Ditch nodeData interface in favor of generated accessors by jakebailey · Pull Request #64063 · microsoft/TypeScript

Jake Bailey (jakebailey) · 2026-08-28T03:50:10Z

This ditches the dynamic dispatch with nodeData in place of generated kind switches, like I did with ForEachChild.

Metric	Merge base	Branch	Change
Binary file	24,658,183 B	23,810,311 B	-847,872 B (-3.44%)
Executable `.text`	9,491,153 B	9,366,833 B	-124,320 B (-1.31%)
Go PC/line metadata `.gopclntab`	9,280,667 B	8,583,938 B	-696,729 B (-7.51%)
Go type metadata `.go.type`	3,447,248 B	3,404,384 B	-42,864 B (-1.24%)
Total allocated sections	24,889,383 B	24,043,814 B	-845,569 B (-3.40%)

Metric	Merge base	Branch	Change
Symbols containing `tsc/internal/ast`	6,331	2,682	-3,649 (-57.64%)
AST pointer-receiver methods	5,477	1,819	-3,658 (-66.79%)

It also makes compiling the ast package 5% faster.

Replace nine nodeData interface methods with generated Kind-switch dispatchers to reduce interface method promotion and itab size.

Jake Bailey (jakebailey) · 2026-08-28T03:51:29Z

TypeScript Bot (@typescript-bot) perf test this

typescript-automation · 2026-08-28T03:51:34Z

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

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

Copilot

Pull request overview

Replaces nodeData interface dispatch with generated kind-based AST accessors to reduce binary size and metadata overhead.

Changes:

Generates AST visitor, clone, subtree-fact, and accessor dispatch.
Updates compiler and language-service consumers for the new representation.
Adds canonical token-payload validation and adjusts direct node construction.

Reviewed changes

Copilot reviewed 23 out of 25 changed files in this pull request and generated 1 comment.

Show a summary per file

File	Description
`tools/scripts/tsc/generate-go-ast.ts`	Generates kind-based AST dispatch.
`tools/scripts/tsc/generate-encoder.ts`	Updates generated private-field access.
`tsc/internal/ast/ast.go`	Reworks node storage and common fields.
`tsc/internal/ast/ast_generated.go`	Contains generated factories and dispatch.
`tsc/internal/ast/flow.go`	Adapts synthetic flow-node construction.
`tsc/internal/ast/token_test.go`	Tests canonical token payloads.
`tsc/internal/ast/utilities.go`	Updates type-only checks.
`tsc/internal/api/encoder/encoder.go`	Updates source-file position access.
`tsc/internal/api/encoder/encoder_generated.go`	Updates generated text access.
`tsc/internal/checker/grammarchecks.go`	Uses common node accessors.
`tsc/internal/checker/nodebuilder_hover.go`	Updates optional-token access.
`tsc/internal/ls/autoimport/fix.go`	Updates type-only import access.
`tsc/internal/ls/completions.go`	Updates source-file access.
`tsc/internal/ls/lsutil/organizeimports.go`	Updates import classification.
`tsc/internal/ls/organizeimports.go`	Updates type-only grouping.
`tsc/internal/ls/signaturehelp.go`	Updates type-argument access.
`tsc/internal/parser/reparser.go`	Updates mutable typed-node casts.
`tsc/internal/printer/printer_test.go`	Adapts transformed source-file casts.
`tsc/internal/scanner/scanner_test.go`	Adapts node initialization.
`tsc/internal/transformers/declarations/transform.go`	Updates syntax-list traversal.
`tsc/internal/transformers/estransforms/optionalchain.go`	Updates element-access casting.
`tsc/internal/transformers/moduletransforms/commonjsmodule.go`	Updates common expression/name access.
`tsc/internal/transformers/tstransforms/legacydecorators.go`	Updates decorator access.
`tsc/internal/transformers/tstransforms/runtimesyntax.go`	Updates parameter-list access.
`tsc/internal/transformers/tstransforms/typeeraser.go`	Updates type-only import access.

Files not reviewed (1)

tsc/internal/api/encoder/encoder_generated.go: Generated file

Suppressed comments (1)

tsc/internal/ast/flow.go:74

This node likewise stores *FlowReduceLabelData under KindUnknown, while the generated Clone and subtree-facts switches assert that every KindUnknown payload is *Token. Those methods now panic for reduce-label nodes; previously dynamic dispatch reached NodeDefault. Use a distinct kind or explicitly handle this synthetic payload in dispatch, with a regression test.

	return newNode(KindUnknown, node.AsNode(), node, NodeFactoryHooks{})

typescript-automation · 2026-08-28T04:19:37Z

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	_115,480	_115,480	_~	_~	_~	_{p=1.000 n=12}
_Types	_96,945	_96,945	_~	_~	_~	_{p=1.000 n=12}
_{Memory Used}	_{148,704k (± 0.63%)}	_{148,990k (± 0.61%)}	_~	_146,603k	_150,783k	_{p=0.619 n=12}
_{Memory Allocs}	_{2,271,343 (± 0.00%)}	_{2,271,370 (± 0.01%)}	_~	_2,271,042	_2,271,725	_{p=0.799 n=12}
_{Config Time}	_0.000s	_0.000s	_~	_~	_~	_{p=1.000 n=12}
_{Parse Time}	_{0.050s (± 3.10%)}	_{0.049s (± 2.83%)}	_~	_0.046s	_0.053s	_{p=0.525 n=12}
_{Bind Time}	_{0.016s (±13.70%)}	_{0.017s (±12.12%)}	_~	_0.013s	_0.022s	_{p=0.462 n=12}
_{Check Time}	_{0.593s (± 0.79%)}	_{0.602s (± 0.99%)}	_{+0.009s (+ 1.50%)}	_0.592s	_0.618s	_{p=0.016 n=12}
_{Emit Time}	_{0.331s (± 2.03%)}	_{0.338s (± 1.95%)}	_~	_0.322s	_0.356s	_{p=0.096 n=12}
_{Total Time}	_{0.997s (± 1.07%)}	_{1.013s (± 0.89%)}	_{+0.016s (+ 1.62%)}	_0.993s	_1.038s	_{p=0.011 n=12}
_{angular-1 - native}
_Errors	₃	₃	_~	_~	_~	_{p=1.000 n=12}
_Symbols	_{847,457 (± 0.08%)}	_{847,042 (± 0.06%)}	_~	_845,864	_848,120	_{p=0.242 n=12}
_Types	_{249,852 (± 0.00%)}	_{249,853 (± 0.00%)}	_~	_249,849	_249,862	_{p=0.497 n=12}
_{Memory Used}	_{793,348k (± 0.05%)}	_{793,428k (± 0.06%)}	_~	_791,771k	_794,529k	_{p=0.410 n=12}
_{Memory Allocs}	_{12,951,967 (± 0.02%)}	_{12,954,725 (± 0.04%)}	_~	_12,948,861	_12,981,625	_{p=0.319 n=12}
_{Config Time}	_0.020s	_{0.022s (± 5.61%)}	_{🔻+0.002s (+ 9.17%)}	_0.020s	_0.024s	_{p=0.005 n=12}
_{Parse Time}	_{0.348s (± 2.62%)}	_{0.358s (± 2.93%)}	_~	_0.331s	_0.382s	_{p=0.213 n=12}
_{Bind Time}	_{0.079s (±10.71%)}	_{0.079s (± 1.48%)}	_{+0.000s (+ 0.42%)}	_0.077s	_0.084s	_{p=0.014 n=12}
_{Check Time}	_0s	_0s	_~	_~	_~	_{p=1.000 n=12}
_{Emit Time}	_{1.964s (± 1.37%)}	_{2.067s (± 1.06%)}	_{🔻+0.103s (+ 5.23%)}	_2.020s	_2.117s	_{p=0.000 n=12}
_{Total Time}	_{2.430s (± 1.24%)}	_{2.544s (± 1.07%)}	_{🔻+0.114s (+ 4.68%)}	_2.491s	_2.619s	_{p=0.000 n=12}
_{mui-docs - native}
_Errors	_{11,277 (± 0.03%)}	_{11,274 (± 0.05%)}	_~	_11,256	_11,281	_{p=0.656 n=12}
_Symbols	_4,268,528	_4,268,528	_~	_~	_~	_{p=1.000 n=12}
_Types	_1,593,260	_1,593,260	_~	_~	_~	_{p=1.000 n=12}
_{Memory Used}	_{4,727,424k (± 0.04%)}	_{4,726,863k (± 0.04%)}	_~	_4,722,770k	_4,733,595k	_{p=0.514 n=12}
_{Memory Allocs}	_{47,631,206 (± 0.03%)}	_{47,634,270 (± 0.05%)}	_~	_47,568,063	_47,703,849	_{p=0.977 n=12}
_{Config Time}	_{0.019s (± 1.60%)}	_{0.019s (± 1.60%)}	_~	_0.019s	_0.020s	_{p=1.000 n=12}
_{Parse Time}	_{0.679s (± 2.38%)}	_{0.686s (± 1.47%)}	_~	_0.655s	_0.706s	_{p=0.451 n=12}
_{Bind Time}	_{0.002s (±12.64%)}	_{0.002s (±13.40%)}	_~	_0.002s	_0.003s	_{p=0.667 n=12}
_{Check Time}	_{19.824s (± 0.54%)}	_{19.921s (± 0.51%)}	_~	_19.751s	_20.285s	_{p=0.071 n=12}
_{Emit Time}	_{0.556s (±14.37%)}	_{0.517s (± 0.44%)}	_~	_0.512s	_0.524s	_{p=0.053 n=12}
_{Total Time}	_{22.005s (± 0.72%)}	_{22.063s (± 0.55%)}	_~	_21.839s	_22.492s	_{p=0.443 n=12}
_{strada-build-src - native}
_Errors	₀	₀	_~	_~	_~	_{p=1.000 n=12}
_Symbols	_1,394,252	_1,394,252	_~	_~	_~	_{p=1.000 n=12}
_Types	_443,418	_443,418	_~	_~	_~	_{p=1.000 n=12}
_{Memory Used}	_{1,644,285k (± 0.19%)}	_{1,644,608k (± 0.21%)}	_~	_1,632,450k	_1,651,134k	_{p=0.630 n=12}
_{Memory Allocs}	_{97,050,478 (± 0.03%)}	_{97,054,471 (± 0.03%)}	_~	_96,986,967	_97,119,845	_{p=0.932 n=12}
_{Config Time}	_{0.006s (±11.44%)}	_{0.005s (±16.17%)}	_~	_0.002s	_0.007s	_{p=0.971 n=12}
_{Parse Time}	_{0.236s (± 2.51%)}	_{0.235s (± 2.67%)}	_~	_0.218s	_0.247s	_{p=0.921 n=12}
_{Bind Time}	_0.000s	_0.000s	_~	_~	_~	_{p=1.000 n=12}
_{Check Time}	_{2.158s (± 0.34%)}	_{2.193s (± 0.55%)}	_{+0.036s (+ 1.67%)}	_2.159s	_2.224s	_{p=0.000 n=12}
_{Emit Time}	_{0.328s (± 3.83%)}	_{0.335s (± 6.32%)}	_~	_0.290s	_0.391s	_{p=0.788 n=12}
_{Total Time}	_{29.760s (± 0.46%)}	_{30.237s (± 0.55%)}	_{+0.477s (+ 1.60%)}	_29.761s	_30.659s	_{p=0.000 n=12}
_{strada-compiler - native}
_Errors	₀	₀	_~	_~	_~	_{p=1.000 n=12}
_Symbols	_337,531	_337,531	_~	_~	_~	_{p=1.000 n=12}
_Types	_198,830	_198,830	_~	_~	_~	_{p=1.000 n=12}
_{Memory Used}	_{319,525k (± 0.03%)}	_{319,545k (± 0.02%)}	_~	_319,381k	_319,705k	_{p=0.713 n=12}
_{Memory Allocs}	_{4,672,822 (± 0.01%)}	_{4,672,757 (± 0.01%)}	_~	_4,671,682	_4,673,967	_{p=0.590 n=12}
_{Config Time}	_0.001s	_0.001s	_~	_~	_~	_{p=1.000 n=12}
_{Parse Time}	_{0.112s (± 5.15%)}	_{0.113s (± 4.16%)}	_~	_0.097s	_0.123s	_{p=0.680 n=12}
_{Bind Time}	_0.000s	_0.000s	_~	_~	_~	_{p=1.000 n=12}
_{Check Time}	_{1.039s (± 0.58%)}	_{1.057s (± 0.52%)}	_{+0.019s (+ 1.79%)}	_1.044s	_1.076s	_{p=0.000 n=12}
_{Emit Time}	_{0.131s (±13.99%)}	_{0.142s (±10.03%)}	_~	_0.104s	_0.167s	_{p=0.417 n=12}
_{Total Time}	_{1.341s (± 0.99%)}	_{1.366s (± 0.98%)}	_{+0.024s (+ 1.81%)}	_1.329s	_1.398s	_{p=0.016 n=12}
_{ts-pre-modules - native}
_Errors	₈₇	₈₇	_~	_~	_~	_{p=1.000 n=12}
_Symbols	_305,179	_305,179	_~	_~	_~	_{p=1.000 n=12}
_Types	_181,876	_181,876	_~	_~	_~	_{p=1.000 n=12}
_{Memory Used}	_{277,177k (± 0.02%)}	_{277,249k (± 0.02%)}	_~	_277,119k	_277,401k	_{p=0.058 n=12}
_{Memory Allocs}	_{1,641,802 (± 0.01%)}	_{1,641,776 (± 0.01%)}	_~	_1,641,330	_1,642,158	_{p=0.977 n=12}
_{Config Time}	_0.000s	_{0.000s (±217.90%)}	_~	_0.000s	_0.001s	_{p=1.000 n=12}
_{Parse Time}	_{0.098s (± 4.32%)}	_{0.101s (± 1.97%)}	_{+0.003s (+ 3.06%)}	_0.094s	_0.107s	_{p=0.027 n=12}
_{Bind Time}	_{0.039s (±11.25%)}	_{0.040s (±10.20%)}	_~	_0.033s	_0.054s	_{p=0.432 n=12}
_{Check Time}	_{0.831s (± 0.67%)}	_{0.846s (± 0.38%)}	_{+0.015s (+ 1.79%)}	_0.838s	_0.855s	_{p=0.000 n=12}
_{Emit Time}	_0.000s	_0.000s	_~	_~	_~	_{p=1.000 n=12}
_{Total Time}	_{0.983s (± 0.91%)}	_{1.001s (± 0.42%)}	_{+0.019s (+ 1.92%)}	_0.991s	_1.013s	_{p=0.001 n=12}
_{vscode - native}
_Errors	₃₄₇	₃₄₇	_~	_~	_~	_{p=1.000 n=12}
_Symbols	_8,099,608	_8,099,608	_~	_~	_~	_{p=1.000 n=12}
_Types	_2,787,191	_2,787,191	_~	_~	_~	_{p=1.000 n=12}
_{Memory Used}	_{5,473,265k (± 0.02%)}	_{5,473,514k (± 0.03%)}	_~	_5,470,222k	_5,479,175k	_{p=0.799 n=12}
_{Memory Allocs}	_{42,145,509 (± 0.04%)}	_{42,141,955 (± 0.04%)}	_~	_42,120,291	_42,208,283	_{p=0.843 n=12}
_{Config Time}	_{0.064s (± 0.51%)}	_{0.064s (± 0.28%)}	_~	_0.063s	_0.064s	_{p=1.000 n=12}
_{Parse Time}	_{1.672s (± 1.61%)}	_{1.598s (± 3.19%)}	_{🟩-0.074s (- 4.42%)}	_1.469s	_1.691s	_{p=0.015 n=12}
_{Bind Time}	_{0.351s (± 2.84%)}	_{0.432s (±19.96%)}	_{🔻+0.081s (+23.13%)}	_0.354s	_0.692s	_{p=0.000 n=12}
_{Check Time}	_{10.073s (± 0.87%)}	_{10.107s (± 1.63%)}	_~	_9.712s	_10.376s	_{p=0.630 n=12}
_{Emit Time}	_{3.226s (± 5.89%)}	_{3.789s (±13.24%)}	_{🔻+0.563s (+17.46%)}	_3.103s	_5.028s	_{p=0.006 n=12}
_{Total Time}	_{15.475s (± 0.75%)}	_{16.084s (± 2.40%)}	_{+0.608s (+ 3.93%)}	_15.409s	_17.070s	_{p=0.000 n=12}
_{webpack - native}
_Errors	₅₃₈	₅₃₈	_~	_~	_~	_{p=1.000 n=12}
_Symbols	_857,681	_857,681	_~	_~	_~	_{p=1.000 n=12}
_Types	_394,496	_394,496	_~	_~	_~	_{p=1.000 n=12}
_{Memory Used}	_{656,000k (± 0.02%)}	_{656,131k (± 0.03%)}	_~	_655,790k	_656,556k	_{p=0.266 n=12}
_{Memory Allocs}	_{4,378,603 (± 0.04%)}	_{4,376,261 (± 0.02%)}	_{-2,342 (- 0.05%)}	_4,374,294	_4,379,723	_{p=0.045 n=12}
_{Config Time}	_0.007s	_0.007s	_~	_~	_~	_{p=1.000 n=12}
_{Parse Time}	_{0.173s (± 1.29%)}	_{0.168s (± 3.73%)}	_~	_0.147s	_0.182s	_{p=0.102 n=12}
_{Bind Time}	_{0.033s (± 2.54%)}	_{0.041s (±19.61%)}	_{🔻+0.008s (+23.12%)}	_0.033s	_0.069s	_{p=0.012 n=12}
_{Check Time}	_{1.143s (± 0.65%)}	_{1.158s (± 0.95%)}	_{+0.015s (+ 1.33%)}	_1.122s	_1.173s	_{p=0.005 n=12}
_{Emit Time}	_0.000s	_0.000s	_~	_~	_~	_{p=1.000 n=12}
_{Total Time}	_{1.375s (± 0.43%)}	_{1.394s (± 0.73%)}	_{+0.019s (+ 1.37%)}	_1.364s	_1.420s	_{p=0.002 n=12}
_{xstate-main - native}
_Errors	₀	₀	_~	_~	_~	_{p=1.000 n=12}
_Symbols	_1,022,487	_1,022,487	_~	_~	_~	_{p=1.000 n=12}
_Types	_376,962	_376,962	_~	_~	_~	_{p=1.000 n=12}
_{Memory Used}	_{603,384k (± 0.02%)}	_{603,441k (± 0.01%)}	_~	_603,289k	_603,638k	_{p=0.755 n=12}
_{Memory Allocs}	_{4,754,818 (± 0.04%)}	_{4,755,010 (± 0.04%)}	_~	_4,750,794	_4,759,753	_{p=0.799 n=12}
_{Config Time}	_0.002s	_0.002s	_~	_~	_~	_{p=1.000 n=12}
_{Parse Time}	_{0.117s (± 3.29%)}	_{0.116s (± 4.46%)}	_~	_0.106s	_0.132s	_{p=0.722 n=12}
_{Bind Time}	_{0.035s (±20.33%)}	_{0.035s (±17.12%)}	_~	_0.026s	_0.056s	_{p=0.394 n=12}
_{Check Time}	_{0.853s (± 0.67%)}	_{0.862s (± 0.88%)}	_~	_0.845s	_0.882s	_{p=0.075 n=12}
_{Emit Time}	_0.000s	_0.000s	_~	_~	_~	_{p=1.000 n=12}
_{Total Time}	_{1.015s (± 1.02%)}	_{1.026s (± 1.01%)}	_~	_1.000s	_1.049s	_{p=0.109 n=12}

System info unknown

Hosts

native

Scenarios

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

_Benchmark	_Name	_Iterations
_Current	_pr	₁₂
_Baseline	_baseline	₁₂

lsp

Comparison Report - baseline..pr

_Metric	_baseline	_pr	_Delta	_Best	_Worst	_p-value
_{Compiler-UnionsLSP - native}
_{Req 1 - updateOpen}	_{15ms (± 3.34%)}	_{15ms (± 2.92%)}	_~	_14ms	_16ms	_{p=0.744 n=12}
_{Req 2 - geterr}	_{682ms (± 0.36%)}	_{690ms (± 0.49%)}	_{+7ms (+ 1.09%)}	_679ms	_698ms	_{p=0.001 n=12}
_{Req 3 - references}	_{58ms (± 4.72%)}	_{58ms (± 6.84%)}	_~	_47ms	_63ms	_{p=0.965 n=12}
_{Req 4 - navto}	_{20ms (± 4.17%)}	_{19ms (± 1.60%)}	_~	_19ms	_20ms	_{p=0.052 n=12}
_{Req 5 - completionInfo count}	_1,363	_1,363	_~	_~	_~	_{p=1.000 n=12}
_{Req 5 - completionInfo}	_{19ms (±10.74%)}	_{18ms (± 6.66%)}	_~	_16ms	_21ms	_{p=0.371 n=12}
_{CompilerLSP - native}
_{Req 1 - updateOpen}	_{13ms (± 6.39%)}	_{13ms (± 3.72%)}	_~	_12ms	_14ms	_{p=0.863 n=12}
_{Req 2 - geterr}	_{295ms (± 0.73%)}	_{301ms (± 0.58%)}	_{+6ms (+ 2.09%)}	_298ms	_305ms	_{p=0.000 n=12}
_{Req 3 - references}	_{51ms (± 3.62%)}	_{51ms (± 4.89%)}	_~	_46ms	_56ms	_{p=0.501 n=12}
_{Req 4 - navto}	_{18ms (± 4.47%)}	_{17ms (± 2.95%)}	_~	_16ms	_18ms	_{p=0.309 n=12}
_{Req 5 - completionInfo count}	_1,525	_1,525	_~	_~	_~	_{p=1.000 n=12}
_{Req 5 - completionInfo}	_{17ms (± 8.93%)}	_{18ms (± 6.14%)}	_~	_15ms	_20ms	_{p=0.512 n=12}

System info unknown

Hosts

native

Scenarios

CompilerLSP - native
Compiler-UnionsLSP - native
xstate-main-1-LSP - native

_Benchmark	_Name	_Iterations
_Current	_pr	₁₂
_Baseline	_baseline	₁₂

startup

Comparison Report - baseline..pr

_Metric	_baseline	_pr	_Delta	_Best	_Worst	_p-value
_{lsp-startup - native}
_{Execution time}	_{4.90ms (±365.09%)}	_{4.72ms (±365.09%)}	_{🟩-0.18ms (- 3.72%)}	_0.00ms	_473.73ms	_{p=0.000 n=1200}
_{tsgo-startup - native}
_{Execution time}	_{4.90ms (±365.10%)}	_{4.72ms (±365.10%)}	_{🟩-0.18ms (- 3.67%)}	_0.00ms	_473.43ms	_{p=0.000 n=1200}

System info unknown

Hosts

native

Scenarios

lsp-startup - native
tsgo-startup - native

_Benchmark	_Name	_Iterations
_Current	_pr	₁₂
_Baseline	_baseline	₁₂

Developer Information:

Download Benchmarks

Copilot

Pull request overview

Copilot reviewed 23 out of 26 changed files in this pull request and generated no new comments.

Files not reviewed (2)

tsc/internal/api/encoder/encoder_generated.go: Generated file
tsc/internal/ast/kind_stringer_generated.go: Generated file

This reverts commit 9baebce.

Copilot

Pull request overview

Copilot reviewed 3 out of 5 changed files in this pull request and generated 2 comments.

Files not reviewed (1)

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

Copilot

Pull request overview

Copilot reviewed 3 out of 5 changed files in this pull request and generated no new comments.

Files not reviewed (1)

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

Jake Bailey (jakebailey) · 2026-08-28T19:17:43Z

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

typescript-automation · 2026-08-28T19:17:48Z

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

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

typescript-automation · 2026-08-28T19:51:43Z

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	_115,480	_115,480	_~	_~	_~	_{p=1.000 n=12}
_Types	_96,945	_96,945	_~	_~	_~	_{p=1.000 n=12}
_{Memory Used}	_{148,801k (± 0.59%)}	_{148,573k (± 0.27%)}	_~	_147,180k	_149,422k	_{p=0.671 n=12}
_{Memory Allocs}	_{2,271,201 (± 0.00%)}	_{2,271,221 (± 0.00%)}	_~	_2,271,070	_2,271,526	_{p=0.712 n=12}
_{Config Time}	_0.000s	_0.000s	_~	_~	_~	_{p=1.000 n=12}
_{Parse Time}	_{0.042s (± 4.22%)}	_{0.041s (± 3.79%)}	_~	_0.038s	_0.044s	_{p=0.447 n=12}
_{Bind Time}	_{0.012s (±12.82%)}	_{0.014s (±12.87%)}	_~	_0.011s	_0.019s	_{p=0.133 n=12}
_{Check Time}	_{0.490s (± 0.59%)}	_{0.495s (± 0.54%)}	_{+0.006s (+ 1.12%)}	_0.489s	_0.502s	_{p=0.015 n=12}
_{Emit Time}	_{0.275s (± 1.88%)}	_{0.276s (± 2.08%)}	_~	_0.267s	_0.299s	_{p=0.788 n=12}
_{Total Time}	_{0.825s (± 0.87%)}	_{0.832s (± 0.57%)}	_~	_0.821s	_0.848s	_{p=0.070 n=12}
_{angular-1 - native}
_Errors	₃	₃	_~	_~	_~	_{p=1.000 n=12}
_Symbols	_{847,129 (± 0.09%)}	_{847,066 (± 0.03%)}	_~	_846,619	_847,610	_{p=0.755 n=12}
_Types	_{249,851 (± 0.00%)}	_{249,852 (± 0.00%)}	_~	_249,849	_249,862	_{p=0.532 n=12}
_{Memory Used}	_{793,675k (± 0.07%)}	_{793,710k (± 0.07%)}	_~	_792,077k	_795,418k	_{p=0.899 n=12}
_{Memory Allocs}	_{12,960,998 (± 0.08%)}	_{12,954,499 (± 0.03%)}	_~	_12,948,811	_12,970,489	_{p=0.443 n=12}
_{Config Time}	_0.016s	_0.016s	_~	_~	_~	_{p=1.000 n=12}
_{Parse Time}	_{0.274s (± 2.34%)}	_{0.274s (± 2.61%)}	_~	_0.258s	_0.290s	_{p=0.809 n=12}
_{Bind Time}	_{0.064s (±11.03%)}	_{0.061s (± 0.86%)}	_{🟩-0.003s (- 4.43%)}	_0.060s	_0.063s	_{p=0.035 n=12}
_{Check Time}	_0s	_0s	_~	_~	_~	_{p=1.000 n=12}
_{Emit Time}	_{1.632s (± 1.26%)}	_{1.665s (± 0.42%)}	_{+0.033s (+ 2.03%)}	_1.647s	_1.684s	_{p=0.001 n=12}
_{Total Time}	_{2.004s (± 1.36%)}	_{2.034s (± 0.42%)}	_{+0.030s (+ 1.48%)}	_2.017s	_2.057s	_{p=0.004 n=12}
_{mui-docs - native}
_Errors	_{11,275 (± 0.02%)}	_{11,277 (± 0.03%)}	_~	_11,261	_11,281	_{p=0.128 n=12}
_Symbols	_4,268,528	_4,268,528	_~	_~	_~	_{p=1.000 n=12}
_Types	_1,593,260	_1,593,260	_~	_~	_~	_{p=1.000 n=12}
_{Memory Used}	_{4,729,019k (± 0.03%)}	_{4,727,598k (± 0.03%)}	_~	_4,724,789k	_4,731,504k	_{p=0.128 n=12}
_{Memory Allocs}	_{47,640,618 (± 0.06%)}	_{47,614,236 (± 0.03%)}	_~	_47,586,332	_47,646,477	_{p=0.068 n=12}
_{Config Time}	_0.016s	_{0.016s (± 1.55%)}	_~	_0.015s	_0.016s	_{p=0.478 n=12}
_{Parse Time}	_{0.545s (± 2.60%)}	_{0.542s (± 3.21%)}	_~	_0.484s	_0.575s	_{p=0.832 n=12}
_{Bind Time}	_0.002s	_0.002s	_~	_~	_~	_{p=1.000 n=12}
_{Check Time}	_{16.530s (± 0.35%)}	_{16.442s (± 0.33%)}	_{-0.088s (- 0.53%)}	_16.355s	_16.612s	_{p=0.014 n=12}
_{Emit Time}	_{0.432s (± 0.32%)}	_{0.432s (± 0.39%)}	_~	_0.429s	_0.437s	_{p=0.944 n=12}
_{Total Time}	_{18.291s (± 0.39%)}	_{18.159s (± 0.40%)}	_{-0.133s (- 0.72%)}	_18.033s	_18.359s	_{p=0.014 n=12}
_{strada-build-src - native}
_Errors	₀	₀	_~	_~	_~	_{p=1.000 n=12}
_Symbols	_1,394,252	_1,394,252	_~	_~	_~	_{p=1.000 n=12}
_Types	_443,418	_443,418	_~	_~	_~	_{p=1.000 n=12}
_{Memory Used}	_{1,647,039k (± 0.13%)}	_{1,648,683k (± 0.27%)}	_~	_1,635,913k	_1,660,011k	_{p=0.478 n=12}
_{Memory Allocs}	_{97,040,533 (± 0.02%)}	_{97,070,577 (± 0.03%)}	_~	_96,996,582	_97,132,508	_{p=0.078 n=12}
_{Config Time}	_{0.004s (±11.61%)}	_{0.004s (± 7.59%)}	_~	_0.003s	_0.004s	_{p=0.508 n=12}
_{Parse Time}	_{0.193s (± 2.45%)}	_{0.195s (± 2.64%)}	_~	_0.180s	_0.213s	_{p=0.311 n=12}
_{Bind Time}	_0.000s	_0.000s	_~	_~	_~	_{p=1.000 n=12}
_{Check Time}	_{1.798s (± 0.34%)}	_{1.833s (± 0.41%)}	_{+0.035s (+ 1.96%)}	_1.815s	_1.855s	_{p=0.000 n=12}
_{Emit Time}	_{0.291s (± 3.66%)}	_{0.276s (± 6.19%)}	_~	_0.244s	_0.319s	_{p=0.174 n=12}
_{Total Time}	_{24.678s (± 0.71%)}	_{25.069s (± 0.70%)}	_{+0.390s (+ 1.58%)}	_24.635s	_25.582s	_{p=0.003 n=12}
_{strada-compiler - native}
_Errors	₀	₀	_~	_~	_~	_{p=1.000 n=12}
_Symbols	_337,531	_337,531	_~	_~	_~	_{p=1.000 n=12}
_Types	_198,830	_198,830	_~	_~	_~	_{p=1.000 n=12}
_{Memory Used}	_{319,495k (± 0.03%)}	_{319,537k (± 0.02%)}	_~	_319,342k	_319,747k	_{p=0.713 n=12}
_{Memory Allocs}	_{4,673,004 (± 0.01%)}	_{4,672,826 (± 0.01%)}	_~	_4,671,211	_4,673,631	_{p=0.767 n=12}
_{Config Time}	_0.001s	_0.001s	_~	_~	_~	_{p=1.000 n=12}
_{Parse Time}	_{0.114s (± 4.25%)}	_{0.118s (± 3.82%)}	_~	_0.102s	_0.127s	_{p=0.283 n=12}
_{Bind Time}	_0.000s	_0.000s	_~	_~	_~	_{p=1.000 n=12}
_{Check Time}	_{1.044s (± 0.38%)}	_{1.067s (± 0.52%)}	_{+0.023s (+ 2.19%)}	_1.057s	_1.084s	_{p=0.000 n=12}
_{Emit Time}	_{0.146s (± 8.69%)}	_{0.133s (±12.22%)}	_~	_0.103s	_0.169s	_{p=0.247 n=12}
_{Total Time}	_{1.355s (± 0.95%)}	_{1.372s (± 1.03%)}	_~	_1.348s	_1.414s	_{p=0.080 n=12}
_{ts-pre-modules - native}
_Errors	₈₇	₈₇	_~	_~	_~	_{p=1.000 n=12}
_Symbols	_305,179	_305,179	_~	_~	_~	_{p=1.000 n=12}
_Types	_181,876	_181,876	_~	_~	_~	_{p=1.000 n=12}
_{Memory Used}	_{277,161k (± 0.03%)}	_{277,189k (± 0.02%)}	_~	_277,068k	_277,328k	_{p=0.443 n=12}
_{Memory Allocs}	_{1,641,803 (± 0.01%)}	_{1,642,066 (± 0.01%)}	_~	_1,641,673	_1,643,018	_{p=0.101 n=12}
_{Config Time}	_0.000s	_{0.000s (±77.74%)}	_{🔻+0.000s (+ ∞%)}	_0.000s	_0.001s	_{p=0.037 n=12}
_{Parse Time}	_{0.098s (± 4.10%)}	_{0.100s (± 3.56%)}	_~	_0.093s	_0.113s	_{p=0.450 n=12}
_{Bind Time}	_{0.040s (± 8.83%)}	_{0.039s (± 7.63%)}	_~	_0.033s	_0.046s	_{p=0.661 n=12}
_{Check Time}	_{0.825s (± 0.78%)}	_{0.848s (± 0.59%)}	_{+0.023s (+ 2.75%)}	_0.837s	_0.859s	_{p=0.000 n=12}
_{Emit Time}	_0.000s	_0.000s	_~	_~	_~	_{p=1.000 n=12}
_{Total Time}	_{0.977s (± 0.84%)}	_{1.000s (± 0.89%)}	_{+0.023s (+ 2.40%)}	_0.981s	_1.025s	_{p=0.000 n=12}
_{vscode - native}
_Errors	₃₄₇	₃₄₇	_~	_~	_~	_{p=1.000 n=12}
_Symbols	_8,077,966	_8,077,966	_~	_~	_~	_{p=1.000 n=12}
_Types	_2,777,715	_2,777,715	_~	_~	_~	_{p=1.000 n=12}
_{Memory Used}	_{5,456,865k (± 0.01%)}	_{5,456,728k (± 0.01%)}	_~	_5,455,211k	_5,458,619k	_{p=0.932 n=12}
_{Memory Allocs}	_{42,186,068 (± 0.03%)}	_{42,183,294 (± 0.02%)}	_~	_42,173,211	_42,208,325	_{p=0.932 n=12}
_{Config Time}	_{0.064s (± 0.28%)}	_{0.063s (± 0.43%)}	_{-0.001s (- 1.69%)}	_0.062s	_0.064s	_{p=0.000 n=12}
_{Parse Time}	_{1.633s (± 3.24%)}	_{1.653s (± 2.41%)}	_~	_1.512s	_1.731s	_{p=0.681 n=12}
_{Bind Time}	_{0.406s (±16.32%)}	_{0.375s (±10.52%)}	_~	_0.350s	_0.574s	_{p=0.123 n=12}
_{Check Time}	_{10.139s (± 1.47%)}	_{10.459s (± 0.87%)}	_{+0.319s (+ 3.15%)}	_10.021s	_10.526s	_{p=0.000 n=12}
_{Emit Time}	_{3.585s (±11.50%)}	_{3.347s (± 8.11%)}	_~	_3.113s	_4.709s	_{p=0.443 n=12}
_{Total Time}	_{15.923s (± 1.82%)}	_{15.985s (± 1.30%)}	_~	_15.698s	_16.992s	_{p=0.143 n=12}
_{webpack - native}
_Errors	₅₄₀	₅₄₀	_~	_~	_~	_{p=1.000 n=12}
_Symbols	_854,568	_854,568	_~	_~	_~	_{p=1.000 n=12}
_Types	_392,241	_392,241	_~	_~	_~	_{p=1.000 n=12}
_{Memory Used}	_{653,940k (± 0.02%)}	_{653,954k (± 0.02%)}	_~	_653,520k	_654,285k	_{p=0.932 n=12}
_{Memory Allocs}	_{4,372,616 (± 0.04%)}	_{4,371,810 (± 0.03%)}	_~	_4,369,781	_4,375,834	_{p=0.514 n=12}
_{Config Time}	_0.008s	_0.008s	_~	_~	_~	_{p=1.000 n=12}
_{Parse Time}	_{0.213s (± 2.69%)}	_{0.216s (± 2.89%)}	_~	_0.202s	_0.236s	_{p=0.618 n=12}
_{Bind Time}	_{0.044s (±15.00%)}	_{0.044s (± 7.80%)}	_{+0.001s (+ 1.33%)}	_0.041s	_0.057s	_{p=0.042 n=12}
_{Check Time}	_{1.375s (± 0.75%)}	_{1.394s (± 0.66%)}	_{+0.020s (+ 1.45%)}	_1.369s	_1.415s	_{p=0.005 n=12}
_{Emit Time}	_0.000s	_0.000s	_~	_~	_~	_{p=1.000 n=12}
_{Total Time}	_{1.662s (± 0.52%)}	_{1.687s (± 0.48%)}	_{+0.025s (+ 1.50%)}	_1.667s	_1.707s	_{p=0.000 n=12}
_{xstate-main - native}
_Errors	₀	₀	_~	_~	_~	_{p=1.000 n=12}
_Symbols	_1,022,487	_1,022,487	_~	_~	_~	_{p=1.000 n=12}
_Types	_376,962	_376,962	_~	_~	_~	_{p=1.000 n=12}
_{Memory Used}	_{603,518k (± 0.01%)}	_{603,559k (± 0.01%)}	_~	_603,410k	_603,712k	_{p=0.266 n=12}
_{Memory Allocs}	_{4,754,306 (± 0.04%)}	_{4,757,092 (± 0.10%)}	_~	_4,750,768	_4,776,446	_{p=0.514 n=12}
_{Config Time}	_0.003s	_{0.003s (± 8.64%)}	_~	_0.002s	_0.003s	_{p=0.478 n=12}
_{Parse Time}	_{0.145s (± 3.25%)}	_{0.145s (± 3.14%)}	_~	_0.133s	_0.158s	_{p=0.660 n=12}
_{Bind Time}	_{0.045s (±18.87%)}	_{0.047s (±20.52%)}	_~	_0.034s	_0.074s	_{p=0.637 n=12}
_{Check Time}	_{1.035s (± 0.81%)}	_{1.043s (± 0.84%)}	_~	_1.022s	_1.075s	_{p=0.235 n=12}
_{Emit Time}	_0.000s	_0.000s	_~	_~	_~	_{p=1.000 n=12}
_{Total Time}	_{1.238s (± 0.91%)}	_{1.249s (± 1.08%)}	_~	_1.220s	_1.278s	_{p=0.116 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

Gabriela Araujo Britto (gabritto)

This looks good to me, and like I said, better for the upcoming extra type checking, but not sure other people have opinions.

Jake Bailey (jakebailey) · 2026-09-01T20:02:41Z

This should be perf neutral but trying one more time

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

typescript-automation · 2026-09-01T20:02:46Z

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

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

typescript-automation · 2026-09-01T20:30:48Z

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	_115,480	_115,480	_~	_~	_~	_{p=1.000 n=12}
_Types	_96,945	_96,945	_~	_~	_~	_{p=1.000 n=12}
_{Memory Used}	_{148,452k (± 0.42%)}	_{149,150k (± 0.48%)}	_~	_147,423k	_150,802k	_{p=0.198 n=12}
_{Memory Allocs}	_{2,271,193 (± 0.00%)}	_{2,271,186 (± 0.00%)}	_~	_2,271,037	_2,271,333	_{p=0.876 n=12}
_{Config Time}	_0.000s	_0.000s	_~	_~	_~	_{p=1.000 n=12}
_{Parse Time}	_{0.041s (± 3.96%)}	_{0.040s (± 2.44%)}	_~	_0.038s	_0.042s	_{p=0.121 n=12}
_{Bind Time}	_{0.012s (±10.28%)}	_{0.012s (±10.28%)}	_~	_0.010s	_0.018s	_{p=0.503 n=12}
_{Check Time}	_{0.496s (± 0.90%)}	_{0.497s (± 1.00%)}	_~	_0.488s	_0.512s	_{p=0.944 n=12}
_{Emit Time}	_{0.271s (± 1.98%)}	_{0.270s (± 2.01%)}	_~	_0.261s	_0.291s	_{p=0.385 n=12}
_{Total Time}	_{0.827s (± 0.96%)}	_{0.824s (± 1.08%)}	_~	_0.810s	_0.853s	_{p=0.369 n=12}
_{angular-1 - native}
_Errors	₃	₃	_~	_~	_~	_{p=1.000 n=12}
_Symbols	_{847,908 (± 0.04%)}	_{847,103 (± 0.10%)}	_~	_843,970	_848,488	_{p=0.178 n=12}
_Types	_{249,852 (± 0.00%)}	_{249,851 (± 0.00%)}	_~	_249,849	_249,853	_{p=0.795 n=12}
_{Memory Used}	_{793,391k (± 0.08%)}	_{793,616k (± 0.06%)}	_~	_792,464k	_794,710k	_{p=0.410 n=12}
_{Memory Allocs}	_{12,952,519 (± 0.04%)}	_{12,953,518 (± 0.04%)}	_~	_12,949,220	_12,979,915	_{p=0.178 n=12}
_{Config Time}	_0.016s	_0.016s	_~	_~	_~	_{p=1.000 n=12}
_{Parse Time}	_{0.274s (± 1.58%)}	_{0.269s (± 3.17%)}	_~	_0.242s	_0.285s	_{p=0.417 n=12}
_{Bind Time}	_{0.063s (± 7.27%)}	_{0.068s (±13.67%)}	_{🔻+0.005s (+ 8.79%)}	_0.060s	_0.106s	_{p=0.013 n=12}
_{Check Time}	_0s	_0s	_~	_~	_~	_{p=1.000 n=12}
_{Emit Time}	_{1.640s (± 0.97%)}	_{1.678s (± 1.27%)}	_{+0.038s (+ 2.33%)}	_1.640s	_1.744s	_{p=0.001 n=12}
_{Total Time}	_{2.010s (± 1.13%)}	_{2.049s (± 1.40%)}	_{+0.039s (+ 1.94%)}	_2.000s	_2.135s	_{p=0.014 n=12}
_{mui-docs - native}
_Errors	_{11,276 (± 0.03%)}	_{11,279 (± 0.01%)}	_~	_11,276	_11,281	_{p=0.195 n=12}
_Symbols	_4,169,590	_4,169,590	_~	_~	_~	_{p=1.000 n=12}
_Types	_1,577,454	_1,577,454	_~	_~	_~	_{p=1.000 n=12}
_{Memory Used}	_{4,678,165k (± 0.04%)}	_{4,678,893k (± 0.03%)}	_~	_4,676,569k	_4,682,543k	_{p=0.478 n=12}
_{Memory Allocs}	_{47,014,381 (± 0.04%)}	_{47,014,840 (± 0.03%)}	_~	_46,966,711	_47,061,525	_{p=0.843 n=12}
_{Config Time}	_{0.016s (± 1.14%)}	_{0.016s (± 1.14%)}	_~	_0.015s	_0.016s	_{p=1.000 n=12}
_{Parse Time}	_{0.553s (± 2.05%)}	_{0.547s (± 2.52%)}	_~	_0.492s	_0.565s	_{p=0.788 n=12}
_{Bind Time}	_0.002s	_{0.002s (±24.21%)}	_~	_0.002s	_0.005s	_{p=1.000 n=12}
_{Check Time}	_{17.292s (± 0.43%)}	_{17.408s (± 0.58%)}	_~	_17.219s	_17.616s	_{p=0.060 n=12}
_{Emit Time}	_{0.434s (± 0.30%)}	_{0.440s (± 2.92%)}	_~	_0.431s	_0.504s	_{p=0.969 n=12}
_{Total Time}	_{19.031s (± 0.48%)}	_{19.171s (± 0.58%)}	_{+0.140s (+ 0.74%)}	_18.959s	_19.393s	_{p=0.033 n=12}
_{strada-build-src - native}
_Errors	₀	₀	_~	_~	_~	_{p=1.000 n=12}
_Symbols	_1,394,252	_1,394,252	_~	_~	_~	_{p=1.000 n=12}
_Types	_443,418	_443,418	_~	_~	_~	_{p=1.000 n=12}
_{Memory Used}	_{1,646,361k (± 0.20%)}	_{1,641,215k (± 0.39%)}	_~	_1,627,712k	_1,661,573k	_{p=0.128 n=12}
_{Memory Allocs}	_{97,045,077 (± 0.02%)}	_{97,001,871 (± 0.05%)}	_{-43,206 (- 0.04%)}	_96,919,801	_97,181,276	_{p=0.008 n=12}
_{Config Time}	_{0.004s (±12.60%)}	_{0.004s (±17.94%)}	_~	_0.002s	_0.007s	_{p=0.619 n=12}
_{Parse Time}	_{0.194s (± 3.48%)}	_{0.188s (± 1.73%)}	_~	_0.181s	_0.198s	_{p=0.247 n=12}
_{Bind Time}	_0.000s	_{0.000s (±217.90%)}	_~	_0.000s	_0.002s	_{p=1.000 n=12}
_{Check Time}	_{1.809s (± 0.44%)}	_{1.833s (± 0.41%)}	_{+0.024s (+ 1.34%)}	_1.810s	_1.851s	_{p=0.000 n=12}
_{Emit Time}	_{0.282s (± 5.32%)}	_{0.293s (± 4.70%)}	_~	_0.251s	_0.327s	_{p=0.219 n=12}
_{Total Time}	_{24.799s (± 0.48%)}	_{25.028s (± 0.50%)}	_{+0.229s (+ 0.92%)}	_24.728s	_25.360s	_{p=0.020 n=12}
_{strada-compiler - native}
_Errors	₀	₀	_~	_~	_~	_{p=1.000 n=12}
_Symbols	_337,531	_337,531	_~	_~	_~	_{p=1.000 n=12}
_Types	_198,830	_198,830	_~	_~	_~	_{p=1.000 n=12}
_{Memory Used}	_{319,536k (± 0.05%)}	_{319,643k (± 0.08%)}	_~	_319,177k	_320,842k	_{p=0.410 n=12}
_{Memory Allocs}	_{4,673,076 (± 0.01%)}	_{4,672,950 (± 0.01%)}	_~	_4,671,172	_4,673,778	_{p=0.977 n=12}
_{Config Time}	_0.001s	_0.001s	_~	_~	_~	_{p=1.000 n=12}
_{Parse Time}	_{0.117s (± 4.12%)}	_{0.114s (± 4.55%)}	_~	_0.100s	_0.126s	_{p=0.384 n=12}
_{Bind Time}	_0.000s	_0.000s	_~	_~	_~	_{p=1.000 n=12}
_{Check Time}	_{1.053s (± 0.54%)}	_{1.067s (± 0.64%)}	_{+0.014s (+ 1.34%)}	_1.053s	_1.091s	_{p=0.002 n=12}
_{Emit Time}	_{0.140s (±13.52%)}	_{0.143s (±10.65%)}	_~	_0.110s	_0.174s	_{p=0.744 n=12}
_{Total Time}	_{1.364s (± 1.35%)}	_{1.379s (± 0.77%)}	_~	_1.353s	_1.410s	_{p=0.235 n=12}
_{ts-pre-modules - native}
_Errors	₈₇	₈₇	_~	_~	_~	_{p=1.000 n=12}
_Symbols	_305,179	_305,179	_~	_~	_~	_{p=1.000 n=12}
_Types	_181,876	_181,876	_~	_~	_~	_{p=1.000 n=12}
_{Memory Used}	_{277,193k (± 0.02%)}	_{277,184k (± 0.02%)}	_~	_276,987k	_277,320k	_{p=0.724 n=12}
_{Memory Allocs}	_{1,641,869 (± 0.01%)}	_{1,641,799 (± 0.01%)}	_~	_1,641,349	_1,642,325	_{p=0.590 n=12}
_{Config Time}	_{0.000s (±217.90%)}	_{0.000s (±217.90%)}	_~	_0.000s	_0.001s	_{p=1.000 n=12}
_{Parse Time}	_{0.103s (± 3.04%)}	_{0.100s (± 4.44%)}	_~	_0.088s	_0.110s	_{p=0.369 n=12}
_{Bind Time}	_{0.035s (±12.75%)}	_{0.036s (± 9.55%)}	_~	_0.029s	_0.047s	_{p=0.559 n=12}
_{Check Time}	_{0.833s (± 0.69%)}	_{0.850s (± 0.51%)}	_{+0.018s (+ 2.13%)}	_0.842s	_0.861s	_{p=0.000 n=12}
_{Emit Time}	_0.000s	_0.000s	_~	_~	_~	_{p=1.000 n=12}
_{Total Time}	_{0.984s (± 0.96%)}	_{0.999s (± 0.80%)}	_{+0.015s (+ 1.53%)}	_0.982s	_1.019s	_{p=0.015 n=12}
_{vscode - native}
_Errors	₃₄₇	₃₄₇	_~	_~	_~	_{p=1.000 n=12}
_Symbols	_8,236,705	_8,236,705	_~	_~	_~	_{p=1.000 n=12}
_Types	_2,824,778	_2,824,778	_~	_~	_~	_{p=1.000 n=12}
_{Memory Used}	_{5,548,891k (± 0.02%)}	_{5,549,162k (± 0.01%)}	_~	_5,547,084k	_5,550,587k	_{p=0.561 n=12}
_{Memory Allocs}	_{42,694,842 (± 0.01%)}	_{42,698,786 (± 0.02%)}	_~	_42,688,501	_42,747,165	_{p=0.319 n=12}
_{Config Time}	_{0.064s (± 0.52%)}	_{0.063s (± 0.29%)}	_~	_0.063s	_0.064s	_{p=0.069 n=12}
_{Parse Time}	_{1.644s (± 2.78%)}	_{1.639s (± 2.40%)}	_~	_1.523s	_1.708s	_{p=0.766 n=12}
_{Bind Time}	_{0.394s (±13.56%)}	_{0.388s (±10.23%)}	_~	_0.359s	_0.558s	_{p=0.084 n=12}
_{Check Time}	_{10.363s (± 1.57%)}	_{10.638s (± 1.29%)}	_{+0.275s (+ 2.66%)}	_10.166s	_10.792s	_{p=0.003 n=12}
_{Emit Time}	_{3.740s (±11.47%)}	_{3.508s (±10.64%)}	_~	_3.149s	_4.998s	_{p=0.767 n=12}
_{Total Time}	_{16.302s (± 1.77%)}	_{16.330s (± 1.63%)}	_~	_15.986s	_17.418s	_{p=0.551 n=12}
_{webpack - native}
_Errors	₅₄₄	₅₄₄	_~	_~	_~	_{p=1.000 n=12}
_Symbols	_858,575	_858,575	_~	_~	_~	_{p=1.000 n=12}
_Types	_396,099	_396,099	_~	_~	_~	_{p=1.000 n=12}
_{Memory Used}	_{658,559k (± 0.02%)}	_{658,512k (± 0.03%)}	_~	_657,858k	_659,304k	_{p=0.410 n=12}
_{Memory Allocs}	_{4,388,526 (± 0.02%)}	_{4,388,378 (± 0.02%)}	_~	_4,386,510	_4,392,543	_{p=0.755 n=12}
_{Config Time}	_0.008s	_{0.008s (± 5.88%)}	_~	_0.008s	_0.010s	_{p=0.478 n=12}
_{Parse Time}	_{0.214s (± 2.09%)}	_{0.218s (± 2.78%)}	_~	_0.199s	_0.231s	_{p=0.234 n=12}
_{Bind Time}	_{0.043s (± 6.95%)}	_{0.052s (±17.77%)}	_{🔻+0.009s (+22.07%)}	_0.042s	_0.079s	_{p=0.001 n=12}
_{Check Time}	_{1.295s (± 0.87%)}	_{1.333s (± 0.88%)}	_{+0.038s (+ 2.90%)}	_1.297s	_1.369s	_{p=0.000 n=12}
_{Emit Time}	_0.000s	_0.000s	_~	_~	_~	_{p=1.000 n=12}
_{Total Time}	_{1.584s (± 0.68%)}	_{1.636s (± 0.65%)}	_{+0.053s (+ 3.34%)}	_1.612s	_1.668s	_{p=0.000 n=12}
_{xstate-main - native}
_Errors	₀	₀	_~	_~	_~	_{p=1.000 n=12}
_Symbols	_1,022,532	_1,022,532	_~	_~	_~	_{p=1.000 n=12}
_Types	_376,962	_376,962	_~	_~	_~	_{p=1.000 n=12}
_{Memory Used}	_{603,547k (± 0.01%)}	_{603,489k (± 0.01%)}	_~	_603,152k	_603,670k	_{p=0.291 n=12}
_{Memory Allocs}	_{4,753,967 (± 0.04%)}	_{4,753,718 (± 0.03%)}	_~	_4,749,569	_4,757,679	_{p=0.843 n=12}
_{Config Time}	_{0.003s (±11.61%)}	_{0.003s (± 8.64%)}	_~	_0.002s	_0.003s	_{p=0.640 n=12}
_{Parse Time}	_{0.147s (± 3.12%)}	_{0.150s (± 4.15%)}	_~	_0.136s	_0.162s	_{p=0.468 n=12}
_{Bind Time}	_{0.045s (±21.77%)}	_{0.046s (±14.68%)}	_~	_0.034s	_0.068s	_{p=0.352 n=12}
_{Check Time}	_{1.034s (± 1.06%)}	_{1.055s (± 1.99%)}	_{+0.020s (+ 1.95%)}	_1.030s	_1.151s	_{p=0.012 n=12}
_{Emit Time}	_0.000s	_0.000s	_~	_~	_~	_{p=1.000 n=12}
_{Total Time}	_{1.239s (± 1.06%)}	_{1.264s (± 2.28%)}	_~	_1.223s	_1.388s	_{p=0.110 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) · 2026-09-01T20:44:51Z

Hm, there's something to this, I think, I need to investigate.

Replace large sparse Kind switches with byte-indexed dispatch tables and dense switches, while leaving small switches unchanged. Keep the concrete calls visible to escape analysis without restoring promoted interface methods. Add accessor correctness tests and fixture-based benchmarks covering both mixed nodes and nodes with populated accessor results.

Jake Bailey (jakebailey) · 2026-09-08T22:11:26Z

Sadly, I had to reintroduce indirection to recover the lost perf (which was in fact a real result). I'm sure this won't make the type checking happier, but it does seem to work and makes the binary smaller yet.

Index generated accessor tables directly with the node kind. Invalid kinds now hit the normal Go bounds check rather than returning nil. Update accessor tests to use valid constructed nodes.

Copilot

🔵 Needs a closer look

It broadly changes core AST dispatch and node construction across the compiler, warranting final human validation.

Review details

Files not reviewed (1)

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

Files reviewed: 5/7 changed files
Comments generated: 0 new
Review effort level: Balanced

Jake Bailey (jakebailey) added 6 commits August 21, 2026 23:28

Reduce AST method promotion

9baebce

Generate AST node data accessor dispatch

8f8cf14

Replace nine nodeData interface methods with generated Kind-switch dispatchers to reduce interface method promotion and itab size.

Remove ForEachChild from nodeData

17a2bf0

Remove AsNode from nodeData

e1cae40

Generate remaining node method dispatch

83f1aa2

Remove nodeData interface

7c6a845

Jake Bailey (jakebailey) requested a balanced review from Copilot August 28, 2026 04:08

Copilot started reviewing on behalf of Jake Bailey (jakebailey) August 28, 2026 04:09 View session

Copilot AI reviewed Aug 28, 2026

View reviewed changes

Comment thread tsc/internal/ast/flow.go Outdated

Jake Bailey (jakebailey) added 2 commits August 27, 2026 22:50

Handle synthetic flow node dispatch

ca6276d

Regenerate Kind stringer

6543bbd

Jake Bailey (jakebailey) requested a balanced review from Copilot August 28, 2026 06:11

Copilot started reviewing on behalf of Jake Bailey (jakebailey) August 28, 2026 06:12 View session

Copilot AI reviewed Aug 28, 2026

View reviewed changes

Jake Bailey (jakebailey) added 4 commits August 27, 2026 23:34

Revert "Reduce AST method promotion"

c3483ef

This reverts commit 9baebce.

Remove redundant NodeDefault methods

216ca65

Remove canonical token data test

1ab4099

Use promoted subtree facts method

e967be7

Jake Bailey (jakebailey) requested a balanced review from Copilot August 28, 2026 18:18

Copilot started reviewing on behalf of Jake Bailey (jakebailey) August 28, 2026 18:18 View session

Copilot AI reviewed Aug 28, 2026

View reviewed changes

Comment thread tsc/internal/ast/ast.go

Comment thread tsc/internal/ast/flow.go

Address AST dispatch review comments

f183b4e

Jake Bailey (jakebailey) requested a balanced review from Copilot August 28, 2026 18:42

Copilot started reviewing on behalf of Jake Bailey (jakebailey) August 28, 2026 18:42 View session

Copilot AI reviewed Aug 28, 2026

View reviewed changes

Jake Bailey (jakebailey) marked this pull request as ready for review August 28, 2026 19:45

typescript-automation Bot assigned Jake Bailey (jakebailey) Aug 30, 2026

typescript-automation Bot added Author: Team For Uncommitted Bug PR for untriaged, rejected, closed or missing bug labels Aug 30, 2026

github-project-automation Bot added this to PR Backlog Aug 30, 2026

github-project-automation Bot moved this to Not started in PR Backlog Aug 30, 2026

Gabriela Araujo Britto (gabritto) approved these changes Sep 1, 2026

View reviewed changes

github-project-automation Bot moved this from Not started to Needs merge in PR Backlog Sep 1, 2026

Jake Bailey (jakebailey) marked this pull request as draft September 1, 2026 20:44

Index AST accessor tables directly

a62dbea

Index generated accessor tables directly with the node kind. Invalid kinds now hit the normal Go bounds check rather than returning nil. Update accessor tests to use valid constructed nodes.

Jake Bailey (jakebailey) requested a review from Gabriela Araujo Britto (gabritto) September 8, 2026 22:31

Jake Bailey (jakebailey) marked this pull request as ready for review September 8, 2026 22:32

Jake Bailey (jakebailey) requested a balanced review from Copilot September 8, 2026 22:32

Copilot started reviewing on behalf of Jake Bailey (jakebailey) September 8, 2026 22:32 View session

Copilot AI reviewed Sep 8, 2026

View reviewed changes

Uh oh!

Conversation

Jake Bailey (jakebailey) commented Aug 28, 2026 • edited Loading Uh oh! There was an error while loading. Please reload this page.

Uh oh!

Uh oh!

Jake Bailey (jakebailey) commented Aug 28, 2026

Uh oh!

typescript-automation Bot commented Aug 28, 2026 • edited Loading Uh oh! There was an error while loading. Please reload this page.

Uh oh!

Uh oh!

Copilot AI left a comment

Choose a reason for hiding this comment

Pull request overview

Reviewed changes

Uh oh!

Uh oh!

typescript-automation Bot commented Aug 28, 2026

tsc

lsp

startup

Uh oh!

Copilot AI left a comment

Choose a reason for hiding this comment

Pull request overview

Uh oh!

Copilot AI left a comment

Choose a reason for hiding this comment

Pull request overview

Uh oh!

Uh oh!

Uh oh!

Copilot AI left a comment

Choose a reason for hiding this comment

Pull request overview

Uh oh!

Jake Bailey (jakebailey) commented Aug 28, 2026

Uh oh!

typescript-automation Bot commented Aug 28, 2026 • edited Loading Uh oh! There was an error while loading. Please reload this page.

Uh oh!

Uh oh!

typescript-automation Bot commented Aug 28, 2026

tsc

Uh oh!

Gabriela Araujo Britto (gabritto) left a comment

Choose a reason for hiding this comment

Uh oh!

Jake Bailey (jakebailey) commented Sep 1, 2026

Uh oh!

typescript-automation Bot commented Sep 1, 2026 • edited Loading Uh oh! There was an error while loading. Please reload this page.

Uh oh!

Uh oh!

typescript-automation Bot commented Sep 1, 2026

tsc

Uh oh!

Jake Bailey (jakebailey) commented Sep 1, 2026

Uh oh!

Jake Bailey (jakebailey) commented Sep 8, 2026

Uh oh!

Copilot AI left a comment

Choose a reason for hiding this comment

🔵 Needs a closer look

Files not reviewed (1)

Uh oh!

Reviewers

Assignees

Labels

Projects

Milestone

Development

Uh oh!

3 participants

Jake Bailey (jakebailey) commented Aug 28, 2026 •

edited

Loading

typescript-automation Bot commented Aug 28, 2026 •

edited

Loading

typescript-automation Bot commented Aug 28, 2026 •

edited

Loading

typescript-automation Bot commented Sep 1, 2026 •

edited

Loading