering we normally discriminate using assignability - thought I guess we're kinda inverting the normal check here - "skip incompatible" instead of "select only compatible". In theory those are compliments, though.

typescript-automation · 2026-10-08T18:37:44Z

Jake Bailey (@jakebailey) Here are the results of running the top 400 repos with tsc comparing baseline and pr:

Everything looks good!

Mateusz Burzyński (Andarist) · 2026-10-11T20:49:58Z

I still have some extra changes that I'd like to push here (maybe ;p) but I'd like to first see how this version performs in the perf tests and in the wild. Could I ask for a full test rerun here? cc Jake Bailey (@jakebailey)

Jake Bailey (jakebailey) · 2026-10-12T21:41:27Z

TypeScript Bot (@typescript-bot) test it

typescript-automation · 2026-10-12T21:41:33Z

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

typescript-automation · 2026-10-12T22:05:50Z

Hey Jake Bailey (@jakebailey), the results of running the DT tests are ready.

Everything looks the same!

You can check the log here.

typescript-automation · 2026-10-12T22:11:20Z

Jake Bailey (@jakebailey) Here are the results of running the user tests with tsc comparing baseline and pr:

Everything looks good!

typescript-automation · 2026-10-12T22:11:22Z

Jake Bailey (@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 - native}
_Errors	₄₁	₄₁	_~	_~	_~	_{p=1.000 n=12}
_Symbols	_115,276	_115,496	_{+220 (+ 0.19%)}	_~	_~	_{p=0.000 n=12}
_Types	_79,613	_79,979	_{+366 (+ 0.46%)}	_~	_~	_{p=0.000 n=12}
_{Memory Used}	_{133,210k (± 0.06%)}	_{135,038k (± 0.05%)}	_{+1,828k (+ 1.37%)}	_134,856k	_135,216k	_{p=0.000 n=12}
_{Memory Allocs}	_{2,190,272 (± 0.01%)}	_{2,200,940 (± 0.01%)}	_{+10,668 (+ 0.49%)}	_2,200,670	_2,201,291	_{p=0.000 n=12}
_{Config Time}	_0.000s	_0.000s	_~	_~	_~	_{p=1.000 n=12}
_{Parse Time}	_{0.042s (± 5.00%)}	_{0.041s (± 4.56%)}	_~	_0.036s	_0.045s	_{p=0.466 n=12}
_{Bind Time}	_{0.013s (±12.93%)}	_{0.012s (±13.78%)}	_~	_0.010s	_0.019s	_{p=0.280 n=12}
_{Check Time}	_{0.498s (± 0.72%)}	_{0.495s (± 0.96%)}	_~	_0.485s	_0.513s	_{p=0.234 n=12}
_{Emit Time}	_{0.272s (± 2.69%)}	_{0.264s (± 2.47%)}	_~	_0.249s	_0.287s	_{p=0.080 n=12}
_{Total Time}	_{0.831s (± 0.79%)}	_{0.818s (± 0.85%)}	_{-0.013s (- 1.54%)}	_0.793s	_0.834s	_{p=0.008 n=12}
_{angular-1 - native}
_Errors	₃	₃	_~	_~	_~	_{p=1.000 n=12}
_Symbols	_{846,205 (± 0.05%)}	_{847,780 (± 0.04%)}	_{+1,575 (+ 0.19%)}	_846,859	_848,754	_{p=0.000 n=12}
_Types	_{248,125 (± 0.00%)}	_{266,277 (± 0.00%)}	_{🔻+18,152 (+ 7.32%)}	_266,274	_266,287	_{p=0.000 n=12}
_{Memory Used}	_{746,148k (± 0.02%)}	_{751,901k (± 0.02%)}	_{+5,753k (+ 0.77%)}	_751,676k	_752,268k	_{p=0.000 n=12}
_{Memory Allocs}	_{12,916,811 (± 0.05%)}	_{12,985,767 (± 0.04%)}	_{+68,956 (+ 0.53%)}	_12,979,162	_13,006,885	_{p=0.000 n=12}
_{Config Time}	_0.017s	_0.017s	_~	_~	_~	_{p=1.000 n=12}
_{Parse Time}	_{0.258s (± 2.46%)}	_{0.255s (± 3.13%)}	_~	_0.229s	_0.274s	_{p=0.504 n=12}
_{Bind Time}	_{0.061s (± 8.52%)}	_{0.067s (±20.47%)}	_~	_0.055s	_0.119s	_{p=0.916 n=12}
_{Check Time}	_0s	_0s	_~	_~	_~	_{p=1.000 n=12}
_{Emit Time}	_{1.560s (± 0.97%)}	_{1.572s (± 0.95%)}	_~	_1.548s	_1.625s	_{p=0.400 n=12}
_{Total Time}	_{1.908s (± 0.96%)}	_{1.923s (± 1.27%)}	_~	_1.891s	_2.013s	_{p=0.600 n=12}
_{mui-docs - native}
_Errors	_11,405	_11,405	_~	_~	_~	_{p=1.000 n=12}
_Symbols	_4,359,614	_4,363,913	_{+4,299 (+ 0.10%)}	_~	_~	_{p=0.000 n=12}
_Types	_1,376,379	_1,385,580	_{+9,201 (+ 0.67%)}	_~	_~	_{p=0.000 n=12}
_{Memory Used}	_{2,781,354k (± 0.06%)}	_{2,788,959k (± 0.05%)}	_{+7,605k (+ 0.27%)}	_2,785,220k	_2,791,665k	_{p=0.000 n=12}
_{Memory Allocs}	_{32,799,591 (± 0.06%)}	_{32,859,819 (± 0.07%)}	_{+60,228 (+ 0.18%)}	_32,794,937	_32,907,659	_{p=0.001 n=12}
_{Config Time}	_{0.017s (± 1.07%)}	_{0.017s (± 1.06%)}	_~	_0.017s	_0.018s	_{p=0.522 n=12}
_{Parse Time}	_{0.499s (± 1.84%)}	_{0.484s (± 4.39%)}	_~	_0.420s	_0.524s	_{p=0.433 n=12}
_{Bind Time}	_0.002s	_0.002s	_~	_~	_~	_{p=1.000 n=12}
_{Check Time}	_{8.675s (± 0.46%)}	_{8.652s (± 0.47%)}	_~	_8.534s	_8.733s	_{p=0.386 n=12}
_{Emit Time}	_{0.437s (± 3.14%)}	_{0.440s (± 4.28%)}	_~	_0.420s	_0.519s	_{p=0.433 n=12}
_{Total Time}	_{10.401s (± 0.47%)}	_{10.360s (± 0.41%)}	_~	_10.214s	_10.423s	_{p=0.070 n=12}
_{strada-build-src - native}
_Errors	₀	₀	_~	_~	_~	_{p=1.000 n=12}
_Symbols	_1,390,229	_1,394,504	_{+4,275 (+ 0.31%)}	_~	_~	_{p=0.000 n=12}
_Types	_441,498	_463,392	_{🔻+21,894 (+ 4.96%)}	_~	_~	_{p=0.000 n=12}
_{Memory Used}	_{1,619,944k (± 0.59%)}	_{1,626,161k (± 0.64%)}	_~	_1,610,961k	_1,660,431k	_{p=0.160 n=12}
_{Memory Allocs}	_{92,057,154 (± 0.11%)}	_{92,900,717 (± 0.16%)}	_{+843,563 (+ 0.92%)}	_92,531,493	_93,245,962	_{p=0.000 n=12}
_{Config Time}	_{0.003s (±16.76%)}	_{0.003s (±14.60%)}	_~	_0.002s	_0.004s	_{p=0.767 n=12}
_{Parse Time}	_{0.192s (± 3.92%)}	_{0.192s (± 4.22%)}	_~	_0.173s	_0.219s	_{p=1.000 n=12}
_{Bind Time}	_0.000s	_0.000s	_~	_~	_~	_{p=1.000 n=12}
_{Check Time}	_{1.812s (± 0.64%)}	_{1.799s (± 0.53%)}	_~	_1.777s	_1.827s	_{p=0.089 n=12}
_{Emit Time}	_{0.306s (± 5.63%)}	_{0.302s (± 5.26%)}	_~	_0.261s	_0.342s	_{p=0.831 n=12}
_{Total Time}	_{23.468s (± 0.67%)}	_{23.373s (± 0.96%)}	_~	_22.849s	_23.896s	_{p=0.443 n=12}
_{strada-compiler - native}
_Errors	₀	₀	_~	_~	_~	_{p=1.000 n=12}
_Symbols	_334,953	_336,483	_{+1,530 (+ 0.46%)}	_~	_~	_{p=0.000 n=12}
_Types	_197,616	_205,554	_{🔻+7,938 (+ 4.02%)}	_~	_~	_{p=0.000 n=12}
_{Memory Used}	_{296,080k (± 0.01%)}	_{298,674k (± 0.02%)}	_{+2,594k (+ 0.88%)}	_298,475k	_298,850k	_{p=0.000 n=12}
_{Memory Allocs}	_{4,621,446 (± 0.01%)}	_{4,662,673 (± 0.01%)}	_{+41,227 (+ 0.89%)}	_4,662,061	_4,663,441	_{p=0.000 n=12}
_{Config Time}	_0.001s	_0.001s	_~	_~	_~	_{p=1.000 n=12}
_{Parse Time}	_{0.118s (± 4.83%)}	_{0.113s (± 3.75%)}	_~	_0.103s	_0.125s	_{p=0.172 n=12}
_{Bind Time}	_0.000s	_0.000s	_~	_~	_~	_{p=1.000 n=12}
_{Check Time}	_{1.038s (± 0.58%)}	_{1.037s (± 0.69%)}	_~	_1.026s	_1.062s	_{p=0.638 n=12}
_{Emit Time}	_{0.149s (± 4.29%)}	_{0.155s (± 3.85%)}	_~	_0.135s	_0.170s	_{p=0.183 n=12}
_{Total Time}	_{1.361s (± 0.68%)}	_{1.361s (± 0.49%)}	_~	_1.339s	_1.379s	_{p=0.723 n=12}
_{ts-pre-modules - native}
_Errors	₈₇	₈₇	_~	_~	_~	_{p=1.000 n=12}
_Symbols	_303,834	_305,154	_{+1,320 (+ 0.43%)}	_~	_~	_{p=0.000 n=12}
_Types	_181,663	_188,573	_{+6,910 (+ 3.80%)}	_~	_~	_{p=0.000 n=12}
_{Memory Used}	_{256,649k (± 0.01%)}	_{258,978k (± 0.01%)}	_{+2,329k (+ 0.91%)}	_258,894k	_259,052k	_{p=0.000 n=12}
_{Memory Allocs}	_{1,614,045 (± 0.01%)}	_{1,642,061 (± 0.01%)}	_{+28,016 (+ 1.74%)}	_1,641,453	_1,642,633	_{p=0.000 n=12}
_{Config Time}	_0.000s	_0.000s	_~	_~	_~	_{p=1.000 n=12}
_{Parse Time}	_{0.095s (± 4.04%)}	_{0.095s (± 3.97%)}	_~	_0.087s	_0.104s	_{p=0.988 n=12}
_{Bind Time}	_{0.040s (±11.75%)}	_{0.039s (±10.29%)}	_~	_0.032s	_0.051s	_{p=0.702 n=12}
_{Check Time}	_{0.814s (± 0.57%)}	_{0.814s (± 0.78%)}	_~	_0.799s	_0.832s	_{p=0.876 n=12}
_{Emit Time}	_0.000s	_0.000s	_~	_~	_~	_{p=1.000 n=12}
_{Total Time}	_{0.963s (± 0.77%)}	_{0.961s (± 0.55%)}	_~	_0.946s	_0.970s	_{p=0.832 n=12}
_{vscode - native}
_Errors	₃₉₅	₃₉₅	_~	_~	_~	_{p=1.000 n=12}
_Symbols	_11,335,260	_11,347,337	_{+12,077 (+ 0.11%)}	_~	_~	_{p=0.000 n=12}
_Types	_3,740,503	_3,829,865	_{+89,362 (+ 2.39%)}	_~	_~	_{p=0.000 n=12}
_{Memory Used}	_{6,458,564k (± 0.01%)}	_{6,491,649k (± 0.01%)}	_{+33,085k (+ 0.51%)}	_6,489,890k	_6,493,812k	_{p=0.000 n=12}
_{Memory Allocs}	_{55,417,594 (± 0.01%)}	_{55,941,662 (± 0.01%)}	_{+524,069 (+ 0.95%)}	_55,930,855	_55,965,440	_{p=0.000 n=12}
_{Config Time}	_{0.075s (± 0.48%)}	_{0.075s (± 0.33%)}	_~	_0.074s	_0.075s	_{p=0.230 n=12}
_{Parse Time}	_{1.850s (± 2.77%)}	_{1.823s (± 4.03%)}	_~	_1.680s	_2.025s	_{p=0.355 n=12}
_{Bind Time}	_{0.534s (±14.88%)}	_{0.632s (±18.48%)}	_~	_0.448s	_0.953s	_{p=0.324 n=12}
_{Check Time}	_{14.115s (± 0.93%)}	_{15.143s (± 0.81%)}	_{🔻+1.027s (+ 7.28%)}	_14.824s	_15.364s	_{p=0.000 n=12}
_{Emit Time}	_{4.926s (± 8.21%)}	_{5.057s (±10.85%)}	_~	_4.200s	_6.109s	_{p=0.887 n=12}
_{Total Time}	_{21.586s (± 1.51%)}	_{22.817s (± 2.17%)}	_{🔻+1.231s (+ 5.70%)}	_21.989s	_23.867s	_{p=0.001 n=12}
_{webpack - native}
_Errors	₅₈₅	₅₈₅	_~	_~	_~	_{p=1.000 n=12}
_Symbols	_1,317,332	_1,318,570	_{+1,238 (+ 0.09%)}	_~	_~	_{p=0.000 n=12}
_Types	_619,546	_629,069	_{+9,523 (+ 1.54%)}	_~	_~	_{p=0.000 n=12}
_{Memory Used}	_{945,374k (± 0.01%)}	_{948,636k (± 0.02%)}	_{+3,262k (+ 0.35%)}	_948,103k	_949,027k	_{p=0.000 n=12}
_{Memory Allocs}	_{6,672,435 (± 0.02%)}	_{6,706,031 (± 0.04%)}	_{+33,596 (+ 0.50%)}	_6,702,370	_6,719,611	_{p=0.000 n=12}
_{Config Time}	_0.009s	_0.009s	_~	_~	_~	_{p=1.000 n=12}
_{Parse Time}	_{0.304s (± 4.10%)}	_{0.300s (± 3.63%)}	_~	_0.279s	_0.335s	_{p=0.541 n=12}
_{Bind Time}	_{0.081s (±20.94%)}	_{0.092s (±18.07%)}	_~	_0.064s	_0.137s	_{p=0.354 n=12}
_{Check Time}	_{2.400s (± 0.59%)}	_{2.397s (± 0.44%)}	_~	_2.370s	_2.431s	_{p=0.486 n=12}
_{Emit Time}	_0.000s	_0.000s	_~	_~	_~	_{p=1.000 n=12}
_{Total Time}	_{2.827s (± 0.41%)}	_{2.835s (± 0.31%)}	_~	_2.817s	_2.871s	_{p=0.370 n=12}
_{xstate-main - native}
_Errors	₀	₀	_~	_~	_~	_{p=1.000 n=12}
_Symbols	_1,061,928	_1,067,952	_{+6,024 (+ 0.57%)}	_~	_~	_{p=0.000 n=12}
_Types	_389,645	_403,065	_{+13,420 (+ 3.44%)}	_~	_~	_{p=0.000 n=12}
_{Memory Used}	_{547,503k (± 0.02%)}	_{553,141k (± 0.01%)}	_{+5,638k (+ 1.03%)}	_552,966k	_553,421k	_{p=0.000 n=12}
_{Memory Allocs}	_{4,882,413 (± 0.07%)}	_{4,973,128 (± 0.06%)}	_{+90,715 (+ 1.86%)}	_4,964,432	_4,979,310	_{p=0.000 n=12}
_{Config Time}	_0.003s	_0.003s	_~	_~	_~	_{p=1.000 n=12}
_{Parse Time}	_{0.140s (± 3.05%)}	_{0.140s (± 1.37%)}	_~	_0.135s	_0.147s	_{p=0.921 n=12}
_{Bind Time}	_{0.051s (±15.31%)}	_{0.044s (±14.80%)}	_~	_0.033s	_0.066s	_{p=0.116 n=12}
_{Check Time}	_{1.125s (± 0.39%)}	_{1.142s (± 0.64%)}	_{+0.017s (+ 1.55%)}	_1.132s	_1.162s	_{p=0.000 n=12}
_{Emit Time}	_0.000s	_0.000s	_~	_~	_~	_{p=1.000 n=12}
_{Total Time}	_{1.329s (± 0.62%)}	_{1.339s (± 0.59%)}	_~	_1.319s	_1.360s	_{p=0.057 n=12}

System info unknown

Hosts

native

Scenarios

Compiler-Unions - native
angular-1 - native
mui-docs - native
strada-build-src - native
strada-compiler - native
ts-pre-modules - native
vscode - native
webpack - native
xstate-main - native

_Benchmark	_Name	_Iterations
_Current	_pr	₁₂
_Baseline	_baseline	₁₂

Developer Information:

Download Benchmarks

typescript-automation · 2026-10-12T23:01:28Z

Jake Bailey (@jakebailey) Here are the results of running the top 400 repos with tsc comparing baseline and pr:

Everything looks good!

Wesley Wigham (weswigham) · 2026-10-19T14:35:32Z

Looks like it's neutral to +8% check time, project dependent. It's not terrible now, compared to the JS codebase (where it cost way way more to do this) - maybe some caching of the discriminable item results could improve the perf back to neutral? Or maybe adding back in the optional prop fast path you had in before? I'm guessing that's where most of the additional cost lies in the new fully-discriminating version, but I don't know for sure.

Could also use some most test cases that show off where is actually makes us produce better inference results, though? A cursory check of the tests don't show me anything that I think improve? I'd assume cases like those from #43853 get improved, though.

Mateusz Burzyński (Andarist) · 2026-10-19T14:50:09Z

Or maybe adding back in the optional prop fast path you had in before?

Yeah, I have it locally for a week already - just gotta find a moment to breathe and push it out and ask for a fresh rerun.

Could also use some most test cases that show off where is actually makes us produce better inference results, though?

I think I already have some here or on that local branch - anyway... I'll get to this some time later this week and push everything I have for this.

I'd assume cases like those from #43853 get improved, though.

Oh, nice! I wasn't aware of this PR - I'll take a closer look at this one too (and its tests)

Jake Bailey (jakebailey) · 2026-10-19T16:50:27Z

I'd hope we can make the perf better still? I really hope to not make us slower if we can avoid it

Jake Bailey (jakebailey) · 2026-10-22T07:21:52Z

TypeScript Bot (@typescript-bot) test it

typescript-automation · 2026-10-22T07:21:59Z

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

typescript-automation · 2026-10-22T07:50:31Z

Hey Jake Bailey (@jakebailey), the results of running the DT tests are ready.

Everything looks the same!

You can check the log here.

typescript-automation · 2026-10-22T07:59:29Z

Jake Bailey (@jakebailey) Here are the results of running the user tests with tsc comparing baseline and pr:

Everything looks good!

typescript-automation · 2026-10-22T08:04:57Z

Jake Bailey (@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 - native}
_Errors	₄₁	₄₁	_~	_~	_~	_{p=1.000 n=12}
_Symbols	_115,276	_115,496	_{+220 (+ 0.19%)}	_~	_~	_{p=0.000 n=12}
_Types	_79,613	_79,979	_{+366 (+ 0.46%)}	_~	_~	_{p=0.000 n=12}
_{Memory Used}	_{113,513k (± 0.08%)}	_{114,966k (± 0.07%)}	_{+1,453k (+ 1.28%)}	_114,773k	_115,177k	_{p=0.000 n=12}
_{Memory Allocs}	_{2,212,319 (± 0.01%)}	_{2,222,105 (± 0.01%)}	_{+9,786 (+ 0.44%)}	_2,221,701	_2,222,551	_{p=0.000 n=12}
_{Config Time}	_0.000s	_0.000s	_~	_~	_~	_{p=1.000 n=12}
_{Parse Time}	_{0.039s (± 3.37%)}	_{0.040s (± 3.66%)}	_{🔻+0.002s (+ 4.75%)}	_0.037s	_0.043s	_{p=0.046 n=12}
_{Bind Time}	_{0.014s (±12.11%)}	_{0.013s (±10.28%)}	_~	_0.011s	_0.017s	_{p=0.594 n=12}
_{Check Time}	_{0.462s (± 0.74%)}	_{0.467s (± 0.82%)}	_{+0.006s (+ 1.21%)}	_0.460s	_0.478s	_{p=0.042 n=12}
_{Emit Time}	_{0.267s (± 2.40%)}	_{0.271s (± 1.84%)}	_~	_0.261s	_0.285s	_{p=0.354 n=12}
_{Total Time}	_{0.788s (± 0.81%)}	_{0.799s (± 0.82%)}	_~	_0.786s	_0.822s	_{p=0.053 n=12}
_{angular-1 - native}
_Errors	₃	₃	_~	_~	_~	_{p=1.000 n=12}
_Symbols	_{846,819 (± 0.07%)}	_{849,226 (± 0.07%)}	_{+2,407 (+ 0.28%)}	_847,556	_850,439	_{p=0.000 n=12}
_Types	_{247,032 (± 0.00%)}	_{266,386 (± 0.00%)}	_{🔻+19,354 (+ 7.83%)}	_266,382	_266,390	_{p=0.000 n=12}
_{Memory Used}	_{596,094k (± 0.02%)}	_{600,933k (± 0.03%)}	_{+4,839k (+ 0.81%)}	_600,506k	_601,215k	_{p=0.000 n=12}
_{Memory Allocs}	_{13,129,352 (± 0.06%)}	_{13,186,552 (± 0.03%)}	_{+57,200 (+ 0.44%)}	_13,179,676	_13,198,378	_{p=0.000 n=12}
_{Config Time}	_{0.017s (± 1.86%)}	_{0.017s (± 1.45%)}	_~	_0.016s	_0.017s	_{p=0.640 n=12}
_{Parse Time}	_{0.220s (± 4.58%)}	_{0.222s (± 2.65%)}	_~	_0.207s	_0.243s	_{p=0.224 n=12}
_{Bind Time}	_{0.086s (±13.42%)}	_{0.090s (±12.54%)}	_~	_0.060s	_0.109s	_{p=0.504 n=12}
_{Check Time}	_0s	_0s	_~	_~	_~	_{p=1.000 n=12}
_{Emit Time}	_{1.533s (± 1.59%)}	_{1.564s (± 1.35%)}	_{+0.030s (+ 1.99%)}	_1.507s	_1.625s	_{p=0.029 n=12}
_{Total Time}	_{1.874s (± 1.57%)}	_{1.913s (± 1.08%)}	_{+0.039s (+ 2.06%)}	_1.863s	_1.974s	_{p=0.027 n=12}
_{arktype - native}
_Errors	₀	₀	_~	_~	_~	_{p=1.000 n=12}
_Symbols	_1,757,463	_1,763,860	_{+6,397 (+ 0.36%)}	_~	_~	_{p=0.000 n=12}
_Types	_943,966	_955,077	_{+11,111 (+ 1.18%)}	_~	_~	_{p=0.000 n=12}
_{Memory Used}	_{703,603k (± 0.01%)}	_{707,828k (± 0.01%)}	_{+4,225k (+ 0.60%)}	_707,627k	_707,939k	_{p=0.000 n=12}
_{Memory Allocs}	_{13,292,125 (± 0.02%)}	_{13,370,204 (± 0.01%)}	_{+78,079 (+ 0.59%)}	_13,368,345	_13,375,410	_{p=0.000 n=12}
_{Config Time}	_0.002s	_0.002s	_~	_~	_~	_{p=1.000 n=12}
_{Parse Time}	_{0.071s (± 4.00%)}	_{0.070s (± 4.10%)}	_~	_0.064s	_0.079s	_{p=0.559 n=12}
_{Bind Time}	_{0.023s (±15.60%)}	_{0.020s (± 7.23%)}	_~	_0.018s	_0.026s	_{p=0.435 n=12}
_{Check Time}	_{2.049s (± 0.55%)}	_{2.102s (± 0.42%)}	_{+0.053s (+ 2.57%)}	_2.078s	_2.125s	_{p=0.000 n=12}
_{Emit Time}	_0.000s	_0.000s	_~	_~	_~	_{p=1.000 n=12}
_{Total Time}	_{2.191s (± 0.38%)}	_{2.236s (± 0.34%)}	_{+0.045s (+ 2.07%)}	_2.215s	_2.260s	_{p=0.000 n=12}
_{mui-docs - native}
_Errors	_11,405	_11,405	_~	_~	_~	_{p=1.000 n=12}
_Symbols	_4,331,983	_4,336,283	_{+4,300 (+ 0.10%)}	_~	_~	_{p=0.000 n=12}
_Types	_1,370,520	_1,379,749	_{+9,229 (+ 0.67%)}	_~	_~	_{p=0.000 n=12}
_{Memory Used}	_{2,626,968k (± 0.06%)}	_{2,631,657k (± 0.05%)}	_{+4,690k (+ 0.18%)}	_2,627,982k	_2,634,713k	_{p=0.000 n=12}
_{Memory Allocs}	_{27,716,388 (± 0.07%)}	_{27,740,170 (± 0.06%)}	_~	_27,694,050	_27,769,554	_{p=0.078 n=12}
_{Config Time}	_{0.017s (± 1.07%)}	_{0.017s (± 1.86%)}	_~	_0.016s	_0.017s	_{p=0.317 n=12}
_{Parse Time}	_{0.478s (± 4.10%)}	_{0.465s (± 2.41%)}	_~	_0.439s	_0.494s	_{p=0.311 n=12}
_{Bind Time}	_0.002s	_0.002s	_~	_~	_~	_{p=1.000 n=12}
_{Check Time}	_{7.153s (± 0.45%)}	_{7.168s (± 0.36%)}	_~	_7.135s	_7.274s	_{p=0.192 n=12}
_{Emit Time}	_{0.507s (±13.46%)}	_{0.586s (± 9.41%)}	_~	_0.415s	_0.660s	_{p=0.075 n=12}
_{Total Time}	_{8.884s (± 0.89%)}	_{8.982s (± 0.55%)}	_~	_8.750s	_9.053s	_{p=0.071 n=12}
_{sentry - native}
_Errors	₂	₂	_~	_~	_~	_{p=1.000 n=12}
_Symbols	_7,459,653	_7,467,866	_{+8,213 (+ 0.11%)}	_~	_~	_{p=0.000 n=12}
_Types	_2,647,172	_2,735,465	_{+88,293 (+ 3.34%)}	_~	_~	_{p=0.000 n=12}
_{Memory Used}	_{3,803,922k (± 0.03%)}	_{3,822,493k (± 0.02%)}	_{+18,571k (+ 0.49%)}	_3,820,246k	_3,825,999k	_{p=0.000 n=12}
_{Memory Allocs}	_{77,213,017 (± 0.07%)}	_{77,418,744 (± 0.06%)}	_{+205,728 (+ 0.27%)}	_77,324,824	_77,578,707	_{p=0.000 n=12}
_{Config Time}	_{0.061s (± 0.40%)}	_{0.060s (± 0.54%)}	_~	_0.060s	_0.061s	_{p=0.089 n=12}
_{Parse Time}	_{1.018s (± 1.99%)}	_{1.010s (± 1.98%)}	_~	_0.955s	_1.068s	_{p=0.469 n=12}
_{Bind Time}	_{0.308s (±12.22%)}	_{0.309s (±10.20%)}	_~	_0.260s	_0.434s	_{p=0.660 n=12}
_{Check Time}	_{14.791s (± 0.73%)}	_{14.878s (± 0.49%)}	_~	_14.733s	_15.088s	_{p=0.076 n=12}
_{Emit Time}	_0.000s	_0.000s	_~	_~	_~	_{p=1.000 n=12}
_{Total Time}	_{16.253s (± 0.68%)}	_{16.337s (± 0.48%)}	_~	_16.168s	_16.551s	_{p=0.128 n=12}
_{social-app - native}
_Errors	₀	₀	_~	_~	_~	_{p=1.000 n=12}
_Symbols	_2,568,629	_2,590,683	_{+22,054 (+ 0.86%)}	_~	_~	_{p=0.000 n=12}
_Types	_1,163,035	_1,192,699	_{+29,664 (+ 2.55%)}	_~	_~	_{p=0.000 n=12}
_{Memory Used}	_{1,212,867k (± 0.02%)}	_{1,228,457k (± 0.02%)}	_{+15,590k (+ 1.29%)}	_1,227,728k	_1,229,293k	_{p=0.000 n=12}
_{Memory Allocs}	_{13,970,870 (± 0.12%)}	_{14,135,045 (± 0.17%)}	_{+164,175 (+ 1.18%)}	_14,085,559	_14,218,567	_{p=0.000 n=12}
_{Config Time}	_{0.017s (± 1.65%)}	_{0.017s (± 1.06%)}	_~	_0.017s	_0.018s	_{p=0.590 n=12}
_{Parse Time}	_{0.351s (± 2.19%)}	_{0.354s (± 2.29%)}	_~	_0.336s	_0.374s	_{p=0.618 n=12}
_{Bind Time}	_{0.085s (±12.54%)}	_{0.075s (± 2.98%)}	_~	_0.067s	_0.078s	_{p=0.172 n=12}
_{Check Time}	_{3.578s (± 0.36%)}	_{3.602s (± 0.29%)}	_{+0.024s (+ 0.68%)}	_3.579s	_3.630s	_{p=0.015 n=12}
_{Emit Time}	_0.000s	_0.000s	_~	_~	_~	_{p=1.000 n=12}
_{Total Time}	_{4.056s (± 0.57%)}	_{4.069s (± 0.34%)}	_~	_4.038s	_4.113s	_{p=0.259 n=12}
_{strada-build-src - native}
_Errors	₀	₀	_~	_~	_~	_{p=1.000 n=12}
_Symbols	_1,388,680	_1,392,969	_{+4,289 (+ 0.31%)}	_~	_~	_{p=0.000 n=12}
_Types	_441,862	_463,230	_{🔻+21,368 (+ 4.84%)}	_~	_~	_{p=0.000 n=12}
_{Memory Used}	_{1,311,852k (± 0.51%)}	_{1,322,366k (± 0.93%)}	_~	_1,303,867k	_1,372,043k	_{p=0.198 n=12}
_{Memory Allocs}	_{78,072,568 (± 0.08%)}	_{78,641,051 (± 0.11%)}	_{+568,484 (+ 0.73%)}	_78,384,943	_78,775,275	_{p=0.000 n=12}
_{Config Time}	_{0.005s (± 9.18%)}	_{0.004s (±11.29%)}	_~	_0.003s	_0.005s	_{p=0.795 n=12}
_{Parse Time}	_{0.305s (± 2.04%)}	_{0.314s (± 1.48%)}	_{+0.009s (+ 2.81%)}	_0.297s	_0.322s	_{p=0.019 n=12}
_{Bind Time}	_0.000s	_0.000s	_~	_~	_~	_{p=1.000 n=12}
_{Check Time}	_{2.010s (± 0.58%)}	_{2.020s (± 0.38%)}	_~	_2.003s	_2.040s	_{p=0.110 n=12}
_{Emit Time}	_{0.347s (± 4.94%)}	_{0.358s (± 4.19%)}	_~	_0.338s	_0.421s	_{p=0.434 n=12}
_{Total Time}	_{23.746s (± 0.51%)}	_{24.053s (± 0.42%)}	_{+0.307s (+ 1.29%)}	_23.918s	_24.383s	_{p=0.001 n=12}
_{strada-compiler - native}
_Errors	₀	₀	_~	_~	_~	_{p=1.000 n=12}
_Symbols	_334,953	_336,483	_{+1,530 (+ 0.46%)}	_~	_~	_{p=0.000 n=12}
_Types	_197,616	_205,554	_{🔻+7,938 (+ 4.02%)}	_~	_~	_{p=0.000 n=12}
_{Memory Used}	_{247,428k (± 0.04%)}	_{249,338k (± 0.02%)}	_{+1,910k (+ 0.77%)}	_249,229k	_249,533k	_{p=0.000 n=12}
_{Memory Allocs}	_{4,326,018 (± 0.02%)}	_{4,360,368 (± 0.01%)}	_{+34,350 (+ 0.79%)}	_4,359,312	_4,360,864	_{p=0.000 n=12}
_{Config Time}	_0.001s	_0.001s	_~	_~	_~	_{p=1.000 n=12}
_{Parse Time}	_{0.112s (± 5.20%)}	_{0.108s (± 3.84%)}	_~	_0.097s	_0.118s	_{p=0.504 n=12}
_{Bind Time}	_0.000s	_0.000s	_~	_~	_~	_{p=1.000 n=12}
_{Check Time}	_{0.958s (± 0.46%)}	_{0.963s (± 0.44%)}	_~	_0.953s	_0.975s	_{p=0.075 n=12}
_{Emit Time}	_{0.150s (± 4.67%)}	_{0.156s (± 4.56%)}	_~	_0.140s	_0.178s	_{p=0.271 n=12}
_{Total Time}	_{1.273s (± 0.86%)}	_{1.284s (± 0.60%)}	_~	_1.258s	_1.301s	_{p=0.124 n=12}
_{t3code-server - native}
_Errors	₀	₀	_~	_~	_~	_{p=1.000 n=12}
_Symbols	_11,588,087	_11,613,949	_{+25,862 (+ 0.22%)}	_~	_~	_{p=0.000 n=12}
_Types	_3,062,556	_3,128,026	_{+65,470 (+ 2.14%)}	_~	_~	_{p=0.000 n=12}
_{Memory Used}	_{3,945,576k (± 0.01%)}	_{3,968,398k (± 0.02%)}	_{+22,821k (+ 0.58%)}	_3,966,843k	_3,970,592k	_{p=0.000 n=12}
_{Memory Allocs}	_{41,558,626 (± 0.08%)}	_{41,918,138 (± 0.04%)}	_{+359,512 (+ 0.87%)}	_41,885,772	_41,968,329	_{p=0.000 n=12}
_{Config Time}	_0.006s	_0.006s	_~	_~	_~	_{p=1.000 n=12}
_{Parse Time}	_{0.573s (± 2.67%)}	_{0.581s (± 2.52%)}	_~	_0.534s	_0.628s	_{p=0.417 n=12}
_{Bind Time}	_{0.197s (±16.30%)}	_{0.166s (±10.43%)}	_~	_0.150s	_0.240s	_{p=0.283 n=12}
_{Check Time}	_{18.578s (± 0.27%)}	_{18.566s (± 0.48%)}	_~	_18.416s	_18.790s	_{p=0.266 n=12}
_{Emit Time}	_0.000s	_0.000s	_~	_~	_~	_{p=1.000 n=12}
_{Total Time}	_{19.370s (± 0.28%)}	_{19.336s (± 0.45%)}	_~	_19.166s	_19.554s	_{p=0.183 n=12}
_{ts-pre-modules - native}
_Errors	₈₇	₈₇	_~	_~	_~	_{p=1.000 n=12}
_Symbols	_303,834	_305,154	_{+1,320 (+ 0.43%)}	_~	_~	_{p=0.000 n=12}
_Types	_181,663	_188,573	_{+6,910 (+ 3.80%)}	_~	_~	_{p=0.000 n=12}
_{Memory Used}	_{215,197k (± 0.02%)}	_{216,969k (± 0.02%)}	_{+1,773k (+ 0.82%)}	_216,878k	_217,057k	_{p=0.000 n=12}
_{Memory Allocs}	_{1,400,536 (± 0.01%)}	_{1,423,507 (± 0.01%)}	_{+22,971 (+ 1.64%)}	_1,423,042	_1,423,980	_{p=0.000 n=12}
_{Config Time}	_0.000s	_0.000s	_~	_~	_~	_{p=1.000 n=12}
_{Parse Time}	_{0.097s (± 4.42%)}	_{0.103s (± 4.79%)}	_~	_0.089s	_0.113s	_{p=0.091 n=12}
_{Bind Time}	_{0.042s (± 9.19%)}	_{0.042s (± 6.66%)}	_~	_0.031s	_0.047s	_{p=0.853 n=12}
_{Check Time}	_{0.745s (± 1.05%)}	_{0.740s (± 0.64%)}	_~	_0.733s	_0.756s	_{p=0.183 n=12}
_{Emit Time}	_0.000s	_0.000s	_~	_~	_~	_{p=1.000 n=12}
_{Total Time}	_{0.899s (± 0.99%)}	_{0.899s (± 0.49%)}	_~	_0.885s	_0.911s	_{p=0.854 n=12}
_{vscode - native}
_Errors	₁₀	₁₀	_~	_~	_~	_{p=1.000 n=12}
_Symbols	_13,087,251	_13,100,868	_{+13,617 (+ 0.10%)}	_~	_~	_{p=0.000 n=12}
_Types	_4,258,642	_4,364,294	_{+105,652 (+ 2.48%)}	_~	_~	_{p=0.000 n=12}
_{Memory Used}	_{6,100,422k (± 0.02%)}	_{6,127,992k (± 0.01%)}	_{+27,570k (+ 0.45%)}	_6,126,193k	_6,131,869k	_{p=0.000 n=12}
_{Memory Allocs}	_{62,048,779 (± 0.01%)}	_{62,659,924 (± 0.01%)}	_{+611,145 (+ 0.98%)}	_62,652,600	_62,681,606	_{p=0.000 n=12}
_{Config Time}	_{0.064s (± 0.28%)}	_0.064s	_~	_~	_~	_{p=1.000 n=12}
_{Parse Time}	_{1.545s (± 2.77%)}	_{1.516s (± 2.30%)}	_~	_1.445s	_1.601s	_{p=0.355 n=12}
_{Bind Time}	_{0.567s (±16.36%)}	_{0.614s (±13.46%)}	_~	_0.439s	_0.803s	_{p=0.355 n=12}
_{Check Time}	_{14.660s (± 1.20%)}	_{16.021s (± 1.07%)}	_{🔻+1.361s (+ 9.28%)}	_15.702s	_16.323s	_{p=0.000 n=12}
_{Emit Time}	_{4.781s (± 5.62%)}	_{4.602s (± 6.88%)}	_~	_3.987s	_5.177s	_{p=0.434 n=12}
_{Total Time}	_{21.687s (± 1.15%)}	_{22.889s (± 0.93%)}	_{🔻+1.202s (+ 5.54%)}	_22.421s	_23.414s	_{p=0.000 n=12}
_{webpack - native}
_Errors	₅₉₉	₅₉₉	_~	_~	_~	_{p=1.000 n=12}
_Symbols	_1,347,473	_1,349,278	_{+1,805 (+ 0.13%)}	_~	_~	_{p=0.000 n=12}
_Types	_651,043	_661,995	_{+10,952 (+ 1.68%)}	_~	_~	_{p=0.000 n=12}
_{Memory Used}	_{858,385k (± 0.02%)}	_{861,221k (± 0.02%)}	_{+2,836k (+ 0.33%)}	_860,767k	_861,684k	_{p=0.000 n=12}
_{Memory Allocs}	_{6,774,849 (± 0.02%)}	_{6,809,140 (± 0.02%)}	_{+34,291 (+ 0.51%)}	_6,805,642	_6,813,580	_{p=0.000 n=12}
_{Config Time}	_0.009s	_0.009s	_~	_~	_~	_{p=1.000 n=12}
_{Parse Time}	_{0.318s (± 2.26%)}	_{0.314s (± 3.78%)}	_~	_0.272s	_0.346s	_{p=0.766 n=12}
_{Bind Time}	_{0.079s (± 7.84%)}	_{0.080s (± 9.65%)}	_~	_0.069s	_0.105s	_{p=0.809 n=12}
_{Check Time}	_{2.975s (± 0.41%)}	_{2.992s (± 0.39%)}	_{+0.017s (+ 0.58%)}	_2.943s	_3.021s	_{p=0.025 n=12}
_{Emit Time}	_0.000s	_0.000s	_~	_~	_~	_{p=1.000 n=12}
_{Total Time}	_{3.418s (± 0.34%)}	_{3.434s (± 0.44%)}	_~	_3.371s	_3.460s	_{p=0.057 n=12}
_{xstate-main - native}
_Errors	₀	₀	_~	_~	_~	_{p=1.000 n=12}
_Symbols	_1,060,810	_1,066,353	_{+5,543 (+ 0.52%)}	_~	_~	_{p=0.000 n=12}
_Types	_389,671	_403,318	_{+13,647 (+ 3.50%)}	_~	_~	_{p=0.000 n=12}
_{Memory Used}	_{471,756k (± 0.03%)}	_{476,156k (± 0.02%)}	_{+4,400k (+ 0.93%)}	_475,932k	_476,384k	_{p=0.000 n=12}
_{Memory Allocs}	_{4,214,897 (± 0.06%)}	_{4,294,355 (± 0.10%)}	_{+79,458 (+ 1.89%)}	_4,283,449	_4,308,944	_{p=0.000 n=12}
_{Config Time}	_0.003s	_0.003s	_~	_~	_~	_{p=1.000 n=12}
_{Parse Time}	_{0.135s (± 2.93%)}	_{0.135s (± 3.15%)}	_~	_0.123s	_0.142s	_{p=0.966 n=12}
_{Bind Time}	_{0.046s (±13.58%)}	_{0.045s (±17.44%)}	_~	_0.033s	_0.065s	_{p=1.000 n=12}
_{Check Time}	_{1.087s (± 0.81%)}	_{1.101s (± 0.84%)}	_{+0.015s (+ 1.35%)}	_1.077s	_1.124s	_{p=0.030 n=12}
_{Emit Time}	_0.000s	_0.000s	_~	_~	_~	_{p=1.000 n=12}
_{Total Time}	_{1.280s (± 0.72%)}	_{1.291s (± 0.70%)}	_~	_1.260s	_1.308s	_{p=0.091 n=12}

System info unknown

Hosts

native

Scenarios

Compiler-Unions - native
angular-1 - native
arktype - native
mui-docs - native
sentry - native
social-app - native
strada-build-src - native
strada-compiler - native
t3code-server - native
ts-pre-modules - native
vscode - native
webpack - native
xstate-main - native

_Benchmark	_Name	_Iterations
_Current	_pr	₁₂
_Baseline	_baseline	₁₂

Developer Information:

Download Benchmarks

typescript-automation · 2026-10-22T08:45:25Z

Jake Bailey (@jakebailey) Here are the results of running the top 400 repos with tsc comparing baseline and pr:

Everything looks good!

…erence-discriminants

Jake Bailey (jakebailey) · 2026-10-22T11:27:00Z

TypeScript Bot (@typescript-bot) test it

typescript-automation · 2026-10-22T11:27:05Z

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

typescript-automation · 2026-10-22T11:50:14Z

Hey Jake Bailey (@jakebailey), the results of running the DT tests are ready.

Everything looks the same!

You can check the log here.

typescript-automation · 2026-10-22T11:57:27Z

Jake Bailey (@jakebailey) Here are the results of running the user tests with tsc comparing baseline and pr:

Everything looks good!

typescript-automation · 2026-10-22T11:58:26Z

Jake Bailey (@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 - native}
_Errors	₄₁	₄₁	_~	_~	_~	_{p=1.000 n=12}
_Symbols	_115,276	_115,496	_{+220 (+ 0.19%)}	_~	_~	_{p=0.000 n=12}
_Types	_79,613	_79,979	_{+366 (+ 0.46%)}	_~	_~	_{p=0.000 n=12}
_{Memory Used}	_{113,501k (± 0.08%)}	_{114,961k (± 0.07%)}	_{+1,460k (+ 1.29%)}	_114,783k	_115,246k	_{p=0.000 n=12}
_{Memory Allocs}	_{2,212,163 (± 0.00%)}	_{2,222,012 (± 0.01%)}	_{+9,849 (+ 0.45%)}	_2,221,785	_2,222,459	_{p=0.000 n=12}
_{Config Time}	_0.000s	_0.000s	_~	_~	_~	_{p=1.000 n=12}
_{Parse Time}	_{0.039s (± 4.01%)}	_{0.039s (± 5.09%)}	_~	_0.035s	_0.044s	_{p=0.741 n=12}
_{Bind Time}	_{0.014s (±10.84%)}	_{0.014s (±12.09%)}	_~	_0.011s	_0.018s	_{p=0.592 n=12}
_{Check Time}	_{0.462s (± 0.65%)}	_{0.468s (± 0.78%)}	_{+0.006s (+ 1.28%)}	_0.458s	_0.479s	_{p=0.014 n=12}
_{Emit Time}	_{0.266s (± 2.13%)}	_{0.269s (± 1.86%)}	_~	_0.257s	_0.286s	_{p=0.599 n=12}
_{Total Time}	_{0.788s (± 0.89%)}	_{0.796s (± 0.80%)}	_~	_0.780s	_0.818s	_{p=0.116 n=12}
_{angular-1 - native}
_Errors	₃	₃	_~	_~	_~	_{p=1.000 n=12}
_Symbols	_{847,198 (± 0.11%)}	_{849,088 (± 0.07%)}	_{+1,890 (+ 0.22%)}	_847,924	_851,228	_{p=0.003 n=12}
_Types	_{247,032 (± 0.00%)}	_{266,387 (± 0.00%)}	_{🔻+19,355 (+ 7.83%)}	_266,384	_266,395	_{p=0.000 n=12}
_{Memory Used}	_{596,265k (± 0.02%)}	_{600,850k (± 0.03%)}	_{+4,585k (+ 0.77%)}	_600,369k	_601,264k	_{p=0.000 n=12}
_{Memory Allocs}	_{13,131,219 (± 0.05%)}	_{13,185,688 (± 0.04%)}	_{+54,468 (+ 0.41%)}	_13,180,656	_13,202,774	_{p=0.000 n=12}
_{Config Time}	_{0.017s (± 1.45%)}	_{0.017s (± 1.70%)}	_~	_0.016s	_0.017s	_{p=1.000 n=12}
_{Parse Time}	_{0.215s (± 1.21%)}	_{0.220s (± 1.63%)}	_~	_0.210s	_0.227s	_{p=0.062 n=12}
_{Bind Time}	_{0.091s (± 7.98%)}	_{0.086s (±13.81%)}	_~	_0.059s	_0.108s	_{p=0.766 n=12}
_{Check Time}	_0s	_0s	_~	_~	_~	_{p=1.000 n=12}
_{Emit Time}	_{1.526s (± 1.04%)}	_{1.551s (± 1.16%)}	_{+0.025s (+ 1.66%)}	_1.508s	_1.616s	_{p=0.028 n=12}
_{Total Time}	_{1.870s (± 1.22%)}	_{1.891s (± 1.15%)}	_~	_1.830s	_1.943s	_{p=0.139 n=12}
_{arktype - native}
_Errors	₀	₀	_~	_~	_~	_{p=1.000 n=12}
_Symbols	_1,757,463	_1,763,860	_{+6,397 (+ 0.36%)}	_~	_~	_{p=0.000 n=12}
_Types	_943,966	_955,077	_{+11,111 (+ 1.18%)}	_~	_~	_{p=0.000 n=12}
_{Memory Used}	_{703,580k (± 0.01%)}	_{707,830k (± 0.01%)}	_{+4,251k (+ 0.60%)}	_707,619k	_707,944k	_{p=0.000 n=12}
_{Memory Allocs}	_{13,288,186 (± 0.02%)}	_{13,370,454 (± 0.01%)}	_{+82,267 (+ 0.62%)}	_13,367,763	_13,378,172	_{p=0.000 n=12}
_{Config Time}	_0.002s	_0.002s	_~	_~	_~	_{p=1.000 n=12}
_{Parse Time}	_{0.069s (± 4.52%)}	_{0.071s (± 4.09%)}	_~	_0.064s	_0.079s	_{p=0.257 n=12}
_{Bind Time}	_{0.020s (±12.84%)}	_{0.021s (±12.05%)}	_~	_0.018s	_0.033s	_{p=0.190 n=12}
_{Check Time}	_{2.052s (± 0.40%)}	_{2.100s (± 0.39%)}	_{+0.048s (+ 2.36%)}	_2.070s	_2.118s	_{p=0.000 n=12}
_{Emit Time}	_0.000s	_0.000s	_~	_~	_~	_{p=1.000 n=12}
_{Total Time}	_{2.186s (± 0.42%)}	_{2.239s (± 0.25%)}	_{+0.052s (+ 2.40%)}	_2.226s	_2.257s	_{p=0.000 n=12}
_{mui-docs - native}
_Errors	_11,405	_11,405	_~	_~	_~	_{p=1.000 n=12}
_Symbols	_4,331,983	_4,336,283	_{+4,300 (+ 0.10%)}	_~	_~	_{p=0.000 n=12}
_Types	_1,370,520	_1,379,749	_{+9,229 (+ 0.67%)}	_~	_~	_{p=0.000 n=12}
_{Memory Used}	_{2,626,358k (± 0.05%)}	_{2,631,279k (± 0.06%)}	_{+4,921k (+ 0.19%)}	_2,626,136k	_2,635,782k	_{p=0.000 n=12}
_{Memory Allocs}	_{27,690,500 (± 0.06%)}	_{27,735,524 (± 0.06%)}	_{+45,024 (+ 0.16%)}	_27,688,434	_27,766,849	_{p=0.005 n=12}
_{Config Time}	_{0.017s (± 1.07%)}	_{0.017s (± 1.70%)}	_~	_0.016s	_0.017s	_{p=0.590 n=12}
_{Parse Time}	_{0.470s (± 2.48%)}	_{0.478s (± 2.29%)}	_~	_0.442s	_0.509s	_{p=0.354 n=12}
_{Bind Time}	_{0.002s (±24.21%)}	_0.002s	_~	_~	_~	_{p=1.000 n=12}
_{Check Time}	_{7.151s (± 0.26%)}	_{7.186s (± 0.53%)}	_{+0.036s (+ 0.50%)}	_7.141s	_7.371s	_{p=0.017 n=12}
_{Emit Time}	_{0.555s (±10.86%)}	_{0.530s (±13.16%)}	_~	_0.415s	_0.661s	_{p=0.723 n=12}
_{Total Time}	_{8.945s (± 0.60%)}	_{8.947s (± 0.93%)}	_~	_8.722s	_9.065s	_{p=0.291 n=12}
_{sentry - native}
_Errors	₂	₂	_~	_~	_~	_{p=1.000 n=12}
_Symbols	_7,459,653	_7,467,866	_{+8,213 (+ 0.11%)}	_~	_~	_{p=0.000 n=12}
_Types	_2,647,172	_2,735,465	_{+88,293 (+ 3.34%)}	_~	_~	_{p=0.000 n=12}
_{Memory Used}	_{3,803,303k (± 0.03%)}	_{3,823,236k (± 0.04%)}	_{+19,933k (+ 0.52%)}	_3,820,562k	_3,828,241k	_{p=0.000 n=12}
_{Memory Allocs}	_{77,155,803 (± 0.09%)}	_{77,408,957 (± 0.09%)}	_{+253,154 (+ 0.33%)}	_77,265,276	_77,604,251	_{p=0.000 n=12}
_{Config Time}	_{0.060s (± 0.51%)}	_{0.061s (± 0.53%)}	_~	_0.060s	_0.061s	_{p=0.414 n=12}
_{Parse Time}	_{1.011s (± 2.89%)}	_{1.020s (± 2.29%)}	_~	_0.956s	_1.087s	_{p=0.370 n=12}
_{Bind Time}	_{0.336s (±13.81%)}	_{0.314s (±13.09%)}	_~	_0.262s	_0.442s	_{p=0.702 n=12}
_{Check Time}	_{14.736s (± 0.33%)}	_{14.861s (± 0.75%)}	_{+0.125s (+ 0.85%)}	_14.698s	_15.188s	_{p=0.017 n=12}
_{Emit Time}	_0.000s	_0.000s	_~	_~	_~	_{p=1.000 n=12}
_{Total Time}	_{16.217s (± 0.32%)}	_{16.333s (± 0.62%)}	_{+0.116s (+ 0.72%)}	_16.154s	_16.641s	_{p=0.032 n=12}
_{social-app - native}
_Errors	₀	₀	_~	_~	_~	_{p=1.000 n=12}
_Symbols	_2,568,629	_2,590,683	_{+22,054 (+ 0.86%)}	_~	_~	_{p=0.000 n=12}
_Types	_1,163,035	_1,192,699	_{+29,664 (+ 2.55%)}	_~	_~	_{p=0.000 n=12}
_{Memory Used}	_{1,212,860k (± 0.02%)}	_{1,228,626k (± 0.02%)}	_{+15,766k (+ 1.30%)}	_1,228,272k	_1,229,503k	_{p=0.000 n=12}
_{Memory Allocs}	_{13,972,384 (± 0.14%)}	_{14,133,510 (± 0.25%)}	_{+161,126 (+ 1.15%)}	_14,084,961	_14,258,551	_{p=0.000 n=12}
_{Config Time}	_{0.017s (± 1.65%)}	_{0.017s (± 1.06%)}	_~	_0.017s	_0.018s	_{p=0.590 n=12}
_{Parse Time}	_{0.356s (± 2.06%)}	_{0.355s (± 2.92%)}	_~	_0.327s	_0.379s	_{p=0.832 n=12}
_{Bind Time}	_{0.074s (± 2.48%)}	_{0.081s (±14.01%)}	_~	_0.071s	_0.127s	_{p=0.737 n=12}
_{Check Time}	_{3.593s (± 0.39%)}	_{3.605s (± 0.33%)}	_~	_3.574s	_3.643s	_{p=0.401 n=12}
_{Emit Time}	_0.000s	_0.000s	_~	_~	_~	_{p=1.000 n=12}
_{Total Time}	_{4.061s (± 0.42%)}	_{4.081s (± 0.45%)}	_~	_4.034s	_4.140s	_{p=0.098 n=12}
_{strada-build-src - native}
_Errors	₀	₀	_~	_~	_~	_{p=1.000 n=12}
_Symbols	_1,388,680	_1,392,969	_{+4,289 (+ 0.31%)}	_~	_~	_{p=0.000 n=12}
_Types	_441,862	_463,230	_{🔻+21,368 (+ 4.84%)}	_~	_~	_{p=0.000 n=12}
_{Memory Used}	_{1,313,243k (± 0.41%)}	_{1,325,521k (± 0.65%)}	_{+12,278k (+ 0.93%)}	_1,304,127k	_1,351,801k	_{p=0.028 n=12}
_{Memory Allocs}	_{78,037,069 (± 0.13%)}	_{78,753,997 (± 0.05%)}	_{+716,928 (+ 0.92%)}	_78,645,454	_78,877,068	_{p=0.000 n=12}
_{Config Time}	_{0.004s (±13.41%)}	_{0.004s (±11.30%)}	_~	_0.003s	_0.005s	_{p=0.230 n=12}
_{Parse Time}	_{0.307s (± 2.74%)}	_{0.307s (± 2.24%)}	_~	_0.292s	_0.326s	_{p=0.810 n=12}
_{Bind Time}	_0.000s	_0.000s	_~	_~	_~	_{p=1.000 n=12}
_{Check Time}	_{2.002s (± 0.54%)}	_{2.007s (± 0.47%)}	_~	_1.980s	_2.030s	_{p=0.580 n=12}
_{Emit Time}	_{0.343s (± 3.10%)}	_{0.356s (± 3.13%)}	_~	_0.335s	_0.391s	_{p=0.147 n=12}
_{Total Time}	_{23.642s (± 0.67%)}	_{23.796s (± 0.51%)}	_~	_23.524s	_24.218s	_{p=0.198 n=12}
_{strada-compiler - native}
_Errors	₀	₀	_~	_~	_~	_{p=1.000 n=12}
_Symbols	_334,953	_336,483	_{+1,530 (+ 0.46%)}	_~	_~	_{p=0.000 n=12}
_Types	_197,616	_205,554	_{🔻+7,938 (+ 4.02%)}	_~	_~	_{p=0.000 n=12}
_{Memory Used}	_{247,433k (± 0.03%)}	_{249,376k (± 0.02%)}	_{+1,943k (+ 0.79%)}	_249,268k	_249,483k	_{p=0.000 n=12}
_{Memory Allocs}	_{4,325,735 (± 0.01%)}	_{4,360,322 (± 0.01%)}	_{+34,587 (+ 0.80%)}	_4,359,362	_4,361,496	_{p=0.000 n=12}
_{Config Time}	_0.001s	_0.001s	_~	_~	_~	_{p=1.000 n=12}
_{Parse Time}	_{0.110s (± 4.40%)}	_{0.115s (± 6.41%)}	_~	_0.099s	_0.130s	_{p=0.310 n=12}
_{Bind Time}	_0.000s	_0.000s	_~	_~	_~	_{p=1.000 n=12}
_{Check Time}	_{0.957s (± 0.59%)}	_{0.960s (± 0.63%)}	_~	_0.948s	_0.977s	_{p=0.401 n=12}
_{Emit Time}	_{0.151s (± 7.31%)}	_{0.160s (± 5.40%)}	_~	_0.131s	_0.181s	_{p=0.259 n=12}
_{Total Time}	_{1.273s (± 1.13%)}	_{1.291s (± 0.66%)}	_{+0.018s (+ 1.45%)}	_1.273s	_1.311s	_{p=0.018 n=12}
_{t3code-server - native}
_Errors	₀	₀	_~	_~	_~	_{p=1.000 n=12}
_Symbols	_11,588,087	_11,613,949	_{+25,862 (+ 0.22%)}	_~	_~	_{p=0.000 n=12}
_Types	_3,062,556	_3,128,028	_{+65,472 (+ 2.14%)}	_~	_~	_{p=0.000 n=12}
_{Memory Used}	_{3,945,988k (± 0.02%)}	_{3,968,627k (± 0.01%)}	_{+22,639k (+ 0.57%)}	_3,967,572k	_3,970,292k	_{p=0.000 n=12}
_{Memory Allocs}	_{41,551,665 (± 0.04%)}	_{41,938,576 (± 0.05%)}	_{+386,911 (+ 0.93%)}	_41,875,127	_41,977,317	_{p=0.000 n=12}
_{Config Time}	_0.006s	_{0.006s (± 2.98%)}	_~	_0.006s	_0.007s	_{p=1.000 n=12}
_{Parse Time}	_{0.581s (± 1.82%)}	_{0.585s (± 2.89%)}	_~	_0.545s	_0.635s	_{p=0.600 n=12}
_{Bind Time}	_{0.162s (± 7.95%)}	_{0.201s (±15.18%)}	_{🔻+0.039s (+24.07%)}	_0.154s	_0.277s	_{p=0.007 n=12}
_{Check Time}	_{18.615s (± 0.49%)}	_{18.918s (± 0.86%)}	_{+0.303s (+ 1.63%)}	_18.546s	_19.545s	_{p=0.001 n=12}
_{Emit Time}	_0.000s	_0.000s	_~	_~	_~	_{p=1.000 n=12}
_{Total Time}	_{19.378s (± 0.50%)}	_{19.729s (± 0.77%)}	_{+0.351s (+ 1.81%)}	_19.389s	_20.326s	_{p=0.000 n=12}
_{ts-pre-modules - native}
_Errors	₈₇	₈₇	_~	_~	_~	_{p=1.000 n=12}
_Symbols	_303,834	_305,154	_{+1,320 (+ 0.43%)}	_~	_~	_{p=0.000 n=12}
_Types	_181,663	_188,573	_{+6,910 (+ 3.80%)}	_~	_~	_{p=0.000 n=12}
_{Memory Used}	_{215,190k (± 0.02%)}	_{216,992k (± 0.02%)}	_{+1,802k (+ 0.84%)}	_216,897k	_217,075k	_{p=0.000 n=12}
_{Memory Allocs}	_{1,400,771 (± 0.01%)}	_{1,423,654 (± 0.01%)}	_{+22,883 (+ 1.63%)}	_1,423,227	_1,424,026	_{p=0.000 n=12}
_{Config Time}	_0.000s	_{0.000s (±217.90%)}	_~	_0.000s	_0.001s	_{p=1.000 n=12}
_{Parse Time}	_{0.096s (± 4.58%)}	_{0.093s (± 3.33%)}	_~	_0.085s	_0.101s	_{p=0.468 n=12}
_{Bind Time}	_{0.039s (± 9.12%)}	_{0.042s (± 7.99%)}	_~	_0.032s	_0.049s	_{p=0.245 n=12}
_{Check Time}	_{0.741s (± 0.81%)}	_{0.742s (± 1.05%)}	_~	_0.730s	_0.767s	_{p=0.966 n=12}
_{Emit Time}	_0.000s	_0.000s	_~	_~	_~	_{p=1.000 n=12}
_{Total Time}	_{0.891s (± 0.66%)}	_{0.892s (± 0.61%)}	_~	_0.875s	_0.903s	_{p=0.619 n=12}
_{vscode - native}
_Errors	₁₀	₁₀	_~	_~	_~	_{p=1.000 n=12}
_Symbols	_13,166,018	_13,179,174	_{+13,156 (+ 0.10%)}	_~	_~	_{p=0.000 n=12}
_Types	_4,291,594	_4,398,140	_{+106,546 (+ 2.48%)}	_~	_~	_{p=0.000 n=12}
_{Memory Used}	_{6,130,662k (± 0.02%)}	_{6,159,893k (± 0.02%)}	_{+29,231k (+ 0.48%)}	_6,157,769k	_6,163,557k	_{p=0.000 n=12}
_{Memory Allocs}	_{62,358,959 (± 0.02%)}	_{62,973,591 (± 0.02%)}	_{+614,632 (+ 0.99%)}	_62,960,645	_63,019,542	_{p=0.000 n=12}
_{Config Time}	_{0.077s (± 0.42%)}	_{0.078s (± 0.23%)}	_{+0.001s (+ 0.75%)}	_0.078s	_0.079s	_{p=0.009 n=12}
_{Parse Time}	_{1.946s (± 1.91%)}	_{1.910s (± 2.40%)}	_~	_1.815s	_2.063s	_{p=0.198 n=12}
_{Bind Time}	_{0.621s (± 9.14%)}	_{0.690s (±12.09%)}	_~	_0.544s	_0.962s	_{p=0.193 n=12}
_{Check Time}	_{16.757s (± 0.51%)}	_{18.236s (± 0.83%)}	_{🔻+1.479s (+ 8.82%)}	_17.896s	_18.458s	_{p=0.000 n=12}
_{Emit Time}	_{5.358s (± 5.95%)}	_{5.495s (± 5.80%)}	_~	_4.815s	_6.256s	_{p=0.579 n=12}
_{Total Time}	_{24.839s (± 1.20%)}	_{26.490s (± 1.01%)}	_{🔻+1.651s (+ 6.65%)}	_25.797s	_27.004s	_{p=0.000 n=12}
_{webpack - native}
_Errors	₆₀₀	₆₀₀	_~	_~	_~	_{p=1.000 n=12}
_Symbols	_1,347,151	_1,348,702	_{+1,551 (+ 0.12%)}	_~	_~	_{p=0.000 n=12}
_Types	_648,706	_659,440	_{+10,734 (+ 1.65%)}	_~	_~	_{p=0.000 n=12}
_{Memory Used}	_{855,102k (± 0.02%)}	_{857,486k (± 0.02%)}	_{+2,384k (+ 0.28%)}	_857,018k	_857,710k	_{p=0.000 n=12}
_{Memory Allocs}	_{6,760,114 (± 0.01%)}	_{6,791,984 (± 0.01%)}	_{+31,870 (+ 0.47%)}	_6,789,031	_6,794,576	_{p=0.000 n=12}
_{Config Time}	_0.009s	_0.009s	_~	_~	_~	_{p=1.000 n=12}
_{Parse Time}	_{0.310s (± 1.83%)}	_{0.312s (± 2.30%)}	_~	_0.285s	_0.329s	_{p=0.434 n=12}
_{Bind Time}	_{0.076s (± 5.36%)}	_{0.082s (±13.09%)}	_~	_0.071s	_0.127s	_{p=0.256 n=12}
_{Check Time}	_{3.026s (± 0.20%)}	_{3.093s (± 0.73%)}	_{+0.067s (+ 2.21%)}	_3.035s	_3.153s	_{p=0.000 n=12}
_{Emit Time}	_0.000s	_0.000s	_~	_~	_~	_{p=1.000 n=12}
_{Total Time}	_{3.459s (± 0.28%)}	_{3.533s (± 0.43%)}	_{+0.075s (+ 2.16%)}	_3.509s	_3.586s	_{p=0.000 n=12}
_{xstate-main - native}
_Errors	₀	₀	_~	_~	_~	_{p=1.000 n=12}
_Symbols	_1,060,810	_1,066,353	_{+5,543 (+ 0.52%)}	_~	_~	_{p=0.000 n=12}
_Types	_389,671	_403,318	_{+13,647 (+ 3.50%)}	_~	_~	_{p=0.000 n=12}
_{Memory Used}	_{471,720k (± 0.02%)}	_{476,141k (± 0.02%)}	_{+4,420k (+ 0.94%)}	_475,963k	_476,405k	_{p=0.000 n=12}
_{Memory Allocs}	_{4,214,758 (± 0.11%)}	_{4,289,049 (± 0.08%)}	_{+74,291 (+ 1.76%)}	_4,280,924	_4,296,561	_{p=0.000 n=12}
_{Config Time}	_0.002s	_0.002s	_~	_~	_~	_{p=1.000 n=12}
_{Parse Time}	_{0.107s (± 3.33%)}	_{0.102s (± 4.01%)}	_{🟩-0.006s (- 5.12%)}	_0.096s	_0.115s	_{p=0.016 n=12}
_{Bind Time}	_{0.036s (±16.14%)}	_{0.041s (±13.81%)}	_~	_0.027s	_0.052s	_{p=0.278 n=12}
_{Check Time}	_{0.903s (± 0.92%)}	_{0.913s (± 0.74%)}	_{+0.010s (+ 1.14%)}	_0.898s	_0.930s	_{p=0.040 n=12}
_{Emit Time}	_0.000s	_0.000s	_~	_~	_~	_{p=1.000 n=12}
_{Total Time}	_{1.055s (± 1.03%)}	_{1.064s (± 0.55%)}	_~	_1.044s	_1.077s	_{p=0.193 n=12}

System info unknown

Hosts

native

Scenarios

Compiler-Unions - native
angular-1 - native
arktype - native
mui-docs - native
sentry - native
social-app - native
strada-build-src - native
strada-compiler - native
t3code-server - native
ts-pre-modules - native
vscode - native
webpack - native
xstate-main - native

_Benchmark	_Name	_Iterations
_Current	_pr	₁₂
_Baseline	_baseline	₁₂

Developer Information:

Download Benchmarks

typescript-automation · 2026-10-22T12:48:10Z

Jake Bailey (@jakebailey) Here are the results of running the top 400 repos with tsc comparing baseline and pr:

Everything looks good!

Mateusz Burzyński (Andarist) · 2026-10-23T11:08:04Z

Jake Bailey (@jakebailey) could u rerun perf tests here?

Jake Bailey (jakebailey) · 2026-10-24T12:26:05Z

TypeScript Bot (@typescript-bot) perf test this faster

typescript-automation · 2026-10-24T12:26:11Z

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

Command	Status	Results
`perf test this faster`	✅ Started	👀 Results

typescript-automation · 2026-10-24T12:58:38Z

Jake Bailey (@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 - native}
_Errors	₄₁	₄₁	_~	_~	_~	_{p=1.000 n=12}
_Symbols	_115,276	_115,496	_{+220 (+ 0.19%)}	_~	_~	_{p=0.000 n=12}
_Types	_79,613	_79,977	_{+364 (+ 0.46%)}	_~	_~	_{p=0.000 n=12}
_{Memory Used}	_{113,425k (± 0.04%)}	_{114,969k (± 0.08%)}	_{+1,544k (+ 1.36%)}	_114,794k	_115,191k	_{p=0.000 n=12}
_{Memory Allocs}	_{2,212,216 (± 0.01%)}	_{2,222,195 (± 0.00%)}	_{+9,979 (+ 0.45%)}	_2,221,963	_2,222,464	_{p=0.000 n=12}
_{Config Time}	_0.000s	_0.000s	_~	_~	_~	_{p=1.000 n=12}
_{Parse Time}	_{0.040s (± 5.30%)}	_{0.040s (± 5.81%)}	_~	_0.036s	_0.046s	_{p=0.639 n=12}
_{Bind Time}	_{0.013s (±11.03%)}	_{0.015s (± 7.61%)}	_~	_0.011s	_0.017s	_{p=0.223 n=12}
_{Check Time}	_{0.466s (± 0.82%)}	_{0.466s (± 1.14%)}	_~	_0.458s	_0.481s	_{p=0.701 n=12}
_{Emit Time}	_{0.266s (± 2.20%)}	_{0.265s (± 1.91%)}	_~	_0.251s	_0.276s	_{p=1.000 n=12}
_{Total Time}	_{0.792s (± 0.86%)}	_{0.792s (± 0.65%)}	_~	_0.781s	_0.807s	_{p=0.854 n=12}
_{angular-1 - native}
_Errors	₃	₃	_~	_~	_~	_{p=1.000 n=12}
_Symbols	_{847,014 (± 0.06%)}	_{849,698 (± 0.07%)}	_{+2,684 (+ 0.32%)}	_848,806	_851,173	_{p=0.000 n=12}
_Types	_{247,032 (± 0.00%)}	_{266,386 (± 0.00%)}	_{🔻+19,355 (+ 7.83%)}	_266,382	_266,397	_{p=0.000 n=12}
_{Memory Used}	_{596,229k (± 0.02%)}	_{601,071k (± 0.01%)}	_{+4,842k (+ 0.81%)}	_600,911k	_601,218k	_{p=0.000 n=12}
_{Memory Allocs}	_{13,138,519 (± 0.09%)}	_{13,187,314 (± 0.02%)}	_{+48,796 (+ 0.37%)}	_13,183,741	_13,198,288	_{p=0.000 n=12}
_{Config Time}	_{0.017s (± 1.45%)}	_{0.017s (± 1.70%)}	_~	_0.016s	_0.017s	_{p=1.000 n=12}
_{Parse Time}	_{0.224s (± 2.66%)}	_{0.221s (± 2.42%)}	_~	_0.211s	_0.236s	_{p=0.468 n=12}
_{Bind Time}	_{0.082s (±13.35%)}	_{0.086s (±12.84%)}	_~	_0.060s	_0.110s	_{p=0.600 n=12}
_{Check Time}	_0s	_0s	_~	_~	_~	_{p=1.000 n=12}
_{Emit Time}	_{1.559s (± 1.15%)}	_{1.590s (± 1.16%)}	_{+0.030s (+ 1.96%)}	_1.550s	_1.627s	_{p=0.040 n=12}
_{Total Time}	_{1.903s (± 1.15%)}	_{1.936s (± 0.76%)}	_{+0.032s (+ 1.69%)}	_1.899s	_1.967s	_{p=0.011 n=12}
_{arktype - native}
_Errors	₀	₀	_~	_~	_~	_{p=1.000 n=12}
_Symbols	_1,757,463	_1,763,860	_{+6,397 (+ 0.36%)}	_~	_~	_{p=0.000 n=12}
_Types	_943,966	_955,077	_{+11,111 (+ 1.18%)}	_~	_~	_{p=0.000 n=12}
_{Memory Used}	_{703,592k (± 0.01%)}	_{707,889k (± 0.01%)}	_{+4,297k (+ 0.61%)}	_707,657k	_708,186k	_{p=0.000 n=12}
_{Memory Allocs}	_{13,290,577 (± 0.01%)}	_{13,371,421 (± 0.01%)}	_{+80,844 (+ 0.61%)}	_13,368,942	_13,378,177	_{p=0.000 n=12}
_{Config Time}	_0.002s	_0.002s	_~	_~	_~	_{p=1.000 n=12}
_{Parse Time}	_{0.068s (± 3.49%)}	_{0.070s (± 3.89%)}	_~	_0.062s	_0.077s	_{p=0.201 n=12}
_{Bind Time}	_{0.023s (±12.67%)}	_{0.023s (±15.61%)}	_~	_0.018s	_0.035s	_{p=0.612 n=12}
_{Check Time}	_{2.049s (± 0.41%)}	_{2.098s (± 0.44%)}	_{+0.050s (+ 2.42%)}	_2.080s	_2.125s	_{p=0.000 n=12}
_{Emit Time}	_0.000s	_0.000s	_~	_~	_~	_{p=1.000 n=12}
_{Total Time}	_{2.185s (± 0.33%)}	_{2.235s (± 0.36%)}	_{+0.050s (+ 2.31%)}	_2.217s	_2.262s	_{p=0.000 n=12}
_{mui-docs - native}
_Errors	_11,405	_11,405	_~	_~	_~	_{p=1.000 n=12}
_Symbols	_4,331,983	_4,336,283	_{+4,300 (+ 0.10%)}	_~	_~	_{p=0.000 n=12}
_Types	_1,370,520	_1,379,749	_{+9,229 (+ 0.67%)}	_~	_~	_{p=0.000 n=12}
_{Memory Used}	_{2,625,884k (± 0.06%)}	_{2,631,716k (± 0.04%)}	_{+5,832k (+ 0.22%)}	_2,627,207k	_2,634,397k	_{p=0.000 n=12}
_{Memory Allocs}	_{27,704,089 (± 0.08%)}	_{27,740,730 (± 0.05%)}	_{+36,641 (+ 0.13%)}	_27,697,468	_27,787,671	_{p=0.004 n=12}
_{Config Time}	_{0.017s (± 1.45%)}	_{0.017s (± 1.45%)}	_~	_0.016s	_0.017s	_{p=1.000 n=12}
_{Parse Time}	_{0.475s (± 2.14%)}	_{0.476s (± 2.70%)}	_~	_0.425s	_0.501s	_{p=0.681 n=12}
_{Bind Time}	_0.002s	_0.002s	_~	_~	_~	_{p=1.000 n=12}
_{Check Time}	_{7.174s (± 0.64%)}	_{7.206s (± 0.50%)}	_~	_7.147s	_7.310s	_{p=0.284 n=12}
_{Emit Time}	_{0.539s (±11.72%)}	_{0.519s (±11.58%)}	_~	_0.413s	_0.653s	_{p=0.681 n=12}
_{Total Time}	_{8.957s (± 0.68%)}	_{8.971s (± 0.57%)}	_~	_8.763s	_9.060s	_{p=0.723 n=12}
_{sentry - native}
_Errors	₂	₂	_~	_~	_~	_{p=1.000 n=12}
_Symbols	_7,459,653	_7,467,866	_{+8,213 (+ 0.11%)}	_~	_~	_{p=0.000 n=12}
_Types	_2,647,172	_2,735,392	_{+88,220 (+ 3.33%)}	_~	_~	_{p=0.000 n=12}
_{Memory Used}	_{3,803,313k (± 0.02%)}	_{3,824,517k (± 0.07%)}	_{+21,204k (+ 0.56%)}	_3,820,966k	_3,834,728k	_{p=0.000 n=12}
_{Memory Allocs}	_{77,241,578 (± 0.22%)}	_{77,564,463 (± 0.09%)}	_{+322,886 (+ 0.42%)}	_77,339,288	_77,718,013	_{p=0.003 n=12}
_{Config Time}	_{0.061s (± 0.53%)}	_{0.061s (± 0.53%)}	_~	_0.060s	_0.061s	_{p=1.000 n=12}
_{Parse Time}	_{1.042s (± 4.16%)}	_{1.016s (± 2.41%)}	_~	_0.962s	_1.077s	_{p=0.580 n=12}
_{Bind Time}	_{0.305s (±10.85%)}	_{0.324s (±15.06%)}	_~	_0.263s	_0.467s	_{p=0.451 n=12}
_{Check Time}	_{14.750s (± 0.42%)}	_{14.760s (± 0.41%)}	_~	_14.631s	_14.960s	_{p=0.831 n=12}
_{Emit Time}	_0.000s	_0.000s	_~	_~	_~	_{p=1.000 n=12}
_{Total Time}	_{16.234s (± 0.44%)}	_{16.231s (± 0.39%)}	_~	_16.089s	_16.424s	_{p=0.921 n=12}
_{social-app - native}
_Errors	₀	₀	_~	_~	_~	_{p=1.000 n=12}
_Symbols	_2,568,629	_2,590,683	_{+22,054 (+ 0.86%)}	_~	_~	_{p=0.000 n=12}
_Types	_1,163,035	_1,192,693	_{+29,658 (+ 2.55%)}	_~	_~	_{p=0.000 n=12}
_{Memory Used}	_{1,212,671k (± 0.02%)}	_{1,228,447k (± 0.01%)}	_{+15,777k (+ 1.30%)}	_1,228,100k	_1,228,764k	_{p=0.000 n=12}
_{Memory Allocs}	_{13,985,566 (± 0.17%)}	_{14,151,756 (± 0.14%)}	_{+166,189 (+ 1.19%)}	_14,111,481	_14,202,702	_{p=0.000 n=12}
_{Config Time}	_{0.017s (± 1.65%)}	_{0.017s (± 1.86%)}	_~	_0.017s	_0.018s	_{p=0.667 n=12}
_{Parse Time}	_{0.359s (± 1.28%)}	_{0.353s (± 1.63%)}	_~	_0.338s	_0.368s	_{p=0.147 n=12}
_{Bind Time}	_{0.077s (± 6.65%)}	_{0.078s (± 6.15%)}	_~	_0.072s	_0.101s	_{p=0.169 n=12}
_{Check Time}	_{3.618s (± 0.26%)}	_{3.620s (± 0.36%)}	_~	_3.585s	_3.651s	_{p=0.854 n=12}
_{Emit Time}	_0.000s	_0.000s	_~	_~	_~	_{p=1.000 n=12}
_{Total Time}	_{4.094s (± 0.26%)}	_{4.090s (± 0.39%)}	_~	_4.047s	_4.121s	_{p=0.745 n=12}
_{strada-build-src - native}
_Errors	₀	₀	_~	_~	_~	_{p=1.000 n=12}
_Symbols	_1,388,680	_1,392,969	_{+4,289 (+ 0.31%)}	_~	_~	_{p=0.000 n=12}
_Types	_441,862	_463,230	_{🔻+21,368 (+ 4.84%)}	_~	_~	_{p=0.000 n=12}
_{Memory Used}	_{1,310,165k (± 0.64%)}	_{1,322,426k (± 0.58%)}	_{+12,261k (+ 0.94%)}	_1,309,654k	_1,343,569k	_{p=0.024 n=12}
_{Memory Allocs}	_{78,126,651 (± 0.05%)}	_{78,670,667 (± 0.11%)}	_{+544,017 (+ 0.70%)}	_78,396,559	_78,807,619	_{p=0.000 n=12}
_{Config Time}	_{0.004s (±11.16%)}	_{0.004s (±15.62%)}	_~	_0.002s	_0.006s	_{p=0.978 n=12}
_{Parse Time}	_{0.311s (± 2.59%)}	_{0.305s (± 2.24%)}	_~	_0.283s	_0.326s	_{p=0.247 n=12}
_{Bind Time}	_{0.000s (±217.90%)}	_{0.000s (±217.90%)}	_~	_0.000s	_0.003s	_{p=1.000 n=12}
_{Check Time}	_{2.004s (± 0.49%)}	_{2.020s (± 0.35%)}	_{+0.016s (+ 0.80%)}	_2.003s	_2.044s	_{p=0.011 n=12}
_{Emit Time}	_{0.356s (± 4.82%)}	_{0.356s (± 4.00%)}	_~	_0.330s	_0.408s	_{p=0.831 n=12}
_{Total Time}	_{23.763s (± 0.60%)}	_{23.990s (± 0.45%)}	_{+0.227s (+ 0.96%)}	_23.805s	_24.262s	_{p=0.015 n=12}
_{strada-compiler - native}
_Errors	₀	₀	_~	_~	_~	_{p=1.000 n=12}
_Symbols	_334,953	_336,483	_{+1,530 (+ 0.46%)}	_~	_~	_{p=0.000 n=12}
_Types	_197,616	_205,554	_{🔻+7,938 (+ 4.02%)}	_~	_~	_{p=0.000 n=12}
_{Memory Used}	_{247,440k (± 0.02%)}	_{249,361k (± 0.02%)}	_{+1,921k (+ 0.78%)}	_249,254k	_249,469k	_{p=0.000 n=12}
_{Memory Allocs}	_{4,326,015 (± 0.01%)}	_{4,360,870 (± 0.01%)}	_{+34,855 (+ 0.81%)}	_4,360,071	_4,361,624	_{p=0.000 n=12}
_{Config Time}	_0.001s	_0.001s	_~	_~	_~	_{p=1.000 n=12}
_{Parse Time}	_{0.111s (± 4.68%)}	_{0.114s (± 4.06%)}	_~	_0.103s	_0.126s	_{p=0.432 n=12}
_{Bind Time}	_0.000s	_0.000s	_~	_~	_~	_{p=1.000 n=12}
_{Check Time}	_{0.959s (± 0.55%)}	_{0.962s (± 0.66%)}	_~	_0.952s	_0.982s	_{p=0.681 n=12}
_{Emit Time}	_{0.146s (± 5.72%)}	_{0.158s (± 4.79%)}	_{🔻+0.012s (+ 8.24%)}	_0.138s	_0.173s	_{p=0.037 n=12}
_{Total Time}	_{1.268s (± 0.69%)}	_{1.289s (± 0.81%)}	_{+0.021s (+ 1.65%)}	_1.258s	_1.307s	_{p=0.002 n=12}
_{t3code-server - native}
_Errors	₀	₀	_~	_~	_~	_{p=1.000 n=12}
_Symbols	_11,588,087	_11,613,949	_{+25,862 (+ 0.22%)}	_~	_~	_{p=0.000 n=12}
_Types	_3,062,556	_3,128,013	_{+65,457 (+ 2.14%)}	_~	_~	_{p=0.000 n=12}
_{Memory Used}	_{3,945,902k (± 0.01%)}	_{3,968,101k (± 0.01%)}	_{+22,198k (+ 0.56%)}	_3,967,358k	_3,969,228k	_{p=0.000 n=12}
_{Memory Allocs}	_{41,529,419 (± 0.04%)}	_{41,956,849 (± 0.04%)}	_{+427,430 (+ 1.03%)}	_41,909,352	_41,995,796	_{p=0.000 n=12}
_{Config Time}	_0.006s	_{0.006s (± 4.55%)}	_~	_0.006s	_0.007s	_{p=0.217 n=12}
_{Parse Time}	_{0.560s (± 2.57%)}	_{0.576s (± 3.28%)}	_~	_0.533s	_0.618s	_{p=0.213 n=12}
_{Bind Time}	_{0.187s (±14.43%)}	_{0.188s (±14.81%)}	_~	_0.152s	_0.273s	_{p=0.766 n=12}
_{Check Time}	_{18.608s (± 0.42%)}	_{18.882s (± 1.26%)}	_{+0.274s (+ 1.47%)}	_18.491s	_19.892s	_{p=0.023 n=12}
_{Emit Time}	_0.000s	_0.000s	_~	_~	_~	_{p=1.000 n=12}
_{Total Time}	_{19.377s (± 0.37%)}	_{19.669s (± 1.27%)}	_{+0.291s (+ 1.50%)}	_19.232s	_20.721s	_{p=0.020 n=12}
_{ts-pre-modules - native}
_Errors	₈₇	₈₇	_~	_~	_~	_{p=1.000 n=12}
_Symbols	_303,834	_305,154	_{+1,320 (+ 0.43%)}	_~	_~	_{p=0.000 n=12}
_Types	_181,663	_188,573	_{+6,910 (+ 3.80%)}	_~	_~	_{p=0.000 n=12}
_{Memory Used}	_{215,185k (± 0.02%)}	_{216,936k (± 0.02%)}	_{+1,751k (+ 0.81%)}	_216,836k	_217,053k	_{p=0.000 n=12}
_{Memory Allocs}	_{1,400,653 (± 0.01%)}	_{1,424,033 (± 0.01%)}	_{+23,381 (+ 1.67%)}	_1,423,626	_1,424,739	_{p=0.000 n=12}
_{Config Time}	_0.000s	_0.000s	_~	_~	_~	_{p=1.000 n=12}
_{Parse Time}	_{0.096s (± 3.54%)}	_{0.094s (± 4.99%)}	_~	_0.083s	_0.106s	_{p=0.486 n=12}
_{Bind Time}	_{0.045s (± 8.08%)}	_{0.042s (± 9.20%)}	_~	_0.034s	_0.049s	_{p=0.353 n=12}
_{Check Time}	_{0.734s (± 0.63%)}	_{0.747s (± 0.83%)}	_{+0.014s (+ 1.84%)}	_0.734s	_0.759s	_{p=0.006 n=12}
_{Emit Time}	_0.000s	_0.000s	_~	_~	_~	_{p=1.000 n=12}
_{Total Time}	_{0.888s (± 0.55%)}	_{0.897s (± 0.81%)}	_~	_0.882s	_0.913s	_{p=0.070 n=12}
_{vscode - native}
_Errors	₁₀	₁₀	_~	_~	_~	_{p=1.000 n=12}
_Symbols	_13,384,621	_13,398,156	_{+13,535 (+ 0.10%)}	_~	_~	_{p=0.000 n=12}
_Types	_4,344,502	_4,453,901	_{+109,399 (+ 2.52%)}	_~	_~	_{p=0.000 n=12}
_{Memory Used}	_{6,217,465k (± 0.01%)}	_{6,243,484k (± 0.02%)}	_{+26,019k (+ 0.42%)}	_6,240,756k	_6,247,422k	_{p=0.000 n=12}
_{Memory Allocs}	_{63,240,388 (± 0.00%)}	_{63,992,424 (± 0.02%)}	_{+752,036 (+ 1.19%)}	_63,979,093	_64,046,630	_{p=0.000 n=12}
_{Config Time}	_{0.078s (± 0.36%)}	_{0.078s (± 0.41%)}	_~	_0.078s	_0.079s	_{p=0.667 n=12}
_{Parse Time}	_{1.914s (± 2.53%)}	_{1.940s (± 2.27%)}	_~	_1.844s	_2.086s	_{p=0.319 n=12}
_{Bind Time}	_{0.773s (±11.91%)}	_{0.701s (±13.52%)}	_~	_0.553s	_0.967s	_{p=0.311 n=12}
_{Check Time}	_{18.006s (± 1.06%)}	_{19.967s (± 0.89%)}	_{🔻+1.960s (+10.89%)}	_19.574s	_20.215s	_{p=0.000 n=12}
_{Emit Time}	_{5.900s (± 6.23%)}	_{5.840s (± 4.98%)}	_~	_4.975s	_6.563s	_{p=0.590 n=12}
_{Total Time}	_{26.761s (± 1.16%)}	_{28.612s (± 0.81%)}	_{🔻+1.850s (+ 6.91%)}	_27.768s	_29.049s	_{p=0.000 n=12}
_{webpack - native}
_Errors	₆₀₂	₆₀₂	_~	_~	_~	_{p=1.000 n=12}
_Symbols	_1,351,469	_1,352,976	_{+1,507 (+ 0.11%)}	_~	_~	_{p=0.000 n=12}
_Types	_656,677	_667,431	_{+10,754 (+ 1.64%)}	_~	_~	_{p=0.000 n=12}
_{Memory Used}	_{860,800k (± 0.02%)}	_{863,697k (± 0.02%)}	_{+2,897k (+ 0.34%)}	_863,344k	_863,920k	_{p=0.000 n=12}
_{Memory Allocs}	_{6,829,772 (± 0.01%)}	_{6,866,199 (± 0.02%)}	_{+36,427 (+ 0.53%)}	_6,863,981	_6,872,104	_{p=0.000 n=12}
_{Config Time}	_0.009s	_0.009s	_~	_~	_~	_{p=1.000 n=12}
_{Parse Time}	_{0.322s (± 2.26%)}	_{0.329s (± 2.72%)}	_~	_0.297s	_0.341s	_{p=0.146 n=12}
_{Bind Time}	_{0.079s (± 4.18%)}	_{0.077s (± 2.72%)}	_~	_0.072s	_0.084s	_{p=0.808 n=12}
_{Check Time}	_{3.144s (± 0.66%)}	_{3.185s (± 0.22%)}	_{+0.041s (+ 1.31%)}	_3.169s	_3.208s	_{p=0.001 n=12}
_{Emit Time}	_0.000s	_0.000s	_~	_~	_~	_{p=1.000 n=12}
_{Total Time}	_{3.594s (± 0.55%)}	_{3.638s (± 0.40%)}	_{+0.045s (+ 1.25%)}	_3.584s	_3.666s	_{p=0.001 n=12}
_{xstate-main - native}
_Errors	₀	₀	_~	_~	_~	_{p=1.000 n=12}
_Symbols	_1,060,810	_1,066,353	_{+5,543 (+ 0.52%)}	_~	_~	_{p=0.000 n=12}
_Types	_389,671	_403,318	_{+13,647 (+ 3.50%)}	_~	_~	_{p=0.000 n=12}
_{Memory Used}	_{471,811k (± 0.03%)}	_{476,201k (± 0.03%)}	_{+4,391k (+ 0.93%)}	_475,948k	_476,611k	_{p=0.000 n=12}
_{Memory Allocs}	_{4,216,164 (± 0.08%)}	_{4,303,458 (± 0.10%)}	_{+87,295 (+ 2.07%)}	_4,291,959	_4,315,456	_{p=0.000 n=12}
_{Config Time}	_0.002s	_0.002s	_~	_~	_~	_{p=1.000 n=12}
_{Parse Time}	_{0.106s (± 3.11%)}	_{0.108s (± 4.74%)}	_~	_0.095s	_0.123s	_{p=1.000 n=12}
_{Bind Time}	_{0.034s (±17.74%)}	_{0.037s (±19.92%)}	_~	_0.026s	_0.055s	_{p=0.384 n=12}
_{Check Time}	_{0.909s (± 1.36%)}	_{0.920s (± 0.99%)}	_~	_0.904s	_0.946s	_{p=0.155 n=12}
_{Emit Time}	_0.000s	_0.000s	_~	_~	_~	_{p=1.000 n=12}
_{Total Time}	_{1.057s (± 1.13%)}	_{1.072s (± 0.89%)}	_~	_1.044s	_1.098s	_{p=0.097 n=12}

System info unknown

Hosts

native

Scenarios

Compiler-Unions - native
angular-1 - native
arktype - native
mui-docs - native
sentry - native
social-app - native
strada-build-src - native
strada-compiler - native
t3code-server - native
ts-pre-modules - native
vscode - native
webpack - native
xstate-main - native

_Benchmark	_Name	_Iterations
_Current	_pr	₁₂
_Baseline	_baseline	₁₂

Developer Information:

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Skip incompatible discriminants when inferring from union sources

5891a10

Copilot AI balanced review requested due to automatic review settings October 8, 2026 17:21

github-project-automation Bot added this to PR Backlog Oct 8, 2026

typescript-automation Bot added the For Uncommitted Bug PR for untriaged, rejected, closed or missing bug label Oct 8, 2026

Copilot started reviewing on behalf of Mateusz Burzyński (Andarist) October 8, 2026 17:22

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Mateusz Burzyński (Andarist) added 3 commits October 10, 2026 12:25

Skip incompatible discriminants when inferring into union targets

555da09

Use assignability to filter inference discriminants

be07e42

Reuse union discrimination when inferring types

7560713

Mateusz Burzyński (Andarist) force-pushed the fix-go/contextual-inference-discriminants branch from 65b5a44 to 7560713 Compare October 11, 2026 09:43

Merge branch 'main' into fix-go/contextual-inference-discriminants

3ed9568

Mateusz Burzyński (Andarist) changed the title ~~[experiment] Skip incompatible discriminants when inferring from union sources~~ [experiment] Skip incompatible discriminants when inferring Oct 13, 2026

typescript-automation 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 Oct 13, 2026

typescript-automation Bot assigned Anders Hejlsberg (ahejlsberg) Oct 13, 2026

Mateusz Burzyński (Andarist) mentioned this pull request Oct 21, 2026

Discriminant overlap in inference: distribute source, use comparability, optional fast path Andarist/TypeScript#5

Merged

Mateusz Burzyński (Andarist) added 4 commits October 22, 2026 08:58

Add tests for discriminant overlap in inference and contextual typing

d9d3228

Distribute source property types when filtering inference candidates

f4329e8

Use comparability when filtering inference discriminants

2af6af9

Skip comparisons for optional discriminants that always overlap

e045b7a

Merge remote-tracking branch 'origin/main' into fix-go/contextual-inf…

dfd496d

…erence-discriminants

Mateusz Burzyński (Andarist) added 2 commits October 23, 2026 01:08

Filter inference candidates without materializing the narrowed unions

a9a5123

Merge branch 'main' into fix-go/contextual-inference-discriminants

78cf9c5

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