Fix symbol table kind mask by jakebailey · Pull Request #64762 · microsoft/TypeScript

Jake Bailey (jakebailey) · 2026-10-13T05:30:26Z

The previous mask retained only one of the three kind bits, disabling alias caching for globals and raw exports and the members fast path. Oops.

The previous mask retained only one of the three kind bits, disabling alias caching for globals and raw exports and the members fast path.

Jake Bailey (jakebailey) · 2026-10-13T05:30:51Z

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

typescript-automation · 2026-10-13T05:30:57Z

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

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

Copilot

🟡 Changes recommended

The corrected mask needs a regression test covering every symbol-table kind.

1 open finding

Add regression test for stKindMask bit preservation · New

What changed in this PR

Corrects symbol-table kind extraction so alias caching and member fast paths work as intended.

Changes:

Preserve all three high-order kind bits in stKindMask.

File	Description
`tsc/internal/checker/symbolaccessibility.go`	Fixes the symbol-table kind mask.

🧠 Review effort: Balanced

Jake Bailey (jakebailey) · 2026-10-13T06:58:50Z


 	// stKindMask extracts the kind bits from a symbolTableID.
-	stKindMask symbolTableID = (iota - 1) << stKindShift
+	stKindMask symbolTableID = ^symbolTableID(1<<stKindShift - 1)


So, yes, but the test just doesn't feel super great so I skipped it

typescript-automation · 2026-10-13T05:57:45Z

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	_115,276	_~	_~	_~	_{p=1.000 n=12}
_Types	_79,613	_79,613	_~	_~	_~	_{p=1.000 n=12}
_{Memory Used}	_{133,221k (± 0.07%)}	_{133,158k (± 0.05%)}	_~	_133,035k	_133,422k	_{p=0.319 n=12}
_{Memory Allocs}	_{2,190,379 (± 0.01%)}	_{2,190,334 (± 0.01%)}	_~	_2,190,086	_2,190,644	_{p=0.932 n=12}
_{Config Time}	_0.000s	_0.000s	_~	_~	_~	_{p=1.000 n=12}
_{Parse Time}	_{0.041s (± 3.23%)}	_{0.040s (± 3.14%)}	_~	_0.038s	_0.044s	_{p=0.552 n=12}
_{Bind Time}	_{0.012s (±14.64%)}	_{0.013s (±16.51%)}	_~	_0.010s	_0.019s	_{p=0.772 n=12}
_{Check Time}	_{0.502s (± 0.72%)}	_{0.502s (± 0.71%)}	_~	_0.491s	_0.510s	_{p=0.923 n=12}
_{Emit Time}	_{0.270s (± 2.16%)}	_{0.266s (± 2.11%)}	_~	_0.248s	_0.277s	_{p=0.400 n=12}
_{Total Time}	_{0.831s (± 0.81%)}	_{0.827s (± 0.67%)}	_~	_0.809s	_0.840s	_{p=0.297 n=12}
_{angular-1 - native}
_Errors	₃	₃	_~	_~	_~	_{p=1.000 n=12}
_Symbols	_{845,704 (± 0.06%)}	_{845,796 (± 0.09%)}	_~	_843,074	_847,198	_{p=0.619 n=12}
_Types	_{248,125 (± 0.00%)}	_{248,124 (± 0.00%)}	_~	_248,122	_248,127	_{p=0.516 n=12}
_{Memory Used}	_{746,081k (± 0.02%)}	_{746,053k (± 0.02%)}	_~	_745,641k	_746,472k	_{p=0.724 n=12}
_{Memory Allocs}	_{12,916,452 (± 0.05%)}	_{12,913,726 (± 0.03%)}	_~	_12,909,166	_12,931,482	_{p=0.478 n=12}
_{Config Time}	_0.017s	_0.017s	_~	_~	_~	_{p=1.000 n=12}
_{Parse Time}	_{0.252s (± 2.20%)}	_{0.258s (± 1.92%)}	_~	_0.246s	_0.269s	_{p=0.080 n=12}
_{Bind Time}	_{0.067s (±18.50%)}	_{0.061s (±10.41%)}	_~	_0.057s	_0.093s	_{p=0.556 n=12}
_{Check Time}	_0s	_0s	_~	_~	_~	_{p=1.000 n=12}
_{Emit Time}	_{1.559s (± 0.98%)}	_{1.557s (± 0.75%)}	_~	_1.534s	_1.590s	_{p=0.966 n=12}
_{Total Time}	_{1.906s (± 1.25%)}	_{1.907s (± 1.05%)}	_~	_1.873s	_1.994s	_{p=0.766 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}	_{2,775,595k (± 0.05%)}	_{2,774,734k (± 0.06%)}	_~	_2,771,953k	_2,779,872k	_{p=0.266 n=12}
_{Memory Allocs}	_{32,731,049 (± 0.08%)}	_{32,729,536 (± 0.05%)}	_~	_32,666,809	_32,774,438	_{p=0.843 n=12}
_{Config Time}	_0.017s	_0.017s	_~	_~	_~	_{p=1.000 n=12}
_{Parse Time}	_{0.505s (± 1.33%)}	_{0.499s (± 2.97%)}	_~	_0.463s	_0.546s	_{p=0.877 n=12}
_{Bind Time}	_0.002s	_0.002s	_~	_~	_~	_{p=1.000 n=12}
_{Check Time}	_{8.868s (± 0.57%)}	_{8.854s (± 0.46%)}	_~	_8.806s	_8.994s	_{p=0.523 n=12}
_{Emit Time}	_{0.465s (±10.39%)}	_{0.432s (± 5.04%)}	_~	_0.419s	_0.541s	_{p=0.943 n=12}
_{Total Time}	_{10.631s (± 0.47%)}	_{10.580s (± 0.48%)}	_~	_10.508s	_10.718s	_{p=0.117 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}	_{1,631,495k (± 1.02%)}	_{1,631,986k (± 0.90%)}	_~	_1,606,265k	_1,671,697k	_{p=0.977 n=12}
_{Memory Allocs}	_{92,242,795 (± 0.17%)}	_{92,295,957 (± 0.14%)}	_~	_91,900,808	_92,599,360	_{p=0.671 n=12}
_{Config Time}	_{0.004s (± 9.39%)}	_{0.003s (±16.58%)}	_~	_0.002s	_0.005s	_{p=0.971 n=12}
_{Parse Time}	_{0.203s (± 3.88%)}	_{0.198s (± 4.78%)}	_~	_0.178s	_0.220s	_{p=0.434 n=12}
_{Bind Time}	_0.000s	_0.000s	_~	_~	_~	_{p=1.000 n=12}
_{Check Time}	_{1.818s (± 0.93%)}	_{1.806s (± 0.42%)}	_~	_1.787s	_1.831s	_{p=0.066 n=12}
_{Emit Time}	_{0.303s (± 3.36%)}	_{0.306s (± 2.51%)}	_~	_0.287s	_0.329s	_{p=0.580 n=12}
_{Total Time}	_{23.484s (± 0.58%)}	_{23.470s (± 0.54%)}	_~	_22.995s	_23.712s	_{p=0.977 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}	_{296,076k (± 0.03%)}	_{296,077k (± 0.02%)}	_~	_295,856k	_296,228k	_{p=0.630 n=12}
_{Memory Allocs}	_{4,621,531 (± 0.01%)}	_{4,621,537 (± 0.01%)}	_~	_4,620,662	_4,622,826	_{p=0.744 n=12}
_{Config Time}	_0.001s	_0.001s	_~	_~	_~	_{p=1.000 n=12}
_{Parse Time}	_{0.115s (± 5.43%)}	_{0.112s (± 5.13%)}	_~	_0.096s	_0.126s	_{p=0.434 n=12}
_{Bind Time}	_0.000s	_0.000s	_~	_~	_~	_{p=1.000 n=12}
_{Check Time}	_{1.045s (± 0.80%)}	_{1.039s (± 0.43%)}	_~	_1.030s	_1.048s	_{p=0.417 n=12}
_{Emit Time}	_{0.140s (±11.66%)}	_{0.153s (± 6.60%)}	_~	_0.129s	_0.176s	_{p=0.272 n=12}
_{Total Time}	_{1.358s (± 0.89%)}	_{1.358s (± 1.19%)}	_~	_1.322s	_1.403s	_{p=0.944 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}	_{256,641k (± 0.02%)}	_{256,653k (± 0.01%)}	_~	_256,585k	_256,723k	_{p=0.810 n=12}
_{Memory Allocs}	_{1,614,053 (± 0.01%)}	_{1,613,923 (± 0.01%)}	_~	_1,613,127	_1,614,466	_{p=0.410 n=12}
_{Config Time}	_0.000s	_0.000s	_~	_~	_~	_{p=1.000 n=12}
_{Parse Time}	_{0.100s (± 5.00%)}	_{0.097s (± 4.97%)}	_~	_0.090s	_0.111s	_{p=0.339 n=12}
_{Bind Time}	_{0.039s (± 7.78%)}	_{0.035s (±10.98%)}	_~	_0.028s	_0.046s	_{p=0.091 n=12}
_{Check Time}	_{0.814s (± 0.62%)}	_{0.820s (± 0.64%)}	_~	_0.809s	_0.835s	_{p=0.201 n=12}
_{Emit Time}	_0.000s	_0.000s	_~	_~	_~	_{p=1.000 n=12}
_{Total Time}	_{0.967s (± 0.65%)}	_{0.966s (± 0.63%)}	_~	_0.950s	_0.985s	_{p=0.832 n=12}
_{vscode - native}
_Errors	₃₉₆	₃₉₆	_~	_~	_~	_{p=1.000 n=12}
_Symbols	_11,292,425	_11,292,425	_~	_~	_~	_{p=1.000 n=12}
_Types	_3,726,187	_3,726,187	_~	_~	_~	_{p=1.000 n=12}
_{Memory Used}	_{6,452,981k (± 0.01%)}	_{6,452,823k (± 0.02%)}	_~	_6,450,982k	_6,456,242k	_{p=0.551 n=12}
_{Memory Allocs}	_{55,522,967 (± 0.03%)}	_{55,515,814 (± 0.02%)}	_~	_55,501,904	_55,553,949	_{p=0.932 n=12}
_{Config Time}	_{0.075s (± 0.56%)}	_{0.075s (± 0.48%)}	_~	_0.074s	_0.076s	_{p=0.494 n=12}
_{Parse Time}	_{1.866s (± 3.03%)}	_{1.846s (± 3.29%)}	_~	_1.699s	_1.968s	_{p=0.682 n=12}
_{Bind Time}	_{0.517s (±18.15%)}	_{0.566s (±18.02%)}	_~	_0.446s	_0.854s	_{p=0.154 n=12}
_{Check Time}	_{14.076s (± 0.72%)}	_{14.018s (± 1.04%)}	_~	_13.619s	_14.308s	_{p=0.682 n=12}
_{Emit Time}	_{4.856s (± 9.52%)}	_{5.057s (± 9.88%)}	_~	_4.158s	_6.063s	_{p=0.468 n=12}
_{Total Time}	_{21.470s (± 1.90%)}	_{21.645s (± 1.99%)}	_~	_20.812s	_22.485s	_{p=0.418 n=12}
_{webpack - native}
_Errors	₅₈₅	₅₈₅	_~	_~	_~	_{p=1.000 n=12}
_Symbols	_1,315,766	_1,315,766	_~	_~	_~	_{p=1.000 n=12}
_Types	_618,033	_618,033	_~	_~	_~	_{p=1.000 n=12}
_{Memory Used}	_{946,594k (± 0.01%)}	_{946,772k (± 0.02%)}	_~	_946,393k	_947,244k	_{p=0.089 n=12}
_{Memory Allocs}	_{6,687,387 (± 0.02%)}	_{6,687,210 (± 0.03%)}	_~	_6,684,400	_6,696,462	_{p=0.887 n=12}
_{Config Time}	_0.009s	_0.009s	_~	_~	_~	_{p=1.000 n=12}
_{Parse Time}	_{0.305s (± 3.59%)}	_{0.306s (± 4.13%)}	_~	_0.283s	_0.339s	_{p=0.966 n=12}
_{Bind Time}	_{0.077s (±18.24%)}	_{0.077s (±15.66%)}	_~	_0.063s	_0.117s	_{p=0.898 n=12}
_{Check Time}	_{2.131s (± 0.55%)}	_{2.142s (± 0.50%)}	_~	_2.111s	_2.161s	_{p=0.075 n=12}
_{Emit Time}	_0.000s	_0.000s	_~	_~	_~	_{p=1.000 n=12}
_{Total Time}	_{2.556s (± 0.49%)}	_{2.569s (± 0.58%)}	_~	_2.532s	_2.609s	_{p=0.147 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}	_{548,213k (± 0.02%)}	_{548,286k (± 0.02%)}	_~	_548,059k	_548,723k	_{p=0.225 n=12}
_{Memory Allocs}	_{4,885,900 (± 0.08%)}	_{4,886,334 (± 0.06%)}	_~	_4,881,192	_4,894,755	_{p=0.514 n=12}
_{Config Time}	_0.003s	_0.003s	_~	_~	_~	_{p=1.000 n=12}
_{Parse Time}	_{0.142s (± 2.78%)}	_{0.145s (± 3.38%)}	_~	_0.133s	_0.158s	_{p=0.384 n=12}
_{Bind Time}	_{0.043s (±15.74%)}	_{0.046s (±16.42%)}	_~	_0.032s	_0.067s	_{p=0.786 n=12}
_{Check Time}	_{1.154s (± 1.07%)}	_{1.146s (± 0.55%)}	_~	_1.137s	_1.171s	_{p=0.130 n=12}
_{Emit Time}	_0.000s	_0.000s	_~	_~	_~	_{p=1.000 n=12}
_{Total Time}	_{1.353s (± 0.83%)}	_{1.350s (± 0.59%)}	_~	_1.327s	_1.368s	_{p=0.702 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

Fix symbol table kind mask

504b0c1

The previous mask retained only one of the three kind bits, disabling alias caching for globals and raw exports and the members fast path.

Copilot AI balanced review requested due to automatic review settings October 13, 2026 05:30

github-project-automation Bot added this to PR Backlog Oct 13, 2026

typescript-automation Bot assigned Jake Bailey (jakebailey) Oct 13, 2026

typescript-automation Bot added Author: Team For Uncommitted Bug PR for untriaged, rejected, closed or missing bug labels Oct 13, 2026

Copilot started reviewing on behalf of Jake Bailey (jakebailey) October 13, 2026 05:31

View session

Copilot AI reviewed Oct 13, 2026

View reviewed changes

Ryan Cavanaugh (RyanCavanaugh) approved these changes Oct 13, 2026

View reviewed changes

github-project-automation Bot moved this from Not started to Needs merge in PR Backlog Oct 13, 2026

Jake Bailey (jakebailey) added this pull request to the merge queue Oct 13, 2026

Merged via the queue into microsoft:main with commit 3789ddb Oct 13, 2026
29 checks passed

Jake Bailey (jakebailey) deleted the symbol-table-kind-mask branch October 13, 2026 20:22

github-project-automation Bot moved this from Needs merge to Done in PR Backlog Oct 13, 2026

Boshen (Boshen) mentioned this pull request Oct 19, 2026

Port upstream TypeScript oxc-project/tsrs#623

Open

Navigation Menu

Repository navigation

Fix symbol table kind mask - #64762

Fix symbol table kind mask#64762
Jake Bailey (jakebailey) merged 1 commit into
microsoft:mainfrom
jakebailey:symbol-table-kind-mask

Jake Bailey (jakebailey) commented Oct 13, 2026

Uh oh!

Jake Bailey (jakebailey) commented Oct 13, 2026

Uh oh!

typescript-automation Bot commented Oct 13, 2026 •

edited

Loading

Uh oh!

Copilot AI left a comment

Uh oh!

Jake Bailey (jakebailey) Oct 13, 2026

Uh oh!

typescript-automation Bot commented Oct 13, 2026

tsc

Uh oh!

Uh oh!

Reviewers

Assignees

Labels

Projects

Milestone

Development

Uh oh!

3 participants

Conversation

Jake Bailey (jakebailey) commented Oct 13, 2026

Uh oh!

Jake Bailey (jakebailey) commented Oct 13, 2026

Uh oh!

typescript-automation Bot commented Oct 13, 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

🟡 Changes recommended

Uh oh!

Jake Bailey (jakebailey) Oct 13, 2026

Choose a reason for hiding this comment

Uh oh!

typescript-automation Bot commented Oct 13, 2026

tsc

Uh oh!

Uh oh!

Reviewers

Assignees

Labels

Projects

Milestone

Development

Uh oh!

3 participants

typescript-automation Bot commented Oct 13, 2026 •

edited

Loading