Cache alias candidates for symbol accessibility by Zzzen · Pull Request #4102 · microsoft/typescript-go

Zzzen (Zzzen) · 2026-05-30T14:19:35Z

Copilot

Pull request overview

Note

Copilot was unable to run its full agentic suite in this review.

This PR optimizes alias resolution by caching exported-symbol alias candidates per container and per resolved/merged target symbol, reducing repeated scans and redundant sorting.

Changes:

Added a Checker-level cache mapping containers to exported-target → candidate-export symbols.
Updated getAliasForSymbolInContainer to populate and consult the cache.
Avoided unnecessary sorting when there is only a single candidate.

Reviewed changes

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

File	Description
internal/checker/symbolaccessibility.go	Adds cached lookup/build path for alias candidates keyed by resolved exported target symbols.
internal/checker/checker.go	Introduces a new `Checker` field to store the alias-candidate cache.

+	target := c.getMergedSymbol(c.resolveSymbol(c.getMergedSymbol(symbol)))
+	if c.aliasCandidatesByExportedTarget != nil {
+		if candidatesByTarget, ok := c.aliasCandidatesByExportedTarget[container]; ok {
+			candidates := candidatesByTarget[target]
+			if len(candidates) > 0 {
+				if len(candidates) > 1 {
+					c.sortSymbols(candidates) // _must_ sort exports for stable results - symbol table is randomly iterated
+				}
+				return candidates[0]
+			}
+			return nil
 		}
+	} else {
+		c.aliasCandidatesByExportedTarget = make(map[*ast.Symbol]map[*ast.Symbol][]*ast.Symbol)
 	}
+
+	candidatesByTarget := make(map[*ast.Symbol][]*ast.Symbol, len(exports))
+	for _, exported := range exports {
+		exportedTarget := c.getMergedSymbol(c.resolveSymbol(c.getMergedSymbol(exported)))
+		candidatesByTarget[exportedTarget] = append(candidatesByTarget[exportedTarget], exported)
+	}
+	c.aliasCandidatesByExportedTarget[container] = candidatesByTarget


-		if c.getSymbolIfSameReference(exported, symbol) != nil {
-			candidates = append(candidates, exported)
+
+	target := c.getMergedSymbol(c.resolveSymbol(c.getMergedSymbol(symbol)))


+
+	candidatesByTarget := make(map[*ast.Symbol][]*ast.Symbol, len(exports))
+	for _, exported := range exports {
+		exportedTarget := c.getMergedSymbol(c.resolveSymbol(c.getMergedSymbol(exported)))


Jake Bailey (jakebailey) · 2026-08-14T21:25:59Z

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

typescript-automation · 2026-08-14T21:26:05Z

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

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

typescript-automation · 2026-08-14T21:55:57Z

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}	_{148,979k (± 0.44%)}	_{149,154k (± 0.51%)}	_~	_147,798k	_151,424k	_{p=0.887 n=12}
_{Memory Allocs}	_{2,247,391 (± 0.00%)}	_{2,247,423 (± 0.01%)}	_~	_2,247,169	_2,247,870	_{p=0.799 n=12}
_{Config Time}	_0.000s	_0.000s	_~	_~	_~	_{p=1.000 n=12}
_{Parse Time}	_{0.041s (± 3.34%)}	_{0.041s (± 4.73%)}	_~	_0.038s	_0.047s	_{p=0.696 n=12}
_{Bind Time}	_{0.012s (± 9.53%)}	_{0.013s (±11.31%)}	_~	_0.010s	_0.017s	_{p=0.538 n=12}
_{Check Time}	_{0.507s (± 0.66%)}	_{0.509s (± 0.96%)}	_~	_0.500s	_0.526s	_{p=0.943 n=12}
_{Emit Time}	_{0.271s (± 1.76%)}	_{0.272s (± 2.75%)}	_~	_0.257s	_0.296s	_{p=0.921 n=12}
_{Total Time}	_{0.838s (± 0.75%)}	_{0.842s (± 1.13%)}	_~	_0.819s	_0.859s	_{p=0.580 n=12}
_{angular-1 - native}
_Errors	₃	₃	_~	_~	_~	_{p=1.000 n=12}
_Symbols	_{847,359 (± 0.08%)}	_{847,037 (± 0.07%)}	_~	_845,770	_848,261	_{p=0.478 n=12}
_Types	_{249,912 (± 0.00%)}	_{249,915 (± 0.00%)}	_~	_249,912	_249,925	_{p=0.159 n=12}
_{Memory Used}	_{793,100k (± 0.05%)}	_{801,222k (± 0.10%)}	_{+8,122k (+ 1.02%)}	_799,777k	_803,565k	_{p=0.000 n=12}
_{Memory Allocs}	_{13,038,162 (± 0.03%)}	_{13,146,562 (± 0.06%)}	_{+108,400 (+ 0.83%)}	_13,140,002	_13,184,688	_{p=0.000 n=12}
_{Config Time}	_{0.016s (± 1.13%)}	_{0.016s (± 1.90%)}	_~	_0.016s	_0.017s	_{p=0.317 n=12}
_{Parse Time}	_{0.281s (± 2.28%)}	_{0.276s (± 2.58%)}	_~	_0.253s	_0.291s	_{p=0.297 n=12}
_{Bind Time}	_{0.064s (±11.28%)}	_{0.065s (±17.07%)}	_~	_0.057s	_0.119s	_{p=0.828 n=12}
_{Check Time}	_0s	_0s	_~	_~	_~	_{p=1.000 n=12}
_{Emit Time}	_{1.646s (± 0.93%)}	_{1.644s (± 1.20%)}	_~	_1.604s	_1.720s	_{p=0.629 n=12}
_{Total Time}	_{2.028s (± 1.25%)}	_{2.017s (± 1.35%)}	_~	_1.955s	_2.112s	_{p=0.183 n=12}
_{mui-docs - native}
_Errors	_{11,274 (± 0.05%)}	_{11,277 (± 0.03%)}	_~	_11,267	_11,282	_{p=0.189 n=12}
_Symbols	_4,230,792	_4,230,792	_~	_~	_~	_{p=1.000 n=12}
_Types	_1,591,020	_1,591,020	_~	_~	_~	_{p=1.000 n=12}
_{Memory Used}	_{4,854,826k (± 0.04%)}	_{4,854,050k (± 0.02%)}	_~	_4,850,807k	_4,857,143k	_{p=0.590 n=12}
_{Memory Allocs}	_{48,408,458 (± 0.03%)}	_{48,408,306 (± 0.02%)}	_~	_48,371,758	_48,429,555	_{p=0.755 n=12}
_{Config Time}	_{0.016s (± 1.81%)}	_{0.016s (± 1.14%)}	_~	_0.015s	_0.016s	_{p=0.590 n=12}
_{Parse Time}	_{0.557s (± 1.33%)}	_{0.547s (± 2.74%)}	_~	_0.499s	_0.575s	_{p=0.385 n=12}
_{Bind Time}	_0.002s	_{0.002s (± 8.72%)}	_~	_0.002s	_0.003s	_{p=1.000 n=12}
_{Check Time}	_{15.456s (± 0.57%)}	_{15.519s (± 0.58%)}	_~	_15.327s	_15.712s	_{p=0.487 n=12}
_{Emit Time}	_{0.435s (± 0.36%)}	_{0.437s (± 0.30%)}	_~	_0.433s	_0.439s	_{p=0.242 n=12}
_{Total Time}	_{17.172s (± 0.69%)}	_{17.252s (± 0.63%)}	_~	_17.017s	_17.467s	_{p=0.347 n=12}
_{strada-build-src - native}
_Errors	₀	₀	_~	_~	_~	_{p=1.000 n=12}
_Symbols	_1,394,411	_1,394,411	_~	_~	_~	_{p=1.000 n=12}
_Types	_443,627	_443,627	_~	_~	_~	_{p=1.000 n=12}
_{Memory Used}	_{1,647,832k (± 0.33%)}	_{1,639,496k (± 0.30%)}	_{-8,336k (- 0.51%)}	_1,623,641k	_1,653,661k	_{p=0.024 n=12}
_{Memory Allocs}	_{96,923,749 (± 0.04%)}	_{96,889,499 (± 0.04%)}	_~	_96,779,090	_97,014,577	_{p=0.198 n=12}
_{Config Time}	_{0.004s (±14.34%)}	_{0.003s (±14.59%)}	_~	_0.002s	_0.004s	_{p=0.583 n=12}
_{Parse Time}	_{0.194s (± 2.40%)}	_{0.195s (± 2.15%)}	_~	_0.186s	_0.206s	_{p=0.898 n=12}
_{Bind Time}	_{0.000s (±217.90%)}	_0.000s	_~	_~	_~	_{p=1.000 n=12}
_{Check Time}	_{1.831s (± 0.67%)}	_{1.835s (± 0.38%)}	_~	_1.817s	_1.851s	_{p=0.580 n=12}
_{Emit Time}	_{0.305s (± 4.80%)}	_{0.295s (± 4.09%)}	_~	_0.259s	_0.318s	_{p=0.340 n=12}
_{Total Time}	_{25.300s (± 0.71%)}	_{25.163s (± 0.50%)}	_~	_24.884s	_25.570s	_{p=0.198 n=12}
_{strada-compiler - native}
_Errors	₀	₀	_~	_~	_~	_{p=1.000 n=12}
_Symbols	_337,618	_337,618	_~	_~	_~	_{p=1.000 n=12}
_Types	_198,941	_198,941	_~	_~	_~	_{p=1.000 n=12}
_{Memory Used}	_{319,623k (± 0.03%)}	_{319,671k (± 0.06%)}	_~	_319,360k	_320,467k	_{p=0.944 n=12}
_{Memory Allocs}	_{4,661,058 (± 0.01%)}	_{4,660,753 (± 0.01%)}	_~	_4,659,676	_4,662,004	_{p=0.160 n=12}
_{Config Time}	_0.001s	_0.001s	_~	_~	_~	_{p=1.000 n=12}
_{Parse Time}	_{0.116s (± 4.04%)}	_{0.117s (± 4.59%)}	_~	_0.105s	_0.135s	_{p=0.842 n=12}
_{Bind Time}	_0.000s	_0.000s	_~	_~	_~	_{p=1.000 n=12}
_{Check Time}	_{1.059s (± 0.55%)}	_{1.062s (± 0.50%)}	_~	_1.047s	_1.077s	_{p=0.163 n=12}
_{Emit Time}	_{0.161s (± 9.43%)}	_{0.163s (± 4.02%)}	_~	_0.141s	_0.177s	_{p=0.599 n=12}
_{Total Time}	_{1.392s (± 1.32%)}	_{1.394s (± 0.62%)}	_~	_1.378s	_1.411s	_{p=0.977 n=12}
_{ts-pre-modules - native}
_Errors	₈₇	₈₇	_~	_~	_~	_{p=1.000 n=12}
_Symbols	_305,341	_305,341	_~	_~	_~	_{p=1.000 n=12}
_Types	_182,038	_182,038	_~	_~	_~	_{p=1.000 n=12}
_{Memory Used}	_{277,299k (± 0.01%)}	_{277,282k (± 0.02%)}	_~	_277,071k	_277,399k	_{p=0.965 n=12}
_{Memory Allocs}	_{1,628,072 (± 0.01%)}	_{1,628,086 (± 0.01%)}	_~	_1,627,695	_1,628,412	_{p=0.755 n=12}
_{Config Time}	_{0.000s (±217.90%)}	_{0.000s (±146.91%)}	_~	_0.000s	_0.001s	_{p=1.000 n=12}
_{Parse Time}	_{0.101s (± 3.60%)}	_{0.099s (± 4.41%)}	_~	_0.087s	_0.107s	_{p=0.599 n=12}
_{Bind Time}	_{0.038s (±11.94%)}	_{0.039s (±10.32%)}	_~	_0.031s	_0.047s	_{p=0.920 n=12}
_{Check Time}	_{0.844s (± 0.61%)}	_{0.842s (± 0.69%)}	_~	_0.827s	_0.857s	_{p=0.809 n=12}
_{Emit Time}	_0.000s	_0.000s	_~	_~	_~	_{p=1.000 n=12}
_{Total Time}	_{0.998s (± 0.66%)}	_{0.994s (± 0.58%)}	_~	_0.979s	_1.007s	_{p=0.259 n=12}
_{vscode - native}
_Errors	₀	₀	_~	_~	_~	_{p=1.000 n=12}
_Symbols	_7,733,268	_7,733,268	_~	_~	_~	_{p=1.000 n=12}
_Types	_2,660,597	_2,660,597	_~	_~	_~	_{p=1.000 n=12}
_{Memory Used}	_{5,225,508k (± 0.01%)}	_{5,226,670k (± 0.01%)}	_{+1,162k (+ 0.02%)}	_5,224,155k	_5,228,154k	_{p=0.017 n=12}
_{Memory Allocs}	_{40,486,174 (± 0.03%)}	_{40,493,869 (± 0.02%)}	_{+7,695 (+ 0.02%)}	_40,478,459	_40,525,639	_{p=0.020 n=12}
_{Config Time}	_{0.061s (± 0.53%)}	_{0.061s (± 0.77%)}	_~	_0.060s	_0.062s	_{p=0.433 n=12}
_{Parse Time}	_{1.600s (± 1.05%)}	_{1.601s (± 2.14%)}	_~	_1.474s	_1.664s	_{p=0.505 n=12}
_{Bind Time}	_{0.329s (± 0.43%)}	_{0.352s (±13.64%)}	_~	_0.328s	_0.594s	_{p=0.184 n=12}
_{Check Time}	_{9.844s (± 0.25%)}	_{9.769s (± 1.10%)}	_~	_9.312s	_9.885s	_{p=0.370 n=12}
_{Emit Time}	_{2.961s (± 0.86%)}	_{3.104s (±10.14%)}	_~	_2.911s	_4.689s	_{p=0.876 n=12}
_{Total Time}	_{14.874s (± 0.29%)}	_{14.968s (± 1.71%)}	_~	_14.661s	_16.236s	_{p=0.744 n=12}
_{webpack - native}
_Errors	₂	₂	_~	_~	_~	_{p=1.000 n=12}
_Symbols	_1,380	_1,380	_~	_~	_~	_{p=1.000 n=12}
_Types	₃₄₀	₃₄₀	_~	_~	_~	_{p=1.000 n=12}
_{Memory Used}	_{194,548k (± 0.07%)}	_{194,545k (± 0.05%)}	_~	_194,279k	_194,810k	_{p=0.932 n=12}
_{Memory Allocs}	_{822,915 (± 0.11%)}	_{822,735 (± 0.14%)}	_~	_821,473	_827,688	_{p=0.514 n=12}
_{Config Time}	_0.008s	_0.008s	_~	_~	_~	_{p=1.000 n=12}
_{Parse Time}	_{0.205s (± 1.82%)}	_{0.201s (± 2.74%)}	_~	_0.185s	_0.214s	_{p=0.235 n=12}
_{Bind Time}	_0s	_0s	_~	_~	_~	_{p=1.000 n=12}
_{Check Time}	_0s	_0s	_~	_~	_~	_{p=1.000 n=12}
_{Emit Time}	_0.000s	_0.000s	_~	_~	_~	_{p=1.000 n=12}
_{Total Time}	_{0.213s (± 1.67%)}	_{0.209s (± 2.64%)}	_~	_0.193s	_0.222s	_{p=0.260 n=12}
_{xstate-main - native}
_Errors	₀	₀	_~	_~	_~	_{p=1.000 n=12}
_Symbols	_1,020,005	_1,020,005	_~	_~	_~	_{p=1.000 n=12}
_Types	_376,891	_376,891	_~	_~	_~	_{p=1.000 n=12}
_{Memory Used}	_{603,428k (± 0.02%)}	_{603,505k (± 0.01%)}	_~	_603,343k	_603,706k	_{p=0.370 n=12}
_{Memory Allocs}	_{4,748,886 (± 0.03%)}	_{4,750,217 (± 0.03%)}	_~	_4,746,931	_4,754,420	_{p=0.219 n=12}
_{Config Time}	_{0.003s (± 6.23%)}	_0.003s	_~	_~	_~	_{p=1.000 n=12}
_{Parse Time}	_{0.147s (± 3.25%)}	_{0.145s (± 2.55%)}	_~	_0.133s	_0.155s	_{p=0.433 n=12}
_{Bind Time}	_{0.046s (±17.01%)}	_{0.045s (±19.17%)}	_~	_0.032s	_0.071s	_{p=0.579 n=12}
_{Check Time}	_{1.094s (± 0.87%)}	_{1.093s (± 0.75%)}	_~	_1.070s	_1.113s	_{p=0.832 n=12}
_{Emit Time}	_0.000s	_0.000s	_~	_~	_~	_{p=1.000 n=12}
_{Total Time}	_{1.302s (± 0.89%)}	_{1.298s (± 0.77%)}	_~	_1.267s	_1.317s	_{p=0.400 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

Ryan Cavanaugh (RyanCavanaugh) · 2026-08-20T05:02:53Z

Thank you for contributing to the TypeScript native port!

Development has moved from this repository back to the main microsoft/TypeScript repository. GitHub does not have PR transfer functionality, so we're closing this PR here.

If this change is still relevant, please reopen it as a new pull request in microsoft/TypeScript. We'd appreciate your help carrying the contribution over, and we apologize for the extra work.

See microsoft/typescript-go#4918 for more information about the move.

Cache alias candidates for symbol accessibility

1642bbd

Copilot AI review requested due to automatic review settings May 30, 2026 14:19

Copilot AI reviewed May 30, 2026

View reviewed changes

Jake Bailey (jakebailey) mentioned this pull request Jun 2, 2026

Declaration emit spends significant CPU in getAliasForSymbolInContainer / getAlternativeContainingModules microsoft/TypeScript#63830

Open

Ryan Cavanaugh (RyanCavanaugh) added this to the Possible Improvement milestone Jun 3, 2026

Ryan Cavanaugh (RyanCavanaugh) added the Unmigrated PR This PR was open at the time of the repo move back to TypeScript label Aug 19, 2026

Ryan Cavanaugh (RyanCavanaugh) closed this Aug 20, 2026

Navigation Menu

Repository navigation

Cache alias candidates for symbol accessibility - #4102

Cache alias candidates for symbol accessibility#4102
Zzzen (Zzzen) wants to merge 1 commit into
microsoft:mainfrom
Zzzen:cache-symbol-accessibility-alias-candidates

Zzzen (Zzzen) commented May 30, 2026

Uh oh!

Copilot AI left a comment

Uh oh!

Jake Bailey (jakebailey) commented Aug 14, 2026

Uh oh!

typescript-automation Bot commented Aug 14, 2026 •

edited

Loading

Uh oh!

typescript-automation Bot commented Aug 14, 2026

tsc

Uh oh!

Ryan Cavanaugh (RyanCavanaugh) commented Aug 20, 2026

Uh oh!

Reviewers

Uh oh!

Assignees

Labels

Projects

Milestone

Development

Uh oh!

4 participants

Conversation

Zzzen (Zzzen) commented May 30, 2026

Uh oh!

Copilot AI left a comment

Choose a reason for hiding this comment

Pull request overview

Reviewed changes

Uh oh!

Jake Bailey (jakebailey) commented Aug 14, 2026

Uh oh!

typescript-automation Bot commented Aug 14, 2026 • edited Loading Uh oh! There was an error while loading. Please reload this page.

Uh oh!

Uh oh!

typescript-automation Bot commented Aug 14, 2026

tsc

Uh oh!

Ryan Cavanaugh (RyanCavanaugh) commented Aug 20, 2026

Uh oh!

Reviewers

Uh oh!

Assignees

Labels

Projects

Milestone

Development

Uh oh!

4 participants

typescript-automation Bot commented Aug 14, 2026 •

edited

Loading