Various memory optimizations by jakebailey · Pull Request #64734 · microsoft/TypeScript

Jake Bailey (jakebailey) · 2026-10-11T15:24:42Z

Overall performance

The latest perf-bot run, with 12 iterations per revision, reports 22.15–29.66% lower memory usage across all nine scenarios. Allocation counts decrease in seven of nine scenarios, by 3.59–16.58%.

Scenario	Memory used	Allocation count	Check time	Total time
MUI docs	−29.66%	−16.58%	−10.86%	−9.39%
VS Code	−27.19%	−3.59%	−2.88%	No significant change
Webpack	−25.65%	−10.29%	+3.25%	No significant change

Allocation counts increase slightly for Compiler-Unions (+0.37%) and Angular (+1.24%). Error counts are unchanged across all nine scenarios.

Stack

This PR is the all-up view of the following stack; review the individual PRs.

Jake Bailey (jakebailey) · 2026-10-11T15:25:26Z

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

typescript-automation · 2026-10-11T15:25:33Z

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

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

typescript-automation · 2026-10-11T15:55:17Z

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	_115,276	_~	_~	_~	_{p=1.000 n=12}
_Types	_79,613	_79,613	_~	_~	_~	_{p=1.000 n=12}
_{Memory Used}	_{133,803k (± 0.04%)}	_{125,133k (± 0.06%)}	_{🟩-8,670k (- 6.48%)}	_124,988k	_125,393k	_{p=0.000 n=12}
_{Memory Allocs}	_{2,190,038 (± 0.01%)}	_{2,034,432 (± 0.01%)}	_{🟩-155,606 (- 7.11%)}	_2,034,076	_2,035,016	_{p=0.000 n=12}
_{Config Time}	_0.000s	_0.000s	_~	_~	_~	_{p=1.000 n=12}
_{Parse Time}	_{0.039s (± 2.50%)}	_{0.040s (± 3.86%)}	_~	_0.037s	_0.044s	_{p=0.991 n=12}
_{Bind Time}	_{0.012s (±11.68%)}	_{0.013s (±12.23%)}	_~	_0.010s	_0.018s	_{p=0.177 n=12}
_{Check Time}	_{0.500s (± 0.68%)}	_{0.477s (± 0.83%)}	_{🟩-0.023s (- 4.62%)}	_0.469s	_0.488s	_{p=0.000 n=12}
_{Emit Time}	_{0.267s (± 2.95%)}	_{0.255s (± 2.21%)}	_{🟩-0.012s (- 4.64%)}	_0.242s	_0.270s	_{p=0.010 n=12}
_{Total Time}	_{0.824s (± 0.92%)}	_{0.790s (± 0.58%)}	_{🟩-0.035s (- 4.20%)}	_0.778s	_0.804s	_{p=0.000 n=12}
_{angular-1 - native}
_Errors	₃	₃	_~	_~	_~	_{p=1.000 n=12}
_Symbols	_{845,677 (± 0.09%)}	_{845,886 (± 0.05%)}	_~	_844,734	_847,254	_{p=0.977 n=12}
_Types	_{248,126 (± 0.00%)}	_{248,125 (± 0.00%)}	_~	_248,122	_248,132	_{p=0.901 n=12}
_{Memory Used}	_{750,477k (± 0.02%)}	_{698,056k (± 0.01%)}	_{🟩-52,420k (- 6.98%)}	_697,852k	_698,248k	_{p=0.000 n=12}
_{Memory Allocs}	_{12,921,721 (± 0.10%)}	_{12,242,893 (± 0.07%)}	_{🟩-678,828 (- 5.25%)}	_12,233,363	_12,273,563	_{p=0.000 n=12}
_{Config Time}	_0.017s	_0.017s	_~	_~	_~	_{p=1.000 n=12}
_{Parse Time}	_{0.258s (± 2.49%)}	_{0.254s (± 2.78%)}	_~	_0.229s	_0.269s	_{p=0.541 n=12}
_{Bind Time}	_{0.065s (±11.85%)}	_{0.064s (±12.72%)}	_~	_0.056s	_0.098s	_{p=0.299 n=12}
_{Check Time}	_0s	_0s	_~	_~	_~	_{p=1.000 n=12}
_{Emit Time}	_{1.573s (± 1.63%)}	_{1.553s (± 1.01%)}	_~	_1.515s	_1.612s	_{p=0.284 n=12}
_{Total Time}	_{1.928s (± 1.72%)}	_{1.900s (± 0.98%)}	_~	_1.861s	_1.982s	_{p=0.265 n=12}
_{mui-docs - native}
_Errors	_11,405	_11,405	_~	_~	_~	_{p=1.000 n=12}
_Symbols	_4,359,614	_4,359,614	_~	_~	_~	_{p=1.000 n=12}
_Types	_1,376,379	_1,376,379	_~	_~	_~	_{p=1.000 n=12}
_{Memory Used}	_{2,813,796k (± 0.05%)}	_{2,422,746k (± 0.06%)}	_{🟩-391,050k (-13.90%)}	_2,418,931k	_2,427,361k	_{p=0.000 n=12}
_{Memory Allocs}	_{32,820,157 (± 0.05%)}	_{27,783,754 (± 0.05%)}	_{🟩-5,036,403 (-15.35%)}	_27,741,907	_27,815,089	_{p=0.000 n=12}
_{Config Time}	_0.017s	_0.017s	_~	_~	_~	_{p=1.000 n=12}
_{Parse Time}	_{0.497s (± 2.91%)}	_{0.496s (± 2.35%)}	_~	_0.461s	_0.513s	_{p=0.810 n=12}
_{Bind Time}	_0.002s	_0.002s	_~	_~	_~	_{p=1.000 n=12}
_{Check Time}	_{8.623s (± 0.55%)}	_{8.584s (± 0.18%)}	_~	_8.542s	_8.624s	_{p=0.147 n=12}
_{Emit Time}	_{0.454s (± 9.62%)}	_{0.423s (± 0.82%)}	_{🟩-0.031s (- 6.84%)}	_0.420s	_0.440s	_{p=0.005 n=12}
_{Total Time}	_{10.360s (± 0.49%)}	_{10.295s (± 0.09%)}	_{-0.066s (- 0.63%)}	_10.268s	_10.323s	_{p=0.037 n=12}
_{strada-build-src - native}
_Errors	₀	₀	_~	_~	_~	_{p=1.000 n=12}
_Symbols	_1,390,229	_1,390,229	_~	_~	_~	_{p=1.000 n=12}
_Types	_441,498	_441,498	_~	_~	_~	_{p=1.000 n=12}
_{Memory Used}	_{1,623,489k (± 0.85%)}	_{1,544,833k (± 0.91%)}	_{🟩-78,657k (- 4.84%)}	_1,522,631k	_1,589,924k	_{p=0.000 n=12}
_{Memory Allocs}	_{92,052,100 (± 0.17%)}	_{81,839,740 (± 0.23%)}	_{🟩-10,212,360 (-11.09%)}	_81,340,633	_82,282,859	_{p=0.000 n=12}
_{Config Time}	_{0.003s (±18.68%)}	_{0.004s (± 6.39%)}	_~	_0.003s	_0.004s	_{p=0.069 n=12}
_{Parse Time}	_{0.195s (± 3.79%)}	_{0.190s (± 4.79%)}	_~	_0.172s	_0.218s	_{p=0.325 n=12}
_{Bind Time}	_0.000s	_0.000s	_~	_~	_~	_{p=1.000 n=12}
_{Check Time}	_{1.804s (± 0.74%)}	_{1.769s (± 0.71%)}	_{-0.034s (- 1.90%)}	_1.745s	_1.798s	_{p=0.001 n=12}
_{Emit Time}	_{0.301s (± 4.36%)}	_{0.314s (± 2.78%)}	_~	_0.289s	_0.329s	_{p=0.131 n=12}
_{Total Time}	_{23.456s (± 0.54%)}	_{22.821s (± 0.39%)}	_{-0.635s (- 2.71%)}	_22.525s	_23.054s	_{p=0.000 n=12}
_{strada-compiler - native}
_Errors	₀	₀	_~	_~	_~	_{p=1.000 n=12}
_Symbols	_334,953	_334,953	_~	_~	_~	_{p=1.000 n=12}
_Types	_197,616	_197,616	_~	_~	_~	_{p=1.000 n=12}
_{Memory Used}	_{297,351k (± 0.02%)}	_{277,550k (± 0.04%)}	_{🟩-19,801k (- 6.66%)}	_277,294k	_277,791k	_{p=0.000 n=12}
_{Memory Allocs}	_{4,621,013 (± 0.01%)}	_{4,062,288 (± 0.01%)}	_{🟩-558,725 (-12.09%)}	_4,061,068	_4,063,556	_{p=0.000 n=12}
_{Config Time}	_0.001s	_0.001s	_~	_~	_~	_{p=1.000 n=12}
_{Parse Time}	_{0.109s (± 5.44%)}	_{0.110s (± 5.04%)}	_~	_0.095s	_0.125s	_{p=0.619 n=12}
_{Bind Time}	_0.000s	_0.000s	_~	_~	_~	_{p=1.000 n=12}
_{Check Time}	_{1.039s (± 0.38%)}	_{1.010s (± 0.40%)}	_{-0.030s (- 2.85%)}	_1.001s	_1.022s	_{p=0.000 n=12}
_{Emit Time}	_{0.149s (± 6.38%)}	_{0.128s (± 7.81%)}	_{🟩-0.021s (-14.25%)}	_0.108s	_0.158s	_{p=0.006 n=12}
_{Total Time}	_{1.355s (± 0.76%)}	_{1.301s (± 0.77%)}	_{🟩-0.054s (- 3.96%)}	_1.274s	_1.328s	_{p=0.000 n=12}
_{ts-pre-modules - native}
_Errors	₈₇	₈₇	_~	_~	_~	_{p=1.000 n=12}
_Symbols	_303,834	_303,834	_~	_~	_~	_{p=1.000 n=12}
_Types	_181,663	_181,663	_~	_~	_~	_{p=1.000 n=12}
_{Memory Used}	_{258,176k (± 0.02%)}	_{238,373k (± 0.02%)}	_{🟩-19,803k (- 7.67%)}	_238,243k	_238,462k	_{p=0.000 n=12}
_{Memory Allocs}	_{1,613,636 (± 0.01%)}	_{1,187,039 (± 0.02%)}	_{🟩-426,598 (-26.44%)}	_1,186,672	_1,187,554	_{p=0.000 n=12}
_{Config Time}	_0.000s	_{0.000s (±217.90%)}	_~	_0.000s	_0.001s	_{p=1.000 n=12}
_{Parse Time}	_{0.098s (± 5.07%)}	_{0.096s (± 4.08%)}	_~	_0.086s	_0.104s	_{p=0.579 n=12}
_{Bind Time}	_{0.038s (± 9.88%)}	_{0.043s (± 9.35%)}	_~	_0.034s	_0.053s	_{p=0.061 n=12}
_{Check Time}	_{0.813s (± 0.59%)}	_{0.797s (± 0.89%)}	_{-0.015s (- 1.87%)}	_0.787s	_0.821s	_{p=0.003 n=12}
_{Emit Time}	_0.000s	_0.000s	_~	_~	_~	_{p=1.000 n=12}
_{Total Time}	_{0.963s (± 0.60%)}	_{0.951s (± 0.58%)}	_{-0.012s (- 1.23%)}	_0.937s	_0.962s	_{p=0.004 n=12}
_{vscode - native}
_Errors	₃₉₅	₃₉₅	_~	_~	_~	_{p=1.000 n=12}
_Symbols	_11,267,011	_11,267,011	_~	_~	_~	_{p=1.000 n=12}
_Types	_3,734,807	_3,734,807	_~	_~	_~	_{p=1.000 n=12}
_{Memory Used}	_{6,512,655k (± 0.02%)}	_{5,805,065k (± 0.01%)}	_{🟩-707,590k (-10.86%)}	_5,803,771k	_5,807,725k	_{p=0.000 n=12}
_{Memory Allocs}	_{55,268,942 (± 0.02%)}	_{46,350,060 (± 0.03%)}	_{🟩-8,918,882 (-16.14%)}	_46,339,609	_46,411,053	_{p=0.000 n=12}
_{Config Time}	_0.075s	_{0.075s (± 0.33%)}	_~	_0.075s	_0.076s	_{p=0.478 n=12}
_{Parse Time}	_{1.861s (± 4.08%)}	_{1.871s (± 4.18%)}	_~	_1.668s	_2.010s	_{p=0.854 n=12}
_{Bind Time}	_{0.593s (±20.31%)}	_{0.577s (±20.65%)}	_~	_0.444s	_0.941s	_{p=0.679 n=12}
_{Check Time}	_{14.220s (± 1.29%)}	_{13.851s (± 1.05%)}	_{-0.369s (- 2.59%)}	_13.525s	_14.143s	_{p=0.012 n=12}
_{Emit Time}	_{4.826s (±10.89%)}	_{4.597s (± 8.43%)}	_~	_4.039s	_5.622s	_{p=0.370 n=12}
_{Total Time}	_{21.663s (± 1.88%)}	_{21.056s (± 1.55%)}	_{-0.607s (- 2.80%)}	_20.489s	_22.032s	_{p=0.004 n=12}
_{webpack - native}
_Errors	₅₈₃	₅₈₃	_~	_~	_~	_{p=1.000 n=12}
_Symbols	_1,310,251	_1,310,251	_~	_~	_~	_{p=1.000 n=12}
_Types	_618,116	_618,116	_~	_~	_~	_{p=1.000 n=12}
_{Memory Used}	_{938,615k (± 0.02%)}	_{836,974k (± 0.02%)}	_{🟩-101,640k (-10.83%)}	_836,594k	_837,297k	_{p=0.000 n=12}
_{Memory Allocs}	_{6,624,350 (± 0.02%)}	_{5,370,326 (± 0.04%)}	_{🟩-1,254,025 (-18.93%)}	_5,368,145	_5,380,129	_{p=0.000 n=12}
_{Config Time}	_{0.009s (± 3.96%)}	_{0.009s (± 5.25%)}	_~	_0.009s	_0.011s	_{p=1.000 n=12}
_{Parse Time}	_{0.294s (± 3.91%)}	_{0.301s (± 4.31%)}	_~	_0.277s	_0.336s	_{p=0.619 n=12}
_{Bind Time}	_{0.083s (±18.52%)}	_{0.095s (±16.82%)}	_~	_0.067s	_0.140s	_{p=0.102 n=12}
_{Check Time}	_{1.999s (± 1.34%)}	_{2.043s (± 2.28%)}	_~	_1.961s	_2.212s	_{p=0.091 n=12}
_{Emit Time}	_0.000s	_0.000s	_~	_~	_~	_{p=1.000 n=12}
_{Total Time}	_{2.419s (± 0.96%)}	_{2.485s (± 2.00%)}	_{+0.065s (+ 2.70%)}	_2.409s	_2.659s	_{p=0.014 n=12}
_{xstate-main - native}
_Errors	₀	₀	_~	_~	_~	_{p=1.000 n=12}
_Symbols	_1,061,928	_1,061,928	_~	_~	_~	_{p=1.000 n=12}
_Types	_389,645	_389,645	_~	_~	_~	_{p=1.000 n=12}
_{Memory Used}	_{554,310k (± 0.02%)}	_{482,407k (± 0.04%)}	_{🟩-71,903k (-12.97%)}	_482,094k	_482,929k	_{p=0.000 n=12}
_{Memory Allocs}	_{4,886,438 (± 0.09%)}	_{3,790,173 (± 0.09%)}	_{🟩-1,096,265 (-22.43%)}	_3,783,016	_3,798,719	_{p=0.000 n=12}
_{Config Time}	_0.003s	_0.003s	_~	_~	_~	_{p=1.000 n=12}
_{Parse Time}	_{0.145s (± 4.19%)}	_{0.149s (± 4.75%)}	_~	_0.135s	_0.171s	_{p=0.619 n=12}
_{Bind Time}	_{0.043s (±19.11%)}	_{0.048s (±21.07%)}	_~	_0.033s	_0.078s	_{p=0.197 n=12}
_{Check Time}	_{1.122s (± 0.52%)}	_{1.109s (± 1.16%)}	_~	_1.084s	_1.155s	_{p=0.062 n=12}
_{Emit Time}	_0.000s	_0.000s	_~	_~	_~	_{p=1.000 n=12}
_{Total Time}	_{1.320s (± 0.81%)}	_{1.318s (± 1.45%)}	_~	_1.280s	_1.383s	_{p=0.369 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

Jake Bailey (jakebailey) · 2026-10-11T16:11:09Z

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

typescript-automation · 2026-10-11T16:11:14Z

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

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

typescript-automation · 2026-10-11T16:40:46Z

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	_115,276	_~	_~	_~	_{p=1.000 n=12}
_Types	_79,613	_79,613	_~	_~	_~	_{p=1.000 n=12}
_{Memory Used}	_{133,852k (± 0.07%)}	_{117,500k (± 0.05%)}	_{🟩-16,352k (-12.22%)}	_117,410k	_117,712k	_{p=0.000 n=12}
_{Memory Allocs}	_{2,189,976 (± 0.00%)}	_{2,034,349 (± 0.01%)}	_{🟩-155,627 (- 7.11%)}	_2,034,045	_2,035,198	_{p=0.000 n=12}
_{Config Time}	_0.000s	_0.000s	_~	_~	_~	_{p=1.000 n=12}
_{Parse Time}	_{0.041s (± 2.64%)}	_{0.037s (± 3.08%)}	_{🟩-0.003s (- 7.98%)}	_0.034s	_0.041s	_{p=0.000 n=12}
_{Bind Time}	_{0.013s (±13.82%)}	_{0.012s (±11.85%)}	_~	_0.010s	_0.018s	_{p=0.780 n=12}
_{Check Time}	_{0.497s (± 0.65%)}	_{0.487s (± 0.93%)}	_{-0.010s (- 2.03%)}	_0.477s	_0.496s	_{p=0.001 n=12}
_{Emit Time}	_{0.274s (± 1.77%)}	_{0.261s (± 1.71%)}	_{🟩-0.013s (- 4.68%)}	_0.249s	_0.274s	_{p=0.000 n=12}
_{Total Time}	_{0.831s (± 0.71%)}	_{0.804s (± 0.48%)}	_{🟩-0.026s (- 3.18%)}	_0.790s	_0.814s	_{p=0.000 n=12}
_{angular-1 - native}
_Errors	₃	₃	_~	_~	_~	_{p=1.000 n=12}
_Symbols	_{845,592 (± 0.09%)}	_{845,712 (± 0.07%)}	_~	_843,849	_847,277	_{p=0.755 n=12}
_Types	_{248,125 (± 0.00%)}	_{248,125 (± 0.00%)}	_~	_248,122	_248,133	_{p=1.000 n=12}
_{Memory Used}	_{750,428k (± 0.03%)}	_{640,898k (± 0.01%)}	_{🟩-109,530k (-14.60%)}	_640,729k	_641,086k	_{p=0.000 n=12}
_{Memory Allocs}	_{12,919,428 (± 0.05%)}	_{12,241,009 (± 0.05%)}	_{🟩-678,419 (- 5.25%)}	_12,233,172	_12,261,372	_{p=0.000 n=12}
_{Config Time}	_0.017s	_{0.017s (± 1.70%)}	_~	_0.016s	_0.017s	_{p=0.217 n=12}
_{Parse Time}	_{0.260s (± 2.56%)}	_{0.243s (± 3.00%)}	_{🟩-0.017s (- 6.70%)}	_0.222s	_0.261s	_{p=0.000 n=12}
_{Bind Time}	_{0.060s (± 9.66%)}	_{0.063s (±14.18%)}	_~	_0.055s	_0.095s	_{p=0.374 n=12}
_{Check Time}	_0s	_0s	_~	_~	_~	_{p=1.000 n=12}
_{Emit Time}	_{1.556s (± 0.53%)}	_{1.581s (± 1.15%)}	_{+0.025s (+ 1.61%)}	_1.535s	_1.631s	_{p=0.019 n=12}
_{Total Time}	_{1.905s (± 0.57%)}	_{1.917s (± 1.33%)}	_~	_1.861s	_1.992s	_{p=0.523 n=12}
_{mui-docs - native}
_Errors	_11,405	_11,405	_~	_~	_~	_{p=1.000 n=12}
_Symbols	_4,359,614	_4,359,614	_~	_~	_~	_{p=1.000 n=12}
_Types	_1,376,379	_1,376,379	_~	_~	_~	_{p=1.000 n=12}
_{Memory Used}	_{2,813,532k (± 0.04%)}	_{2,367,720k (± 0.07%)}	_{🟩-445,812k (-15.85%)}	_2,364,186k	_2,371,864k	_{p=0.000 n=12}
_{Memory Allocs}	_{32,835,994 (± 0.10%)}	_{27,821,991 (± 0.14%)}	_{🟩-5,014,003 (-15.27%)}	_27,757,874	_27,985,117	_{p=0.000 n=12}
_{Config Time}	_0.017s	_{0.017s (± 1.45%)}	_~	_0.016s	_0.017s	_{p=0.478 n=12}
_{Parse Time}	_{0.488s (± 3.25%)}	_{0.490s (± 2.48%)}	_~	_0.443s	_0.512s	_{p=1.000 n=12}
_{Bind Time}	_0.002s	_0.002s	_~	_~	_~	_{p=1.000 n=12}
_{Check Time}	_{8.658s (± 0.48%)}	_{8.781s (± 0.51%)}	_{+0.123s (+ 1.42%)}	_8.650s	_8.848s	_{p=0.000 n=12}
_{Emit Time}	_{0.447s (± 6.47%)}	_{0.470s (±11.21%)}	_~	_0.420s	_0.615s	_{p=0.172 n=12}
_{Total Time}	_{10.381s (± 0.48%)}	_{10.508s (± 0.32%)}	_{+0.128s (+ 1.23%)}	_10.381s	_10.560s	_{p=0.000 n=12}
_{strada-build-src - native}
_Errors	₀	₀	_~	_~	_~	_{p=1.000 n=12}
_Symbols	_1,390,229	_1,390,229	_~	_~	_~	_{p=1.000 n=12}
_Types	_441,498	_441,498	_~	_~	_~	_{p=1.000 n=12}
_{Memory Used}	_{1,625,134k (± 0.90%)}	_{1,428,447k (± 0.68%)}	_{🟩-196,687k (-12.10%)}	_1,413,413k	_1,463,533k	_{p=0.000 n=12}
_{Memory Allocs}	_{92,035,904 (± 0.20%)}	_{81,875,639 (± 0.17%)}	_{🟩-10,160,266 (-11.04%)}	_81,587,387	_82,233,700	_{p=0.000 n=12}
_{Config Time}	_{0.003s (±15.49%)}	_{0.003s (±12.31%)}	_~	_0.002s	_0.004s	_{p=0.227 n=12}
_{Parse Time}	_{0.197s (± 3.28%)}	_{0.183s (± 3.20%)}	_{🟩-0.013s (- 6.74%)}	_0.167s	_0.194s	_{p=0.002 n=12}
_{Bind Time}	_0.000s	_0.000s	_~	_~	_~	_{p=1.000 n=12}
_{Check Time}	_{1.803s (± 0.62%)}	_{1.796s (± 0.63%)}	_~	_1.768s	_1.835s	_{p=0.247 n=12}
_{Emit Time}	_{0.309s (± 4.28%)}	_{0.316s (± 2.89%)}	_~	_0.290s	_0.333s	_{p=0.469 n=12}
_{Total Time}	_{23.547s (± 0.61%)}	_{22.949s (± 0.42%)}	_{-0.598s (- 2.54%)}	_22.695s	_23.219s	_{p=0.000 n=12}
_{strada-compiler - native}
_Errors	₀	₀	_~	_~	_~	_{p=1.000 n=12}
_Symbols	_334,953	_334,953	_~	_~	_~	_{p=1.000 n=12}
_Types	_197,616	_197,616	_~	_~	_~	_{p=1.000 n=12}
_{Memory Used}	_{297,376k (± 0.02%)}	_{258,302k (± 0.02%)}	_{🟩-39,074k (-13.14%)}	_258,200k	_258,413k	_{p=0.000 n=12}
_{Memory Allocs}	_{4,621,046 (± 0.01%)}	_{4,062,479 (± 0.01%)}	_{🟩-558,566 (-12.09%)}	_4,061,538	_4,063,423	_{p=0.000 n=12}
_{Config Time}	_0.001s	_0.001s	_~	_~	_~	_{p=1.000 n=12}
_{Parse Time}	_{0.114s (± 5.48%)}	_{0.107s (± 2.96%)}	_~	_0.100s	_0.115s	_{p=0.070 n=12}
_{Bind Time}	_0.000s	_0.000s	_~	_~	_~	_{p=1.000 n=12}
_{Check Time}	_{1.042s (± 0.61%)}	_{1.033s (± 0.49%)}	_{-0.009s (- 0.88%)}	_1.026s	_1.049s	_{p=0.017 n=12}
_{Emit Time}	_{0.140s (± 8.33%)}	_{0.140s (± 3.99%)}	_~	_0.120s	_0.157s	_{p=0.809 n=12}
_{Total Time}	_{1.348s (± 0.87%)}	_{1.330s (± 0.76%)}	_{-0.018s (- 1.34%)}	_1.309s	_1.363s	_{p=0.025 n=12}
_{ts-pre-modules - native}
_Errors	₈₇	₈₇	_~	_~	_~	_{p=1.000 n=12}
_Symbols	_303,834	_303,834	_~	_~	_~	_{p=1.000 n=12}
_Types	_181,663	_181,663	_~	_~	_~	_{p=1.000 n=12}
_{Memory Used}	_{258,169k (± 0.01%)}	_{222,060k (± 0.02%)}	_{🟩-36,109k (-13.99%)}	_221,974k	_222,173k	_{p=0.000 n=12}
_{Memory Allocs}	_{1,613,482 (± 0.01%)}	_{1,187,169 (± 0.02%)}	_{🟩-426,313 (-26.42%)}	_1,186,684	_1,187,957	_{p=0.000 n=12}
_{Config Time}	_0.000s	_0.000s	_~	_~	_~	_{p=1.000 n=12}
_{Parse Time}	_{0.099s (± 4.09%)}	_{0.091s (± 3.56%)}	_{🟩-0.008s (- 8.50%)}	_0.083s	_0.100s	_{p=0.005 n=12}
_{Bind Time}	_{0.038s (±10.34%)}	_{0.037s (±11.20%)}	_~	_0.028s	_0.050s	_{p=0.598 n=12}
_{Check Time}	_{0.818s (± 0.80%)}	_{0.821s (± 0.69%)}	_~	_0.808s	_0.840s	_{p=0.521 n=12}
_{Emit Time}	_0.000s	_0.000s	_~	_~	_~	_{p=1.000 n=12}
_{Total Time}	_{0.969s (± 0.84%)}	_{0.962s (± 0.69%)}	_~	_0.944s	_0.981s	_{p=0.234 n=12}
_{vscode - native}
_Errors	₃₉₅	₃₉₅	_~	_~	_~	_{p=1.000 n=12}
_Symbols	_11,267,011	_11,267,011	_~	_~	_~	_{p=1.000 n=12}
_Types	_3,734,807	_3,734,807	_~	_~	_~	_{p=1.000 n=12}
_{Memory Used}	_{6,512,004k (± 0.02%)}	_{5,423,329k (± 0.02%)}	_{🟩-1,088,675k (-16.72%)}	_5,421,718k	_5,428,744k	_{p=0.000 n=12}
_{Memory Allocs}	_{55,277,174 (± 0.03%)}	_{46,352,448 (± 0.02%)}	_{🟩-8,924,726 (-16.15%)}	_46,338,482	_46,402,668	_{p=0.000 n=12}
_{Config Time}	_{0.075s (± 0.33%)}	_{0.074s (± 0.44%)}	_~	_0.074s	_0.075s	_{p=0.089 n=12}
_{Parse Time}	_{1.810s (± 3.26%)}	_{1.711s (± 3.48%)}	_{🟩-0.099s (- 5.49%)}	_1.583s	_1.875s	_{p=0.024 n=12}
_{Bind Time}	_{0.618s (±19.67%)}	_{0.600s (±18.65%)}	_~	_0.436s	_0.920s	_{p=0.811 n=12}
_{Check Time}	_{14.163s (± 1.28%)}	_{13.810s (± 0.92%)}	_{-0.353s (- 2.49%)}	_13.535s	_14.057s	_{p=0.006 n=12}
_{Emit Time}	_{5.134s (± 9.45%)}	_{5.196s (± 9.72%)}	_~	_4.177s	_5.916s	_{p=0.843 n=12}
_{Total Time}	_{21.888s (± 1.74%)}	_{21.481s (± 1.99%)}	_~	_20.551s	_22.082s	_{p=0.192 n=12}
_{webpack - native}
_Errors	₅₈₃	₅₈₃	_~	_~	_~	_{p=1.000 n=12}
_Symbols	_1,310,251	_1,310,251	_~	_~	_~	_{p=1.000 n=12}
_Types	_618,116	_618,116	_~	_~	_~	_{p=1.000 n=12}
_{Memory Used}	_{938,625k (± 0.01%)}	_{781,561k (± 0.01%)}	_{🟩-157,064k (-16.73%)}	_781,380k	_781,958k	_{p=0.000 n=12}
_{Memory Allocs}	_{6,624,096 (± 0.02%)}	_{5,369,434 (± 0.02%)}	_{🟩-1,254,662 (-18.94%)}	_5,366,370	_5,372,100	_{p=0.000 n=12}
_{Config Time}	_0.009s	_0.009s	_~	_~	_~	_{p=1.000 n=12}
_{Parse Time}	_{0.291s (± 2.82%)}	_{0.286s (± 2.83%)}	_~	_0.263s	_0.307s	_{p=0.504 n=12}
_{Bind Time}	_{0.081s (±16.28%)}	_{0.075s (±15.51%)}	_~	_0.062s	_0.128s	_{p=0.338 n=12}
_{Check Time}	_{2.000s (± 0.96%)}	_{2.008s (± 0.65%)}	_~	_1.979s	_2.046s	_{p=0.744 n=12}
_{Emit Time}	_0.000s	_0.000s	_~	_~	_~	_{p=1.000 n=12}
_{Total Time}	_{2.416s (± 0.54%)}	_{2.416s (± 0.66%)}	_~	_2.391s	_2.478s	_{p=0.876 n=12}
_{xstate-main - native}
_Errors	₀	₀	_~	_~	_~	_{p=1.000 n=12}
_Symbols	_1,061,928	_1,061,928	_~	_~	_~	_{p=1.000 n=12}
_Types	_389,645	_389,645	_~	_~	_~	_{p=1.000 n=12}
_{Memory Used}	_{554,243k (± 0.02%)}	_{458,722k (± 0.03%)}	_{🟩-95,522k (-17.23%)}	_458,476k	_459,220k	_{p=0.000 n=12}
_{Memory Allocs}	_{4,886,102 (± 0.07%)}	_{3,787,351 (± 0.10%)}	_{🟩-1,098,751 (-22.49%)}	_3,779,778	_3,795,388	_{p=0.000 n=12}
_{Config Time}	_0.003s	_{0.003s (± 8.64%)}	_~	_0.002s	_0.003s	_{p=0.478 n=12}
_{Parse Time}	_{0.141s (± 3.48%)}	_{0.135s (± 2.26%)}	_{🟩-0.006s (- 4.53%)}	_0.127s	_0.142s	_{p=0.027 n=12}
_{Bind Time}	_{0.047s (±19.14%)}	_{0.039s (±13.66%)}	_~	_0.031s	_0.056s	_{p=0.163 n=12}
_{Check Time}	_{1.129s (± 0.69%)}	_{1.100s (± 0.79%)}	_{-0.029s (- 2.55%)}	_1.087s	_1.129s	_{p=0.000 n=12}
_{Emit Time}	_0.000s	_0.000s	_~	_~	_~	_{p=1.000 n=12}
_{Total Time}	_{1.330s (± 0.91%)}	_{1.288s (± 0.65%)}	_{🟩-0.042s (- 3.14%)}	_1.262s	_1.309s	_{p=0.000 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

Jake Bailey (jakebailey) · 2026-10-11T18:22:49Z

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

typescript-automation · 2026-10-11T18:22:54Z

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

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

typescript-automation · 2026-10-11T18:51:45Z

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	_94,933	_{🟩-20,343 (-17.65%)}	_~	_~	_{p=0.000 n=12}
_Types	_79,613	_79,613	_~	_~	_~	_{p=1.000 n=12}
_{Memory Used}	_{133,858k (± 0.03%)}	_{115,512k (± 0.05%)}	_{🟩-18,346k (-13.71%)}	_115,407k	_115,652k	_{p=0.000 n=12}
_{Memory Allocs}	_{2,190,149 (± 0.01%)}	_{2,056,888 (± 0.01%)}	_{🟩-133,261 (- 6.08%)}	_2,056,653	_2,057,151	_{p=0.000 n=12}
_{Config Time}	_0.000s	_0.000s	_~	_~	_~	_{p=1.000 n=12}
_{Parse Time}	_{0.040s (± 5.97%)}	_{0.038s (± 2.56%)}	_~	_0.036s	_0.041s	_{p=0.336 n=12}
_{Bind Time}	_{0.012s (±13.20%)}	_{0.011s (± 5.74%)}	_~	_0.010s	_0.012s	_{p=0.431 n=12}
_{Check Time}	_{0.500s (± 0.76%)}	_{0.489s (± 0.54%)}	_{-0.010s (- 2.07%)}	_0.486s	_0.498s	_{p=0.000 n=12}
_{Emit Time}	_{0.273s (± 1.87%)}	_{0.268s (± 2.00%)}	_~	_0.256s	_0.282s	_{p=0.131 n=12}
_{Total Time}	_{0.830s (± 0.68%)}	_{0.812s (± 0.62%)}	_{-0.018s (- 2.21%)}	_0.801s	_0.831s	_{p=0.000 n=12}
_{angular-1 - native}
_Errors	₃	₃	_~	_~	_~	_{p=1.000 n=12}
_Symbols	_{845,208 (± 0.09%)}	_{632,796 (± 0.03%)}	_{🟩-212,412 (-25.13%)}	_632,412	_633,255	_{p=0.000 n=12}
_Types	_{248,125 (± 0.00%)}	_{248,126 (± 0.00%)}	_~	_248,122	_248,136	_{p=0.851 n=12}
_{Memory Used}	_{750,333k (± 0.02%)}	_{617,373k (± 0.02%)}	_{🟩-132,960k (-17.72%)}	_617,182k	_617,764k	_{p=0.000 n=12}
_{Memory Allocs}	_{12,918,167 (± 0.08%)}	_{12,367,382 (± 0.02%)}	_{🟩-550,785 (- 4.26%)}	_12,361,957	_12,375,459	_{p=0.000 n=12}
_{Config Time}	_0.017s	_0.017s	_~	_~	_~	_{p=1.000 n=12}
_{Parse Time}	_{0.260s (± 1.49%)}	_{0.241s (± 2.48%)}	_{🟩-0.019s (- 7.33%)}	_0.225s	_0.254s	_{p=0.000 n=12}
_{Bind Time}	_{0.058s (± 0.94%)}	_{0.058s (± 7.62%)}	_{+0.001s (+ 1.01%)}	_0.055s	_0.079s	_{p=0.007 n=12}
_{Check Time}	_0s	_0s	_~	_~	_~	_{p=1.000 n=12}
_{Emit Time}	_{1.557s (± 0.58%)}	_{1.570s (± 1.96%)}	_~	_1.510s	_1.662s	_{p=0.944 n=12}
_{Total Time}	_{1.903s (± 0.53%)}	_{1.899s (± 1.67%)}	_~	_1.834s	_1.975s	_{p=0.401 n=12}
_{mui-docs - native}
_Errors	_11,405	_11,405	_~	_~	_~	_{p=1.000 n=12}
_Symbols	_4,359,614	_4,156,944	_{🟩-202,670 (- 4.65%)}	_~	_~	_{p=0.000 n=12}
_Types	_1,376,379	_1,376,379	_~	_~	_~	_{p=1.000 n=12}
_{Memory Used}	_{2,813,847k (± 0.04%)}	_{2,310,970k (± 0.06%)}	_{🟩-502,877k (-17.87%)}	_2,308,317k	_2,314,701k	_{p=0.000 n=12}
_{Memory Allocs}	_{32,831,491 (± 0.07%)}	_{28,366,731 (± 0.08%)}	_{🟩-4,464,760 (-13.60%)}	_28,320,867	_28,439,156	_{p=0.000 n=12}
_{Config Time}	_0.017s	_0.017s	_~	_~	_~	_{p=1.000 n=12}
_{Parse Time}	_{0.496s (± 2.56%)}	_{0.479s (± 2.43%)}	_~	_0.455s	_0.512s	_{p=0.066 n=12}
_{Bind Time}	_0.002s	_0.002s	_~	_~	_~	_{p=1.000 n=12}
_{Check Time}	_{8.613s (± 0.60%)}	_{9.419s (± 0.34%)}	_{🔻+0.806s (+ 9.36%)}	_9.277s	_9.478s	_{p=0.000 n=12}
_{Emit Time}	_{0.482s (± 9.70%)}	_{0.425s (± 0.43%)}	_{🟩-0.058s (-11.93%)}	_0.420s	_0.429s	_{p=0.003 n=12}
_{Total Time}	_{10.383s (± 0.49%)}	_{11.088s (± 0.37%)}	_{🔻+0.705s (+ 6.79%)}	_10.904s	_11.174s	_{p=0.000 n=12}
_{strada-build-src - native}
_Errors	₀	₀	_~	_~	_~	_{p=1.000 n=12}
_Symbols	_1,390,229	_1,242,234	_{🟩-147,995 (-10.65%)}	_~	_~	_{p=0.000 n=12}
_Types	_441,498	_441,498	_~	_~	_~	_{p=1.000 n=12}
_{Memory Used}	_{1,618,221k (± 0.55%)}	_{1,389,721k (± 0.25%)}	_{🟩-228,500k (-14.12%)}	_1,378,292k	_1,397,026k	_{p=0.000 n=12}
_{Memory Allocs}	_{91,951,986 (± 0.17%)}	_{82,821,244 (± 0.13%)}	_{🟩-9,130,742 (- 9.93%)}	_82,577,853	_83,053,086	_{p=0.000 n=12}
_{Config Time}	_{0.003s (±10.50%)}	_{0.004s (± 9.48%)}	_{🔻+0.001s (+29.73%)}	_0.003s	_0.005s	_{p=0.002 n=12}
_{Parse Time}	_{0.186s (± 2.55%)}	_{0.183s (± 2.18%)}	_~	_0.171s	_0.193s	_{p=0.384 n=12}
_{Bind Time}	_{0.000s (±217.90%)}	_0.000s	_~	_~	_~	_{p=1.000 n=12}
_{Check Time}	_{1.814s (± 0.61%)}	_{1.789s (± 0.40%)}	_{-0.025s (- 1.38%)}	_1.772s	_1.815s	_{p=0.001 n=12}
_{Emit Time}	_{0.304s (± 3.91%)}	_{0.315s (± 3.43%)}	_~	_0.291s	_0.340s	_{p=0.247 n=12}
_{Total Time}	_{23.402s (± 0.38%)}	_{22.827s (± 0.66%)}	_{-0.575s (- 2.46%)}	_22.491s	_23.277s	_{p=0.000 n=12}
_{strada-compiler - native}
_Errors	₀	₀	_~	_~	_~	_{p=1.000 n=12}
_Symbols	_334,953	_285,011	_{🟩-49,942 (-14.91%)}	_~	_~	_{p=0.000 n=12}
_Types	_197,616	_197,616	_~	_~	_~	_{p=1.000 n=12}
_{Memory Used}	_{297,376k (± 0.02%)}	_{252,320k (± 0.01%)}	_{🟩-45,056k (-15.15%)}	_252,241k	_252,400k	_{p=0.000 n=12}
_{Memory Allocs}	_{4,621,456 (± 0.01%)}	_{4,108,355 (± 0.01%)}	_{🟩-513,101 (-11.10%)}	_4,107,518	_4,109,094	_{p=0.000 n=12}
_{Config Time}	_0.001s	_0.001s	_~	_~	_~	_{p=1.000 n=12}
_{Parse Time}	_{0.117s (± 3.68%)}	_{0.106s (± 5.47%)}	_{🟩-0.012s (-10.01%)}	_0.094s	_0.122s	_{p=0.003 n=12}
_{Bind Time}	_0.000s	_0.000s	_~	_~	_~	_{p=1.000 n=12}
_{Check Time}	_{1.040s (± 0.29%)}	_{1.026s (± 0.48%)}	_{-0.014s (- 1.30%)}	_1.014s	_1.039s	_{p=0.000 n=12}
_{Emit Time}	_{0.143s (± 8.54%)}	_{0.141s (± 1.14%)}	_~	_0.136s	_0.145s	_{p=0.966 n=12}
_{Total Time}	_{1.352s (± 0.91%)}	_{1.318s (± 0.64%)}	_{-0.033s (- 2.47%)}	_1.303s	_1.343s	_{p=0.000 n=12}
_{ts-pre-modules - native}
_Errors	₈₇	₈₇	_~	_~	_~	_{p=1.000 n=12}
_Symbols	_303,834	_256,365	_{🟩-47,469 (-15.62%)}	_~	_~	_{p=0.000 n=12}
_Types	_181,663	_181,663	_~	_~	_~	_{p=1.000 n=12}
_{Memory Used}	_{258,119k (± 0.02%)}	_{217,006k (± 0.01%)}	_{🟩-41,113k (-15.93%)}	_216,928k	_217,083k	_{p=0.000 n=12}
_{Memory Allocs}	_{1,613,566 (± 0.01%)}	_{1,231,859 (± 0.02%)}	_{🟩-381,707 (-23.66%)}	_1,231,399	_1,232,491	_{p=0.000 n=12}
_{Config Time}	_0.000s	_0.000s	_~	_~	_~	_{p=1.000 n=12}
_{Parse Time}	_{0.101s (± 3.90%)}	_{0.090s (± 2.45%)}	_{🟩-0.011s (-10.79%)}	_0.086s	_0.098s	_{p=0.000 n=12}
_{Bind Time}	_{0.035s (± 9.10%)}	_{0.037s (±10.30%)}	_~	_0.031s	_0.047s	_{p=0.541 n=12}
_{Check Time}	_{0.815s (± 0.77%)}	_{0.811s (± 0.83%)}	_~	_0.794s	_0.830s	_{p=0.311 n=12}
_{Emit Time}	_0.000s	_0.000s	_~	_~	_~	_{p=1.000 n=12}
_{Total Time}	_{0.965s (± 0.80%)}	_{0.952s (± 0.45%)}	_{-0.013s (- 1.38%)}	_0.943s	_0.963s	_{p=0.006 n=12}
_{vscode - native}
_Errors	₃₉₅	₃₉₅	_~	_~	_~	_{p=1.000 n=12}
_Symbols	_11,183,338	_8,221,517	_{🟩-2,961,821 (-26.48%)}	_~	_~	_{p=0.000 n=12}
_Types	_3,710,990	_3,710,990	_~	_~	_~	_{p=1.000 n=12}
_{Memory Used}	_{6,490,115k (± 0.01%)}	_{5,099,257k (± 0.02%)}	_{🟩-1,390,859k (-21.43%)}	_5,097,374k	_5,102,244k	_{p=0.000 n=12}
_{Memory Allocs}	_{55,152,736 (± 0.01%)}	_{47,863,796 (± 0.04%)}	_{🟩-7,288,940 (-13.22%)}	_47,833,536	_47,906,364	_{p=0.000 n=12}
_{Config Time}	_{0.075s (± 0.51%)}	_{0.075s (± 0.43%)}	_~	_0.074s	_0.076s	_{p=0.963 n=12}
_{Parse Time}	_{1.840s (± 2.18%)}	_{1.742s (± 3.24%)}	_{🟩-0.098s (- 5.33%)}	_1.596s	_1.868s	_{p=0.004 n=12}
_{Bind Time}	_{0.539s (±11.43%)}	_{0.554s (±20.37%)}	_~	_0.429s	_0.906s	_{p=0.260 n=12}
_{Check Time}	_{13.890s (± 0.66%)}	_{13.603s (± 0.65%)}	_{-0.287s (- 2.06%)}	_13.343s	_13.768s	_{p=0.000 n=12}
_{Emit Time}	_{4.903s (±10.71%)}	_{5.312s (± 7.62%)}	_~	_4.300s	_5.953s	_{p=0.160 n=12}
_{Total Time}	_{21.336s (± 2.18%)}	_{21.369s (± 1.72%)}	_~	_20.424s	_22.027s	_{p=0.810 n=12}
_{webpack - native}
_Errors	₅₈₃	₅₈₃	_~	_~	_~	_{p=1.000 n=12}
_Symbols	_1,310,251	_1,103,596	_{🟩-206,655 (-15.77%)}	_~	_~	_{p=0.000 n=12}
_Types	_618,116	_618,116	_~	_~	_~	_{p=1.000 n=12}
_{Memory Used}	_{938,645k (± 0.02%)}	_{758,255k (± 0.02%)}	_{🟩-180,391k (-19.22%)}	_757,886k	_758,742k	_{p=0.000 n=12}
_{Memory Allocs}	_{6,624,457 (± 0.02%)}	_{5,627,294 (± 0.04%)}	_{🟩-997,163 (-15.05%)}	_5,623,995	_5,635,050	_{p=0.000 n=12}
_{Config Time}	_0.009s	_0.009s	_~	_~	_~	_{p=1.000 n=12}
_{Parse Time}	_{0.304s (± 3.47%)}	_{0.279s (± 3.08%)}	_{🟩-0.025s (- 8.33%)}	_0.251s	_0.297s	_{p=0.001 n=12}
_{Bind Time}	_{0.078s (±18.44%)}	_{0.073s (±15.83%)}	_~	_0.060s	_0.108s	_{p=0.338 n=12}
_{Check Time}	_{2.004s (± 1.05%)}	_{2.119s (± 0.24%)}	_{🔻+0.115s (+ 5.75%)}	_2.105s	_2.135s	_{p=0.000 n=12}
_{Emit Time}	_0.000s	_0.000s	_~	_~	_~	_{p=1.000 n=12}
_{Total Time}	_{2.430s (± 0.66%)}	_{2.516s (± 0.46%)}	_{+0.086s (+ 3.54%)}	_2.490s	_2.552s	_{p=0.000 n=12}
_{xstate-main - native}
_Errors	₀	₀	_~	_~	_~	_{p=1.000 n=12}
_Symbols	_1,061,928	_815,636	_{🟩-246,292 (-23.19%)}	_~	_~	_{p=0.000 n=12}
_Types	_389,645	_389,645	_~	_~	_~	_{p=1.000 n=12}
_{Memory Used}	_{554,383k (± 0.02%)}	_{436,063k (± 0.03%)}	_{🟩-118,320k (-21.34%)}	_435,861k	_436,321k	_{p=0.000 n=12}
_{Memory Allocs}	_{4,887,281 (± 0.07%)}	_{4,059,206 (± 0.10%)}	_{🟩-828,075 (-16.94%)}	_4,050,318	_4,072,713	_{p=0.000 n=12}
_{Config Time}	_0.003s	_{0.003s (±10.34%)}	_~	_0.002s	_0.003s	_{p=0.217 n=12}
_{Parse Time}	_{0.146s (± 3.15%)}	_{0.139s (± 3.13%)}	_~	_0.128s	_0.150s	_{p=0.085 n=12}
_{Bind Time}	_{0.044s (±15.47%)}	_{0.040s (±18.29%)}	_~	_0.031s	_0.066s	_{p=0.075 n=12}
_{Check Time}	_{1.134s (± 0.88%)}	_{1.142s (± 0.92%)}	_~	_1.116s	_1.164s	_{p=0.247 n=12}
_{Emit Time}	_0.000s	_0.000s	_~	_~	_~	_{p=1.000 n=12}
_{Total Time}	_{1.336s (± 0.82%)}	_{1.333s (± 0.44%)}	_~	_1.320s	_1.348s	_{p=0.486 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

Jake Bailey (jakebailey) · 2026-10-12T00:00:26Z

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

typescript-automation · 2026-10-12T00:00:32Z

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

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

typescript-automation · 2026-10-12T00:30:22Z

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	_94,933	_{🟩-20,343 (-17.65%)}	_~	_~	_{p=0.000 n=12}
_Types	_79,613	_79,613	_~	_~	_~	_{p=1.000 n=12}
_{Memory Used}	_{133,853k (± 0.06%)}	_{107,060k (± 0.06%)}	_{🟩-26,793k (-20.02%)}	_106,942k	_107,257k	_{p=0.000 n=12}
_{Memory Allocs}	_{2,190,089 (± 0.01%)}	_{2,230,720 (± 0.01%)}	_{+40,631 (+ 1.86%)}	_2,230,364	_2,230,988	_{p=0.000 n=12}
_{Config Time}	_0.000s	_0.000s	_~	_~	_~	_{p=1.000 n=12}
_{Parse Time}	_{0.040s (± 4.56%)}	_{0.040s (± 5.05%)}	_~	_0.036s	_0.046s	_{p=0.990 n=12}
_{Bind Time}	_{0.013s (±14.15%)}	_{0.014s (±10.34%)}	_~	_0.011s	_0.018s	_{p=0.334 n=12}
_{Check Time}	_{0.502s (± 0.94%)}	_{0.488s (± 0.67%)}	_{-0.014s (- 2.81%)}	_0.477s	_0.494s	_{p=0.000 n=12}
_{Emit Time}	_{0.264s (± 2.17%)}	_{0.267s (± 2.39%)}	_~	_0.259s	_0.293s	_{p=0.521 n=12}
_{Total Time}	_{0.824s (± 0.74%)}	_{0.814s (± 0.91%)}	_{-0.010s (- 1.18%)}	_0.800s	_0.843s	_{p=0.032 n=12}
_{angular-1 - native}
_Errors	₃	₃	_~	_~	_~	_{p=1.000 n=12}
_Symbols	_{845,874 (± 0.07%)}	_{632,796 (± 0.04%)}	_{🟩-213,078 (-25.19%)}	_632,284	_633,476	_{p=0.000 n=12}
_Types	_{248,124 (± 0.00%)}	_{248,125 (± 0.00%)}	_~	_248,122	_248,136	_{p=0.746 n=12}
_{Memory Used}	_{750,446k (± 0.02%)}	_{544,157k (± 0.01%)}	_{🟩-206,290k (-27.49%)}	_543,981k	_544,399k	_{p=0.000 n=12}
_{Memory Allocs}	_{12,919,294 (± 0.08%)}	_{13,235,462 (± 0.07%)}	_{+316,168 (+ 2.45%)}	_13,227,097	_13,280,337	_{p=0.000 n=12}
_{Config Time}	_0.017s	_0.017s	_~	_~	_~	_{p=1.000 n=12}
_{Parse Time}	_{0.257s (± 2.53%)}	_{0.217s (± 1.96%)}	_{🟩-0.040s (-15.71%)}	_0.209s	_0.229s	_{p=0.000 n=12}
_{Bind Time}	_{0.062s (±13.58%)}	_{0.099s (± 9.38%)}	_{🔻+0.037s (+59.46%)}	_0.068s	_0.115s	_{p=0.000 n=12}
_{Check Time}	_0s	_0s	_~	_~	_~	_{p=1.000 n=12}
_{Emit Time}	_{1.563s (± 1.17%)}	_{1.584s (± 0.90%)}	_{+0.021s (+ 1.35%)}	_1.551s	_1.629s	_{p=0.037 n=12}
_{Total Time}	_{1.911s (± 1.17%)}	_{1.935s (± 0.65%)}	_{+0.023s (+ 1.22%)}	_1.897s	_1.968s	_{p=0.010 n=12}
_{mui-docs - native}
_Errors	_11,405	_11,405	_~	_~	_~	_{p=1.000 n=12}
_Symbols	_4,359,614	_4,156,944	_{🟩-202,670 (- 4.65%)}	_~	_~	_{p=0.000 n=12}
_Types	_1,376,379	_1,376,379	_~	_~	_~	_{p=1.000 n=12}
_{Memory Used}	_{2,812,975k (± 0.06%)}	_{2,179,113k (± 0.05%)}	_{🟩-633,862k (-22.53%)}	_2,176,722k	_2,182,702k	_{p=0.000 n=12}
_{Memory Allocs}	_{32,810,258 (± 0.05%)}	_{29,933,331 (± 0.04%)}	_{🟩-2,876,927 (- 8.77%)}	_29,898,380	_29,960,296	_{p=0.000 n=12}
_{Config Time}	_0.017s	_0.017s	_~	_~	_~	_{p=1.000 n=12}
_{Parse Time}	_{0.491s (± 3.94%)}	_{0.477s (± 3.19%)}	_~	_0.426s	_0.526s	_{p=0.173 n=12}
_{Bind Time}	_0.002s	_{0.002s (±37.57%)}	_~	_0.002s	_0.007s	_{p=1.000 n=12}
_{Check Time}	_{8.612s (± 0.61%)}	_{9.455s (± 0.37%)}	_{🔻+0.844s (+ 9.80%)}	_9.369s	_9.516s	_{p=0.000 n=12}
_{Emit Time}	_{0.462s (± 9.92%)}	_{0.421s (± 0.33%)}	_{🟩-0.041s (- 8.94%)}	_0.416s	_0.424s	_{p=0.003 n=12}
_{Total Time}	_{10.349s (± 0.69%)}	_{11.115s (± 0.42%)}	_{🔻+0.766s (+ 7.40%)}	_10.975s	_11.197s	_{p=0.000 n=12}
_{strada-build-src - native}
_Errors	₀	₀	_~	_~	_~	_{p=1.000 n=12}
_Symbols	_1,390,229	_1,242,234	_{🟩-147,995 (-10.65%)}	_~	_~	_{p=0.000 n=12}
_Types	_441,498	_441,498	_~	_~	_~	_{p=1.000 n=12}
_{Memory Used}	_{1,627,246k (± 0.86%)}	_{1,254,515k (± 0.64%)}	_{🟩-372,732k (-22.91%)}	_1,239,328k	_1,282,590k	_{p=0.000 n=12}
_{Memory Allocs}	_{92,046,449 (± 0.17%)}	_{88,295,940 (± 0.15%)}	_{🟩-3,750,509 (- 4.07%)}	_87,951,691	_88,684,463	_{p=0.000 n=12}
_{Config Time}	_{0.003s (±14.26%)}	_{0.003s (±14.59%)}	_~	_0.002s	_0.004s	_{p=0.874 n=12}
_{Parse Time}	_{0.193s (± 3.21%)}	_{0.187s (± 3.05%)}	_~	_0.174s	_0.205s	_{p=0.147 n=12}
_{Bind Time}	_{0.000s (±217.90%)}	_0.000s	_~	_~	_~	_{p=1.000 n=12}
_{Check Time}	_{1.809s (± 0.54%)}	_{1.800s (± 0.56%)}	_~	_1.782s	_1.828s	_{p=0.128 n=12}
_{Emit Time}	_{0.306s (± 3.28%)}	_{0.312s (± 2.81%)}	_~	_0.288s	_0.334s	_{p=0.284 n=12}
_{Total Time}	_{23.461s (± 0.50%)}	_{23.263s (± 0.54%)}	_{-0.197s (- 0.84%)}	_22.886s	_23.554s	_{p=0.039 n=12}
_{strada-compiler - native}
_Errors	₀	₀	_~	_~	_~	_{p=1.000 n=12}
_Symbols	_334,953	_285,011	_{🟩-49,942 (-14.91%)}	_~	_~	_{p=0.000 n=12}
_Types	_197,616	_197,616	_~	_~	_~	_{p=1.000 n=12}
_{Memory Used}	_{297,328k (± 0.02%)}	_{232,523k (± 0.03%)}	_{🟩-64,805k (-21.80%)}	_232,373k	_232,769k	_{p=0.000 n=12}
_{Memory Allocs}	_{4,621,013 (± 0.01%)}	_{4,386,464 (± 0.01%)}	_{🟩-234,549 (- 5.08%)}	_4,385,917	_4,387,339	_{p=0.000 n=12}
_{Config Time}	_0.001s	_0.001s	_~	_~	_~	_{p=1.000 n=12}
_{Parse Time}	_{0.112s (± 3.82%)}	_{0.109s (± 4.05%)}	_~	_0.097s	_0.122s	_{p=0.258 n=12}
_{Bind Time}	_0.000s	_0.000s	_~	_~	_~	_{p=1.000 n=12}
_{Check Time}	_{1.040s (± 0.56%)}	_{1.040s (± 0.63%)}	_~	_1.022s	_1.053s	_{p=0.943 n=12}
_{Emit Time}	_{0.142s (± 6.62%)}	_{0.136s (±10.95%)}	_~	_0.097s	_0.163s	_{p=0.898 n=12}
_{Total Time}	_{1.348s (± 1.05%)}	_{1.342s (± 0.93%)}	_~	_1.299s	_1.365s	_{p=0.832 n=12}
_{ts-pre-modules - native}
_Errors	₈₇	₈₇	_~	_~	_~	_{p=1.000 n=12}
_Symbols	_303,834	_256,365	_{🟩-47,469 (-15.62%)}	_~	_~	_{p=0.000 n=12}
_Types	_181,663	_181,663	_~	_~	_~	_{p=1.000 n=12}
_{Memory Used}	_{258,133k (± 0.01%)}	_{199,919k (± 0.01%)}	_{🟩-58,214k (-22.55%)}	_199,843k	_199,988k	_{p=0.000 n=12}
_{Memory Allocs}	_{1,613,693 (± 0.01%)}	_{1,460,506 (± 0.01%)}	_{🟩-153,187 (- 9.49%)}	_1,460,034	_1,461,120	_{p=0.000 n=12}
_{Config Time}	_0.000s	_0.000s	_~	_~	_~	_{p=1.000 n=12}
_{Parse Time}	_{0.100s (± 3.97%)}	_{0.096s (± 4.38%)}	_~	_0.087s	_0.108s	_{p=0.097 n=12}
_{Bind Time}	_{0.039s (±13.11%)}	_{0.040s (± 9.78%)}	_~	_0.030s	_0.048s	_{p=0.580 n=12}
_{Check Time}	_{0.817s (± 0.81%)}	_{0.817s (± 0.55%)}	_~	_0.803s	_0.828s	_{p=0.809 n=12}
_{Emit Time}	_0.000s	_0.000s	_~	_~	_~	_{p=1.000 n=12}
_{Total Time}	_{0.971s (± 0.90%)}	_{0.967s (± 0.76%)}	_~	_0.950s	_0.987s	_{p=0.542 n=12}
_{vscode - native}
_Errors	₃₉₅	₃₉₅	_~	_~	_~	_{p=1.000 n=12}
_Symbols	_11,251,632	_8,277,461	_{🟩-2,974,171 (-26.43%)}	_~	_~	_{p=0.000 n=12}
_Types	_3,734,289	_3,734,289	_~	_~	_~	_{p=1.000 n=12}
_{Memory Used}	_{6,510,406k (± 0.01%)}	_{4,533,568k (± 0.02%)}	_{🟩-1,976,838k (-30.36%)}	_4,532,003k	_4,537,209k	_{p=0.000 n=12}
_{Memory Allocs}	_{55,322,973 (± 0.02%)}	_{55,006,824 (± 0.02%)}	_{-316,149 (- 0.57%)}	_54,993,680	_55,043,114	_{p=0.000 n=12}
_{Config Time}	_{0.075s (± 0.72%)}	_{0.075s (± 0.43%)}	_~	_0.074s	_0.076s	_{p=0.682 n=12}
_{Parse Time}	_{1.883s (± 3.38%)}	_{1.677s (± 3.00%)}	_{🟩-0.207s (-10.97%)}	_1.582s	_1.819s	_{p=0.000 n=12}
_{Bind Time}	_{0.528s (±18.45%)}	_{0.623s (±15.12%)}	_{🔻+0.094s (+17.85%)}	_0.454s	_0.819s	_{p=0.017 n=12}
_{Check Time}	_{13.911s (± 0.93%)}	_{13.642s (± 0.79%)}	_{-0.268s (- 1.93%)}	_13.486s	_14.008s	_{p=0.005 n=12}
_{Emit Time}	_{4.563s (± 9.38%)}	_{5.122s (± 3.62%)}	_{🔻+0.560s (+12.27%)}	_4.835s	_5.752s	_{p=0.020 n=12}
_{Total Time}	_{21.038s (± 1.73%)}	_{21.222s (± 1.16%)}	_{+0.183s (+ 0.87%)}	_20.886s	_22.137s	_{p=0.014 n=12}
_{webpack - native}
_Errors	₅₈₃	₅₈₃	_~	_~	_~	_{p=1.000 n=12}
_Symbols	_1,310,251	_1,103,596	_{🟩-206,655 (-15.77%)}	_~	_~	_{p=0.000 n=12}
_Types	_618,116	_618,116	_~	_~	_~	_{p=1.000 n=12}
_{Memory Used}	_{938,662k (± 0.01%)}	_{692,705k (± 0.02%)}	_{🟩-245,958k (-26.20%)}	_692,263k	_693,059k	_{p=0.000 n=12}
_{Memory Allocs}	_{6,625,296 (± 0.02%)}	_{6,335,722 (± 0.01%)}	_{🟩-289,574 (- 4.37%)}	_6,333,805	_6,337,956	_{p=0.000 n=12}
_{Config Time}	_0.009s	_0.009s	_~	_~	_~	_{p=1.000 n=12}
_{Parse Time}	_{0.293s (± 2.42%)}	_{0.286s (± 2.71%)}	_~	_0.266s	_0.309s	_{p=0.124 n=12}
_{Bind Time}	_{0.081s (±19.22%)}	_{0.070s (± 2.07%)}	_~	_0.067s	_0.076s	_{p=0.921 n=12}
_{Check Time}	_{1.997s (± 0.95%)}	_{2.150s (± 0.56%)}	_{🔻+0.153s (+ 7.66%)}	_2.136s	_2.197s	_{p=0.000 n=12}
_{Emit Time}	_0.000s	_0.000s	_~	_~	_~	_{p=1.000 n=12}
_{Total Time}	_{2.415s (± 0.49%)}	_{2.548s (± 0.63%)}	_{🔻+0.133s (+ 5.50%)}	_2.521s	_2.606s	_{p=0.000 n=12}
_{xstate-main - native}
_Errors	₀	₀	_~	_~	_~	_{p=1.000 n=12}
_Symbols	_1,061,928	_815,636	_{🟩-246,292 (-23.19%)}	_~	_~	_{p=0.000 n=12}
_Types	_389,645	_389,645	_~	_~	_~	_{p=1.000 n=12}
_{Memory Used}	_{554,419k (± 0.02%)}	_{395,313k (± 0.03%)}	_{🟩-159,105k (-28.70%)}	_395,112k	_395,642k	_{p=0.000 n=12}
_{Memory Allocs}	_{4,885,075 (± 0.08%)}	_{4,444,680 (± 0.07%)}	_{🟩-440,395 (- 9.02%)}	_4,439,160	_4,450,744	_{p=0.000 n=12}
_{Config Time}	_0.003s	_0.003s	_~	_~	_~	_{p=1.000 n=12}
_{Parse Time}	_{0.141s (± 2.90%)}	_{0.134s (± 2.94%)}	_{🟩-0.007s (- 5.01%)}	_0.126s	_0.145s	_{p=0.018 n=12}
_{Bind Time}	_{0.046s (±18.07%)}	_{0.045s (±14.93%)}	_~	_0.033s	_0.065s	_{p=0.854 n=12}
_{Check Time}	_{1.130s (± 0.54%)}	_{1.159s (± 1.11%)}	_{+0.029s (+ 2.57%)}	_1.127s	_1.185s	_{p=0.001 n=12}
_{Emit Time}	_0.000s	_0.000s	_~	_~	_~	_{p=1.000 n=12}
_{Total Time}	_{1.330s (± 0.75%)}	_{1.348s (± 0.67%)}	_{+0.018s (+ 1.34%)}	_1.321s	_1.365s	_{p=0.013 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

Jake Bailey (jakebailey) · 2026-10-12T04:21:35Z

CPU regression appears to be due to #64735

Jake Bailey (jakebailey) · 2026-10-12T05:17:22Z

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

typescript-automation · 2026-10-12T05:17:28Z

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

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

typescript-automation · 2026-10-12T05:47:15Z

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	_94,933	_{🟩-20,343 (-17.65%)}	_~	_~	_{p=0.000 n=12}
_Types	_79,613	_79,613	_~	_~	_~	_{p=1.000 n=12}
_{Memory Used}	_{133,834k (± 0.06%)}	_{101,788k (± 0.05%)}	_{🟩-32,045k (-23.94%)}	_101,708k	_101,941k	_{p=0.000 n=12}
_{Memory Allocs}	_{2,189,988 (± 0.01%)}	_{2,225,259 (± 0.01%)}	_{+35,271 (+ 1.61%)}	_2,224,923	_2,225,675	_{p=0.000 n=12}
_{Config Time}	_0.000s	_0.000s	_~	_~	_~	_{p=1.000 n=12}
_{Parse Time}	_{0.040s (± 3.91%)}	_{0.040s (± 3.13%)}	_~	_0.037s	_0.044s	_{p=0.772 n=12}
_{Bind Time}	_{0.012s (±14.09%)}	_{0.013s (±10.71%)}	_{🔻+0.002s (+13.48%)}	_0.011s	_0.018s	_{p=0.029 n=12}
_{Check Time}	_{0.504s (± 0.73%)}	_{0.480s (± 0.47%)}	_{🟩-0.024s (- 4.80%)}	_0.475s	_0.485s	_{p=0.000 n=12}
_{Emit Time}	_{0.270s (± 2.28%)}	_{0.267s (± 2.25%)}	_~	_0.254s	_0.292s	_{p=0.297 n=12}
_{Total Time}	_{0.831s (± 0.84%)}	_{0.807s (± 0.81%)}	_{-0.025s (- 2.99%)}	_0.788s	_0.828s	_{p=0.000 n=12}
_{angular-1 - native}
_Errors	₃	₃	_~	_~	_~	_{p=1.000 n=12}
_Symbols	_{845,590 (± 0.05%)}	_{632,761 (± 0.04%)}	_{🟩-212,829 (-25.17%)}	_632,311	_633,521	_{p=0.000 n=12}
_Types	_{248,126 (± 0.00%)}	_{248,126 (± 0.00%)}	_~	_248,123	_248,135	_{p=1.000 n=12}
_{Memory Used}	_{750,384k (± 0.02%)}	_{537,054k (± 0.02%)}	_{🟩-213,331k (-28.43%)}	_536,823k	_537,268k	_{p=0.000 n=12}
_{Memory Allocs}	_{12,917,874 (± 0.05%)}	_{13,206,192 (± 0.03%)}	_{+288,317 (+ 2.23%)}	_13,200,348	_13,223,873	_{p=0.000 n=12}
_{Config Time}	_0.017s	_0.017s	_~	_~	_~	_{p=1.000 n=12}
_{Parse Time}	_{0.257s (± 2.81%)}	_{0.223s (± 3.12%)}	_{🟩-0.034s (-13.34%)}	_0.207s	_0.242s	_{p=0.000 n=12}
_{Bind Time}	_{0.063s (±13.13%)}	_{0.084s (±17.92%)}	_{🔻+0.020s (+32.37%)}	_0.051s	_0.116s	_{p=0.011 n=12}
_{Check Time}	_0s	_0s	_~	_~	_~	_{p=1.000 n=12}
_{Emit Time}	_{1.556s (± 0.72%)}	_{1.545s (± 1.60%)}	_~	_1.495s	_1.617s	_{p=0.272 n=12}
_{Total Time}	_{1.907s (± 0.89%)}	_{1.882s (± 1.02%)}	_{-0.025s (- 1.31%)}	_1.820s	_1.930s	_{p=0.030 n=12}
_{mui-docs - native}
_Errors	_11,405	_11,405	_~	_~	_~	_{p=1.000 n=12}
_Symbols	_4,359,614	_4,156,944	_{🟩-202,670 (- 4.65%)}	_~	_~	_{p=0.000 n=12}
_Types	_1,376,379	_1,376,379	_~	_~	_~	_{p=1.000 n=12}
_{Memory Used}	_{2,813,496k (± 0.04%)}	_{2,164,084k (± 0.08%)}	_{🟩-649,412k (-23.08%)}	_2,160,983k	_2,168,961k	_{p=0.000 n=12}
_{Memory Allocs}	_{32,823,862 (± 0.05%)}	_{29,814,130 (± 0.07%)}	_{🟩-3,009,732 (- 9.17%)}	_29,753,699	_29,868,151	_{p=0.000 n=12}
_{Config Time}	_0.017s	_0.017s	_~	_~	_~	_{p=1.000 n=12}
_{Parse Time}	_{0.501s (± 3.50%)}	_{0.468s (± 2.25%)}	_{🟩-0.033s (- 6.58%)}	_0.439s	_0.505s	_{p=0.003 n=12}
_{Bind Time}	_0.002s	_0.002s	_~	_~	_~	_{p=1.000 n=12}
_{Check Time}	_{8.618s (± 0.62%)}	_{9.113s (± 0.26%)}	_{🔻+0.494s (+ 5.74%)}	_9.026s	_9.147s	_{p=0.000 n=12}
_{Emit Time}	_{0.468s (± 9.20%)}	_{0.421s (± 0.34%)}	_{🟩-0.047s (-10.12%)}	_0.416s	_0.425s	_{p=0.000 n=12}
_{Total Time}	_{10.374s (± 0.56%)}	_{10.754s (± 0.36%)}	_{+0.381s (+ 3.67%)}	_10.623s	_10.810s	_{p=0.000 n=12}
_{strada-build-src - native}
_Errors	₀	₀	_~	_~	_~	_{p=1.000 n=12}
_Symbols	_1,390,229	_1,242,234	_{🟩-147,995 (-10.65%)}	_~	_~	_{p=0.000 n=12}
_Types	_441,498	_441,498	_~	_~	_~	_{p=1.000 n=12}
_{Memory Used}	_{1,626,894k (± 0.73%)}	_{1,253,541k (± 0.62%)}	_{🟩-373,354k (-22.95%)}	_1,238,150k	_1,278,151k	_{p=0.000 n=12}
_{Memory Allocs}	_{92,134,278 (± 0.19%)}	_{87,969,162 (± 0.19%)}	_{🟩-4,165,116 (- 4.52%)}	_87,657,809	_88,476,369	_{p=0.000 n=12}
_{Config Time}	_{0.004s (±11.74%)}	_{0.003s (±14.60%)}	_~	_0.002s	_0.004s	_{p=0.757 n=12}
_{Parse Time}	_{0.192s (± 3.21%)}	_{0.189s (± 2.88%)}	_~	_0.173s	_0.205s	_{p=0.325 n=12}
_{Bind Time}	_0.000s	_0.000s	_~	_~	_~	_{p=1.000 n=12}
_{Check Time}	_{1.793s (± 0.60%)}	_{1.782s (± 0.49%)}	_~	_1.766s	_1.811s	_{p=0.097 n=12}
_{Emit Time}	_{0.307s (± 3.74%)}	_{0.316s (± 2.20%)}	_~	_0.301s	_0.335s	_{p=0.183 n=12}
_{Total Time}	_{23.487s (± 0.66%)}	_{23.142s (± 0.52%)}	_{-0.346s (- 1.47%)}	_22.766s	_23.378s	_{p=0.003 n=12}
_{strada-compiler - native}
_Errors	₀	₀	_~	_~	_~	_{p=1.000 n=12}
_Symbols	_334,953	_285,011	_{🟩-49,942 (-14.91%)}	_~	_~	_{p=0.000 n=12}
_Types	_197,616	_197,616	_~	_~	_~	_{p=1.000 n=12}
_{Memory Used}	_{297,281k (± 0.02%)}	_{227,231k (± 0.02%)}	_{🟩-70,050k (-23.56%)}	_227,115k	_227,359k	_{p=0.000 n=12}
_{Memory Allocs}	_{4,620,901 (± 0.01%)}	_{4,372,682 (± 0.00%)}	_{🟩-248,219 (- 5.37%)}	_4,372,304	_4,373,278	_{p=0.000 n=12}
_{Config Time}	_0.001s	_0.001s	_~	_~	_~	_{p=1.000 n=12}
_{Parse Time}	_{0.117s (± 5.05%)}	_{0.113s (± 5.40%)}	_~	_0.103s	_0.128s	_{p=0.271 n=12}
_{Bind Time}	_0.000s	_0.000s	_~	_~	_~	_{p=1.000 n=12}
_{Check Time}	_{1.039s (± 0.49%)}	_{1.020s (± 0.44%)}	_{-0.019s (- 1.84%)}	_1.011s	_1.036s	_{p=0.000 n=12}
_{Emit Time}	_{0.150s (± 5.28%)}	_{0.146s (± 3.31%)}	_~	_0.136s	_0.164s	_{p=0.163 n=12}
_{Total Time}	_{1.357s (± 0.68%)}	_{1.333s (± 0.87%)}	_{-0.024s (- 1.75%)}	_1.310s	_1.375s	_{p=0.003 n=12}
_{ts-pre-modules - native}
_Errors	₈₇	₈₇	_~	_~	_~	_{p=1.000 n=12}
_Symbols	_303,834	_256,365	_{🟩-47,469 (-15.62%)}	_~	_~	_{p=0.000 n=12}
_Types	_181,663	_181,663	_~	_~	_~	_{p=1.000 n=12}
_{Memory Used}	_{258,147k (± 0.02%)}	_{196,654k (± 0.01%)}	_{🟩-61,493k (-23.82%)}	_196,564k	_196,709k	_{p=0.000 n=12}
_{Memory Allocs}	_{1,613,609 (± 0.02%)}	_{1,455,468 (± 0.02%)}	_{🟩-158,141 (- 9.80%)}	_1,454,894	_1,455,942	_{p=0.000 n=12}
_{Config Time}	_0.000s	_0.000s	_~	_~	_~	_{p=1.000 n=12}
_{Parse Time}	_{0.094s (± 4.31%)}	_{0.099s (± 3.59%)}	_~	_0.092s	_0.108s	_{p=0.085 n=12}
_{Bind Time}	_{0.036s (±11.33%)}	_{0.041s (± 8.81%)}	_{🔻+0.005s (+13.75%)}	_0.032s	_0.052s	_{p=0.021 n=12}
_{Check Time}	_{0.814s (± 0.53%)}	_{0.810s (± 0.98%)}	_~	_0.796s	_0.832s	_{p=0.385 n=12}
_{Emit Time}	_0.000s	_0.000s	_~	_~	_~	_{p=1.000 n=12}
_{Total Time}	_{0.958s (± 0.50%)}	_{0.963s (± 0.71%)}	_~	_0.942s	_0.983s	_{p=0.155 n=12}
_{vscode - native}
_Errors	₃₉₅	₃₉₅	_~	_~	_~	_{p=1.000 n=12}
_Symbols	_11,378,289	_8,350,812	_{🟩-3,027,477 (-26.61%)}	_~	_~	_{p=0.000 n=12}
_Types	_3,767,672	_3,767,672	_~	_~	_~	_{p=1.000 n=12}
_{Memory Used}	_{6,548,115k (± 0.03%)}	_{4,477,944k (± 0.02%)}	_{🟩-2,070,171k (-31.61%)}	_4,476,443k	_4,481,745k	_{p=0.000 n=12}
_{Memory Allocs}	_{55,630,881 (± 0.07%)}	_{54,849,595 (± 0.07%)}	_{-781,286 (- 1.40%)}	_54,825,315	_55,036,829	_{p=0.000 n=12}
_{Config Time}	_{0.075s (± 0.24%)}	_{0.075s (± 0.43%)}	_~	_0.074s	_0.076s	_{p=1.000 n=12}
_{Parse Time}	_{1.855s (± 3.91%)}	_{1.700s (± 2.76%)}	_{🟩-0.155s (- 8.38%)}	_1.605s	_1.849s	_{p=0.002 n=12}
_{Bind Time}	_{0.613s (±20.64%)}	_{0.599s (±13.76%)}	_~	_0.464s	_0.814s	_{p=0.542 n=12}
_{Check Time}	_{13.572s (± 1.30%)}	_{12.893s (± 0.69%)}	_{🟩-0.679s (- 5.00%)}	_12.730s	_13.197s	_{p=0.000 n=12}
_{Emit Time}	_{4.996s (±10.61%)}	_{5.237s (± 4.54%)}	_~	_4.682s	_5.767s	_{p=0.514 n=12}
_{Total Time}	_{21.198s (± 2.03%)}	_{20.590s (± 1.17%)}	_{-0.607s (- 2.87%)}	_20.058s	_21.189s	_{p=0.017 n=12}
_{webpack - native}
_Errors	₅₈₃	₅₈₃	_~	_~	_~	_{p=1.000 n=12}
_Symbols	_1,305,849	_1,100,509	_{🟩-205,340 (-15.72%)}	_~	_~	_{p=0.000 n=12}
_Types	_613,709	_613,709	_~	_~	_~	_{p=1.000 n=12}
_{Memory Used}	_{936,877k (± 0.01%)}	_{682,239k (± 0.03%)}	_{🟩-254,638k (-27.18%)}	_681,802k	_682,739k	_{p=0.000 n=12}
_{Memory Allocs}	_{6,598,871 (± 0.05%)}	_{6,248,169 (± 0.02%)}	_{🟩-350,702 (- 5.31%)}	_6,246,284	_6,250,676	_{p=0.000 n=12}
_{Config Time}	_0.009s	_0.009s	_~	_~	_~	_{p=1.000 n=12}
_{Parse Time}	_{0.291s (± 2.51%)}	_{0.288s (± 2.72%)}	_~	_0.264s	_0.312s	_{p=0.832 n=12}
_{Bind Time}	_{0.085s (±14.96%)}	_{0.076s (±11.05%)}	_~	_0.066s	_0.107s	_{p=0.155 n=12}
_{Check Time}	_{1.776s (± 1.24%)}	_{1.809s (± 0.86%)}	_~	_1.780s	_1.857s	_{p=0.068 n=12}
_{Emit Time}	_0.000s	_0.000s	_~	_~	_~	_{p=1.000 n=12}
_{Total Time}	_{2.198s (± 0.57%)}	_{2.217s (± 0.88%)}	_~	_2.183s	_2.261s	_{p=0.086 n=12}
_{xstate-main - native}
_Errors	₀	₀	_~	_~	_~	_{p=1.000 n=12}
_Symbols	_1,061,928	_815,636	_{🟩-246,292 (-23.19%)}	_~	_~	_{p=0.000 n=12}
_Types	_389,645	_389,645	_~	_~	_~	_{p=1.000 n=12}
_{Memory Used}	_{554,349k (± 0.02%)}	_{392,565k (± 0.03%)}	_{🟩-161,784k (-29.18%)}	_392,371k	_393,002k	_{p=0.000 n=12}
_{Memory Allocs}	_{4,885,785 (± 0.05%)}	_{4,389,821 (± 0.07%)}	_{🟩-495,964 (-10.15%)}	_4,383,552	_4,400,452	_{p=0.000 n=12}
_{Config Time}	_0.003s	_0.003s	_~	_~	_~	_{p=1.000 n=12}
_{Parse Time}	_{0.143s (± 3.19%)}	_{0.138s (± 2.50%)}	_~	_0.132s	_0.149s	_{p=0.084 n=12}
_{Bind Time}	_{0.047s (±13.31%)}	_{0.037s (± 5.93%)}	_{🟩-0.010s (-21.28%)}	_0.034s	_0.043s	_{p=0.022 n=12}
_{Check Time}	_{1.126s (± 0.71%)}	_{1.118s (± 0.91%)}	_~	_1.095s	_1.145s	_{p=0.235 n=12}
_{Emit Time}	_0.000s	_0.000s	_~	_~	_~	_{p=1.000 n=12}
_{Total Time}	_{1.331s (± 0.75%)}	_{1.306s (± 0.51%)}	_{-0.026s (- 1.93%)}	_1.290s	_1.322s	_{p=0.000 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

Jake Bailey (jakebailey) · 2026-10-12T15:06:27Z

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

typescript-automation · 2026-10-12T15:06:33Z

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

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

typescript-automation · 2026-10-12T15:35:43Z

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	_94,933	_{🟩-20,343 (-17.65%)}	_~	_~	_{p=0.000 n=12}
_Types	_79,613	_79,613	_~	_~	_~	_{p=1.000 n=12}
_{Memory Used}	_{133,868k (± 0.05%)}	_{101,569k (± 0.07%)}	_{🟩-32,299k (-24.13%)}	_101,453k	_101,736k	_{p=0.000 n=12}
_{Memory Allocs}	_{2,190,049 (± 0.01%)}	_{2,217,166 (± 0.01%)}	_{+27,117 (+ 1.24%)}	_2,216,840	_2,217,626	_{p=0.000 n=12}
_{Config Time}	_0.000s	_0.000s	_~	_~	_~	_{p=1.000 n=12}
_{Parse Time}	_{0.040s (± 5.07%)}	_{0.040s (± 4.63%)}	_~	_0.035s	_0.044s	_{p=0.431 n=12}
_{Bind Time}	_{0.013s (±13.69%)}	_{0.015s (± 6.69%)}	_~	_0.012s	_0.017s	_{p=0.065 n=12}
_{Check Time}	_{0.498s (± 0.67%)}	_{0.475s (± 0.68%)}	_{🟩-0.023s (- 4.55%)}	_0.468s	_0.483s	_{p=0.000 n=12}
_{Emit Time}	_{0.268s (± 1.94%)}	_{0.270s (± 2.18%)}	_~	_0.254s	_0.286s	_{p=0.681 n=12}
_{Total Time}	_{0.825s (± 0.77%)}	_{0.805s (± 0.99%)}	_{-0.020s (- 2.38%)}	_0.786s	_0.830s	_{p=0.001 n=12}
_{angular-1 - native}
_Errors	₃	₃	_~	_~	_~	_{p=1.000 n=12}
_Symbols	_{845,646 (± 0.08%)}	_{632,900 (± 0.02%)}	_{🟩-212,746 (-25.16%)}	_632,676	_633,263	_{p=0.000 n=12}
_Types	_{248,123 (± 0.00%)}	_{248,124 (± 0.00%)}	_~	_248,122	_248,125	_{p=0.741 n=12}
_{Memory Used}	_{750,418k (± 0.01%)}	_{536,823k (± 0.01%)}	_{🟩-213,595k (-28.46%)}	_536,586k	_537,047k	_{p=0.000 n=12}
_{Memory Allocs}	_{12,925,237 (± 0.11%)}	_{13,177,609 (± 0.01%)}	_{+252,372 (+ 1.95%)}	_13,174,776	_13,181,575	_{p=0.000 n=12}
_{Config Time}	_0.017s	_0.017s	_~	_~	_~	_{p=1.000 n=12}
_{Parse Time}	_{0.261s (± 2.49%)}	_{0.219s (± 1.98%)}	_{🟩-0.042s (-16.06%)}	_0.211s	_0.232s	_{p=0.000 n=12}
_{Bind Time}	_{0.062s (± 9.82%)}	_{0.084s (±13.64%)}	_{🔻+0.023s (+37.26%)}	_0.059s	_0.110s	_{p=0.000 n=12}
_{Check Time}	_0s	_0s	_~	_~	_~	_{p=1.000 n=12}
_{Emit Time}	_{1.555s (± 0.92%)}	_{1.543s (± 1.85%)}	_~	_1.466s	_1.621s	_{p=0.369 n=12}
_{Total Time}	_{1.907s (± 1.00%)}	_{1.878s (± 1.48%)}	_~	_1.787s	_1.951s	_{p=0.091 n=12}
_{mui-docs - native}
_Errors	_11,405	_11,405	_~	_~	_~	_{p=1.000 n=12}
_Symbols	_4,359,614	_4,156,944	_{🟩-202,670 (- 4.65%)}	_~	_~	_{p=0.000 n=12}
_Types	_1,376,379	_1,376,379	_~	_~	_~	_{p=1.000 n=12}
_{Memory Used}	_{2,812,061k (± 0.04%)}	_{1,963,390k (± 0.05%)}	_{🟩-848,671k (-30.18%)}	_1,960,352k	_1,966,087k	_{p=0.000 n=12}
_{Memory Allocs}	_{32,815,350 (± 0.05%)}	_{27,853,955 (± 0.05%)}	_{🟩-4,961,396 (-15.12%)}	_27,821,139	_27,896,807	_{p=0.000 n=12}
_{Config Time}	_0.017s	_0.017s	_~	_~	_~	_{p=1.000 n=12}
_{Parse Time}	_{0.502s (± 1.63%)}	_{0.475s (± 2.44%)}	_{🟩-0.026s (- 5.25%)}	_0.438s	_0.500s	_{p=0.000 n=12}
_{Bind Time}	_0.002s	_0.002s	_~	_~	_~	_{p=1.000 n=12}
_{Check Time}	_{8.666s (± 0.28%)}	_{7.915s (± 0.37%)}	_{🟩-0.751s (- 8.67%)}	_7.854s	_7.993s	_{p=0.000 n=12}
_{Emit Time}	_{0.461s (± 6.68%)}	_{0.485s (± 7.43%)}	_~	_0.424s	_0.601s	_{p=0.325 n=12}
_{Total Time}	_{10.423s (± 0.35%)}	_{9.640s (± 0.38%)}	_{🟩-0.783s (- 7.51%)}	_9.518s	_9.715s	_{p=0.000 n=12}
_{strada-build-src - native}
_Errors	₀	₀	_~	_~	_~	_{p=1.000 n=12}
_Symbols	_1,390,229	_1,242,234	_{🟩-147,995 (-10.65%)}	_~	_~	_{p=0.000 n=12}
_Types	_441,498	_441,498	_~	_~	_~	_{p=1.000 n=12}
_{Memory Used}	_{1,628,857k (± 0.76%)}	_{1,256,565k (± 0.79%)}	_{🟩-372,292k (-22.86%)}	_1,236,822k	_1,282,283k	_{p=0.000 n=12}
_{Memory Allocs}	_{92,044,442 (± 0.16%)}	_{87,144,263 (± 0.18%)}	_{🟩-4,900,180 (- 5.32%)}	_86,681,101	_87,475,446	_{p=0.000 n=12}
_{Config Time}	_{0.003s (±23.23%)}	_{0.004s (±11.74%)}	_~	_0.003s	_0.005s	_{p=0.303 n=12}
_{Parse Time}	_{0.193s (± 3.31%)}	_{0.194s (± 3.09%)}	_~	_0.182s	_0.212s	_{p=0.810 n=12}
_{Bind Time}	_0.000s	_0.000s	_~	_~	_~	_{p=1.000 n=12}
_{Check Time}	_{1.803s (± 0.56%)}	_{1.770s (± 0.64%)}	_{-0.033s (- 1.81%)}	_1.746s	_1.802s	_{p=0.000 n=12}
_{Emit Time}	_{0.307s (± 4.46%)}	_{0.322s (± 4.17%)}	_~	_0.287s	_0.354s	_{p=0.066 n=12}
_{Total Time}	_{23.442s (± 0.61%)}	_{23.066s (± 0.58%)}	_{-0.376s (- 1.60%)}	_22.658s	_23.344s	_{p=0.001 n=12}
_{strada-compiler - native}
_Errors	₀	₀	_~	_~	_~	_{p=1.000 n=12}
_Symbols	_334,953	_285,011	_{🟩-49,942 (-14.91%)}	_~	_~	_{p=0.000 n=12}
_Types	_197,616	_197,616	_~	_~	_~	_{p=1.000 n=12}
_{Memory Used}	_{297,287k (± 0.03%)}	_{225,911k (± 0.02%)}	_{🟩-71,376k (-24.01%)}	_225,756k	_226,046k	_{p=0.000 n=12}
_{Memory Allocs}	_{4,620,545 (± 0.01%)}	_{4,320,055 (± 0.01%)}	_{🟩-300,491 (- 6.50%)}	_4,318,803	_4,321,061	_{p=0.000 n=12}
_{Config Time}	_0.001s	_0.001s	_~	_~	_~	_{p=1.000 n=12}
_{Parse Time}	_{0.110s (± 2.67%)}	_{0.113s (± 6.11%)}	_~	_0.097s	_0.131s	_{p=0.618 n=12}
_{Bind Time}	_0.000s	_0.000s	_~	_~	_~	_{p=1.000 n=12}
_{Check Time}	_{1.039s (± 0.39%)}	_{1.007s (± 0.61%)}	_{🟩-0.032s (- 3.05%)}	_0.999s	_1.032s	_{p=0.000 n=12}
_{Emit Time}	_{0.144s (± 3.77%)}	_{0.142s (± 4.24%)}	_~	_0.121s	_0.159s	_{p=0.467 n=12}
_{Total Time}	_{1.341s (± 0.66%)}	_{1.317s (± 0.93%)}	_{-0.024s (- 1.81%)}	_1.284s	_1.349s	_{p=0.005 n=12}
_{ts-pre-modules - native}
_Errors	₈₇	₈₇	_~	_~	_~	_{p=1.000 n=12}
_Symbols	_303,834	_256,365	_{🟩-47,469 (-15.62%)}	_~	_~	_{p=0.000 n=12}
_Types	_181,663	_181,663	_~	_~	_~	_{p=1.000 n=12}
_{Memory Used}	_{258,128k (± 0.02%)}	_{195,835k (± 0.01%)}	_{🟩-62,293k (-24.13%)}	_195,762k	_195,916k	_{p=0.000 n=12}
_{Memory Allocs}	_{1,613,861 (± 0.01%)}	_{1,427,612 (± 0.01%)}	_{🟩-186,250 (-11.54%)}	_1,427,319	_1,428,101	_{p=0.000 n=12}
_{Config Time}	_0.000s	_0.000s	_~	_~	_~	_{p=1.000 n=12}
_{Parse Time}	_{0.098s (± 3.66%)}	_{0.099s (± 5.33%)}	_~	_0.087s	_0.115s	_{p=0.787 n=12}
_{Bind Time}	_{0.038s (±11.42%)}	_{0.041s (± 6.18%)}	_~	_0.034s	_0.047s	_{p=0.235 n=12}
_{Check Time}	_{0.816s (± 0.75%)}	_{0.802s (± 0.73%)}	_{-0.014s (- 1.75%)}	_0.788s	_0.817s	_{p=0.005 n=12}
_{Emit Time}	_0.000s	_0.000s	_~	_~	_~	_{p=1.000 n=12}
_{Total Time}	_{0.966s (± 0.76%)}	_{0.956s (± 0.72%)}	_~	_0.936s	_0.974s	_{p=0.066 n=12}
_{vscode - native}
_Errors	₃₉₅	₃₉₅	_~	_~	_~	_{p=1.000 n=12}
_Symbols	_11,346,995	_8,323,702	_{🟩-3,023,293 (-26.64%)}	_~	_~	_{p=0.000 n=12}
_Types	_3,762,529	_3,762,529	_~	_~	_~	_{p=1.000 n=12}
_{Memory Used}	_{6,544,236k (± 0.02%)}	_{4,472,338k (± 0.03%)}	_{🟩-2,071,898k (-31.66%)}	_4,469,583k	_4,477,074k	_{p=0.000 n=12}
_{Memory Allocs}	_{55,570,960 (± 0.03%)}	_{54,633,527 (± 0.03%)}	_{-937,434 (- 1.69%)}	_54,612,658	_54,713,726	_{p=0.000 n=12}
_{Config Time}	_{0.075s (± 0.41%)}	_{0.075s (± 0.54%)}	_~	_0.074s	_0.076s	_{p=1.000 n=12}
_{Parse Time}	_{1.867s (± 3.12%)}	_{1.711s (± 2.26%)}	_{🟩-0.155s (- 8.33%)}	_1.619s	_1.786s	_{p=0.000 n=12}
_{Bind Time}	_{0.542s (±13.98%)}	_{0.567s (±13.06%)}	_~	_0.465s	_0.793s	_{p=0.203 n=12}
_{Check Time}	_{13.465s (± 0.99%)}	_{12.710s (± 0.82%)}	_{🟩-0.756s (- 5.61%)}	_12.456s	_12.908s	_{p=0.000 n=12}
_{Emit Time}	_{4.794s (±10.45%)}	_{5.168s (± 6.77%)}	_~	_4.257s	_5.777s	_{p=0.259 n=12}
_{Total Time}	_{20.830s (± 1.92%)}	_{20.315s (± 1.52%)}	_~	_19.555s	_20.945s	_{p=0.114 n=12}
_{webpack - native}
_Errors	₅₈₄	₅₈₄	_~	_~	_~	_{p=1.000 n=12}
_Symbols	_1,320,229	_1,113,974	_{🟩-206,255 (-15.62%)}	_~	_~	_{p=0.000 n=12}
_Types	_625,283	_625,283	_~	_~	_~	_{p=1.000 n=12}
_{Memory Used}	_{952,980k (± 0.02%)}	_{688,662k (± 0.02%)}	_{🟩-264,318k (-27.74%)}	_688,209k	_688,988k	_{p=0.000 n=12}
_{Memory Allocs}	_{6,695,417 (± 0.01%)}	_{6,200,080 (± 0.05%)}	_{🟩-495,337 (- 7.40%)}	_6,197,454	_6,214,145	_{p=0.000 n=12}
_{Config Time}	_0.009s	_{0.009s (± 4.23%)}	_~	_0.009s	_0.011s	_{p=0.478 n=12}
_{Parse Time}	_{0.299s (± 2.90%)}	_{0.292s (± 2.27%)}	_~	_0.269s	_0.307s	_{p=0.213 n=12}
_{Bind Time}	_{0.083s (±19.79%)}	_{0.071s (± 3.24%)}	_~	_0.067s	_0.079s	_{p=0.502 n=12}
_{Check Time}	_{2.159s (± 0.92%)}	_{2.148s (± 0.23%)}	_~	_2.134s	_2.167s	_{p=0.504 n=12}
_{Emit Time}	_0.000s	_0.000s	_~	_~	_~	_{p=1.000 n=12}
_{Total Time}	_{2.584s (± 0.52%)}	_{2.553s (± 0.38%)}	_{-0.031s (- 1.19%)}	_2.531s	_2.584s	_{p=0.001 n=12}
_{xstate-main - native}
_Errors	₀	₀	_~	_~	_~	_{p=1.000 n=12}
_Symbols	_1,061,928	_815,636	_{🟩-246,292 (-23.19%)}	_~	_~	_{p=0.000 n=12}
_Types	_389,645	_389,645	_~	_~	_~	_{p=1.000 n=12}
_{Memory Used}	_{554,290k (± 0.02%)}	_{389,215k (± 0.04%)}	_{🟩-165,075k (-29.78%)}	_388,945k	_389,763k	_{p=0.000 n=12}
_{Memory Allocs}	_{4,884,902 (± 0.10%)}	_{4,307,981 (± 0.07%)}	_{🟩-576,921 (-11.81%)}	_4,300,464	_4,317,948	_{p=0.000 n=12}
_{Config Time}	_0.003s	_{0.003s (± 6.23%)}	_~	_0.002s	_0.003s	_{p=1.000 n=12}
_{Parse Time}	_{0.148s (± 4.25%)}	_{0.137s (± 3.53%)}	_{🟩-0.012s (- 7.81%)}	_0.127s	_0.154s	_{p=0.006 n=12}
_{Bind Time}	_{0.045s (±16.86%)}	_{0.043s (±14.02%)}	_~	_0.034s	_0.060s	_{p=0.831 n=12}
_{Check Time}	_{1.129s (± 0.39%)}	_{1.104s (± 0.89%)}	_{-0.025s (- 2.24%)}	_1.077s	_1.127s	_{p=0.000 n=12}
_{Emit Time}	_0.000s	_0.000s	_~	_~	_~	_{p=1.000 n=12}
_{Total Time}	_{1.336s (± 0.72%)}	_{1.294s (± 0.92%)}	_{🟩-0.042s (- 3.13%)}	_1.263s	_1.317s	_{p=0.000 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

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🔵 Needs a closer look

The broad unsafe layout and memory-lifetime refactor warrants final human validation despite extensive tests.

0 open findings

What changed in this PR

Optimizes memory usage across the native Go compiler while preserving compiler and language-service behavior.

Changes:

Replaces interface-backed AST, type, and mapper payloads with compact tagged layouts.
Adds arenas, pointer-free indexes, lazy metadata, and reusable checker workspaces.
Adds regression tests, benchmarks, and compiler baselines.

File	Description
`tsc/testdata/tests/cases/compiler/instantiatedReferenceMemberResolution.ts`	Adds member-resolution regression coverage.
`tsc/testdata/baselines/reference/compiler/instantiatedReferenceMemberResolution.types`	Records inferred types.
`tsc/testdata/baselines/reference/compiler/instantiatedReferenceMemberResolution.symbols`	Records resolved symbols.
`tsc/testdata/baselines/reference/compiler/instantiatedReferenceMemberResolution.js`	Records emit and declarations.
`tsc/testdata/baselines/reference/compiler/instantiatedReferenceMemberResolution.errors.txt`	Records expected diagnostics.
`tsc/internal/fourslash/tests/completionListForGenericInstance1_test.go`	Tests generic completion stability.
`tsc/internal/core/linkstore.go`	Compresses paged link storage.
`tsc/internal/core/linkstore_test.go`	Tests and benchmarks arenas/link stores.
`tsc/internal/core/arena.go`	Bounds arena chunks and adds indexed arenas.
`tsc/internal/checker/utilities.go`	Adds reusable checker workspaces.
`tsc/internal/checker/types.go`	Compacts checker types and metadata.
`tsc/internal/checker/types_test.go`	Tests layouts, caches, and allocation behavior.
`tsc/internal/checker/tracer.go`	Updates tracing for tagged types.
`tsc/internal/checker/services.go`	Uses compact member and metadata accessors.
`tsc/internal/checker/relater.go`	Compresses relation caches and signature access.
`tsc/internal/checker/pseudotypenodebuilder.go`	Uses compact signature accessors.
`tsc/internal/checker/nodecopy.go`	Updates signature type-parameter access.
`tsc/internal/checker/nodebuilderscopes.go`	Updates signature scope handling.
`tsc/internal/checker/nodebuilderimpl.go`	Adapts node building to compact metadata.
`tsc/internal/checker/mapper.go`	Replaces mapper interfaces with tagged dispatch.
`tsc/internal/checker/jsx.go`	Uses optional composite signature metadata.
`tsc/internal/checker/inference.go`	Embeds inference mapper storage.
`tsc/internal/checker/flow.go`	Uses compact signature accessors.
`tsc/internal/checker/exports.go`	Updates symbol metadata access.
`tsc/internal/checker/checker_test.go`	Adds member-resolution tests and benchmarks.
`tsc/internal/binder/binder.go`	Allocates optional symbol metadata in arenas.
`tsc/internal/ast/utilities.go`	Updates member/export initialization APIs.
`tsc/internal/ast/symbol.go`	Moves optional symbol fields out of hot records.
`tsc/internal/ast/symbol_test.go`	Tests compact symbol storage and lifetime.
`tsc/internal/ast/nodeaccessors_test.go`	Tests kind-dispatched AST accessors.
`tsc/internal/ast/nodeaccessors_bench_test.go`	Benchmarks AST accessor dispatch.
`tsc/internal/ast/kind_stringer_generated.go`	Includes synthetic flow-node kinds.
`tsc/internal/ast/flow.go`	Tags synthetic flow-node payloads.
`tsc/internal/ast/ast.go`	Removes AST payload interfaces.
`tools/scripts/tsc/generate-go-ast.ts`	Generates compact kind-based AST dispatch.

Files not reviewed (1)

tsc/internal/ast/kind_stringer_generated.go: Generated file

🧠 Review effort: Balanced

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Jake Bailey (jakebailey) · 2026-10-12T23:34:14Z

Ripped #64735 out for now. This still includes #64063.

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

typescript-automation · 2026-10-12T23:34:19Z

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

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

typescript-automation · 2026-10-13T00:04:32Z

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	_115,276	_~	_~	_~	_{p=1.000 n=12}
_Types	_79,613	_79,613	_~	_~	_~	_{p=1.000 n=12}
_{Memory Used}	_{133,237k (± 0.04%)}	_{102,799k (± 0.06%)}	_{🟩-30,438k (-22.85%)}	_102,703k	_102,976k	_{p=0.000 n=12}
_{Memory Allocs}	_{2,190,292 (± 0.01%)}	_{2,198,415 (± 0.00%)}	_{+8,123 (+ 0.37%)}	_2,198,215	_2,198,730	_{p=0.000 n=12}
_{Config Time}	_0.000s	_0.000s	_~	_~	_~	_{p=1.000 n=12}
_{Parse Time}	_{0.040s (± 3.88%)}	_{0.039s (± 3.07%)}	_~	_0.036s	_0.042s	_{p=0.639 n=12}
_{Bind Time}	_{0.012s (±11.20%)}	_{0.015s (± 7.64%)}	_{🔻+0.003s (+24.83%)}	_0.012s	_0.018s	_{p=0.002 n=12}
_{Check Time}	_{0.499s (± 0.67%)}	_{0.479s (± 0.68%)}	_{🟩-0.020s (- 4.01%)}	_0.472s	_0.489s	_{p=0.000 n=12}
_{Emit Time}	_{0.277s (± 2.19%)}	_{0.270s (± 1.31%)}	_{-0.007s (- 2.49%)}	_0.262s	_0.283s	_{p=0.049 n=12}
_{Total Time}	_{0.835s (± 0.81%)}	_{0.810s (± 0.66%)}	_{-0.025s (- 2.97%)}	_0.796s	_0.829s	_{p=0.000 n=12}
_{angular-1 - native}
_Errors	₃	₃	_~	_~	_~	_{p=1.000 n=12}
_Symbols	_{845,242 (± 0.11%)}	_{845,124 (± 0.06%)}	_~	_843,863	_846,437	_{p=0.551 n=12}
_Types	_{248,124 (± 0.00%)}	_{248,124 (± 0.00%)}	_~	_248,122	_248,127	_{p=0.452 n=12}
_{Memory Used}	_{746,093k (± 0.02%)}	_{552,834k (± 0.02%)}	_{🟩-193,259k (-25.90%)}	_552,598k	_553,084k	_{p=0.000 n=12}
_{Memory Allocs}	_{12,920,897 (± 0.08%)}	_{13,081,363 (± 0.01%)}	_{+160,465 (+ 1.24%)}	_13,078,812	_13,087,281	_{p=0.000 n=12}
_{Config Time}	_{0.020s (± 1.60%)}	_{0.020s (± 0.90%)}	_~	_0.020s	_0.021s	_{p=0.069 n=12}
_{Parse Time}	_{0.328s (± 1.96%)}	_{0.284s (± 2.83%)}	_{🟩-0.044s (-13.52%)}	_0.268s	_0.306s	_{p=0.000 n=12}
_{Bind Time}	_{0.072s (± 1.34%)}	_{0.090s (±10.88%)}	_{🔻+0.018s (+25.29%)}	_0.075s	_0.114s	_{p=0.000 n=12}
_{Check Time}	_0s	_0s	_~	_~	_~	_{p=1.000 n=12}
_{Emit Time}	_{1.861s (± 0.99%)}	_{1.901s (± 1.61%)}	_{+0.040s (+ 2.12%)}	_1.824s	_1.968s	_{p=0.037 n=12}
_{Total Time}	_{2.296s (± 0.81%)}	_{2.315s (± 1.35%)}	_~	_2.230s	_2.388s	_{p=0.192 n=12}
_{mui-docs - native}
_Errors	_11,405	_11,405	_~	_~	_~	_{p=1.000 n=12}
_Symbols	_4,339,337	_4,339,337	_~	_~	_~	_{p=1.000 n=12}
_Types	_1,379,387	_1,379,387	_~	_~	_~	_{p=1.000 n=12}
_{Memory Used}	_{2,774,696k (± 0.05%)}	_{1,951,648k (± 0.05%)}	_{🟩-823,049k (-29.66%)}	_1,948,139k	_1,953,815k	_{p=0.000 n=12}
_{Memory Allocs}	_{32,721,586 (± 0.07%)}	_{27,296,350 (± 0.07%)}	_{🟩-5,425,236 (-16.58%)}	_27,256,360	_27,348,724	_{p=0.000 n=12}
_{Config Time}	_0.017s	_{0.017s (± 1.07%)}	_~	_0.016s	_0.017s	_{p=1.000 n=12}
_{Parse Time}	_{0.497s (± 3.36%)}	_{0.465s (± 3.67%)}	_{🟩-0.033s (- 6.60%)}	_0.414s	_0.498s	_{p=0.007 n=12}
_{Bind Time}	_0.002s	_0.002s	_~	_~	_~	_{p=1.000 n=12}
_{Check Time}	_{8.871s (± 0.49%)}	_{7.908s (± 0.44%)}	_{🟩-0.963s (-10.86%)}	_7.821s	_8.017s	_{p=0.000 n=12}
_{Emit Time}	_{0.421s (± 0.75%)}	_{0.444s (± 5.84%)}	_{🔻+0.023s (+ 5.45%)}	_0.421s	_0.527s	_{p=0.001 n=12}
_{Total Time}	_{10.574s (± 0.51%)}	_{9.580s (± 0.27%)}	_{🟩-0.993s (- 9.39%)}	_9.520s	_9.662s	_{p=0.000 n=12}
_{strada-build-src - native}
_Errors	₀	₀	_~	_~	_~	_{p=1.000 n=12}
_Symbols	_1,388,669	_1,388,669	_~	_~	_~	_{p=1.000 n=12}
_Types	_441,862	_441,862	_~	_~	_~	_{p=1.000 n=12}
_{Memory Used}	_{1,628,939k (± 0.84%)}	_{1,268,198k (± 0.75%)}	_{🟩-360,741k (-22.15%)}	_1,245,065k	_1,302,483k	_{p=0.000 n=12}
_{Memory Allocs}	_{92,200,976 (± 0.17%)}	_{86,513,256 (± 0.17%)}	_{🟩-5,687,720 (- 6.17%)}	_85,968,706	_86,847,914	_{p=0.000 n=12}
_{Config Time}	_{0.003s (±12.31%)}	_{0.004s (±12.12%)}	_~	_0.002s	_0.004s	_{p=0.893 n=12}
_{Parse Time}	_{0.194s (± 5.11%)}	_{0.190s (± 2.51%)}	_~	_0.177s	_0.200s	_{p=0.799 n=12}
_{Bind Time}	_{0.000s (±217.90%)}	_0.000s	_~	_~	_~	_{p=1.000 n=12}
_{Check Time}	_{1.818s (± 0.58%)}	_{1.775s (± 0.64%)}	_{-0.043s (- 2.36%)}	_1.748s	_1.807s	_{p=0.000 n=12}
_{Emit Time}	_{0.313s (± 4.90%)}	_{0.323s (± 4.48%)}	_~	_0.285s	_0.350s	_{p=0.325 n=12}
_{Total Time}	_{23.553s (± 0.56%)}	_{23.155s (± 0.76%)}	_{-0.398s (- 1.69%)}	_22.650s	_23.657s	_{p=0.001 n=12}
_{strada-compiler - native}
_Errors	₀	₀	_~	_~	_~	_{p=1.000 n=12}
_Symbols	_334,953	_334,953	_~	_~	_~	_{p=1.000 n=12}
_Types	_197,616	_197,616	_~	_~	_~	_{p=1.000 n=12}
_{Memory Used}	_{296,057k (± 0.03%)}	_{229,435k (± 0.02%)}	_{🟩-66,622k (-22.50%)}	_229,357k	_229,554k	_{p=0.000 n=12}
_{Memory Allocs}	_{4,621,528 (± 0.01%)}	_{4,284,288 (± 0.01%)}	_{🟩-337,240 (- 7.30%)}	_4,283,283	_4,285,080	_{p=0.000 n=12}
_{Config Time}	_{0.001s (±19.81%)}	_{0.000s (±146.91%)}	_{🟩-0.001s (-81.82%)}	_0.000s	_0.001s	_{p=0.001 n=12}
_{Parse Time}	_{0.089s (± 4.85%)}	_{0.096s (± 3.75%)}	_{🔻+0.008s (+ 8.64%)}	_0.080s	_0.101s	_{p=0.007 n=12}
_{Bind Time}	_0.000s	_0.000s	_~	_~	_~	_{p=1.000 n=12}
_{Check Time}	_{0.864s (± 0.55%)}	_{0.850s (± 0.67%)}	_{-0.014s (- 1.62%)}	_0.838s	_0.863s	_{p=0.000 n=12}
_{Emit Time}	_{0.119s (±10.42%)}	_{0.114s (± 4.59%)}	_~	_0.102s	_0.131s	_{p=0.054 n=12}
_{Total Time}	_{1.120s (± 0.83%)}	_{1.105s (± 0.86%)}	_{-0.015s (- 1.38%)}	_1.081s	_1.132s	_{p=0.021 n=12}
_{ts-pre-modules - native}
_Errors	₈₇	₈₇	_~	_~	_~	_{p=1.000 n=12}
_Symbols	_303,834	_303,834	_~	_~	_~	_{p=1.000 n=12}
_Types	_181,663	_181,663	_~	_~	_~	_{p=1.000 n=12}
_{Memory Used}	_{256,627k (± 0.02%)}	_{198,510k (± 0.01%)}	_{🟩-58,117k (-22.65%)}	_198,432k	_198,569k	_{p=0.000 n=12}
_{Memory Allocs}	_{1,614,052 (± 0.01%)}	_{1,386,150 (± 0.02%)}	_{🟩-227,902 (-14.12%)}	_1,385,755	_1,387,001	_{p=0.000 n=12}
_{Config Time}	_0.000s	_0.000s	_~	_~	_~	_{p=1.000 n=12}
_{Parse Time}	_{0.099s (± 4.49%)}	_{0.097s (± 4.39%)}	_~	_0.088s	_0.108s	_{p=0.368 n=12}
_{Bind Time}	_{0.040s (±11.11%)}	_{0.040s (± 6.04%)}	_~	_0.035s	_0.048s	_{p=0.898 n=12}
_{Check Time}	_{0.816s (± 0.90%)}	_{0.817s (± 0.61%)}	_~	_0.803s	_0.830s	_{p=0.522 n=12}
_{Emit Time}	_0.000s	_0.000s	_~	_~	_~	_{p=1.000 n=12}
_{Total Time}	_{0.969s (± 0.89%)}	_{0.967s (± 0.69%)}	_~	_0.947s	_0.981s	_{p=0.788 n=12}
_{vscode - native}
_Errors	₃₉₆	₃₉₆	_~	_~	_~	_{p=1.000 n=12}
_Symbols	_11,348,832	_11,348,832	_~	_~	_~	_{p=1.000 n=12}
_Types	_3,744,021	_3,744,021	_~	_~	_~	_{p=1.000 n=12}
_{Memory Used}	_{6,462,500k (± 0.01%)}	_{4,705,304k (± 0.02%)}	_{🟩-1,757,196k (-27.19%)}	_4,703,453k	_4,710,028k	_{p=0.000 n=12}
_{Memory Allocs}	_{55,478,541 (± 0.02%)}	_{53,488,848 (± 0.02%)}	_{🟩-1,989,693 (- 3.59%)}	_53,477,113	_53,542,988	_{p=0.000 n=12}
_{Config Time}	_{0.075s (± 0.24%)}	_{0.075s (± 0.41%)}	_~	_0.074s	_0.075s	_{p=0.317 n=12}
_{Parse Time}	_{1.748s (± 2.75%)}	_{1.684s (± 2.34%)}	_{🟩-0.064s (- 3.64%)}	_1.612s	_1.803s	_{p=0.046 n=12}
_{Bind Time}	_{0.720s (±16.86%)}	_{0.644s (±14.84%)}	_~	_0.457s	_0.841s	_{p=0.325 n=12}
_{Check Time}	_{14.917s (± 0.88%)}	_{14.488s (± 0.85%)}	_{-0.429s (- 2.88%)}	_14.290s	_14.803s	_{p=0.000 n=12}
_{Emit Time}	_{5.273s (± 9.44%)}	_{5.151s (± 4.84%)}	_~	_4.209s	_5.700s	_{p=0.443 n=12}
_{Total Time}	_{22.821s (± 2.02%)}	_{22.123s (± 1.15%)}	_~	_21.217s	_22.562s	_{p=0.052 n=12}
_{webpack - native}
_Errors	₅₈₅	₅₈₅	_~	_~	_~	_{p=1.000 n=12}
_Symbols	_1,316,105	_1,316,105	_~	_~	_~	_{p=1.000 n=12}
_Types	_617,840	_617,840	_~	_~	_~	_{p=1.000 n=12}
_{Memory Used}	_{947,852k (± 0.02%)}	_{704,713k (± 0.02%)}	_{🟩-243,139k (-25.65%)}	_704,362k	_705,037k	_{p=0.000 n=12}
_{Memory Allocs}	_{6,673,137 (± 0.02%)}	_{5,986,383 (± 0.02%)}	_{🟩-686,754 (-10.29%)}	_5,983,639	_5,991,416	_{p=0.000 n=12}
_{Config Time}	_0.009s	_{0.009s (± 3.96%)}	_~	_0.009s	_0.011s	_{p=1.000 n=12}
_{Parse Time}	_{0.291s (± 3.90%)}	_{0.297s (± 2.67%)}	_~	_0.277s	_0.320s	_{p=0.451 n=12}
_{Bind Time}	_{0.093s (±21.01%)}	_{0.071s (± 2.10%)}	_~	_0.068s	_0.075s	_{p=0.270 n=12}
_{Check Time}	_{2.216s (± 0.58%)}	_{2.288s (± 2.80%)}	_{+0.072s (+ 3.25%)}	_2.232s	_2.547s	_{p=0.000 n=12}
_{Emit Time}	_0.000s	_0.000s	_~	_~	_~	_{p=1.000 n=12}
_{Total Time}	_{2.644s (± 0.37%)}	_{2.700s (± 2.63%)}	_~	_2.631s	_2.989s	_{p=0.183 n=12}
_{xstate-main - native}
_Errors	₀	₀	_~	_~	_~	_{p=1.000 n=12}
_Symbols	_1,065,632	_1,065,632	_~	_~	_~	_{p=1.000 n=12}
_Types	_390,378	_390,378	_~	_~	_~	_{p=1.000 n=12}
_{Memory Used}	_{548,183k (± 0.01%)}	_{405,019k (± 0.03%)}	_{🟩-143,164k (-26.12%)}	_404,804k	_405,382k	_{p=0.000 n=12}
_{Memory Allocs}	_{4,889,311 (± 0.08%)}	_{4,106,501 (± 0.11%)}	_{🟩-782,810 (-16.01%)}	_4,094,696	_4,122,225	_{p=0.000 n=12}
_{Config Time}	_0.003s	_{0.003s (± 8.64%)}	_~	_0.002s	_0.003s	_{p=0.478 n=12}
_{Parse Time}	_{0.142s (± 2.70%)}	_{0.135s (± 3.15%)}	_{🟩-0.007s (- 4.99%)}	_0.125s	_0.147s	_{p=0.019 n=12}
_{Bind Time}	_{0.050s (±16.27%)}	_{0.045s (±15.31%)}	_~	_0.034s	_0.065s	_{p=0.522 n=12}
_{Check Time}	_{1.144s (± 0.41%)}	_{1.125s (± 1.02%)}	_{-0.018s (- 1.62%)}	_1.108s	_1.155s	_{p=0.021 n=12}
_{Emit Time}	_0.000s	_0.000s	_~	_~	_~	_{p=1.000 n=12}
_{Total Time}	_{1.348s (± 0.60%)}	_{1.316s (± 0.88%)}	_{-0.032s (- 2.39%)}	_1.287s	_1.345s	_{p=0.000 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

Most resolved type nodes never need an anonymous object's outer type parameter list. Reserving a slice header for every node makes the common case needlessly expensive to retain and scan. TypeNodeLinks now occupies 16 rather than 32 bytes on amd64. An optional checker-owned arena entry preserves computed-empty lists and the original slice aliasing without introducing a separate allocation per cached list. VS Code src/tsconfig.json versus the parent commit, six fresh-process interleaved pairs with the normal GC policy. Retained bytes fall 0.43%, scan bytes 0.47%, and allocated bytes 0.33%. Allocation events and instruction counts are not statistically different; no CPU improvement is claimed. Exact production diagnostics and semantic counts match. goos: linux goarch: amd64 pkg: github.com/microsoft/TypeScript/tsc/internal/checker cpu: Intel(R) Core(TM) i9-10900K CPU @ 3.70GHz │ vscode-typeparams-before.txt │ vscode-typeparams.txt │ │ retained-B │ retained-B vs base │ ExternalProgram-20 3.864Gi ± 0% 3.847Gi ± 0% -0.43% (p=0.002 n=6) │ vscode-typeparams-before.txt │ vscode-typeparams.txt │ │ scan-B │ scan-B vs base │ ExternalProgram-20 3.459Gi ± 0% 3.443Gi ± 0% -0.47% (p=0.002 n=6) │ vscode-typeparams-before.txt │ vscode-typeparams.txt │ │ B/op │ B/op vs base │ ExternalProgram-20 5.484Gi ± 0% 5.466Gi ± 0% -0.33% (p=0.002 n=6) │ vscode-typeparams-before.txt │ vscode-typeparams.txt │ │ allocs/op │ allocs/op vs base │ ExternalProgram-20 27.38M ± 0% 27.35M ± 0% ~ (p=0.093 n=6) │ typeparams-before-instructions.txt │ typeparams-instructions.txt │ │ instructions/op │ instructions/op vs base │ ExternalInstructions-20 297.2G ± 2% 290.9G ± 4% ~ (p=0.310 n=6)

Most signatures have no type parameters, explicit this parameter, predicate, composite constituents, or isolated-type cache. Reserving this state for every instantiated signature wastes memory and GC scanning. Negative predicate results need no pointer at all. Signature shrinks from 128 to 80 bytes on amd64. Checker-owned cold storage preserves slice aliasing and independent clone caches; a private, non-propagating flag retains the recursive no-predicate guard. A full VS Code field census found 648637 signatures and only 84956 requiring cold storage (13.1%). Six fresh-process interleaved comparisons against the parent commit, with normal GC, save 0.65% retained bytes, 0.73% scan bytes, and 0.49% allocated bytes. Allocation events and instructions are not statistically different. This is incremental, not a CPU breakthrough. Production diagnostics and semantic counts match exactly. goos: linux goarch: amd64 pkg: github.com/microsoft/TypeScript/tsc/internal/checker cpu: Intel(R) Core(TM) i9-10900K CPU @ 3.70GHz │ vscode-signature-before.txt │ vscode-signature.txt │ │ retained-B │ retained-B vs base │ ExternalProgram-20 3.848Gi ± 0% 3.823Gi ± 0% -0.65% (p=0.002 n=6) │ vscode-signature-before.txt │ vscode-signature.txt │ │ scan-B │ scan-B vs base │ ExternalProgram-20 3.443Gi ± 0% 3.418Gi ± 0% -0.73% (p=0.002 n=6) │ vscode-signature-before.txt │ vscode-signature.txt │ │ B/op │ B/op vs base │ ExternalProgram-20 5.468Gi ± 0% 5.441Gi ± 0% -0.49% (p=0.002 n=6) │ vscode-signature-before.txt │ vscode-signature.txt │ │ allocs/op │ allocs/op vs base │ ExternalProgram-20 27.36M ± 0% 27.36M ± 0% ~ (p=0.589 n=6) │ signature-before-instructions.txt │ signature-instructions.txt │ │ instructions/op │ instructions/op vs base │ ExternalInstructions-20 297.9G ± 3% 296.1G ± 3% ~ (p=0.699 n=6)

A live pointer into an arena chunk retains the entire backing allocation, including unused capacity and unrelated dead values. Resetting typed parser and binder arenas at every file multiplies terminal chunk slack. Uniform 256-object chunks are especially wasteful for large records. Target 512 bytes per chunk before allocator rounding, preserving stable direct pointers and exact-capacity slices. Larger contiguous slices keep their separate allocation path. No GC settings, cross-file pooling, or pointer decoding are introduced. Six fresh-process interleaved VS Code comparisons against the parent commit, using normal GC, reduce retained bytes 8.54%, scan bytes 10.44%, allocated bytes 5.74%, and whole-process instructions 9.43%. Allocation events rise 13.91%; wall time is inconclusive on the shared machine (p=0.937). Four-object chunks saved slightly more heap but raised allocation events 32.15%. A 512-byte target keeps most of the memory savings with less than half that allocation penalty. Reusing partial parser and binder chunks also saved memory but would couple otherwise independent file lifetimes. The retention regression fails with the old allocator. Mixed singleton, slice, clone, growth, zero-size, and GC cases preserve addresses and data. Production diagnostics and file, line, identifier, symbol, type, and instantiation counts match exactly. goos: linux goarch: amd64 pkg: github.com/microsoft/TypeScript/tsc/internal/checker cpu: Intel(R) Core(TM) i9-10900K CPU @ 3.70GHz │ vscode-arena-before.txt │ vscode-arena.txt │ │ retained-B │ retained-B vs base │ ExternalProgram-20 3.823Gi ± 0% 3.497Gi ± 0% -8.54% (p=0.002 n=6) │ vscode-arena-before.txt │ vscode-arena.txt │ │ scan-B │ scan-B vs base │ ExternalProgram-20 3.418Gi ± 0% 3.062Gi ± 0% -10.44% (p=0.002 n=6) │ vscode-arena-before.txt │ vscode-arena.txt │ │ B/op │ B/op vs base │ ExternalProgram-20 5.442Gi ± 0% 5.130Gi ± 0% -5.74% (p=0.002 n=6) │ vscode-arena-before.txt │ vscode-arena.txt │ │ allocs/op │ allocs/op vs base │ ExternalProgram-20 27.36M ± 0% 31.17M ± 0% +13.91% (p=0.002 n=6) │ arena-before-instructions.txt │ arena-instructions.txt │ │ instructions/op │ instructions/op vs base │ ExternalInstructions-20 300.8G ± 3% 272.5G ± 6% -9.43% (p=0.002 n=6)

Resolved type nodes and signatures still kept AST pointers as map keys despite already having stable node identities. Those maps add redundant pointer storage, GC scanning, hashing, and growth allocations. Reuse the existing node-link store's pointer-free paged indexes for these two high-volume caches. Ordinary IDs and IDs outside the dense reserved range retain the existing fallback, and caches stay checker-local. Six fresh-process interleaved VS Code comparisons against the parent commit, using normal GC, reduce retained heap 1.20%, scan bytes 2.12%, allocated bytes 2.11%, and allocation events 0.20%. Instructions are inconclusive. This saves another roughly 43 MiB of heap and 66 MiB of scanning. Production diagnostics and semantic counts match exactly. Tests cover cache identity, ordinary/reserved IDs, clone isolation, growth, GC reachability, and independent checkers. goos: linux goarch: amd64 pkg: github.com/microsoft/TypeScript/tsc/internal/checker cpu: Intel(R) Core(TM) i9-10900K CPU @ 3.70GHz │ vscode-paged-before-6.txt │ vscode-paged-6.txt │ │ retained-B │ retained-B vs base │ ExternalProgram-20 3.497Gi ± 0% 3.455Gi ± 0% -1.20% (p=0.002 n=6) │ vscode-paged-before-6.txt │ vscode-paged-6.txt │ │ scan-B │ scan-B vs base │ ExternalProgram-20 3.061Gi ± 0% 2.997Gi ± 0% -2.12% (p=0.002 n=6) │ vscode-paged-before-6.txt │ vscode-paged-6.txt │ │ B/op │ B/op vs base │ ExternalProgram-20 5.129Gi ± 0% 5.021Gi ± 0% -2.11% (p=0.002 n=6) │ vscode-paged-before-6.txt │ vscode-paged-6.txt │ │ allocs/op │ allocs/op vs base │ ExternalProgram-20 31.16M ± 0% 31.09M ± 0% -0.20% (p=0.002 n=6) │ paged-before-instructions.txt │ paged-instructions.txt │ │ instructions/op │ instructions/op vs base │ ExternalInstructions-20 279.8G ± 5% 270.5G ± 2% ~ (p=0.589 n=6)

Intersection reduction repeatedly allocates temporary property-count tables. On MUI, this one allocation site accounts for roughly a quarter of all allocated bytes, despite none of the tables needing to survive the reduction. Reusing this workspace removes substantial allocation churn without changing the first-seen property order or caching results. Each recursive reduction borrows an independent checker-local table. Returning a table clears its names and counts, including on early returns; tables exceeding 4096 properties are not retained. Against the parent commit, six fresh-process MUI single-checker pairs save 1.36 GiB of allocation per run, reduce allocation events by 7.59%, and reduce instructions by 6.02%. Default-threaded production MUI instructions decrease 8.88%. Retained heap and scannable heap are essentially unchanged: this is an allocation-churn optimization. VS Code allocation savings are smaller. Production VS Code instructions remain inconclusive after twelve pairs, with a higher point estimate; Webpack instructions are also inconclusive. Wall times are noisy on this shared host. All production diagnostic text and semantic counts match between revisions. The regression test allocated 21 times per warmed reduction before this change and now allocates zero times. Tests also cover nested borrowing, property order, clearing, oversized tables, and early-return cleanup. Six fresh-process single-checker pairs, ordinary GC: │ mui-property-counts-memory-before.txt │ mui-property-counts-memory-after.txt │ │ retained-B │ retained-B vs base │ ExternalMemory-20 1.492Gi ± 0% 1.492Gi ± 0% ~ (p=0.310 n=6) │ mui-property-counts-memory-before.txt │ mui-property-counts-memory-after.txt │ │ scan-B │ scan-B vs base │ ExternalMemory-20 1.270Gi ± 0% 1.270Gi ± 0% ~ (p=0.310 n=6) │ mui-property-counts-memory-before.txt │ mui-property-counts-memory-after.txt │ │ B/op │ B/op vs base │ ExternalMemory-20 5.122Gi ± 0% 3.757Gi ± 0% -26.64% (p=0.002 n=6) │ mui-property-counts-memory-before.txt │ mui-property-counts-memory-after.txt │ │ allocs/op │ allocs/op vs base │ ExternalMemory-20 24.77M ± 0% 22.89M ± 0% -7.59% (p=0.002 n=6) │ mui-property-counts-memory-before.instructions │ mui-property-counts-memory-after.instructions │ │ instructions/op │ instructions/op vs base │ mui-20 213.7G ± 3% 200.8G ± 3% -6.02% (p=0.002 n=6) │ vscode-property-counts-memory-before.txt │ vscode-property-counts-memory-after.txt │ │ retained-B │ retained-B vs base │ ExternalMemory-20 2.615Gi ± 0% 2.615Gi ± 0% ~ (p=0.589 n=6) │ vscode-property-counts-memory-before.txt │ vscode-property-counts-memory-after.txt │ │ scan-B │ scan-B vs base │ ExternalMemory-20 2.287Gi ± 0% 2.287Gi ± 0% ~ (p=0.589 n=6) │ vscode-property-counts-memory-before.txt │ vscode-property-counts-memory-after.txt │ │ B/op │ B/op vs base │ ExternalMemory-20 3.749Gi ± 0% 3.714Gi ± 0% -0.92% (p=0.002 n=6) │ vscode-property-counts-memory-before.txt │ vscode-property-counts-memory-after.txt │ │ allocs/op │ allocs/op vs base │ ExternalMemory-20 23.60M ± 0% 23.49M ± 0% -0.47% (p=0.002 n=6) │ vscode-property-counts-memory-before.instructions │ vscode-property-counts-memory-after.instructions │ │ instructions/op │ instructions/op vs base │ vscode-20 193.0G ± 4% 193.2G ± 5% ~ (p=0.818 n=6) Default-threaded production CLI (six pairs; VS Code twelve pairs): │ mui-property-counts-cli-before.txt │ mui-property-counts-cli-after.txt │ │ heap-B/op │ heap-B/op vs base │ mui-20 1.867Gi ± 0% 1.868Gi ± 0% ~ (p=0.589 n=6) │ mui-property-counts-cli-before.txt │ mui-property-counts-cli-after.txt │ │ allocs/op │ allocs/op vs base │ mui-20 29.52M ± 0% 27.84M ± 0% -5.69% (p=0.002 n=6) │ mui-property-counts-cli-before.txt │ mui-property-counts-cli-after.txt │ │ check-sec/op │ check-sec/op vs base │ mui-20 11.59 ± 3% 10.67 ± 5% -7.86% (p=0.004 n=6) │ mui-property-counts-cli-before.instructions │ mui-property-counts-cli-after.instructions │ │ instructions/op │ instructions/op vs base │ mui-20 274.6G ± 2% 250.2G ± 4% -8.88% (p=0.002 n=6) │ vscode-property-counts-cli-before.txt │ vscode-property-counts-cli-after.txt │ │ heap-B/op │ heap-B/op vs base │ vscode-20 2.828Gi ± 0% 2.828Gi ± 0% ~ (p=0.843 n=12) │ vscode-property-counts-cli-before.txt │ vscode-property-counts-cli-after.txt │ │ allocs/op │ allocs/op vs base │ vscode-20 36.62M ± 0% 36.54M ± 0% -0.21% (p=0.000 n=12) │ vscode-property-counts-cli-before.txt │ vscode-property-counts-cli-after.txt │ │ check-sec/op │ check-sec/op vs base │ vscode-20 8.671 ± 21% 8.409 ± 26% ~ (p=0.799 n=12) │ vscode-property-counts-cli-before.instructions │ vscode-property-counts-cli-after.instructions │ │ instructions/op │ instructions/op vs base │ vscode-20 296.5G ± 4% 307.6G ± 3% ~ (p=0.242 n=12) │ webpack-property-counts-cli-before.txt │ webpack-property-counts-cli-after.txt │ │ heap-B/op │ heap-B/op vs base │ webpack-20 663.0Mi ± 0% 663.1Mi ± 0% ~ (p=0.699 n=6) │ webpack-property-counts-cli-before.txt │ webpack-property-counts-cli-after.txt │ │ allocs/op │ allocs/op vs base │ webpack-20 6.208M ± 0% 6.096M ± 0% -1.80% (p=0.002 n=6) │ webpack-property-counts-cli-before.txt │ webpack-property-counts-cli-after.txt │ │ check-sec/op │ check-sec/op vs base │ webpack-20 1.765 ± 8% 1.711 ± 6% ~ (p=0.180 n=6) │ webpack-property-counts-cli-before.instructions │ webpack-property-counts-cli-after.instructions │ │ instructions/op │ instructions/op vs base │ webpack-20 52.37G ± 2% 51.78G ± 3% ~ (p=0.394 n=6)

The compact compiler layouts depend on every header belonging to the concrete allocation identified by its tag. Unchecked kinds, retagging, and detached headers can otherwise turn a routine mistake into an invalid memory access. Keep that invariant mechanically enforced without adding layout tags or checks to hot accessors.

The owning packages may allocate records directly, but a fresh record carries a zero tag until newType, newNode, or its mapper tag assignment runs. If it escaped before then, the mistake surfaced only as a later cast panic. Fresh allocations must now be upcast straight into their constructor, or held in a local used only through its own fields until that upcast; mappers must be tagged immediately.

A zero-value node or type record has never been tagged, and returning its address yields a compiler record that skipped checked construction. Named or aliased unsafe.Pointer types also hid reinterpreting conversions from the cast boundary. Both left holes in the invariant the analyzer exists to enforce.

Enumerating copy and declaration forms one at a time left gaps: range assignments could retag records, named results and parameters could carry untagged zero values, and index, receive, and call expressions could copy a record off its header. Checking every value-producing expression and signature for records held by value closes the class rather than individual forms.

A record copied into a range variable or a value receiver detaches from the arena slot that owns its tagged header, so later writes are lost and reads can observe a stale kind. Those declarations never appear as typed expressions, so the copy check could not see them. Checking every defined variable also covers parameters and results, which replaces the narrower function signature rule.

Mapper storage held by value starts with a zero tag. The lint exempted mappers from its zero-value rule so coallocated inference mappers could live inside their owning context, but that also let a standalone mapper, or the address of untagged coallocated storage, escape and later panic in Map on kind 0. The exemption now applies only to mappers stored as struct fields, and their storage may only be addressed, explicitly or via a pointer-receiver method call, as an argument to an init*TypeMapper function that tags it.

A local that shadows the constructor's kind parameter passed the spelling-only check, so newType or newNode could tag a header with an unrelated value while the lint reported checked construction. Bulk copies through copy or variadic append also duplicated records by value without any diagnostic, because their arguments are slices.

Mapper kind constants are now public TypeMapperKind values, so the lint's pairing between concrete mappers and their kind constants has to look them up by the new names.

Dense checker link stores still keep a pointer for every occupied slot. Those tables cost memory and require GC scanning even though values already live in arenas. Use four-byte indexes in the page tables. Retain bounded arena blocks so references stay stable without geometrically over-allocating large stores. Keep map-backed stores unchanged: compressing those did not improve allocation usage.

A presence query needs only the page entry, not its value. Resolving an occupied index adds arena lookup work to a boolean check. Keep presence checks on the compressed page table, and apply the repository linter fixes to the link-store tests.

The checker's link-store wrappers answered Has by calling TryGet, so presence checks still resolved arena indexes even though the paged store can answer from the page entry alone. Route them to the store presence checks so checker queries get the cheaper path.

Instantiated and inherited object types retain a name-to-symbol map beside their ordered property list. Those maps duplicate symbol pointers and string headers across millions of types, increasing both live heap and the amount of memory the collector must scan. Use the existing property list as the source of truth for immutable named members. Small types need no separate index; larger types need only pointer-free integer slots. Keep map semantics for mutable module exports, reserved members, mismatched names, and recursive member resolution. VS Code src, six samples versus cold value-symbol links: goos: linux goarch: amd64 pkg: github.com/microsoft/TypeScript/tsc/internal/checker cpu: Intel(R) Core(TM) i9-10900K CPU @ 3.70GHz │ vscode-cold-links.txt │ vscode-member-index-owned.txt │ │ retained-B │ retained-B vs base │ ExternalProgram-20 4.874Gi ± 0% 4.503Gi ± 0% -7.61% (p=0.002 n=6) │ vscode-cold-links.txt │ vscode-member-index-owned.txt │ │ scan-B │ scan-B vs base │ ExternalProgram-20 4.508Gi ± 0% 4.062Gi ± 0% -9.89% (p=0.002 n=6) │ vscode-cold-links.txt │ vscode-member-index-owned.txt │ │ B/op │ B/op vs base │ ExternalProgram-20 6.043Gi ± 0% 5.982Gi ± 0% -1.00% (p=0.002 n=6) │ vscode-cold-links.txt │ vscode-member-index-owned.txt │ │ allocs/op │ allocs/op vs base │ ExternalProgram-20 26.23M ± 0% 26.04M ± 0% -0.71% (p=0.002 n=6) All 321 semantic diagnostics and 10284 files are identical. CLI diagnostic text and compiler counts match exactly. Instruction measurements remain noisy; this change does not claim an established CPU improvement. No GC tuning is used.

The name index and the instantiated fast path both assumed a table whose properties are found under their own names has no other keys. A symbol stored under its own name and an alias satisfies every reverse lookup, so the alias was silently dropped. Checking each (key, symbol) pair directly keeps such tables on the map path.

Ordinary type comparisons need only two 32-bit IDs and intersection context, but retained a 128-bit hash for every cached result. Hashing and storing twice the necessary key width wastes allocations and memory. Keep exact 64-bit pairs in separate maps for the four intersection states. Generic-reference normalization still uses its original full-width hash. An explicit key tag separates both namespaces, including recursion guards, without sacrificing hash bits or changing constrained generic behavior. Six fresh-process interleaved VS Code comparisons against the parent commit, using normal GC, reduce retained heap 0.94% (roughly 33 MiB) and total allocated bytes 1.29%. GC scanning, allocation events, and instruction counts are not statistically different. Tests cover directional and identity comparisons, all intersection contexts, result replacement, exact high-bit IDs, namespace isolation, generic parameter normalization, and constrained versus unconstrained recursion keys. Production diagnostics and all semantic counts match exactly. goos: linux goarch: amd64 pkg: github.com/microsoft/TypeScript/tsc/internal/checker cpu: Intel(R) Core(TM) i9-10900K CPU @ 3.70GHz │ vscode-relation-before-6.txt │ vscode-relation-6.txt │ │ retained-B │ retained-B vs base │ ExternalProgram-20 3.456Gi ± 0% 3.424Gi ± 0% -0.94% (p=0.002 n=6) │ vscode-relation-before-6.txt │ vscode-relation-6.txt │ │ scan-B │ scan-B vs base │ ExternalProgram-20 2.998Gi ± 0% 2.997Gi ± 0% ~ (p=0.310 n=6) │ vscode-relation-before-6.txt │ vscode-relation-6.txt │ │ B/op │ B/op vs base │ ExternalProgram-20 5.021Gi ± 0% 4.956Gi ± 0% -1.29% (p=0.002 n=6) │ vscode-relation-before-6.txt │ vscode-relation-6.txt │ │ allocs/op │ allocs/op vs base │ ExternalProgram-20 31.08M ± 0% 31.07M ± 0% ~ (p=0.240 n=6) │ relation-before-instructions.txt │ relation-instructions.txt │ │ instructions/op │ instructions/op vs base │ ExternalInstructions-20 269.3G ± 2% 270.0G ± 3% ~ (p=0.937 n=6)

Complete non-augmented properties are valid for augmented lookup, but copying each result into both caches retains duplicate name tables. MUI keeps 2,734,919 identical entries this way, nearly doubling its union/intersection cache storage without adding semantic information. Preserve independent augmented results and partial-property behavior while sharing complete entries. A failed lookup needs no empty table. The MUI census falls from 230242 tables and 5628201 entries to 116635 tables and 2893282 entries; all distinct cached identities remain. Six fresh-process interleaved single-checker comparisons against the parent commit, with ordinary GC, save 135.63 MiB of retained MUI heap (-8.15%) and 132.00 MiB of GC scanning (-9.22%). Total allocated bytes fall 4.45% and allocation events fall 1.46%. VS Code's corresponding reductions are small: retained -0.15%, scan -0.17%, allocated -0.16%. Instruction differences in these single-checker comparisons are inconclusive; elapsed time is noisy on the shared machine. Six default-threaded production CLI pairs confirm MUI's reported heap falls 9.29% and instructions fall 2.60%. VS Code and Webpack have small heap reductions and inconclusive instruction differences. These are incremental savings on top of the earlier branch optimizations. CLI-reported heap is not the forced-GC retained-heap measure above. MUI uses the CI-pinned source and restored scenario dependencies at 6780195595c12252a130aa5ae5c5bd461229c6b7. VS Code uses 8bf178e1e1c2be3723f14683f7b1e5fdb3f780e4. Webpack uses an isolated 2289141381f2c1c965cb65118fa0ffe2e9e19834 with restored dependencies. Production diagnostics and all semantic counts match exactly. Tests cover both query orders, both composite kinds, cache growth and GC reachability, missing entries, read/write partial flags, differing mode-specific identities, and real function-property augmentation. The storage regressions fail before this change. Single-checker retained heap and allocation measurements: │ mui-shared-union-before.txt │ mui-shared-union-shared.txt │ │ retained-B │ retained-B vs base │ ExternalMemory-20 1.624Gi ± 0% 1.492Gi ± 0% -8.15% (p=0.002 n=6) │ mui-shared-union-before.txt │ mui-shared-union-shared.txt │ │ scan-B │ scan-B vs base │ ExternalMemory-20 1.398Gi ± 0% 1.270Gi ± 0% -9.22% (p=0.002 n=6) │ mui-shared-union-before.txt │ mui-shared-union-shared.txt │ │ B/op │ B/op vs base │ ExternalMemory-20 5.364Gi ± 0% 5.125Gi ± 0% -4.45% (p=0.002 n=6) │ mui-shared-union-before.txt │ mui-shared-union-shared.txt │ │ allocs/op │ allocs/op vs base │ ExternalMemory-20 25.17M ± 0% 24.80M ± 1% -1.46% (p=0.002 n=6) │ vscode-shared-union-before.txt │ vscode-shared-union-shared.txt │ │ retained-B │ retained-B vs base │ ExternalMemory-20 2.619Gi ± 0% 2.615Gi ± 0% -0.15% (p=0.002 n=6) │ vscode-shared-union-before.txt │ vscode-shared-union-shared.txt │ │ scan-B │ scan-B vs base │ ExternalMemory-20 2.291Gi ± 0% 2.287Gi ± 0% -0.17% (p=0.002 n=6) │ vscode-shared-union-before.txt │ vscode-shared-union-shared.txt │ │ B/op │ B/op vs base │ ExternalMemory-20 3.754Gi ± 0% 3.748Gi ± 0% -0.16% (p=0.002 n=6) │ vscode-shared-union-before.txt │ vscode-shared-union-shared.txt │ │ allocs/op │ allocs/op vs base │ ExternalMemory-20 23.61M ± 0% 23.59M ± 0% -0.08% (p=0.002 n=6) Single-checker instructions: │ mui-shared-union-before.instructions │ mui-shared-union-shared.instructions │ │ instructions/op │ instructions/op vs base │ ExternalInstructions-20 218.9G ± 3% 217.3G ± 2% ~ (p=0.310 n=6) │ vscode-shared-union-before.instructions │ vscode-shared-union-shared.instructions │ │ instructions/op │ instructions/op vs base │ ExternalInstructions-20 188.8G ± 3% 192.1G ± 2% ~ (p=0.394 n=6) Default-threaded production CLI: │ shared-union-cli-before.txt │ shared-union-cli-after.txt │ │ instructions/op │ instructions/op vs base │ mui-20 283.3G ± 1% 275.9G ± 2% -2.60% (p=0.015 n=6) vscode-20 308.2G ± 7% 293.0G ± 6% ~ (p=0.818 n=6) webpack-20 51.96G ± 5% 51.82G ± 4% ~ (p=1.000 n=6) geomean 165.6G 161.2G -2.62% │ shared-union-cli-before.txt │ shared-union-cli-after.txt │ │ heap-B/op │ heap-B/op vs base │ mui-20 2.059Gi ± 0% 1.868Gi ± 0% -9.29% (p=0.002 n=6) vscode-20 2.835Gi ± 0% 2.829Gi ± 0% -0.21% (p=0.004 n=6) webpack-20 666.9Mi ± 0% 663.0Mi ± 0% -0.57% (p=0.002 n=6) geomean 1.561Gi 1.507Gi -3.45% │ shared-union-cli-before.txt │ shared-union-cli-after.txt │ │ allocs/op │ allocs/op vs base │ mui-20 29.84M ± 0% 29.55M ± 0% -0.97% (p=0.002 n=6) vscode-20 36.67M ± 2% 36.64M ± 0% ~ (p=0.132 n=6) webpack-20 6.235M ± 2% 6.208M ± 0% -0.43% (p=0.002 n=6) geomean 18.97M 18.87M -0.49% │ shared-union-cli-before.txt │ shared-union-cli-after.txt │ │ check-sec/op │ check-sec/op vs base │ mui-20 8.986 ± 6% 8.559 ± 4% -4.75% (p=0.026 n=6) vscode-20 8.345 ± 4% 8.900 ± 10% ~ (p=0.132 n=6) webpack-20 1.851 ± 8% 1.818 ± 8% ~ (p=0.310 n=6) geomean 5.178 5.173 -0.08%

getReducedType runs somePropertyReducesToNever on intersections. It used to create and cache a synthetic property for every property name shared by more than one constituent, only to inspect its flags. With large JSX prop intersections, as in MUI, most of those properties were never looked up again, yet they stayed in the intersection's property cache with their symbols and links. Collect the constituent properties without building the combined symbol, and only create the real property in the rare merged instantiation case. mui-docs: │ before │ after │ │ memory-used-B │ memory-used-B vs base │ MUIDocs 1.857Gi ± 0% 1.717Gi ± 0% -7.55% (p=0.002 n=6) │ before │ after │ │ allocs │ allocs vs base │ MUIDocs 27.29M ± 0% 25.19M ± 0% -7.72% (p=0.002 n=6) │ before │ after │ │ allocated-B │ allocated-B vs base │ MUIDocs 4.730Gi ± 0% 4.556Gi ± 0% -3.68% (p=0.002 n=6) │ before │ after │ │ symbols │ symbols vs base │ MUIDocs 4.332M ± 0% 3.663M ± 0% -15.43% (p=0.002 n=6)

Synthesizing or probing a union or intersection property gathers the distinct constituent properties into a set. That set rarely holds more than a handful of symbols, but collections.OrderedSet always allocates both a map and a key slice, and this runs for every property of every combined type that is enumerated during relation checks. Keep the distinct properties in a plain slice, and index them with a map only once the slice passes the same threshold used by orderedSet. mui-docs: │ before │ after │ │ allocs │ allocs vs base │ MUIDocs 25.19M ± 0% 23.32M ± 1% -7.41% (p=0.002 n=6) │ before │ after │ │ allocated-B │ allocated-B vs base │ MUIDocs 4.556Gi ± 0% 4.389Gi ± 1% -3.66% (p=0.002 n=6)

Enumerating the properties of a union or intersection tracks which names have already been combined. A fresh set is allocated for every enumeration, and on large projects those sets account for a sizable share of all allocated bytes, adding GC work for no lasting benefit. Borrow the set from a per-checker free list instead. Enumeration can recurse into other combined types, so each call still takes its own set. mui-docs: │ before │ after │ │ allocated-B │ allocated-B vs base │ MUIDocs 4.389Gi ± 1% 4.092Gi ± 0% -6.76% (p=0.002 n=6) │ before │ after │ │ allocs │ allocs vs base │ MUIDocs 23.32M ± 1% 23.18M ± 0% -0.60% (p=0.002 n=6)

Jake Bailey (jakebailey) · 2026-10-14T16:57:06Z

The remaining work is now in independent PRs: #64775, #64781, #64788, #64789, #64791, #64815.

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Jake Bailey (jakebailey) force-pushed the data-oriented-compiler branch from 8cf1e6d to 05fdf40 Compare October 12, 2026 23:32

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Jake Bailey (jakebailey) added 23 commits October 14, 2026 07:17

Match the public mapper kind names in layout lint

0db41f9

Mapper kind constants are now public TypeMapperKind values, so the lint's pairing between concrete mappers and their kind constants has to look them up by the new names.

Jake Bailey (jakebailey) force-pushed the data-oriented-compiler branch from 0aaf90f to da7313e Compare October 14, 2026 14:19

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Avoid short-lived allocations in union and intersection property handling #64815

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Use small slices for union and intersection property sources #64816

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Reuse name sets when enumerating union and intersection properties #64817

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