FazBrowse GitHub Viewer | Trending |
URL:
| Home
Tools: [Download Repo ZIP]   [Original HTTPS Page]

Add cache to `getSimplifiedConditionalType` by ahejlsberg · Pull Request #64648 · microsoft/TypeScript · GitHub

  1. microsoft
  2. TypeScript

Repository navigation

Add cache to getSimplifiedConditionalType - #64648

Open
Anders Hejlsberg (ahejlsberg) wants to merge 1 commit into
mainfrom
cacheSimplifiedConditionalTypes
ConversationCommits (1)ChecksFiles changed
Open

Add cache to getSimplifiedConditionalType#64648
Anders Hejlsberg (ahejlsberg) wants to merge 1 commit into
mainfrom
cacheSimplifiedConditionalTypes

Conversation

Anders Hejlsberg (ahejlsberg) commented Oct 5, 2026

Copy link
Copy Markdown
Member

With this PR we consistently cache results in getSimplifiedType. Previously, we cached results for indexed access types but not conditional types. Found in performance experiments by Bun team.

Copilot AI balanced review requested due to automatic review settings October 5, 2026 19:34
typescript-automation Bot added Author: Team For Uncommitted Bug PR for untriaged, rejected, closed or missing bug labels Oct 5, 2026

Anders Hejlsberg (ahejlsberg) commented Oct 5, 2026

Copy link
Copy Markdown
Member Author

TypeScript Bot (@typescript-bot) test it

typescript-automation Bot commented Oct 5, 2026 •
edited
Loading

Copy link
Copy Markdown
Contributor

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

Command Status Results
test top400 ✅ Started ✅ Results
user test this ✅ Started ✅ Results
run dt ✅ Started ✅ Results
perf test this faster ✅ Started 👀 Results

typescript-automation Bot commented Oct 5, 2026

Copy link
Copy Markdown
Contributor

Hey Anders Hejlsberg (@ahejlsberg), the results of running the DT tests are ready.

Everything looks the same!

You can check the log here.

Copilot AI reviewed Oct 5, 2026
View reviewed changes

Copilot AI left a comment

Copy link
Copy Markdown
Contributor

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

Choose a reason Spam Abuse Off Topic Outdated Duplicate Resolved Low Quality

Copilot review overview

🟡 Changes recommended

The cache must distinguish read and write simplification modes to avoid reusing incorrect results.

Review effort: Balanced
Findings: 1

Open (1) What changed in this PR

Adds caching for simplified conditional types to improve checker performance.

Changes:

  • Adds a conditional-type cache kind.
  • Splits cached orchestration from simplification logic.
File Description
tsc/​internal/​checker/​checker.go Caches conditional-type simplification results.

💡 Add a code-review agent skill for context-aware, tailored reviews. Learn more in the docs.

Comment thread tsc/internal/checker/checker.go
}

func (c *Checker) getSimplifiedConditionalType(t *Type, writing bool) *Type {
key := CachedTypeKey{kind: CachedTypeKindSimplifiedConditionalType, typeId: t.id}

Mateusz Burzyński (Andarist) Oct 6, 2026

Copy link
Copy Markdown
Contributor

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

Choose a reason Spam Abuse Off Topic Outdated Duplicate Resolved Low Quality

regression tests for the above:

type Value<T extends { a: string; b: number }> = T["a" | "b"] extends unknown
  ? T["a" | "b"]
  : never;

function test<T extends { a: string; b: number }>(value: Value<T>, a: T["a"]) {
  const read: T["a"] | T["b"] = value;
  const write: Value<T> = a; // errors
}

typescript-automation Bot commented Oct 5, 2026

Copy link
Copy Markdown
Contributor

Anders Hejlsberg (@ahejlsberg)
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 141,886k (± 0.52%) 141,762k (± 0.38%) ~ 140,749k 143,935k p=0.590 n=12
Memory Allocs 2,193,643 (± 0.01%) 2,193,559 (± 0.01%) ~ 2,193,188 2,193,961 p=0.478 n=12
Config Time 0.000s 0.000s ~ ~ ~ p=1.000 n=12
Parse Time 0.041s (± 3.00%) 0.042s (± 3.35%) ~ 0.039s 0.046s p=0.612 n=12
Bind Time 0.012s (±14.80%) 0.012s (± 9.22%) ~ 0.010s 0.016s p=0.603 n=12
Check Time 0.497s (± 0.86%) 0.495s (± 0.61%) ~ 0.487s 0.502s p=0.448 n=12
Emit Time 0.272s (± 1.97%) 0.267s (± 2.00%) ~ 0.248s 0.279s p=0.325 n=12
Total Time 0.829s (± 0.88%) 0.823s (± 0.76%) ~ 0.808s 0.841s p=0.163 n=12
angular-1 - native
Errors 3 3 ~ ~ ~ p=1.000 n=12
Symbols 847,041 (± 0.06%) 847,021 (± 0.07%) ~ 845,274 848,203 p=0.887 n=12
Types 249,941 (± 0.00%) 249,941 (± 0.00%) ~ 249,937 249,950 p=0.444 n=12
Memory Used 789,597k (± 0.08%) 789,537k (± 0.09%) ~ 787,622k 791,463k p=0.977 n=12
Memory Allocs 12,867,863 (± 0.07%) 12,865,722 (± 0.06%) ~ 12,854,690 12,892,669 p=0.590 n=12
Config Time 0.017s (± 1.95%) 0.017s +0.000s (+ 2.51%) ~ ~ p=0.037 n=12
Parse Time 0.255s (± 3.01%) 0.259s (± 2.28%) ~ 0.239s 0.269s p=0.325 n=12
Bind Time 0.066s (±17.51%) 0.061s (±11.68%) 🟩-0.005s (- 7.57%) 0.057s 0.097s p=0.029 n=12
Check Time 0s 0s ~ ~ ~ p=1.000 n=12
Emit Time 1.601s (± 0.96%) 1.593s (± 0.74%) ~ 1.565s 1.630s p=0.561 n=12
Total Time 1.951s (± 1.09%) 1.941s (± 0.71%) ~ 1.906s 1.995s p=0.765 n=12
mui-docs - native
Errors 11,405 11,405 ~ ~ ~ p=1.000 n=12
Symbols 4,351,480 4,351,480 ~ ~ ~ p=1.000 n=12
Types 1,380,970 1,380,970 ~ ~ ~ p=1.000 n=12
Memory Used 2,975,362k (± 0.04%) 2,974,730k (± 0.04%) ~ 2,970,822k 2,978,067k p=0.671 n=12
Memory Allocs 32,840,597 (± 0.05%) 32,787,989 (± 0.05%) -52,608 (- 0.16%) 32,750,727 32,825,128 p=0.000 n=12
Config Time 0.017s (± 1.86%) 0.017s (± 1.70%) ~ 0.016s 0.017s p=1.000 n=12
Parse Time 0.504s (± 2.33%) 0.500s (± 2.13%) ~ 0.471s 0.523s p=0.660 n=12
Bind Time 0.002s 0.002s ~ ~ ~ p=1.000 n=12
Check Time 8.504s (± 0.87%) 8.481s (± 0.72%) ~ 8.289s 8.608s p=0.504 n=12
Emit Time 0.440s (± 7.01%) 0.434s (± 3.42%) ~ 0.419s 0.496s p=0.221 n=12
Total Time 10.228s (± 0.56%) 10.203s (± 0.42%) ~ 10.084s 10.322s p=0.401 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 1,694,289k (± 1.04%) 1,689,782k (± 1.03%) ~ 1,648,439k 1,724,345k p=0.755 n=12
Memory Allocs 92,233,428 (± 0.10%) 92,212,096 (± 0.17%) ~ 91,795,070 92,518,137 p=0.713 n=12
Config Time 0.003s (±14.26%) 0.003s (±12.31%) ~ 0.002s 0.004s p=0.496 n=12
Parse Time 0.197s (± 4.94%) 0.203s (± 3.69%) ~ 0.184s 0.218s p=0.325 n=12
Bind Time 0.000s 0.000s ~ ~ ~ p=1.000 n=12
Check Time 1.810s (± 0.59%) 1.803s (± 0.61%) ~ 1.775s 1.836s p=0.340 n=12
Emit Time 0.285s (± 4.91%) 0.303s (± 5.69%) ~ 0.261s 0.351s p=0.075 n=12
Total Time 23.396s (± 0.79%) 23.572s (± 0.78%) ~ 23.182s 24.077s p=0.219 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 313,310k (± 0.03%) 313,334k (± 0.03%) ~ 313,130k 313,597k p=0.843 n=12
Memory Allocs 4,623,066 (± 0.01%) 4,622,687 (± 0.02%) ~ 4,620,003 4,623,784 p=0.443 n=12
Config Time 0.001s 0.001s ~ ~ ~ p=1.000 n=12
Parse Time 0.115s (± 5.89%) 0.113s (± 5.28%) ~ 0.102s 0.135s p=0.619 n=12
Bind Time 0.000s 0.000s ~ ~ ~ p=1.000 n=12
Check Time 1.050s (± 0.49%) 1.044s (± 0.41%) ~ 1.033s 1.056s p=0.060 n=12
Emit Time 0.135s (±11.97%) 0.130s (±12.31%) ~ 0.091s 0.165s p=0.504 n=12
Total Time 1.351s (± 1.26%) 1.339s (± 1.03%) ~ 1.306s 1.387s p=0.139 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 273,915k (± 0.02%) 273,909k (± 0.04%) ~ 273,417k 274,129k p=0.660 n=12
Memory Allocs 1,615,853 (± 0.02%) 1,615,912 (± 0.01%) ~ 1,615,351 1,616,485 p=0.799 n=12
Config Time 0.000s 0.000s ~ ~ ~ p=1.000 n=12
Parse Time 0.099s (± 5.64%) 0.100s (± 5.26%) ~ 0.090s 0.112s p=0.744 n=12
Bind Time 0.036s (± 8.36%) 0.036s (± 8.36%) ~ 0.030s 0.045s p=0.898 n=12
Check Time 0.823s (± 0.52%) 0.824s (± 1.07%) ~ 0.811s 0.853s p=0.701 n=12
Emit Time 0.000s 0.000s ~ ~ ~ p=1.000 n=12
Total Time 0.973s (± 0.80%) 0.974s (± 1.31%) ~ 0.950s 1.014s p=0.899 n=12
vscode - native
Errors 380 380 ~ ~ ~ p=1.000 n=12
Symbols 10,591,714 10,591,714 ~ ~ ~ p=1.000 n=12
Types 3,537,253 3,537,253 ~ ~ ~ p=1.000 n=12
Memory Used 6,870,134k (± 0.02%) 6,868,705k (± 0.01%) ~ 6,866,420k 6,870,554k p=0.052 n=12
Memory Allocs 52,733,074 (± 0.02%) 52,724,484 (± 0.03%) -8,590 (- 0.02%) 52,707,198 52,793,992 p=0.045 n=12
Config Time 0.073s (± 0.37%) 0.073s (± 0.50%) ~ 0.072s 0.074s p=0.496 n=12
Parse Time 1.808s (± 3.58%) 1.775s (± 3.75%) ~ 1.621s 1.926s p=0.340 n=12
Bind Time 0.547s (±20.58%) 0.556s (±20.58%) ~ 0.428s 0.901s p=0.560 n=12
Check Time 13.323s (± 1.27%) 13.280s (± 1.22%) ~ 12.936s 13.584s p=0.799 n=12
Emit Time 4.636s (±10.41%) 5.155s (± 9.81%) ~ 3.916s 5.986s p=0.219 n=12
Total Time 20.467s (± 1.85%) 20.922s (± 1.82%) ~ 19.953s 21.570s p=0.060 n=12
webpack - native
Errors 589 589 ~ ~ ~ p=1.000 n=12
Symbols 1,303,232 1,303,232 ~ ~ ~ p=1.000 n=12
Types 618,887 618,887 ~ ~ ~ p=1.000 n=12
Memory Used 1,005,469k (± 0.02%) 1,005,584k (± 0.01%) ~ 1,005,244k 1,005,927k p=0.551 n=12
Memory Allocs 6,545,098 (± 0.03%) 6,539,428 (± 0.02%) -5,670 (- 0.09%) 6,536,137 6,543,213 p=0.000 n=12
Config Time 0.009s 0.009s ~ ~ ~ p=1.000 n=12
Parse Time 0.282s (± 3.42%) 0.281s (± 2.43%) ~ 0.263s 0.307s p=0.723 n=12
Bind Time 0.085s (±20.63%) 0.084s (±14.27%) ~ 0.063s 0.120s p=0.680 n=12
Check Time 1.991s (± 0.58%) 1.980s (± 0.92%) ~ 1.939s 2.022s p=0.325 n=12
Emit Time 0.000s 0.000s ~ ~ ~ p=1.000 n=12
Total Time 2.400s (± 0.31%) 2.393s (± 0.62%) ~ 2.341s 2.422s p=0.921 n=12
xstate-main - native
Errors 0 0 ~ ~ ~ p=1.000 n=12
Symbols 1,055,167 1,055,167 ~ ~ ~ p=1.000 n=12
Types 387,939 387,939 ~ ~ ~ p=1.000 n=12
Memory Used 610,319k (± 0.02%) 610,351k (± 0.03%) ~ 609,818k 610,905k p=0.831 n=12
Memory Allocs 4,880,869 (± 0.14%) 4,873,857 (± 0.08%) ~ 4,864,898 4,886,162 p=0.143 n=12
Config Time 0.003s (± 8.64%) 0.003s (±10.34%) ~ 0.002s 0.003s p=1.000 n=12
Parse Time 0.143s (± 2.88%) 0.145s (± 3.16%) ~ 0.134s 0.160s p=0.541 n=12
Bind Time 0.043s (±19.29%) 0.041s (±14.82%) ~ 0.032s 0.061s p=0.853 n=12
Check Time 1.291s (± 0.52%) 1.295s (± 1.01%) ~ 1.272s 1.343s p=0.944 n=12
Emit Time 0.000s 0.000s ~ ~ ~ p=1.000 n=12
Total Time 1.489s (± 0.54%) 1.494s (± 0.78%) ~ 1.474s 1.543s 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

typescript-automation Bot commented Oct 5, 2026

Copy link
Copy Markdown
Contributor

Anders Hejlsberg (@ahejlsberg) Here are the results of running the user tests with tsc comparing baseline and pr:

Everything looks good!

typescript-automation Bot commented Oct 5, 2026

Copy link
Copy Markdown
Contributor

Anders Hejlsberg (@ahejlsberg) Here are the results of running the top 400 repos with tsc comparing baseline and pr:

Everything looks good!

Anders Hejlsberg (ahejlsberg) commented Oct 5, 2026

Copy link
Copy Markdown
Member Author

No measurable effect on perf tests, likely because we don't have react tests which is where it's supposed to help.

This branch has not been deployed

No deployments
This file contains hidden or bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters. Learn more about bidirectional Unicode characters
Show hidden characters
Sign up for free to join this conversation on GitHub. Already have an account? Sign in to comment

Reviewers

Copilot code review Copilot
Copilot review effort
Applies to this pull request for everyone.Learn more about Copilot code review.
Copilot left review comments
+1 more reviewer
Mateusz Burzyński (Andarist) Andarist left review comments
Reviewers whose approvals may not affect merge requirements

At least 1 approving review is required to merge this pull request.

Assignees

Anders Hejlsberg (ahejlsberg)

Labels

Author: Team For Uncommitted Bug PR for untriaged, rejected, closed or missing bug

Projects

PR Backlog
Status: Not started

Milestone

No milestone

Development

Successfully merging this pull request may close these issues.

3 participants

Back | FazBrowse Home | New Git URL