Speed up property and index signature lookups by jakebailey · Pull Request #65043 · microsoft/TypeScript

Jake Bailey (jakebailey) · 2026-10-29T22:38:40Z

Thanks Steven (@teamchong) for finding these!

Both functions are called on nearly every property, signature, and index lookup, and the overwhelmingly common input is a plain object type, for which both return the type unchanged. They were only able to reach that answer after a chain of flag tests (and, for getApparentType, a non-inlinable call), and getReducedApparentType paid for it three times. Split each into a small inlinable wrapper that returns early for types that cannot change (non-mapped object types for the apparent type, anything other than a union or intersection for reduction), and let getReducedApparentType skip all three steps for non-mapped object types. Co-authored-by: Steven Chong <[email protected]>

getApplicableIndexInfoForName runs for every property name that is missing from a union constituent, and most types have no index signatures at all. It still created (and interned) a string literal type for the name before discovering there was nothing to match. Check for index infos first. findApplicableIndexInfo also allocated an 8-element slice on every call to collect applicable infos, although at most one is applicable in almost all cases. Track the first applicable info directly and only collect value types once a second one is found. Co-authored-by: Steven Chong <[email protected]>

Synthesizing a union or intersection property looks the name up in every constituent. Constituents are most often object types whose members are already resolved, where the lookup amounts to a single member table probe, yet each one went through getApparentType and the general getPropertyOfTypeEx path (reduced apparent type, member resolution, module and value checks) first. For such constituents, read the member directly when it is a plain value, or when it is missing and Object/Function augmentation is not requested. All other cases (module types, aliases, missing members that may come from the global Object or Function types) still take the full lookup, so the resulting property is unchanged. Co-authored-by: Steven Chong <[email protected]>

getTypeOfPropertyOfContextualType runs for every property of every contextually typed object literal. It passed a closure to mapTypeEx even though the contextual type is usually not a union, so the closure was allocated only to be called once. Handle non-union types directly and keep mapTypeEx for unions. Also, as with getApplicableIndexInfoForName, don't create a string literal type for the property name when the contextual type has no index signatures that it could be matched against. Co-authored-by: Steven Chong <[email protected]>

Resolving the members of a derived class's constructor type cloned the class's exports table so that static members of the base constructor could be added to it. But the base constructor's properties are often all shadowed: every class has its own 'prototype', and many bases have no other statics. In that case the clone was identical to the original and the members were stored a second time for nothing. Find the first base property that would actually be inherited and only clone the table (and reset the type's members) when there is one. The base constructor's properties are still resolved at the same point, so resolution order is unchanged. Co-authored-by: Steven Chong <[email protected]>

Jake Bailey (jakebailey) · 2026-10-29T22:38:50Z

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

typescript-automation · 2026-10-29T22:38:55Z

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

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

Copilot

🟢 Approval recommended

No active review issues are identified for the checker lookup optimizations.

No open issues 🎉

What changed in this PR

This PR optimizes property and index-signature lookups in the native TypeScript checker by reducing common-path work and allocations.

Changes:

Adds fast paths for resolved object members, apparent types, and type reduction.
Avoids unnecessary literal-type creation and allocations during index-signature and contextual-property lookups.
Skips cloning static member tables when no base members need to be inherited.

File	Description
`tsc/internal/checker/checker.go`	Optimizes checker lookups with fast paths, deferred allocations, and conditional member-table cloning.

_{Review effort: Balanced}

typescript-automation · 2026-10-29T23:40:58Z

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=20}
_Symbols	_88,466	_88,466	_~	_~	_~	_{p=1.000 n=20}
_Types	_79,607	_79,184	_{-423 (- 0.53%)}	_~	_~	_{p=0.000 n=20}
_{Memory Used}	_{104,133k (± 0.02%)}	_{104,121k (± 0.03%)}	_~	_104,019k	_104,220k	_{p=0.490 n=20}
_{Memory Allocs}	_{1,263,820 (± 0.01%)}	_{1,263,286 (± 0.01%)}	_{-534 (- 0.04%)}	_1,263,004	_1,263,561	_{p=0.000 n=20}
_{Config Time}	_0.000s	_0.000s	_~	_~	_~	_{p=1.000 n=20}
_{Parse Time}	_{0.025s (±18.66%)}	_{0.023s (± 2.35%)}	_~	_0.021s	_0.025s	_{p=0.821 n=20}
_{Bind Time}	_{0.009s (±14.30%)}	_{0.009s (± 6.89%)}	_~	_0.007s	_0.012s	_{p=0.829 n=20}
_{Check Time}	_{0.215s (± 1.63%)}	_{0.204s (± 0.66%)}	_{🟩-0.010s (- 4.75%)}	_0.199s	_0.210s	_{p=0.000 n=20}
_{Emit Time}	_{0.138s (± 0.74%)}	_{0.138s (± 0.50%)}	_~	_0.136s	_0.141s	_{p=0.524 n=20}
_{Total Time}	_{0.390s (± 2.52%)}	_{0.378s (± 0.31%)}	_{🟩-0.012s (- 3.12%)}	_0.372s	_0.381s	_{p=0.000 n=20}
_{angular-1 - native}
_Errors	₃	₃	_~	_~	_~	_{p=1.000 n=20}
_Symbols	_{586,556 (± 0.02%)}	_{586,519 (± 0.02%)}	_~	_586,030	_586,791	_{p=0.733 n=20}
_Types	_{241,687 (± 0.00%)}	_{239,573 (± 0.00%)}	_{-2,114 (- 0.87%)}	_239,571	_239,583	_{p=0.000 n=20}
_{Memory Used}	_{517,985k (± 0.01%)}	_{517,715k (± 0.01%)}	_{-270k (- 0.05%)}	_517,482k	_517,989k	_{p=0.000 n=20}
_{Memory Allocs}	_{7,804,334 (± 0.14%)}	_{7,800,774 (± 0.12%)}	_~	_7,784,743	_7,847,690	_{p=0.461 n=20}
_{Config Time}	_{0.009s (± 1.15%)}	_0.009s	_~	_~	_~	_{p=1.000 n=20}
_{Parse Time}	_{0.127s (± 1.96%)}	_{0.126s (± 2.51%)}	_~	_0.114s	_0.136s	_{p=0.673 n=20}
_{Bind Time}	_{0.043s (± 9.20%)}	_{0.045s (±10.35%)}	_~	_0.037s	_0.068s	_{p=0.586 n=20}
_{Check Time}	_0s	_0s	_~	_~	_~	_{p=1.000 n=20}
_{Emit Time}	_{0.852s (± 0.98%)}	_{0.851s (± 0.89%)}	_~	_0.822s	_0.878s	_{p=0.931 n=20}
_{Total Time}	_{1.042s (± 1.23%)}	_{1.041s (± 1.08%)}	_~	_1.007s	_1.090s	_{p=0.952 n=20}
_{arktype - native}
_Errors	₀	₀	_~	_~	_~	_{p=1.000 n=20}
_Symbols	_685,920	_685,920	_~	_~	_~	_{p=1.000 n=20}
_Types	_939,467	_939,206	_{-261 (- 0.03%)}	_~	_~	_{p=0.000 n=20}
_{Memory Used}	_{497,266k (± 0.01%)}	_{497,218k (± 0.01%)}	_{-48k (- 0.01%)}	_497,039k	_497,369k	_{p=0.022 n=20}
_{Memory Allocs}	_{12,107,878 (± 0.01%)}	_{12,107,878 (± 0.01%)}	_~	_12,103,591	_12,113,155	_{p=0.820 n=20}
_{Config Time}	_0.001s	_0.001s	_~	_~	_~	_{p=1.000 n=20}
_{Parse Time}	_{0.043s (± 3.37%)}	_{0.044s (± 2.93%)}	_~	_0.039s	_0.049s	_{p=0.210 n=20}
_{Bind Time}	_{0.014s (± 9.91%)}	_{0.014s (±10.08%)}	_~	_0.011s	_0.021s	_{p=0.888 n=20}
_{Check Time}	_{1.003s (± 0.75%)}	_{0.985s (± 0.79%)}	_{-0.018s (- 1.78%)}	_0.959s	_1.025s	_{p=0.001 n=20}
_{Emit Time}	_0.000s	_0.000s	_~	_~	_~	_{p=1.000 n=20}
_{Total Time}	_{1.090s (± 0.75%)}	_{1.075s (± 0.56%)}	_{-0.015s (- 1.42%)}	_1.056s	_1.108s	_{p=0.003 n=20}
_{class-transformer - native}
_Errors	₀	₀	_~	_~	_~	_{p=1.000 n=20}
_Symbols	_45,376	_45,376	_~	_~	_~	_{p=1.000 n=20}
_Types	_7,573	_7,565	_{-8 (- 0.11%)}	_~	_~	_{p=0.000 n=20}
_{Memory Used}	_{27,842k (± 0.01%)}	_{27,837k (± 0.02%)}	_~	_27,814k	_27,856k	_{p=0.171 n=20}
_{Memory Allocs}	_{248,783 (± 0.05%)}	_{248,589 (± 0.05%)}	_{-194 (- 0.08%)}	_248,235	_249,278	_{p=0.023 n=20}
_{Config Time}	_0.000s	_0.000s	_~	_~	_~	_{p=1.000 n=20}
_{Parse Time}	_{0.011s (± 3.88%)}	_{0.011s (± 4.42%)}	_~	_0.009s	_0.012s	_{p=0.916 n=20}
_{Bind Time}	_{0.003s (±13.57%)}	_{0.003s (± 9.29%)}	_~	_0.002s	_0.005s	_{p=0.166 n=20}
_{Check Time}	_{0.008s (± 5.72%)}	_{0.008s (± 5.20%)}	_~	_0.007s	_0.009s	_{p=0.590 n=20}
_{Emit Time}	_{0.009s (± 6.37%)}	_{0.009s (± 5.99%)}	_~	_0.007s	_0.011s	_{p=0.596 n=20}
_{Total Time}	_{0.032s (± 2.07%)}	_{0.032s (± 1.95%)}	_~	_0.029s	_0.034s	_{p=0.854 n=20}
_{effect - native}
_Errors	₁₂	₁₂	_~	_~	_~	_{p=1.000 n=20}
_Symbols	_1,235,115	_1,235,115	_~	_~	_~	_{p=1.000 n=20}
_Types	_894,113	_893,278	_{-835 (- 0.09%)}	_~	_~	_{p=0.000 n=20}
_{Memory Used}	_{940,635k (± 0.02%)}	_{940,428k (± 0.02%)}	_~	_939,677k	_941,392k	_{p=0.069 n=20}
_{Memory Allocs}	_{12,670,681 (± 0.03%)}	_{12,670,765 (± 0.03%)}	_~	_12,661,076	_12,697,993	_{p=0.862 n=20}
_{Config Time}	_0.002s	_0.002s	_~	_~	_~	_{p=1.000 n=20}
_{Parse Time}	_{0.148s (± 1.35%)}	_{0.149s (± 1.64%)}	_~	_0.142s	_0.160s	_{p=0.432 n=20}
_{Bind Time}	_0.000s	_0.000s	_~	_~	_~	_{p=1.000 n=20}
_{Check Time}	_{0.936s (± 0.71%)}	_{0.921s (± 0.74%)}	_{-0.015s (- 1.64%)}	_0.897s	_0.947s	_{p=0.005 n=20}
_{Emit Time}	_{0.498s (± 2.19%)}	_{0.506s (± 1.98%)}	_~	_0.465s	_0.550s	_{p=0.317 n=20}
_{Total Time}	_{1.675s (± 0.55%)}	_{1.671s (± 0.50%)}	_~	_1.642s	_1.715s	_{p=0.256 n=20}
_{mui-docs - native}
_Errors	_11,405	_11,405	_~	_~	_~	_{p=1.000 n=20}
_Symbols	_3,784,019	_3,784,019	_~	_~	_~	_{p=1.000 n=20}
_Types	_1,355,974	_1,354,375	_{-1,599 (- 0.12%)}	_~	_~	_{p=0.000 n=20}
_{Memory Used}	_{1,836,713k (± 0.09%)}	_{1,835,485k (± 0.07%)}	_~	_1,831,583k	_1,839,890k	_{p=0.301 n=20}
_{Memory Allocs}	_{26,015,818 (± 0.14%)}	_{26,004,973 (± 0.11%)}	_~	_25,924,906	_26,108,125	_{p=0.678 n=20}
_{Config Time}	_{0.009s (± 2.73%)}	_{0.009s (± 2.82%)}	_~	_0.008s	_0.009s	_{p=0.751 n=20}
_{Parse Time}	_{0.299s (± 2.24%)}	_{0.299s (± 1.72%)}	_~	_0.282s	_0.321s	_{p=0.963 n=20}
_{Bind Time}	_0.001s	_0.001s	_~	_~	_~	_{p=1.000 n=20}
_{Check Time}	_{3.265s (± 1.28%)}	_{3.224s (± 1.45%)}	_~	_3.042s	_3.403s	_{p=0.292 n=20}
_{Emit Time}	_{0.258s (± 2.04%)}	_{0.256s (± 2.01%)}	_~	_0.237s	_0.279s	_{p=0.587 n=20}
_{Total Time}	_{4.345s (± 1.28%)}	_{4.301s (± 1.38%)}	_~	_4.031s	_4.509s	_{p=0.373 n=20}
_{sentry - native}
_Errors	₂	₂	_~	_~	_~	_{p=1.000 n=20}
_Symbols	_4,793,245	_4,793,245	_~	_~	_~	_{p=1.000 n=20}
_Types	_2,607,045	_2,604,654	_{-2,391 (- 0.09%)}	_~	_~	_{p=0.000 n=20}
_{Memory Used}	_{2,882,235k (± 0.04%)}	_{2,879,947k (± 0.03%)}	_{-2,288k (- 0.08%)}	_2,877,727k	_2,883,490k	_{p=0.003 n=20}
_{Memory Allocs}	_{75,452,587 (± 0.39%)}	_{75,223,344 (± 0.24%)}	_~	_74,819,955	_76,299,611	_{p=0.301 n=20}
_{Config Time}	_{0.025s (± 0.84%)}	_{0.025s (± 0.98%)}	_~	_0.024s	_0.025s	_{p=0.191 n=20}
_{Parse Time}	_{0.483s (± 4.57%)}	_{0.465s (± 4.14%)}	_~	_0.423s	_0.593s	_{p=0.208 n=20}
_{Bind Time}	_{0.158s (± 9.92%)}	_{0.178s (± 9.91%)}	_{🔻+0.020s (+12.64%)}	_0.139s	_0.244s	_{p=0.030 n=20}
_{Check Time}	_{6.741s (± 0.54%)}	_{6.619s (± 0.44%)}	_{-0.122s (- 1.81%)}	_6.538s	_6.748s	_{p=0.000 n=20}
_{Emit Time}	_0.000s	_0.000s	_~	_~	_~	_{p=1.000 n=20}
_{Total Time}	_{7.456s (± 0.54%)}	_{7.343s (± 0.40%)}	_{-0.113s (- 1.52%)}	_7.238s	_7.453s	_{p=0.000 n=20}
_{social-app - native}
_Errors	₀	₀	_~	_~	_~	_{p=1.000 n=20}
_Symbols	_1,883,074	_1,883,074	_~	_~	_~	_{p=1.000 n=20}
_Types	_1,158,168	_1,157,065	_{-1,103 (- 0.10%)}	_~	_~	_{p=0.000 n=20}
_{Memory Used}	_{972,433k (± 0.01%)}	_{971,996k (± 0.01%)}	_{-437k (- 0.04%)}	_971,495k	_972,366k	_{p=0.000 n=20}
_{Memory Allocs}	_{13,552,506 (± 0.09%)}	_{13,579,684 (± 0.28%)}	_~	_13,512,666	_13,824,095	_{p=0.947 n=20}
_{Config Time}	_{0.008s (± 1.30%)}	_0.008s	_~	_~	_~	_{p=1.000 n=20}
_{Parse Time}	_{0.165s (± 3.07%)}	_{0.161s (± 2.62%)}	_~	_0.147s	_0.182s	_{p=0.317 n=20}
_{Bind Time}	_{0.044s (± 7.40%)}	_{0.051s (±12.43%)}	_~	_0.041s	_0.077s	_{p=0.181 n=20}
_{Check Time}	_{1.537s (± 0.66%)}	_{1.530s (± 0.75%)}	_~	_1.495s	_1.587s	_{p=0.267 n=20}
_{Emit Time}	_0.000s	_0.000s	_~	_~	_~	_{p=1.000 n=20}
_{Total Time}	_{1.772s (± 0.61%)}	_{1.767s (± 0.84%)}	_~	_1.723s	_1.823s	_{p=0.507 n=20}
_{strada-build-src - native}
_Errors	₀	₀	_~	_~	_~	_{p=1.000 n=20}
_Symbols	_1,184,972	_1,184,972	_~	_~	_~	_{p=1.000 n=20}
_Types	_438,963	_435,976	_{-2,987 (- 0.68%)}	_~	_~	_{p=0.000 n=20}
_{Memory Used}	_{1,167,825k (± 0.33%)}	_{1,166,790k (± 0.33%)}	_~	_1,152,702k	_1,183,823k	_{p=0.602 n=20}
_{Memory Allocs}	_{47,696,097 (± 0.11%)}	_{47,651,206 (± 0.12%)}	_~	_47,418,517	_47,879,221	_{p=0.277 n=20}
_{Config Time}	_{0.002s (±17.44%)}	_{0.002s (±11.84%)}	_~	_0.001s	_0.002s	_{p=0.320 n=20}
_{Parse Time}	_{0.140s (± 1.36%)}	_{0.139s (± 1.37%)}	_~	_0.132s	_0.147s	_{p=0.233 n=20}
_{Bind Time}	_0.000s	_{0.000s (±208.60%)}	_~	_0.000s	_0.001s	_{p=1.000 n=20}
_{Check Time}	_{0.809s (± 0.40%)}	_{0.807s (± 0.66%)}	_~	_0.795s	_0.850s	_{p=0.100 n=20}
_{Emit Time}	_{0.141s (± 1.92%)}	_{0.140s (± 1.27%)}	_~	_0.135s	_0.149s	_{p=0.586 n=20}
_{Total Time}	_{9.378s (± 0.30%)}	_{9.360s (± 0.79%)}	_~	_9.195s	_9.931s	_{p=0.081 n=20}
_{strada-compiler - native}
_Errors	₀	₀	_~	_~	_~	_{p=1.000 n=20}
_Symbols	_263,511	_263,511	_~	_~	_~	_{p=1.000 n=20}
_Types	_196,116	_195,166	_{-950 (- 0.48%)}	_~	_~	_{p=0.000 n=20}
_{Memory Used}	_{224,612k (± 0.02%)}	_{224,510k (± 0.02%)}	_{-102k (- 0.05%)}	_224,315k	_224,632k	_{p=0.001 n=20}
_{Memory Allocs}	_{2,401,550 (± 0.01%)}	_{2,400,331 (± 0.01%)}	_{-1,219 (- 0.05%)}	_2,399,183	_2,401,287	_{p=0.000 n=20}
_{Config Time}	_0.000s	_0.000s	_~	_~	_~	_{p=1.000 n=20}
_{Parse Time}	_{0.050s (± 3.59%)}	_{0.049s (± 2.72%)}	_~	_0.044s	_0.056s	_{p=0.246 n=20}
_{Bind Time}	_0.000s	_0.000s	_~	_~	_~	_{p=1.000 n=20}
_{Check Time}	_{0.394s (± 5.63%)}	_{0.387s (± 3.15%)}	_~	_0.368s	_0.492s	_{p=0.693 n=20}
_{Emit Time}	_{0.048s (± 5.16%)}	_{0.048s (± 4.77%)}	_~	_0.041s	_0.057s	_{p=0.930 n=20}
_{Total Time}	_{0.520s (± 4.46%)}	_{0.510s (± 2.23%)}	_~	_0.491s	_0.606s	_{p=0.151 n=20}
_{t3code-server - native}
_Errors	₀	₀	_~	_~	_~	_{p=1.000 n=20}
_Symbols	_4,350,661	_4,350,661	_~	_~	_~	_{p=1.000 n=20}
_Types	_3,040,644	_3,038,632	_{-2,012 (- 0.07%)}	_~	_~	_{p=0.000 n=20}
_{Memory Used}	_{2,433,806k (± 0.03%)}	_{2,433,076k (± 0.02%)}	_~	_2,431,799k	_2,435,211k	_{p=0.063 n=20}
_{Memory Allocs}	_{37,372,053 (± 0.08%)}	_{37,397,732 (± 0.11%)}	_~	_37,297,768	_37,718,224	_{p=0.355 n=20}
_{Config Time}	_0.003s	_0.003s	_~	_~	_~	_{p=1.000 n=20}
_{Parse Time}	_{0.252s (± 1.74%)}	_{0.252s (± 2.52%)}	_~	_0.225s	_0.279s	_{p=0.931 n=20}
_{Bind Time}	_{0.088s (± 9.54%)}	_{0.089s (± 9.96%)}	_~	_0.075s	_0.136s	_{p=0.702 n=20}
_{Check Time}	_{7.219s (± 0.59%)}	_{7.142s (± 0.65%)}	_{-0.077s (- 1.06%)}	_7.033s	_7.387s	_{p=0.011 n=20}
_{Emit Time}	_0.000s	_0.000s	_~	_~	_~	_{p=1.000 n=20}
_{Total Time}	_{7.573s (± 0.57%)}	_{7.496s (± 0.62%)}	_{-0.077s (- 1.02%)}	_7.380s	_7.726s	_{p=0.013 n=20}
_{tanstack-router - native}
_Errors	₁	₁	_~	_~	_~	_{p=1.000 n=20}
_Symbols	_571,756	_571,756	_~	_~	_~	_{p=1.000 n=20}
_Types	_397,689	_397,368	_{-321 (- 0.08%)}	_~	_~	_{p=0.000 n=20}
_{Memory Used}	_{331,443k (± 0.01%)}	_{331,365k (± 0.01%)}	_{-78k (- 0.02%)}	_331,188k	_331,545k	_{p=0.009 n=20}
_{Memory Allocs}	_{4,388,230 (± 0.28%)}	_{4,390,475 (± 0.23%)}	_~	_4,375,348	_4,445,364	_{p=0.134 n=20}
_{Config Time}	_0.001s	_0.001s	_~	_~	_~	_{p=1.000 n=20}
_{Parse Time}	_{0.040s (± 3.94%)}	_{0.040s (± 4.35%)}	_~	_0.035s	_0.047s	_{p=0.721 n=20}
_{Bind Time}	_{0.013s (±11.58%)}	_{0.013s (± 8.48%)}	_~	_0.011s	_0.019s	_{p=0.909 n=20}
_{Check Time}	_{0.570s (± 1.04%)}	_{0.563s (± 1.23%)}	_~	_0.537s	_0.596s	_{p=0.075 n=20}
_{Emit Time}	_0.000s	_0.000s	_~	_~	_~	_{p=1.000 n=20}
_{Total Time}	_{0.643s (± 1.07%)}	_{0.635s (± 1.20%)}	_~	_0.608s	_0.669s	_{p=0.092 n=20}
_{ts-pre-modules - native}
_Errors	₈₇	₈₇	_~	_~	_~	_{p=1.000 n=20}
_Symbols	_231,616	_231,616	_~	_~	_~	_{p=1.000 n=20}
_Types	_181,195	_180,608	_{-587 (- 0.32%)}	_~	_~	_{p=0.000 n=20}
_{Memory Used}	_{193,502k (± 0.02%)}	_{193,489k (± 0.01%)}	_~	_193,437k	_193,579k	_{p=0.337 n=20}
_{Memory Allocs}	_{1,317,922 (± 0.01%)}	_{1,317,467 (± 0.02%)}	_{-455 (- 0.03%)}	_1,316,746	_1,318,335	_{p=0.001 n=20}
_{Config Time}	_0.000s	_0.000s	_~	_~	_~	_{p=1.000 n=20}
_{Parse Time}	_{0.042s (± 2.75%)}	_{0.043s (± 2.70%)}	_~	_0.039s	_0.047s	_{p=0.792 n=20}
_{Bind Time}	_{0.020s (± 5.88%)}	_{0.021s (± 5.04%)}	_~	_0.017s	_0.026s	_{p=0.681 n=20}
_{Check Time}	_{0.294s (± 0.82%)}	_{0.288s (± 0.91%)}	_{-0.005s (- 1.87%)}	_0.279s	_0.298s	_{p=0.001 n=20}
_{Emit Time}	_0.000s	_0.000s	_~	_~	_~	_{p=1.000 n=20}
_{Total Time}	_{0.362s (± 0.52%)}	_{0.358s (± 0.70%)}	_{-0.005s (- 1.27%)}	_0.349s	_0.368s	_{p=0.005 n=20}
_{vscode - native}
_Errors	₁₁	₁₁	_~	_~	_~	_{p=1.000 n=20}
_Symbols	_7,495,105	_7,495,105	_~	_~	_~	_{p=1.000 n=20}
_Types	_4,406,091	_4,390,662	_{-15,429 (- 0.35%)}	_~	_~	_{p=0.000 n=20}
_{Memory Used}	_{5,204,759k (± 0.03%)}	_{5,202,723k (± 0.02%)}	_{-2,035k (- 0.04%)}	_5,199,675k	_5,206,401k	_{p=0.023 n=20}
_{Memory Allocs}	_{57,155,141 (± 0.03%)}	_{57,113,196 (± 0.02%)}	_{-41,945 (- 0.07%)}	_57,085,958	_57,178,854	_{p=0.001 n=20}
_{Config Time}	_{0.034s (± 1.28%)}	_{0.034s (± 1.29%)}	_~	_0.033s	_0.035s	_{p=0.666 n=20}
_{Parse Time}	_{0.921s (± 1.77%)}	_{0.926s (± 2.02%)}	_~	_0.869s	_0.999s	_{p=0.805 n=20}
_{Bind Time}	_{0.330s (±12.11%)}	_{0.305s (± 1.16%)}	_~	_0.289s	_0.318s	_{p=0.783 n=20}
_{Check Time}	_{8.350s (± 1.20%)}	_{8.233s (± 1.10%)}	_~	_7.985s	_8.561s	_{p=0.059 n=20}
_{Emit Time}	_{2.824s (± 4.55%)}	_{2.792s (± 2.67%)}	_~	_2.659s	_3.369s	_{p=0.703 n=20}
_{Total Time}	_{12.517s (± 1.45%)}	_{12.346s (± 1.13%)}	_~	_11.958s	_12.957s	_{p=0.134 n=20}
_{webpack - native}
_Errors	₆₁₆	₆₁₆	_~	_~	_~	_{p=1.000 n=20}
_Symbols	_917,188	_917,188	_~	_~	_~	_{p=1.000 n=20}
_Types	_636,859	_623,227	_{-13,632 (- 2.14%)}	_~	_~	_{p=0.000 n=20}
_{Memory Used}	_{693,459k (± 0.01%)}	_{691,671k (± 0.01%)}	_{-1,788k (- 0.26%)}	_691,398k	_692,021k	_{p=0.000 n=20}
_{Memory Allocs}	_{6,499,966 (± 0.04%)}	_{6,482,229 (± 0.03%)}	_{-17,737 (- 0.27%)}	_6,475,185	_6,495,212	_{p=0.000 n=20}
_{Config Time}	_0.004s	_0.004s	_~	_~	_~	_{p=1.000 n=20}
_{Parse Time}	_{0.136s (± 3.02%)}	_{0.141s (± 3.40%)}	_~	_0.121s	_0.161s	_{p=0.125 n=20}
_{Bind Time}	_{0.045s (± 9.51%)}	_{0.046s (±11.92%)}	_~	_0.037s	_0.074s	_{p=0.642 n=20}
_{Check Time}	_{1.124s (± 0.58%)}	_{1.103s (± 0.36%)}	_{-0.021s (- 1.90%)}	_1.084s	_1.114s	_{p=0.000 n=20}
_{Emit Time}	_0.000s	_0.000s	_~	_~	_~	_{p=1.000 n=20}
_{Total Time}	_{1.333s (± 0.54%)}	_{1.317s (± 0.51%)}	_{-0.016s (- 1.22%)}	_1.294s	_1.354s	_{p=0.002 n=20}
_{xstate-main - native}
_Errors	₀	₀	_~	_~	_~	_{p=1.000 n=20}
_Symbols	_640,490	_640,490	_~	_~	_~	_{p=1.000 n=20}
_Types	_387,984	_387,726	_{-258 (- 0.07%)}	_~	_~	_{p=0.000 n=20}
_{Memory Used}	_{350,933k (± 0.03%)}	_{350,827k (± 0.02%)}	_~	_350,633k	_351,108k	_{p=0.063 n=20}
_{Memory Allocs}	_{3,994,723 (± 0.10%)}	_{3,991,730 (± 0.08%)}	_~	_3,978,568	_4,005,354	_{p=0.512 n=20}
_{Config Time}	_0.001s	_0.001s	_~	_~	_~	_{p=1.000 n=20}
_{Parse Time}	_{0.061s (± 3.10%)}	_{0.062s (± 3.13%)}	_~	_0.055s	_0.068s	_{p=0.973 n=20}
_{Bind Time}	_{0.021s (±10.53%)}	_{0.020s (± 8.09%)}	_~	_0.017s	_0.028s	_{p=0.916 n=20}
_{Check Time}	_{0.416s (± 0.80%)}	_{0.412s (± 0.74%)}	_~	_0.400s	_0.424s	_{p=0.118 n=20}
_{Emit Time}	_0.000s	_0.000s	_~	_~	_~	_{p=1.000 n=20}
_{Total Time}	_{0.504s (± 0.87%)}	_{0.500s (± 0.81%)}	_~	_0.486s	_0.516s	_{p=0.291 n=20}

System info unknown

Hosts

native

Scenarios

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

_Benchmark	_Name	_Iterations
_Current	_pr	₂₀
_Baseline	_baseline	₂₀

Developer Information:

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Jake Bailey (jakebailey) and others added 5 commits October 29, 2026 14:58

Copilot AI balanced review requested due to automatic review settings October 29, 2026 22:38

github-project-automation Bot added this to PR Backlog Oct 29, 2026

typescript-automation Bot assigned Jake Bailey (jakebailey) Oct 29, 2026

github-project-automation Bot moved this to Not started in PR Backlog Oct 29, 2026

typescript-automation Bot added Author: Team For Uncommitted Bug PR for untriaged, rejected, closed or missing bug labels Oct 29, 2026

Copilot started reviewing on behalf of Jake Bailey (jakebailey) October 29, 2026 22:39

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Jake Bailey (jakebailey) added the Domain: Performance Reports of unusually slow behavior label Oct 29, 2026

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Speed up property and index signature lookups - #65043

Speed up property and index signature lookups#65043
Jake Bailey (jakebailey) wants to merge 5 commits into
microsoft:mainfrom
jakebailey:perf/member-lookup

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