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.

Changes

Includes Ditch nodeData interface in favor of generated accessors #64063 as the first, squashed commit
- Replaces the nodeData interface's method dispatch with generated kind-based AST accessors.
- This is another PR's foundation, kept separate so it can be reviewed or removed independently.
- Its gains should not be attributed to the subsequent changes.
Compact checker type headers
- Removes the self-referential interface used to recover each type's concrete representation.
- Saves 16 bytes per type on 64-bit systems and removes redundant GC-visible pointer storage.
Compressed paged link stores
- Replaces pointer-sized page entries with four-byte arena indexes, halving entry storage on 64-bit systems and making the page tables pointer-free.
- Presence checks avoid resolving an index when only a boolean is needed.
Batched allocations of common checker types
- Uses typed arenas for frequently allocated type records, reducing small-object allocation overhead.
- Blocks remain independently collectible rather than giving every type the lifetime of the entire checker.
Presized type-list cache keys
- Reserves the known encoded size instead of repeatedly growing temporary buffers.
- For a 4,096-element key, allocations fall 13 → 1 and allocated bytes fall 77.85%.
- Small keys retain their allocation-free path.
Reusable union/intersection normalization scratch
- Avoids allocating temporary constituent lists on interning-cache hits, while preserving independent ownership of published types.
- The fresh parse/bind/check fixture used 8.51% fewer allocated bytes and 18.26% fewer allocations.
- Retained heap was effectively unchanged.
Compact type mappers and coallocated inference mappers
- Removes mapper interfaces and places an inference context's two mappers in one allocation.
- The fixture used 3.90% fewer allocations.
- VS Code allocations fell 28.52M → 27.17M, with retained heap effectively unchanged.
Cold value-symbol metadata
- Moves write types, computed name types, and containing types into an optional arena-backed sidecar.
- The current hot record is 32 bytes versus main's 48 bytes.
- Historical VS Code measurements showed 3.09% less retained heap, 3.33% less GC scanning, and 2.54% fewer allocated bytes.
Compact member indexes
- Reuses ordered property lists instead of retaining duplicate name-to-symbol maps.
- Small types need no index; larger types use pointer-free integer slots, with map fallbacks where required.
- VS Code measurements showed 7.61% less retained heap and 9.89% less GC scanning.
Direct embedded AST headers
- Removes the remaining self-referential interface from each node, recovering concrete nodes from their offset-zero headers.
- Node headers shrink 48 → 32 bytes.
- Beyond the generated-accessor foundation, VS Code measurements showed 7.18% less retained heap, 8.00% less GC scanning, and 5.41% fewer allocated bytes.
Cold symbol metadata
- Moves optional members, exports, and export-symbol links out of common symbol records.
- SymbolWithData shrinks 104 → 88 bytes.
- VS Code measurements showed 1.21% less retained heap and 1.34% less GC scanning.
Cold structured-type metadata
- Moves signatures, index information, and the abstract-constructor cache into optional storage.
- StructuredType shrinks 144 → 88 bytes.
- Historical VS Code measurements showed 1.81% less retained heap and 2.01% less GC scanning.
- Retains ordinary eager member resolution, not Resolve instantiated object members through a shared worker #64735's worker.
Cold type-node and signature metadata
- Moves optional outer type parameters out of type-node links (32 → 16 bytes).
- Moves optional signature state out of signatures (128 → 80 bytes).
- Historical VS Code retained-heap reductions were 0.43% and 0.65%, respectively.
Byte-sized arena chunks
- Targets approximately 512 bytes per typed-arena chunk instead of 256 objects, reducing unused capacity and dead objects retained by surviving pointers.
- VS Code measurements showed 8.54% less retained heap, 10.44% less GC scanning, and 9.43% fewer instructions.
- The tradeoff is 13.91% more allocation events.
Indexed type-node and signature caches
- Replaces two pointer-keyed maps with the existing paged node-link stores, preserving fallback behavior for other IDs.
- VS Code measurements showed 1.20% less retained heap, 2.12% less GC scanning, and 2.11% fewer allocated bytes.
Exact ordinary relationship-cache keys
- Stores ordinary comparisons as 64-bit type-ID pairs rather than 128-bit hashes.
- Retains full-width hashes for generic normalization.
- VS Code measurements showed 0.94% less retained heap and 1.29% fewer allocated bytes.
Shared union/intersection property-cache entries
- Shares complete entries between augmented and non-augmented lookup modes without merging genuinely different results.
- MUI measurements showed 8.15% less retained heap, 9.22% less GC scanning, and 4.45% fewer allocated bytes.
- The production CLI measured 2.60% fewer instructions.
- VS Code savings were much smaller.
Reusable intersection property-count tables
- Reuses bounded, checker-local temporary tables while preserving property order and recursive isolation.
- MUI measurements showed 26.64% fewer allocated bytes, 7.59% fewer allocations, and 8.88% fewer production CLI instructions.
- Retained heap did not materially change.
- The warmed regression case goes 21 allocations → 0.
Mechanically enforced unsafe-layout invariants
- Adds generated factory-kind guards, exhaustive construction/cast tests, and a type-aware analyzer guarding construction, retagging, header copying, and unsafe-cast boundaries.
- Declaration emit now constructs ordinary imports instead of retagging JSDoc imports.
- Protects the compact layouts without adding a physical-layout tag to every AST node.
Coverage-build disk mitigation and supporting cleanup
- Omits DWARF generation in non-debug coverage builds to counter Go 1.27's duplicated promoted wrappers.
- Normal production builds and coverage instrumentation are unchanged.
- Makes the union-property regression independent of embedded libraries and includes formatting/import fixes.

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:

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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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Dynamic interface dispatch obscures the concrete AST layout and adds indirection to frequently used compiler accessors. Generated kind-based dispatch keeps those access paths explicit and checked against the node schema. Keep the method-generation foundation together so it can be reviewed or removed independently of the subsequent storage optimizations.

Each type carries a self-referential interface solely to recover its concrete representation. That costs space in every type and adds GC pointer work even though the representation is fixed at construction. A compact concrete-kind tag saves 16 bytes per type on 64-bit hosts. Keep it separate from mutable semantic flags so casts stay valid as checking discovers more information.

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.

Common type representations create many small heap objects during checking, adding allocator and GC bookkeeping costs. Use the existing bounded typed arenas for frequently allocated types. Unlike an arena that owns the entire graph, old blocks can still be reclaimed when no live type references them.

Large type lists repeatedly grow temporary hash buffers even though their encoded length is already known. These discarded allocations account for a substantial part of checker allocation traffic. Reserve enough capacity before writing each list, retaining the small inline path and the exact existing hash byte stream. Allocation tests cover the inline boundary and large lists, and a fresh-program benchmark includes parsing and binding rather than relying only on warmed ASTs. CPU wall timings are noisy on this machine; report bytes and allocation counts instead. goos: linux goarch: amd64 pkg: github.com/microsoft/TypeScript/tsc/internal/checker cpu: Intel(R) Core(TM) i9-10900K CPU @ 3.70GHz │ key-before.txt │ key-reserve.txt │ │ B/op │ B/op vs base │ TypeListKey/8-20 0.000 ± 0% 0.000 ± 0% ~ (p=1.000 n=6) ¹ TypeListKey/46-20 0.000 ± 0% 0.000 ± 0% ~ (p=1.000 n=6) ¹ TypeListKey/47-20 576.0 ± 0% 208.0 ± 0% -63.89% (p=0.002 n=6) TypeListKey/256-20 2.375Ki ± 0% 1.125Ki ± 0% -52.63% (p=0.002 n=6) TypeListKey/4096-20 81.25Ki ± 0% 18.00Ki ± 0% -77.85% (p=0.002 n=6) geomean ² -48.03% ² ¹ all samples are equal ² summaries must be >0 to compute geomean │ key-before.txt │ key-reserve.txt │ │ allocs/op │ allocs/op vs base │ TypeListKey/8-20 0.000 ± 0% 0.000 ± 0% ~ (p=1.000 n=6) ¹ TypeListKey/46-20 0.000 ± 0% 0.000 ± 0% ~ (p=1.000 n=6) ¹ TypeListKey/47-20 2.000 ± 0% 1.000 ± 0% -50.00% (p=0.002 n=6) TypeListKey/256-20 4.000 ± 0% 1.000 ± 0% -75.00% (p=0.002 n=6) TypeListKey/4096-20 13.000 ± 0% 1.000 ± 0% -92.31% (p=0.002 n=6) geomean ² -60.50% ² ¹ all samples are equal ² summaries must be >0 to compute geomean

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 linter rewrites integer formatting calls without updating their imports. Keep the corrected test code buildable with strconv.

Union and intersection normalization creates temporary lists even when an equivalent type already exists. Mapping and narrowing repeat this work throughout checking, producing unnecessary garbage. Reentrant, bounded workspaces let canonicalization reuse that storage while published types and subtype-reduction caches retain independently owned constituents. Fresh parse, bind, and check of the compiler fixture (six samples): │ before │ after │ │ B/op │ B/op vs base │ CheckFreshProgram-20 303.0Mi 277.2Mi -8.51% (p=0.002 n=6) │ before │ after │ │ allocs/op │ allocs/op vs base │ CheckFreshProgram-20 1.393M 1.139M -18.26% (p=0.002 n=6) VS Code src: identical diagnostics and compiler counts, 31.01M to 28.52M allocations. One fixed-work instruction sample fell from 344.57B to 324.08B; timing is noisy and not evidence of a reliable wall-time gain. Retained memory was effectively unchanged at 5.38 GiB. npx hereby validate passed; focused ownership tests also passed with race and checkptr instrumentation.

Every mapper currently carries a self-referential interface, and each inference context separately allocates two mappers with the same lifetime. A concrete kind header eliminates the interface and lets inference contexts own their fixing and non-fixing mappers in one allocation. Fresh parse, bind, and check versus reusable normalization workspaces: │ before │ after │ │ B/op │ B/op vs base │ CheckFreshProgram-20 277.2Mi 276.0Mi -0.44% (p=0.002 n=6) │ before │ after │ │ allocs/op │ allocs/op vs base │ CheckFreshProgram-20 1.139M 1.094M -3.90% (p=0.002 n=6) VS Code allocations decrease from 28.52M to 27.17M with identical compiler counts and diagnostics. Retained memory is effectively unchanged. Three interleaved fixture runs show fewer fixed-work instructions, but a single VS Code run is noisy; no wall-time claim is made. npx hereby validate and focused race/checkptr tests passed.

Most value symbols never need write types, computed names, or containing types. These three pointers nevertheless occupy every checker link record, which is the largest retained allocation on the VS Code workload. Allocate that metadata only when it is used, shrinking the hot record from 56 to 40 bytes without changing symbol identity or cache semantics. VS Code src, six samples versus compact inference mappers: │ before │ after │ │ retained-B │ retained-B vs base │ ExternalProgram-20 5.029Gi 4.874Gi -3.09% (p=0.002 n=6) │ before │ after │ │ scan-B │ scan-B vs base │ ExternalProgram-20 4.664Gi 4.508Gi -3.33% (p=0.002 n=6) │ before │ after │ │ B/op │ B/op vs base │ ExternalProgram-20 6.200Gi 6.043Gi -2.54% (p=0.002 n=6) Allocation count is unchanged. All 321 semantic diagnostics and all 10284 files are identical. CLI diagnostic text and compiler counts match exactly as well. No GC tuning is used. npx hereby validate and focused race/checkptr ownership tests passed.

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. npx hereby validate and focused race/checkptr tests passed. Existing compiler and editor baselines are unchanged, including recursive CommonJS member resolution.

Every node retains a self-referential interface even though its concrete allocation embeds the node header and its kind already selects dispatch. Across the VS Code source tree, that redundant metadata keeps hundreds of megabytes live and exposes another pointer per node to the collector. Remove the redundant reference without compressing parent or child pointers. The node header shrinks from 48 to 32 bytes on amd64, while generated casts check the concrete kind and enforce offset-zero embedding at compile time. Direct pointers preserve cheap navigation and do not introduce factory-wide ownership or cross-factory lookup tables. Baseline: 70510c0, which already includes the existing generated nodeData accessor work and all preceding checker optimizations. These numbers do not attribute the accessor foundation's gains to this change. VS Code src, six interleaved fresh-process samples: goos: linux goarch: amd64 pkg: github.com/microsoft/TypeScript/tsc/internal/checker cpu: Intel(R) Core(TM) i9-10900K CPU @ 3.70GHz │ vscode-direct-node-foundation.txt │ vscode-direct-node.txt │ │ retained-B │ retained-B vs base │ ExternalProgram-20 4.504Gi ± 0% 4.180Gi ± 0% -7.18% (p=0.002 n=6) │ vscode-direct-node-foundation.txt │ vscode-direct-node.txt │ │ scan-B │ scan-B vs base │ ExternalProgram-20 4.063Gi ± 0% 3.738Gi ± 0% -8.00% (p=0.002 n=6) │ vscode-direct-node-foundation.txt │ vscode-direct-node.txt │ │ B/op │ B/op vs base │ ExternalProgram-20 5.983Gi ± 0% 5.659Gi ± 0% -5.41% (p=0.002 n=6) │ vscode-direct-node-foundation.txt │ vscode-direct-node.txt │ │ allocs/op │ allocs/op vs base │ ExternalProgram-20 26.04M ± 0% 26.05M ± 0% ~ (p=0.589 n=6) │ direct-node-foundation-instructions.txt │ direct-node-instructions.txt │ │ instructions/op │ instructions/op vs base │ ExternalProgram-20 315.0G ± 5% 302.7G ± 4% ~ (p=0.132 n=6) Instruction counts are statistically inconclusive on this noisy machine. All 321 semantic diagnostics and 10284 files are unchanged. CLI diagnostic text and symbol, type, and instantiation counts match exactly. No GC settings are changed. npx hereby validate --all passed. Compiler and editor baselines remain unchanged. Focused race/checkptr checks cover layout, wrong-kind casts, canonical token representations, shared kinds, cloning, and GC reachability.

Most symbols do not need members, exports, or an export-symbol link. Keeping all three pointers in every symbol's shared metadata charges every property, parameter, and synthetic symbol for those features. Move them into optional shared metadata, reducing SymbolWithData from 104 to 88 bytes on amd64. Binder- and checker-owned typed arenas batch the sidecars without adding an allocator pointer to every symbol. Shared symbolData still sees sidecars created through either alias. Compared with 823a64b, which already includes the checker storage and direct-header AST changes. Six fresh-process interleaved samples parse, bind, and check ../vscode/src with the same single checker and normal GC settings. Both workloads report 321 diagnostics, 10284 files. Exact CLI diagnostics and compiler counts also match. CPU timings are noisy. Hardware instructions and allocation counts show no statistically established difference; do not claim CPU gains. Validation: npx hereby validate --all passed. Focused symbol tests also passed with -race and -gcflags=all=-d=checkptr=2. goos: linux goarch: amd64 pkg: github.com/microsoft/TypeScript/tsc/internal/checker cpu: Intel(R) Core(TM) i9-10900K CPU @ 3.70GHz │ vscode-symbol-batched-before.txt │ vscode-symbol-batched.txt │ │ retained-B │ retained-B vs base │ ExternalProgram-20 4.180Gi ± 0% 4.129Gi ± 0% -1.21% (p=0.002 n=6) │ vscode-symbol-batched-before.txt │ vscode-symbol-batched.txt │ │ scan-B │ scan-B vs base │ ExternalProgram-20 3.738Gi ± 0% 3.687Gi ± 0% -1.34% (p=0.002 n=6) │ vscode-symbol-batched-before.txt │ vscode-symbol-batched.txt │ │ B/op │ B/op vs base │ ExternalProgram-20 5.659Gi ± 2% 5.606Gi ± 0% -0.93% (p=0.002 n=6) │ vscode-symbol-batched-before.txt │ vscode-symbol-batched.txt │ │ allocs/op │ allocs/op vs base │ ExternalProgram-20 26.06M ± 2% 26.08M ± 0% ~ (p=0.310 n=6) │ symbol-batched-before-instructions.txt │ symbol-batched-instructions.txt │ │ instructions/op │ instructions/op vs base │ ExternalInstructions-20 302.1G ± 4% 299.9G ± 3% ~ (p=0.589 n=6)

Every object, union, and intersection paid for signature and index-info slice headers, a call-signature count, and a node-builder cache, even when none were needed. Those fields made StructuredType 144 bytes on amd64. Keep them in an optional checker-arena sidecar and reduce the hot record to 88 bytes. Preserve signature publication during recursive anonymous resolution, clipped public signature slices, index-info nil/empty distinctions, and independent node-builder cache identity. Empty unresolved shape does not allocate a sidecar. Compared with 1ef0b40, including unified member resolution and all previous checker, AST, and symbol reductions. Six fresh-process interleaved samples parse, bind, and check the actual VS Code project using one checker and normal GC settings. Live heap falls another 1.81%, GC scan bytes fall 2.01%, and allocated bytes fall 1.28%. Allocation counts do not differ significantly. Neither hardware instructions nor elapsed time establishes a change; this does not claim a CPU improvement. Exact CLI diagnostic text and compiler counts match the baseline. Validation passed: npx hereby validate --all, plus focused checker tests with -race and -gcflags=all=-d=checkptr=2. Exact benchstat output: goos: linux goarch: amd64 pkg: github.com/microsoft/TypeScript/tsc/internal/checker cpu: Intel(R) Core(TM) i9-10900K CPU @ 3.70GHz │ vscode-shape-before.txt │ vscode-shape.txt │ │ sec/op │ sec/op vs base │ ExternalProgram-20 41.55 ± 6% 41.84 ± 13% ~ (p=0.937 n=6) │ vscode-shape-before.txt │ vscode-shape.txt │ │ diagnostics │ diagnostics vs base │ ExternalProgram-20 321.0 ± 0% 321.0 ± 0% ~ (p=1.000 n=6) ¹ ¹ all samples are equal │ vscode-shape-before.txt │ vscode-shape.txt │ │ files │ files vs base │ ExternalProgram-20 10.28k ± 0% 10.28k ± 0% ~ (p=1.000 n=6) ¹ ¹ all samples are equal │ vscode-shape-before.txt │ vscode-shape.txt │ │ retained-B │ retained-B vs base │ ExternalProgram-20 3.959Gi ± 0% 3.887Gi ± 0% -1.81% (p=0.002 n=6) │ vscode-shape-before.txt │ vscode-shape.txt │ │ scan-B │ scan-B vs base │ ExternalProgram-20 3.553Gi ± 0% 3.482Gi ± 0% -2.01% (p=0.002 n=6) │ vscode-shape-before.txt │ vscode-shape.txt │ │ symbols │ symbols vs base │ ExternalProgram-20 4.154M ± 0% 4.154M ± 0% ~ (p=1.000 n=6) ¹ ¹ all samples are equal │ vscode-shape-before.txt │ vscode-shape.txt │ │ B/op │ B/op vs base │ ExternalProgram-20 5.577Gi ± 0% 5.506Gi ± 0% -1.28% (p=0.002 n=6) │ vscode-shape-before.txt │ vscode-shape.txt │ │ allocs/op │ allocs/op vs base │ ExternalProgram-20 27.36M ± 0% 27.35M ± 0% ~ (p=0.818 n=6) │ shape-before-instructions.txt │ shape-instructions.txt │ │ instructions/op │ instructions/op vs base │ ExternalInstructions-20 292.5G ± 4% 301.6G ± 4% ~ (p=0.093 n=6)

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 1d11625, 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. Compiler, fourslash, unit, focused race/checkptr tests, and hereby validate --all pass. 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 efe6e90, 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. Full compiler, fourslash and unit tests, focused race/checkptr tests, and npx hereby validate --all pass. 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. Indexed arenas retain their index layout. No GC settings, cross-file pooling, or pointer decoding are introduced. Six fresh-process interleaved VS Code comparisons against 69d9821, 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. Focused race/checkptr checks and npx hereby validate --all pass, including 166152 Go tests and 954 API tests. 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 e97c4aa, 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. The full compiler, fourslash, and unit suite passes, as do focused race/checkptr checks for 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)

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 27786ef, 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. Focused race/checkptr checks and npx hereby validate --all pass, including 166156 Go tests and 954 API tests. 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 72f191f, 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. Focused race/checkptr and npx hereby validate --all pass, including 166172 Go tests and 954 API tests. Temporary profiling helpers are not part of the 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%

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 parent 6801884, 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. Validation passed: focused race and checkptr tests, and npx hereby validate --all (166175 Go tests and 954 API tests). 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 function-augmentation regression needs the global callable function shape, but its virtual filesystem cannot read the on-disk libraries in noembed builds. The inherited call property is therefore absent in that configuration, causing CI to fail before exercising the cache invariant. Both configurations need the same explicit function shape to exercise the intended property-lookup and enumeration behavior.

Go 1.27 duplicates promoted AST wrappers, making whole-module coverage builds exhaust ARM64 CI disk quotas. Test executables discard DWARF, but temporary and cached object archives still retain it. Avoid generating discarded metadata to restore disk headroom without changing coverage or production compiler behavior. Keep DWARF available for explicitly requested debug runs.

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:

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typescript-automation Bot assigned Jake Bailey (jakebailey) Oct 11, 2026

typescript-automation Bot added Author: Team For Uncommitted Bug PR for untriaged, rejected, closed or missing bug labels Oct 11, 2026

Jake Bailey (jakebailey) requested a balanced review from Copilot October 12, 2026 16:41

Copilot started reviewing on behalf of Jake Bailey (jakebailey) October 12, 2026 16:42 View session

Copilot AI reviewed Oct 12, 2026

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Jake Bailey (jakebailey) added 5 commits October 12, 2026 15:50

Jake Bailey (jakebailey) added 20 commits October 12, 2026 15:50

Format checker type casts

c803170

Update imports for integer-format lint fixes

7fb7c36

The linter rewrites integer formatting calls without updating their imports. Keep the corrected test code buildable with strconv.

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

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