fix: report optional-chain tagged templates after non-null assertions by camc314 · Pull Request #64226 · microsoft/TypeScript

Cameron (camc314) · 2026-09-10T09:59:20Z

Non-null assertions currently allow tagged templates to bypass TS1358 errors:

var f: any;
f?.x!`text`; // Previously accepted; now reports TS1358 (Tagged template expressions are not permitted in an optional chain.).

Update the tagged-template grammar check to look through non-null assertions when checking for an optional chain.

typescript-automation · 2026-09-10T09:59:25Z

This PR doesn't have any linked issues. Please open an issue that references this PR. From there we can discuss and prioritise.

Copilot

Copilot was unable to review this pull request because the user who requested the review has reached their quota limit.

Jake Bailey (jakebailey) · 2026-09-15T17:54:03Z

TypeScript Bot (@typescript-bot) test it

typescript-automation · 2026-09-15T17:54:08Z

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
`perf test this faster`	✅ Started	👀 Results

Copilot

🟢 Approval recommended

The focused grammar change correctly preserves parenthesis boundaries and has comprehensive regression baselines.

Review details

Files reviewed: 10/10 changed files
Comments generated: 0 new
Review effort level: Balanced

typescript-automation · 2026-09-15T18:26:18Z

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}	_{148,405k (± 0.60%)}	_{148,478k (± 0.38%)}	_~	_147,181k	_149,844k	_{p=0.755 n=12}
_{Memory Allocs}	_{2,271,241 (± 0.00%)}	_{2,271,293 (± 0.01%)}	_~	_2,271,048	_2,271,603	_{p=0.514 n=12}
_{Config Time}	_0.000s	_0.000s	_~	_~	_~	_{p=1.000 n=12}
_{Parse Time}	_{0.050s (± 2.73%)}	_{0.051s (± 2.41%)}	_~	_0.047s	_0.054s	_{p=0.534 n=12}
_{Bind Time}	_{0.016s (±11.24%)}	_{0.015s (±14.22%)}	_~	_0.012s	_0.022s	_{p=0.294 n=12}
_{Check Time}	_{0.596s (± 0.95%)}	_{0.593s (± 0.61%)}	_~	_0.582s	_0.599s	_{p=0.469 n=12}
_{Emit Time}	_{0.328s (± 1.62%)}	_{0.327s (± 1.91%)}	_~	_0.314s	_0.342s	_{p=0.853 n=12}
_{Total Time}	_{0.999s (± 0.66%)}	_{0.994s (± 0.71%)}	_~	_0.979s	_1.013s	_{p=0.284 n=12}
_{angular-1 - native}
_Errors	₃	₃	_~	_~	_~	_{p=1.000 n=12}
_Symbols	_{846,918 (± 0.08%)}	_{847,261 (± 0.07%)}	_~	_845,756	_849,169	_{p=0.514 n=12}
_Types	_{249,851 (± 0.00%)}	_{249,852 (± 0.00%)}	_~	_249,849	_249,863	_{p=0.616 n=12}
_{Memory Used}	_{793,042k (± 0.03%)}	_{793,505k (± 0.06%)}	_~	_792,733k	_795,004k	_{p=0.266 n=12}
_{Memory Allocs}	_{12,954,569 (± 0.05%)}	_{12,962,306 (± 0.09%)}	_~	_12,949,197	_13,012,254	_{p=0.266 n=12}
_{Config Time}	_0.020s	_{0.020s (± 0.91%)}	_~	_0.019s	_0.020s	_{p=1.000 n=12}
_{Parse Time}	_{0.342s (± 2.87%)}	_{0.353s (± 1.63%)}	_~	_0.336s	_0.363s	_{p=0.053 n=12}
_{Bind Time}	_{0.088s (±19.49%)}	_{0.074s (± 1.50%)}	_~	_0.072s	_0.079s	_{p=0.081 n=12}
_{Check Time}	_0s	_0s	_~	_~	_~	_{p=1.000 n=12}
_{Emit Time}	_{1.988s (± 1.24%)}	_{1.955s (± 0.48%)}	_{-0.033s (- 1.66%)}	_1.931s	_1.982s	_{p=0.002 n=12}
_{Total Time}	_{2.456s (± 1.47%)}	_{2.418s (± 0.51%)}	_~	_2.389s	_2.452s	_{p=0.054 n=12}
_{mui-docs - native}
_Errors	_{11,318 (± 0.03%)}	_{11,317 (± 0.04%)}	_~	_11,295	_11,322	_{p=0.574 n=12}
_Symbols	_4,082,255	_4,082,255	_~	_~	_~	_{p=1.000 n=12}
_Types	_1,497,312	_1,497,312	_~	_~	_~	_{p=1.000 n=12}
_{Memory Used}	_{4,080,657k (± 0.04%)}	_{4,079,950k (± 0.03%)}	_~	_4,077,634k	_4,083,454k	_{p=0.514 n=12}
_{Memory Allocs}	_{43,628,952 (± 0.04%)}	_{43,628,104 (± 0.04%)}	_~	_43,579,500	_43,680,288	_{p=0.843 n=12}
_{Config Time}	_0.019s	_0.019s	_~	_~	_~	_{p=1.000 n=12}
_{Parse Time}	_{0.691s (± 1.09%)}	_{0.682s (± 2.15%)}	_~	_0.637s	_0.713s	_{p=0.325 n=12}
_{Bind Time}	_{0.003s (±13.14%)}	_{0.003s (±26.03%)}	_~	_0.002s	_0.006s	_{p=1.000 n=12}
_{Check Time}	_{17.050s (± 0.47%)}	_{17.040s (± 0.39%)}	_~	_16.809s	_17.207s	_{p=0.701 n=12}
_{Emit Time}	_{0.529s (± 1.86%)}	_{0.560s (±15.23%)}	_~	_0.515s	_0.990s	_{p=0.202 n=12}
_{Total Time}	_{19.218s (± 0.23%)}	_{19.240s (± 0.30%)}	_~	_19.134s	_19.452s	_{p=0.660 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}	_{1,647,763k (± 0.25%)}	_{1,648,493k (± 0.23%)}	_~	_1,635,922k	_1,656,650k	_{p=0.932 n=12}
_{Memory Allocs}	_{97,061,187 (± 0.03%)}	_{97,056,188 (± 0.03%)}	_~	_96,969,057	_97,125,796	_{p=0.713 n=12}
_{Config Time}	_{0.005s (±12.66%)}	_{0.006s (±13.97%)}	_~	_0.004s	_0.007s	_{p=0.702 n=12}
_{Parse Time}	_{0.235s (± 3.07%)}	_{0.240s (± 2.68%)}	_~	_0.220s	_0.252s	_{p=0.354 n=12}
_{Bind Time}	_0.000s	_{0.000s (±217.90%)}	_~	_0.000s	_0.001s	_{p=1.000 n=12}
_{Check Time}	_{2.163s (± 0.31%)}	_{2.158s (± 0.39%)}	_~	_2.133s	_2.185s	_{p=0.224 n=12}
_{Emit Time}	_{0.334s (± 5.11%)}	_{0.345s (± 5.30%)}	_~	_0.300s	_0.373s	_{p=0.224 n=12}
_{Total Time}	_{29.895s (± 0.63%)}	_{29.996s (± 0.67%)}	_~	_29.400s	_30.452s	_{p=0.410 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}	_{319,526k (± 0.02%)}	_{319,484k (± 0.02%)}	_~	_319,281k	_319,719k	_{p=0.386 n=12}
_{Memory Allocs}	_{4,672,698 (± 0.01%)}	_{4,672,706 (± 0.01%)}	_~	_4,671,537	_4,673,935	_{p=0.977 n=12}
_{Config Time}	_0.001s	_0.001s	_~	_~	_~	_{p=1.000 n=12}
_{Parse Time}	_{0.095s (± 3.06%)}	_{0.092s (± 6.67%)}	_~	_0.080s	_0.106s	_{p=0.258 n=12}
_{Bind Time}	_0.000s	_0.000s	_~	_~	_~	_{p=1.000 n=12}
_{Check Time}	_{0.874s (± 0.33%)}	_{0.874s (± 0.47%)}	_~	_0.864s	_0.888s	_{p=0.742 n=12}
_{Emit Time}	_{0.108s (±13.14%)}	_{0.117s (±10.40%)}	_~	_0.078s	_0.132s	_{p=0.468 n=12}
_{Total Time}	_{1.121s (± 1.05%)}	_{1.126s (± 0.93%)}	_~	_1.087s	_1.152s	_{p=0.401 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}	_{277,206k (± 0.02%)}	_{277,177k (± 0.02%)}	_~	_277,002k	_277,321k	_{p=0.630 n=12}
_{Memory Allocs}	_{1,641,803 (± 0.01%)}	_{1,641,748 (± 0.01%)}	_~	_1,641,279	_1,642,262	_{p=0.671 n=12}
_{Config Time}	_{0.000s (±77.74%)}	_{0.001s (±46.46%)}	_~	_0.000s	_0.001s	_{p=0.414 n=12}
_{Parse Time}	_{0.103s (± 4.53%)}	_{0.099s (± 3.11%)}	_~	_0.092s	_0.108s	_{p=0.202 n=12}
_{Bind Time}	_{0.037s (±10.60%)}	_{0.037s (±13.36%)}	_~	_0.028s	_0.053s	_{p=0.679 n=12}
_{Check Time}	_{0.833s (± 0.49%)}	_{0.835s (± 0.59%)}	_~	_0.822s	_0.847s	_{p=0.311 n=12}
_{Emit Time}	_0.000s	_0.000s	_~	_~	_~	_{p=1.000 n=12}
_{Total Time}	_{0.986s (± 0.89%)}	_{0.986s (± 0.82%)}	_~	_0.966s	_1.011s	_{p=0.788 n=12}
_{vscode - native}
_Errors	₃₅₁	₃₅₁	_~	_~	_~	_{p=1.000 n=12}
_Symbols	_8,856,348	_8,856,348	_~	_~	_~	_{p=1.000 n=12}
_Types	_3,024,061	_3,024,061	_~	_~	_~	_{p=1.000 n=12}
_{Memory Used}	_{5,924,126k (± 0.02%)}	_{5,923,707k (± 0.01%)}	_~	_5,922,236k	_5,925,990k	_{p=0.671 n=12}
_{Memory Allocs}	_{45,567,431 (± 0.01%)}	_{45,571,400 (± 0.03%)}	_~	_45,559,966	_45,631,303	_{p=0.843 n=12}
_{Config Time}	_{0.065s (± 0.51%)}	_{0.065s (± 0.87%)}	_~	_0.064s	_0.067s	_{p=0.338 n=12}
_{Parse Time}	_{1.722s (± 3.18%)}	_{1.691s (± 3.27%)}	_~	_1.585s	_1.824s	_{p=0.370 n=12}
_{Bind Time}	_{0.453s (±17.63%)}	_{0.510s (±16.62%)}	_~	_0.372s	_0.702s	_{p=0.384 n=12}
_{Check Time}	_{11.105s (± 1.44%)}	_{11.040s (± 1.66%)}	_~	_10.712s	_11.387s	_{p=0.551 n=12}
_{Emit Time}	_{4.144s (±11.21%)}	_{4.454s (±12.89%)}	_~	_3.352s	_5.342s	_{p=0.242 n=12}
_{Total Time}	_{17.589s (± 1.90%)}	_{17.867s (± 2.44%)}	_~	_17.040s	_18.579s	_{p=0.434 n=12}
_{webpack - native}
_Errors	₈₃₇	₈₃₇	_~	_~	_~	_{p=1.000 n=12}
_Symbols	_1,125,807	_1,125,807	_~	_~	_~	_{p=1.000 n=12}
_Types	_480,798	_480,798	_~	_~	_~	_{p=1.000 n=12}
_{Memory Used}	_{813,947k (± 0.03%)}	_{813,907k (± 0.01%)}	_~	_813,724k	_814,345k	_{p=0.630 n=12}
_{Memory Allocs}	_{5,145,400 (± 0.02%)}	_{5,145,195 (± 0.02%)}	_~	_5,143,496	_5,149,502	_{p=0.410 n=12}
_{Config Time}	_0.007s	_0.007s	_~	_~	_~	_{p=1.000 n=12}
_{Parse Time}	_{0.194s (± 3.60%)}	_{0.190s (± 3.24%)}	_~	_0.175s	_0.205s	_{p=0.326 n=12}
_{Bind Time}	_{0.044s (±12.92%)}	_{0.048s (±18.62%)}	_~	_0.038s	_0.075s	_{p=0.944 n=12}
_{Check Time}	_{1.366s (± 0.80%)}	_{1.363s (± 0.46%)}	_~	_1.339s	_1.377s	_{p=0.486 n=12}
_{Emit Time}	_0.000s	_0.000s	_~	_~	_~	_{p=1.000 n=12}
_{Total Time}	_{1.641s (± 0.70%)}	_{1.636s (± 0.65%)}	_~	_1.602s	_1.660s	_{p=0.451 n=12}
_{xstate-main - native}
_Errors	₀	₀	_~	_~	_~	_{p=1.000 n=12}
_Symbols	_1,045,691	_1,045,691	_~	_~	_~	_{p=1.000 n=12}
_Types	_381,854	_381,854	_~	_~	_~	_{p=1.000 n=12}
_{Memory Used}	_{611,203k (± 0.01%)}	_{611,229k (± 0.01%)}	_~	_611,087k	_611,421k	_{p=0.831 n=12}
_{Memory Allocs}	_{4,828,162 (± 0.05%)}	_{4,826,869 (± 0.06%)}	_~	_4,822,935	_4,836,768	_{p=0.284 n=12}
_{Config Time}	_{0.003s (± 8.64%)}	_{0.003s (± 6.23%)}	_~	_0.002s	_0.003s	_{p=1.000 n=12}
_{Parse Time}	_{0.144s (± 3.24%)}	_{0.147s (± 3.31%)}	_~	_0.136s	_0.160s	_{p=0.353 n=12}
_{Bind Time}	_{0.050s (±15.90%)}	_{0.046s (±18.57%)}	_~	_0.034s	_0.069s	_{p=0.521 n=12}
_{Check Time}	_{1.190s (± 0.42%)}	_{1.197s (± 0.54%)}	_~	_1.176s	_1.215s	_{p=0.137 n=12}
_{Emit Time}	_0.000s	_0.000s	_~	_~	_~	_{p=1.000 n=12}
_{Total Time}	_{1.401s (± 0.77%)}	_{1.405s (± 0.69%)}	_~	_1.371s	_1.428s	_{p=0.640 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 · 2026-09-15T19:02:26Z

Jake Bailey (@jakebailey) Here are the results of running the user tests with tsc comparing main and refs/pull/64226/merge:

There were infrastructure failures potentially unrelated to your change:

2 instances of "Package install failed"
1 instance of "Git clone failed"

Otherwise...

Everything looks good!

typescript-automation · 2026-09-15T19:18:27Z

Jake Bailey (@jakebailey) Here are the results of running the top 400 repos with tsc comparing main and refs/pull/64226/merge:

Everything looks good!

Copilot

🟢 Approval recommended

The focused grammar fix correctly preserves parenthesis boundaries and is covered by comprehensive compiler baselines.

Review details

Files reviewed: 10/10 changed files
Comments generated: 0 new
Review effort level: Balanced

Cameron (camc314) · 2026-09-16T04:58:55Z

I can't see logs for these so I assume they're fine?

Jake Bailey (jakebailey) · 2026-09-16T16:48:25Z

The DT runner is currently broken in TS7+, so can be ignored.

fix: report optional-chain tagged templates after non-null assertions

eee5e38

Copilot AI balanced review requested due to automatic review settings September 10, 2026 09:59

github-project-automation Bot added this to PR Backlog Sep 10, 2026

github-project-automation Bot moved this to Not started in PR Backlog Sep 10, 2026

typescript-automation Bot added the For Uncommitted Bug PR for untriaged, rejected, closed or missing bug label Sep 10, 2026

Copilot AI reviewed Sep 10, 2026

Jake Bailey (jakebailey) requested a balanced review from Copilot September 15, 2026 17:53

Copilot started reviewing on behalf of Jake Bailey (jakebailey) September 15, 2026 17:54 View session

Copilot AI reviewed Sep 15, 2026

View reviewed changes

Jake Bailey (jakebailey) requested a balanced review from Copilot September 15, 2026 22:00

Copilot started reviewing on behalf of Jake Bailey (jakebailey) September 15, 2026 22:01 View session

Copilot AI reviewed Sep 15, 2026

View reviewed changes

Jake Bailey (jakebailey) requested a review from Ryan Cavanaugh (RyanCavanaugh) September 16, 2026 17:26

Navigation Menu

fix: report optional-chain tagged templates after non-null assertions - #64226

fix: report optional-chain tagged templates after non-null assertions#64226
Cameron (camc314) wants to merge 1 commit into
microsoft:mainfrom
camc314:c/missing-1358

Cameron (camc314) commented Sep 10, 2026 •

edited

Loading

Uh oh!

typescript-automation Bot commented Sep 10, 2026

Uh oh!

Copilot AI left a comment

Uh oh!

Jake Bailey (jakebailey) commented Sep 15, 2026

Uh oh!

typescript-automation Bot commented Sep 15, 2026 •

edited

Loading

Uh oh!

Copilot AI left a comment

Uh oh!

typescript-automation Bot commented Sep 15, 2026

tsc

Uh oh!

typescript-automation Bot commented Sep 15, 2026

Uh oh!

typescript-automation Bot commented Sep 15, 2026

Uh oh!

Copilot AI left a comment

Uh oh!

Cameron (camc314) commented Sep 16, 2026

Uh oh!

Jake Bailey (jakebailey) commented Sep 16, 2026

Uh oh!

Reviewers

Assignees

Labels

Projects

Milestone

Development

Uh oh!

3 participants

Conversation

Cameron (camc314) commented Sep 10, 2026 • edited Loading Uh oh! There was an error while loading. Please reload this page.

Uh oh!

Uh oh!

typescript-automation Bot commented Sep 10, 2026

Uh oh!

Copilot AI left a comment

Choose a reason for hiding this comment

Uh oh!

Jake Bailey (jakebailey) commented Sep 15, 2026

Uh oh!

typescript-automation Bot commented Sep 15, 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

🟢 Approval recommended

Uh oh!

typescript-automation Bot commented Sep 15, 2026

tsc

Uh oh!

typescript-automation Bot commented Sep 15, 2026

Uh oh!

typescript-automation Bot commented Sep 15, 2026

Uh oh!

Copilot AI left a comment

Choose a reason for hiding this comment

🟢 Approval recommended

Uh oh!

Cameron (camc314) commented Sep 16, 2026

Uh oh!

Jake Bailey (jakebailey) commented Sep 16, 2026

Uh oh!

Reviewers

Assignees

Labels

Projects

Milestone

Development

Uh oh!

3 participants

Cameron (camc314) commented Sep 10, 2026 •

edited

Loading

typescript-automation Bot commented Sep 15, 2026 •

edited

Loading