Skip non-scope ancestors quickly in NameResolver.Resolve by jakebailey · Pull Request #65017 · microsoft/TypeScript

Jake Bailey (jakebailey) · 2026-10-29T19:56:03Z

Resolve walks every ancestor of the reference location, and for each one it fetches locals, evaluates getIsDeferredContext, runs a large switch on the kind, and checks isSelfReferenceLocation. Most ancestors (expressions, statements, type nodes, and so on) are not scopes, so all of that work does nothing for them.

Classify node kinds up front: kinds that the loop body never acts on are climbed past directly, and simple block-like scopes (blocks, loops, case blocks, catch clauses, mapped types) only need a plain lookup in their locals. Everything else, including any locals container not explicitly listed, still runs the full loop body, so resolution results are unchanged. A const name keeps using the full path since every ancestor must be checked for a const assertion.

Thanks Steven (@teamchong) for finding this!

Resolve walks every ancestor of the reference location, and for each one it fetches locals, evaluates getIsDeferredContext, runs a large switch on the kind, and checks isSelfReferenceLocation. Most ancestors (expressions, statements, type nodes, and so on) are not scopes, so all of that work does nothing for them. Classify node kinds up front: kinds that the loop body never acts on are climbed past directly, and simple block-like scopes (blocks, loops, case blocks, catch clauses, mapped types) only need a plain lookup in their locals. Everything else, including any locals container not explicitly listed, still runs the full loop body, so resolution results are unchanged. A `const` name keeps using the full path since every ancestor must be checked for a const assertion. Co-authored-by: Steven Chong <25894545+teamchong@users.noreply.github.com>

Jake Bailey (jakebailey) · 2026-10-29T19:56:17Z

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

typescript-automation · 2026-10-29T19:56:22Z

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

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

Copilot

🟢 Approval recommended

The ancestor-traversal optimization has no active review issues blocking approval.

No open issues 🎉

What changed in this PR

This PR optimizes ancestor traversal in the native compiler’s name resolver by skipping work for nodes that do not affect name resolution.

Changes:

Classifies node kinds into skip, locals-only lookup, or full-resolution paths.
Preserves full traversal for const names and special-case scopes.
Adds a kind-based helper for identifying locals containers.

File	Description
`tsc/internal/binder/nameresolver.go`	Adds node-kind classification and fast paths for ancestor traversal.
`tsc/internal/ast/ast.go`	Adds `IsLocalsContainerKind` to support scope classification.

_{Review effort: Balanced}

typescript-automation · 2026-10-29T20:48:03Z

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	_79,607	_~	_~	_~	_{p=1.000 n=20}
_{Memory Used}	_{104,136k (± 0.03%)}	_{104,127k (± 0.03%)}	_~	_104,034k	_104,253k	_{p=0.482 n=20}
_{Memory Allocs}	_{1,263,758 (± 0.01%)}	_{1,263,788 (± 0.01%)}	_~	_1,263,543	_1,264,122	_{p=0.794 n=20}
_{Config Time}	_0.000s	_0.000s	_~	_~	_~	_{p=1.000 n=20}
_{Parse Time}	_{0.023s (± 3.52%)}	_{0.023s (± 2.59%)}	_~	_0.021s	_0.025s	_{p=0.918 n=20}
_{Bind Time}	_{0.009s (± 5.21%)}	_{0.009s (± 6.10%)}	_~	_0.007s	_0.011s	_{p=0.916 n=20}
_{Check Time}	_{0.216s (± 0.74%)}	_{0.214s (± 0.70%)}	_~	_0.207s	_0.220s	_{p=0.144 n=20}
_{Emit Time}	_{0.140s (± 0.80%)}	_{0.140s (± 1.15%)}	_~	_0.130s	_0.146s	_{p=0.772 n=20}
_{Total Time}	_{0.391s (± 0.66%)}	_{0.389s (± 0.39%)}	_~	_0.384s	_0.396s	_{p=0.355 n=20}
_{angular-1 - native}
_Errors	₃	₃	_~	_~	_~	_{p=1.000 n=20}
_Symbols	_{586,484 (± 0.01%)}	_{586,566 (± 0.01%)}	_~	_586,222	_586,926	_{p=0.107 n=20}
_Types	_{241,688 (± 0.00%)}	_{241,688 (± 0.00%)}	_~	_241,683	_241,695	_{p=0.854 n=20}
_{Memory Used}	_{517,888k (± 0.02%)}	_{517,924k (± 0.01%)}	_~	_517,711k	_518,341k	_{p=0.560 n=20}
_{Memory Allocs}	_{7,800,015 (± 0.10%)}	_{7,791,956 (± 0.04%)}	_~	_7,784,890	_7,809,290	_{p=0.060 n=20}
_{Config Time}	_{0.008s (± 2.73%)}	_{0.008s (± 2.79%)}	_~	_0.008s	_0.009s	_{p=1.000 n=20}
_{Parse Time}	_{0.133s (± 4.89%)}	_{0.126s (± 2.23%)}	_~	_0.115s	_0.138s	_{p=0.097 n=20}
_{Bind Time}	_{0.044s (± 9.61%)}	_{0.048s (±10.06%)}	_~	_0.039s	_0.068s	_{p=0.115 n=20}
_{Check Time}	_0s	_0s	_~	_~	_~	_{p=1.000 n=20}
_{Emit Time}	_{0.869s (± 1.47%)}	_{0.860s (± 1.26%)}	_~	_0.822s	_0.893s	_{p=0.516 n=20}
_{Total Time}	_{1.066s (± 1.78%)}	_{1.055s (± 1.40%)}	_~	_1.009s	_1.104s	_{p=0.507 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	_939,467	_~	_~	_~	_{p=1.000 n=20}
_{Memory Used}	_{497,284k (± 0.01%)}	_{497,259k (± 0.01%)}	_~	_497,062k	_497,508k	_{p=0.358 n=20}
_{Memory Allocs}	_{12,107,452 (± 0.01%)}	_{12,108,695 (± 0.01%)}	_~	_12,103,698	_12,118,414	_{p=0.174 n=20}
_{Config Time}	_0.001s	_0.001s	_~	_~	_~	_{p=1.000 n=20}
_{Parse Time}	_{0.041s (± 2.65%)}	_{0.041s (± 3.46%)}	_~	_0.036s	_0.048s	_{p=0.761 n=20}
_{Bind Time}	_{0.012s (± 7.70%)}	_{0.013s (± 9.99%)}	_~	_0.011s	_0.019s	_{p=0.147 n=20}
_{Check Time}	_{0.962s (± 0.58%)}	_{0.962s (± 0.58%)}	_~	_0.937s	_0.985s	_{p=1.000 n=20}
_{Emit Time}	_0.000s	_0.000s	_~	_~	_~	_{p=1.000 n=20}
_{Total Time}	_{1.045s (± 0.47%)}	_{1.046s (± 0.44%)}	_~	_1.023s	_1.066s	_{p=0.654 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	_7,573	_~	_~	_~	_{p=1.000 n=20}
_{Memory Used}	_{27,841k (± 0.02%)}	_{27,837k (± 0.02%)}	_~	_27,818k	_27,850k	_{p=0.273 n=20}
_{Memory Allocs}	_{248,693 (± 0.06%)}	_{248,722 (± 0.06%)}	_~	_248,123	_249,244	_{p=0.602 n=20}
_{Config Time}	_0.000s	_0.000s	_~	_~	_~	_{p=1.000 n=20}
_{Parse Time}	_{0.012s (± 3.12%)}	_{0.012s (± 4.26%)}	_~	_0.010s	_0.016s	_{p=0.116 n=20}
_{Bind Time}	_{0.004s (±12.97%)}	_{0.003s (± 9.17%)}	_~	_0.002s	_0.005s	_{p=0.098 n=20}
_{Check Time}	_{0.008s (± 5.03%)}	_{0.008s (± 5.87%)}	_~	_0.006s	_0.009s	_{p=0.929 n=20}
_{Emit Time}	_{0.008s (± 6.34%)}	_{0.009s (±11.26%)}	_~	_0.007s	_0.016s	_{p=0.749 n=20}
_{Total Time}	_{0.033s (± 2.84%)}	_{0.033s (± 3.43%)}	_~	_0.029s	_0.039s	_{p=0.738 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	_894,113	_~	_~	_~	_{p=1.000 n=20}
_{Memory Used}	_{940,649k (± 0.02%)}	_{940,392k (± 0.02%)}	_~	_939,958k	_941,222k	_{p=0.052 n=20}
_{Memory Allocs}	_{12,670,742 (± 0.02%)}	_{12,669,941 (± 0.03%)}	_~	_12,661,667	_12,703,019	_{p=0.086 n=20}
_{Config Time}	_0.002s	_{0.002s (± 5.09%)}	_~	_0.002s	_0.003s	_{p=1.000 n=20}
_{Parse Time}	_{0.152s (± 1.57%)}	_{0.150s (± 1.88%)}	_~	_0.140s	_0.161s	_{p=0.393 n=20}
_{Bind Time}	_0.000s	_0.000s	_~	_~	_~	_{p=1.000 n=20}
_{Check Time}	_{0.991s (± 1.26%)}	_{0.989s (± 0.92%)}	_~	_0.960s	_1.021s	_{p=0.984 n=20}
_{Emit Time}	_{0.530s (± 2.54%)}	_{0.526s (± 2.23%)}	_~	_0.481s	_0.557s	_{p=0.723 n=20}
_{Total Time}	_{1.777s (± 0.92%)}	_{1.766s (± 0.91%)}	_~	_1.699s	_1.840s	_{p=0.199 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	_1,355,974	_~	_~	_~	_{p=1.000 n=20}
_{Memory Used}	_{1,836,703k (± 0.07%)}	_{1,837,016k (± 0.08%)}	_~	_1,830,543k	_1,841,369k	_{p=0.620 n=20}
_{Memory Allocs}	_{25,985,950 (± 0.11%)}	_{25,996,784 (± 0.14%)}	_~	_25,885,651	_26,172,247	_{p=0.779 n=20}
_{Config Time}	_0.009s	_0.009s	_~	_~	_~	_{p=1.000 n=20}
_{Parse Time}	_{0.303s (± 2.04%)}	_{0.302s (± 2.12%)}	_~	_0.277s	_0.335s	_{p=0.952 n=20}
_{Bind Time}	_0.001s	_0.001s	_~	_~	_~	_{p=1.000 n=20}
_{Check Time}	_{3.192s (± 0.51%)}	_{3.180s (± 0.50%)}	_~	_3.129s	_3.243s	_{p=0.304 n=20}
_{Emit Time}	_{0.254s (± 1.24%)}	_{0.255s (± 1.02%)}	_~	_0.245s	_0.263s	_{p=0.899 n=20}
_{Total Time}	_{4.263s (± 0.39%)}	_{4.248s (± 0.41%)}	_~	_4.180s	_4.319s	_{p=0.292 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	_2,607,045	_~	_~	_~	_{p=1.000 n=20}
_{Memory Used}	_{2,881,974k (± 0.03%)}	_{2,880,550k (± 0.02%)}	_{-1,424k (- 0.05%)}	_2,878,005k	_2,883,253k	_{p=0.024 n=20}
_{Memory Allocs}	_{75,545,345 (± 0.62%)}	_{75,345,991 (± 0.17%)}	_~	_75,019,885	_75,997,895	_{p=0.799 n=20}
_{Config Time}	_{0.026s (± 0.55%)}	_{0.026s (± 0.87%)}	_~	_0.025s	_0.027s	_{p=0.062 n=20}
_{Parse Time}	_{0.495s (± 4.32%)}	_{0.493s (± 4.35%)}	_~	_0.444s	_0.625s	_{p=0.878 n=20}
_{Bind Time}	_{0.184s (±12.53%)}	_{0.181s (±11.41%)}	_~	_0.147s	_0.262s	_{p=0.920 n=20}
_{Check Time}	_{7.126s (± 0.68%)}	_{7.117s (± 0.85%)}	_~	_6.956s	_7.512s	_{p=0.461 n=20}
_{Emit Time}	_0.000s	_0.000s	_~	_~	_~	_{p=1.000 n=20}
_{Total Time}	_{7.884s (± 0.60%)}	_{7.872s (± 0.90%)}	_~	_7.663s	_8.359s	_{p=0.365 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	_1,158,168	_~	_~	_~	_{p=1.000 n=20}
_{Memory Used}	_{972,281k (± 0.02%)}	_{972,489k (± 0.01%)}	_~	_972,047k	_973,071k	_{p=0.086 n=20}
_{Memory Allocs}	_{13,560,558 (± 0.11%)}	_{13,558,138 (± 0.11%)}	_~	_13,517,352	_13,618,466	_{p=0.841 n=20}
_{Config Time}	_0.008s	_0.008s	_~	_~	_~	_{p=1.000 n=20}
_{Parse Time}	_{0.160s (± 1.73%)}	_{0.164s (± 2.29%)}	_~	_0.148s	_0.177s	_{p=0.089 n=20}
_{Bind Time}	_{0.044s (± 7.40%)}	_{0.046s (±11.44%)}	_~	_0.038s	_0.078s	_{p=0.494 n=20}
_{Check Time}	_{1.516s (± 0.68%)}	_{1.514s (± 0.74%)}	_~	_1.455s	_1.555s	_{p=0.857 n=20}
_{Emit Time}	_0.000s	_0.000s	_~	_~	_~	_{p=1.000 n=20}
_{Total Time}	_{1.745s (± 0.65%)}	_{1.749s (± 0.63%)}	_~	_1.705s	_1.792s	_{p=0.560 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	_438,963	_~	_~	_~	_{p=1.000 n=20}
_{Memory Used}	_{1,165,620k (± 0.35%)}	_{1,164,190k (± 0.21%)}	_~	_1,150,588k	_1,171,482k	_{p=0.862 n=20}
_{Memory Allocs}	_{47,667,286 (± 0.10%)}	_{47,687,194 (± 0.11%)}	_~	_47,458,542	_47,884,059	_{p=0.478 n=20}
_{Config Time}	_{0.002s (± 7.95%)}	_{0.002s (±12.90%)}	_{🟩-0.000s (-20.93%)}	_0.001s	_0.002s	_{p=0.004 n=20}
_{Parse Time}	_{0.141s (± 1.79%)}	_{0.139s (± 1.28%)}	_~	_0.131s	_0.143s	_{p=0.217 n=20}
_{Bind Time}	_0.000s	_0.000s	_~	_~	_~	_{p=1.000 n=20}
_{Check Time}	_{0.807s (± 0.37%)}	_{0.801s (± 0.43%)}	_{-0.006s (- 0.79%)}	_0.787s	_0.816s	_{p=0.005 n=20}
_{Emit Time}	_{0.140s (± 1.45%)}	_{0.140s (± 1.16%)}	_~	_0.134s	_0.148s	_{p=0.586 n=20}
_{Total Time}	_{9.370s (± 0.35%)}	_{9.317s (± 0.34%)}	_{-0.053s (- 0.57%)}	_9.236s	_9.443s	_{p=0.021 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	_196,116	_~	_~	_~	_{p=1.000 n=20}
_{Memory Used}	_{224,609k (± 0.02%)}	_{224,606k (± 0.02%)}	_~	_224,412k	_224,795k	_{p=0.984 n=20}
_{Memory Allocs}	_{2,401,166 (± 0.01%)}	_{2,401,457 (± 0.02%)}	_{+291 (+ 0.01%)}	_2,399,694	_2,402,465	_{p=0.021 n=20}
_{Config Time}	_0.000s	_0.000s	_~	_~	_~	_{p=1.000 n=20}
_{Parse Time}	_{0.051s (± 2.27%)}	_{0.050s (± 2.74%)}	_~	_0.046s	_0.056s	_{p=0.502 n=20}
_{Bind Time}	_0.000s	_0.000s	_~	_~	_~	_{p=1.000 n=20}
_{Check Time}	_{0.396s (± 1.10%)}	_{0.388s (± 0.96%)}	_{-0.007s (- 1.82%)}	_0.374s	_0.403s	_{p=0.024 n=20}
_{Emit Time}	_{0.047s (± 5.01%)}	_{0.050s (± 5.99%)}	_~	_0.042s	_0.060s	_{p=0.099 n=20}
_{Total Time}	_{0.520s (± 0.85%)}	_{0.516s (± 1.06%)}	_~	_0.495s	_0.536s	_{p=0.250 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	_3,040,644	_~	_~	_~	_{p=1.000 n=20}
_{Memory Used}	_{2,433,890k (± 0.03%)}	_{2,433,736k (± 0.02%)}	_~	_2,431,668k	_2,436,496k	_{p=0.799 n=20}
_{Memory Allocs}	_{37,383,968 (± 0.11%)}	_{37,372,662 (± 0.06%)}	_~	_37,320,161	_37,485,763	_{p=0.968 n=20}
_{Config Time}	_0.003s	_0.003s	_~	_~	_~	_{p=1.000 n=20}
_{Parse Time}	_{0.249s (± 2.39%)}	_{0.251s (± 1.63%)}	_~	_0.234s	_0.264s	_{p=0.481 n=20}
_{Bind Time}	_{0.087s (± 9.58%)}	_{0.093s (±12.10%)}	_~	_0.076s	_0.140s	_{p=0.422 n=20}
_{Check Time}	_{7.150s (± 0.31%)}	_{7.174s (± 0.96%)}	_~	_7.036s	_7.773s	_{p=0.931 n=20}
_{Emit Time}	_0.000s	_0.000s	_~	_~	_~	_{p=1.000 n=20}
_{Total Time}	_{7.501s (± 0.30%)}	_{7.532s (± 0.90%)}	_~	_7.388s	_8.120s	_{p=0.542 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	_397,689	_~	_~	_~	_{p=1.000 n=20}
_{Memory Used}	_{331,418k (± 0.01%)}	_{331,404k (± 0.01%)}	_~	_331,212k	_331,620k	_{p=0.883 n=20}
_{Memory Allocs}	_{4,393,683 (± 0.18%)}	_{4,389,224 (± 0.10%)}	_~	_4,378,724	_4,409,572	_{p=0.659 n=20}
_{Config Time}	_{0.001s (± 9.93%)}	_{0.001s (± 9.93%)}	_~	_0.001s	_0.002s	_{p=1.000 n=20}
_{Parse Time}	_{0.040s (± 5.46%)}	_{0.041s (± 4.89%)}	_~	_0.035s	_0.050s	_{p=0.662 n=20}
_{Bind Time}	_{0.014s (±11.40%)}	_{0.014s (±10.04%)}	_~	_0.011s	_0.022s	_{p=0.464 n=20}
_{Check Time}	_{0.578s (± 1.01%)}	_{0.577s (± 1.26%)}	_~	_0.555s	_0.615s	_{p=0.693 n=20}
_{Emit Time}	_0.000s	_0.000s	_~	_~	_~	_{p=1.000 n=20}
_{Total Time}	_{0.653s (± 0.95%)}	_{0.652s (± 1.37%)}	_~	_0.627s	_0.700s	_{p=0.441 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	_181,195	_~	_~	_~	_{p=1.000 n=20}
_{Memory Used}	_{193,522k (± 0.01%)}	_{193,517k (± 0.01%)}	_~	_193,458k	_193,606k	_{p=0.857 n=20}
_{Memory Allocs}	_{1,318,307 (± 0.03%)}	_{1,318,222 (± 0.02%)}	_~	_1,317,450	_1,319,182	_{p=0.947 n=20}
_{Config Time}	_0.000s	_0.000s	_~	_~	_~	_{p=1.000 n=20}
_{Parse Time}	_{0.045s (± 3.69%)}	_{0.045s (± 3.01%)}	_~	_0.041s	_0.051s	_{p=0.282 n=20}
_{Bind Time}	_{0.023s (± 5.85%)}	_{0.023s (± 8.17%)}	_~	_0.018s	_0.034s	_{p=0.430 n=20}
_{Check Time}	_{0.323s (± 1.59%)}	_{0.320s (± 1.81%)}	_~	_0.296s	_0.355s	_{p=0.507 n=20}
_{Emit Time}	_0.000s	_0.000s	_~	_~	_~	_{p=1.000 n=20}
_{Total Time}	_{0.398s (± 1.32%)}	_{0.395s (± 1.88%)}	_~	_0.369s	_0.441s	_{p=0.515 n=20}
_{vscode - native}
_Errors	₁₁	₁₁	_~	_~	_~	_{p=1.000 n=20}
_Symbols	_7,493,593	_7,493,593	_~	_~	_~	_{p=1.000 n=20}
_Types	_4,404,145	_4,404,145	_~	_~	_~	_{p=1.000 n=20}
_{Memory Used}	_{5,199,219k (± 0.02%)}	_{5,199,925k (± 0.02%)}	_~	_5,196,214k	_5,202,860k	_{p=0.341 n=20}
_{Memory Allocs}	_{56,879,799 (± 0.02%)}	_{56,883,072 (± 0.02%)}	_~	_56,859,471	_56,925,075	_{p=0.314 n=20}
_{Config Time}	_{0.037s (± 1.13%)}	_{0.037s (± 1.24%)}	_~	_0.035s	_0.038s	_{p=0.819 n=20}
_{Parse Time}	_{0.941s (± 2.04%)}	_{0.940s (± 2.61%)}	_~	_0.840s	_1.104s	_{p=0.962 n=20}
_{Bind Time}	_{0.327s (± 7.56%)}	_{0.328s (± 7.75%)}	_~	_0.291s	_0.547s	_{p=0.941 n=20}
_{Check Time}	_{7.985s (± 0.95%)}	_{7.962s (± 1.20%)}	_~	_7.486s	_8.306s	_{p=0.516 n=20}
_{Emit Time}	_{2.769s (± 4.39%)}	_{2.799s (± 4.12%)}	_~	_2.577s	_3.706s	_{p=0.317 n=20}
_{Total Time}	_{12.117s (± 1.33%)}	_{12.123s (± 1.55%)}	_~	_11.364s	_13.105s	_{p=0.794 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	_636,859	_~	_~	_~	_{p=1.000 n=20}
_{Memory Used}	_{693,445k (± 0.01%)}	_{693,523k (± 0.01%)}	_~	_693,203k	_693,844k	_{p=0.090 n=20}
_{Memory Allocs}	_{6,498,194 (± 0.03%)}	_{6,499,327 (± 0.04%)}	_~	_6,492,927	_6,511,924	_{p=0.718 n=20}
_{Config Time}	_0.004s	_0.004s	_~	_~	_~	_{p=1.000 n=20}
_{Parse Time}	_{0.139s (± 3.21%)}	_{0.142s (± 2.91%)}	_~	_0.123s	_0.157s	_{p=0.155 n=20}
_{Bind Time}	_{0.044s (± 7.69%)}	_{0.045s (± 8.18%)}	_~	_0.038s	_0.067s	_{p=0.866 n=20}
_{Check Time}	_{1.124s (± 0.43%)}	_{1.118s (± 0.44%)}	_~	_1.098s	_1.135s	_{p=0.097 n=20}
_{Emit Time}	_0.000s	_0.000s	_~	_~	_~	_{p=1.000 n=20}
_{Total Time}	_{1.335s (± 0.47%)}	_{1.334s (± 0.47%)}	_~	_1.312s	_1.372s	_{p=0.654 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	_387,984	_~	_~	_~	_{p=1.000 n=20}
_{Memory Used}	_{350,895k (± 0.01%)}	_{350,934k (± 0.02%)}	_~	_350,721k	_351,179k	_{p=0.763 n=20}
_{Memory Allocs}	_{3,990,548 (± 0.07%)}	_{3,993,311 (± 0.07%)}	_~	_3,986,724	_4,008,293	_{p=0.301 n=20}
_{Config Time}	_0.001s	_{0.001s (±18.96%)}	_~	_0.001s	_0.003s	_{p=1.000 n=20}
_{Parse Time}	_{0.061s (± 2.58%)}	_{0.069s (±28.59%)}	_~	_0.055s	_0.248s	_{p=0.348 n=20}
_{Bind Time}	_{0.021s (±10.14%)}	_{0.021s (± 9.60%)}	_~	_0.017s	_0.030s	_{p=0.728 n=20}
_{Check Time}	_{0.414s (± 0.79%)}	_{0.432s (± 8.56%)}	_~	_0.403s	_0.767s	_{p=0.867 n=20}
_{Emit Time}	_0.000s	_0.000s	_~	_~	_~	_{p=1.000 n=20}
_{Total Time}	_{0.503s (± 0.86%)}	_{0.528s (±10.73%)}	_~	_0.483s	_1.042s	_{p=0.825 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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Ryan Cavanaugh (RyanCavanaugh)

Reviewed at 2545a54. The classification preserves full handling for special scopes, deferred contexts, and self references, updates lastLocation when skipping ancestors, and retains const-assertion traversal. Targeted compiler baselines covering parameter scope, arguments, computed/static members, decorators, infer constraints, and self references passed. No blocking issue found.

Jake Bailey (jakebailey) · 2026-10-30T19:09:15Z

This also seems like virtually no difference...

Copilot AI balanced review requested due to automatic review settings October 29, 2026 19:56

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

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

typescript-automation Bot added the Author: Team label Oct 29, 2026

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

typescript-automation Bot added the For Uncommitted Bug PR for untriaged, rejected, closed or missing bug label Oct 29, 2026

Copilot started reviewing on behalf of Jake Bailey (jakebailey) October 29, 2026 19:56

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

Ryan Cavanaugh (RyanCavanaugh) approved these changes Oct 30, 2026

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github-project-automation Bot moved this from Not started to Needs merge in PR Backlog Oct 30, 2026

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Skip non-scope ancestors quickly in NameResolver.Resolve - #65017

Skip non-scope ancestors quickly in NameResolver.Resolve#65017
Jake Bailey (jakebailey) wants to merge 1 commit into
microsoft:mainfrom
jakebailey:perf/name-resolver-loop

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tsc

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