fix(60908): Unexpected "'Type' is declared but its value is never read." error with jsdoc @import syntax #60921

a-tarasyuk · 2025-01-06T13:37:21Z

Fixes #60908
Fixes #58368

…ainer

regseb · 2025-01-11T17:45:42Z

Maybe this pull request also fixes the issue #58368 (and its duplicate #58969).

jakebailey · 2025-01-13T19:13:45Z

@typescript-bot test it
@typescript-bot pack this

typescript-bot · 2025-01-13T19:13:49Z

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

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

typescript-bot · 2025-01-13T19:15:54Z

Hey @jakebailey, I've packed this into an installable tgz. You can install it for testing by referencing it in your package.json like so:

{
    "devDependencies": {
        "typescript": "https://typescript.visualstudio.com/cf7ac146-d525-443c-b23c-0d58337efebc/_apis/build/builds/164532/artifacts?artifactName=tgz&fileId=878483ACBB3ADF254CED52B3B2040E424AF942FC5EA4126C9A5FE68FE33F4ADC02&fileName=/typescript-5.8.0-insiders.20250113.tgz"
    }
}

and then running npm install.

There is also a playground for this build and an npm module you can use via "typescript": "npm:@typescript-deploys/[email protected]".;

typescript-bot · 2025-01-13T19:34:11Z

Hey @jakebailey, the results of running the DT tests are ready.

Everything looks the same!

You can check the log here.

typescript-bot · 2025-01-13T19:35:55Z

@jakebailey Here are the results of running the user tests with tsc comparing main and refs/pull/60921/merge:

Everything looks good!

typescript-bot · 2025-01-13T20:02:45Z

@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 - node (v18.15.0, x64)}
_Errors	₃₄	₃₄	_~	_~	_~	_{p=1.000 n=6}
_Symbols	_62,390	_62,390	_~	_~	_~	_{p=1.000 n=6}
_Types	_50,395	_50,395	_~	_~	_~	_{p=1.000 n=6}
_{Memory used}	_{195,638k (± 0.92%)}	_{195,640k (± 0.95%)}	_~	_193,245k	_196,877k	_{p=0.521 n=6}
_{Parse Time}	_{1.61s (± 1.24%)}	_{1.61s (± 2.07%)}	_~	_1.54s	_1.63s	_{p=1.000 n=6}
_{Bind Time}	_{0.87s (± 0.93%)}	_{0.88s (± 1.12%)}	_~	_0.87s	_0.89s	_{p=0.498 n=6}
_{Check Time}	_{11.79s (± 0.56%)}	_{11.87s (± 0.95%)}	_~	_11.75s	_12.01s	_{p=0.423 n=6}
_{Emit Time}	_{3.34s (± 3.05%)}	_{3.31s (± 1.17%)}	_~	_3.27s	_3.37s	_{p=0.872 n=6}
_{Total Time}	_{17.62s (± 0.62%)}	_{17.66s (± 0.75%)}	_~	_17.51s	_17.82s	_{p=0.748 n=6}
_{angular-1 - node (v18.15.0, x64)}
_Errors	₃₇	₃₇	_~	_~	_~	_{p=1.000 n=6}
_Symbols	_947,969	_947,969	_~	_~	_~	_{p=1.000 n=6}
_Types	_410,955	_410,955	_~	_~	_~	_{p=1.000 n=6}
_{Memory used}	_{1,225,839k (± 0.01%)}	_{1,225,843k (± 0.00%)}	_~	_1,225,769k	_1,225,886k	_{p=0.936 n=6}
_{Parse Time}	_{8.04s (± 0.82%)}	_{8.04s (± 1.02%)}	_~	_7.93s	_8.13s	_{p=0.747 n=6}
_{Bind Time}	_{2.28s (± 0.28%)}	_{2.28s (± 1.22%)}	_~	_2.25s	_2.32s	_{p=0.739 n=6}
_{Check Time}	_{38.04s (± 0.21%)}	_{38.23s (± 0.60%)}	_~	_37.98s	_38.56s	_{p=0.078 n=6}
_{Emit Time}	_{18.20s (± 0.97%)}	_{18.17s (± 0.84%)}	_~	_17.96s	_18.38s	_{p=0.810 n=6}
_{Total Time}	_{66.56s (± 0.37%)}	_{66.72s (± 0.39%)}	_~	_66.41s	_67.14s	_{p=0.422 n=6}
_{mui-docs - node (v18.15.0, x64)}
_Errors	₀	₀	_~	_~	_~	_{p=1.000 n=6}
_Symbols	_2,445,991	_2,445,991	_~	_~	_~	_{p=1.000 n=6}
_Types	_896,571	_896,571	_~	_~	_~	_{p=1.000 n=6}
_{Memory used}	_{2,309,956k (± 0.00%)}	_{2,309,948k (± 0.01%)}	_~	_2,309,803k	_2,310,154k	_{p=0.689 n=6}
_{Parse Time}	_{10.79s (± 0.39%)}	_{10.83s (± 0.39%)}	_~	_10.76s	_10.87s	_{p=0.170 n=6}
_{Bind Time}	_{2.51s (± 1.33%)}	_{2.53s (± 0.82%)}	_~	_2.50s	_2.55s	_{p=0.121 n=6}
_{Check Time}	_{87.76s (± 1.05%)}	_{88.81s (± 1.88%)}	_~	_87.07s	_91.07s	_{p=0.298 n=6}
_{Emit Time}	_{0.34s (± 3.06%)}	_{0.35s (± 2.35%)}	_~	_0.34s	_0.36s	_{p=0.121 n=6}
_{Total Time}	_{101.39s (± 0.92%)}	_{102.52s (± 1.59%)}	_~	_100.84s	_104.67s	_{p=0.149 n=6}
_{self-build-src - node (v18.15.0, x64)}
_Errors	₀	₀	_~	_~	_~	_{p=1.000 n=6}
_Symbols	_1,228,377	_1,228,378	_{+1 (+ 0.00%)}	_~	_~	_{p=0.001 n=6}
_Types	_266,839	_266,839	_~	_~	_~	_{p=1.000 n=6}
_{Memory used}	_{2,727,704k (±14.62%)}	_{2,630,600k (±13.74%)}	_~	_2,360,771k	_3,091,916k	_{p=0.378 n=6}
_{Parse Time}	_{6.70s (± 1.30%)}	_{6.59s (± 1.85%)}	_~	_6.47s	_6.79s	_{p=0.149 n=6}
_{Bind Time}	_{2.16s (± 1.93%)}	_{2.17s (± 1.41%)}	_~	_2.11s	_2.19s	_{p=0.806 n=6}
_{Check Time}	_{42.62s (± 0.37%)}	_{42.82s (± 0.86%)}	_~	_42.24s	_43.28s	_{p=0.230 n=6}
_{Emit Time}	_{3.47s (± 1.96%)}	_{3.50s (± 2.13%)}	_~	_3.42s	_3.59s	_{p=0.471 n=6}
_{Total Time}	_{54.94s (± 0.35%)}	_{55.08s (± 0.78%)}	_~	_54.36s	_55.57s	_{p=0.230 n=6}
_{self-build-src-public-api - node (v18.15.0, x64)}
_Errors	₀	₀	_~	_~	_~	_{p=1.000 n=6}
_Symbols	_1,228,377	_1,228,378	_{+1 (+ 0.00%)}	_~	_~	_{p=0.001 n=6}
_Types	_266,839	_266,839	_~	_~	_~	_{p=1.000 n=6}
_{Memory used}	_{3,157,184k (± 0.03%)}	_{3,156,995k (± 0.02%)}	_~	_3,156,486k	_3,157,887k	_{p=0.936 n=6}
_{Parse Time}	_{8.69s (± 0.52%)}	_{8.67s (± 0.82%)}	_~	_8.56s	_8.74s	_{p=0.748 n=6}
_{Bind Time}	_{2.64s (± 0.52%)}	_{2.63s (± 1.54%)}	_~	_2.58s	_2.67s	_{p=0.514 n=6}
_{Check Time}	_{53.31s (± 0.26%)}	_{53.37s (± 0.37%)}	_~	_53.07s	_53.63s	_{p=0.575 n=6}
_{Emit Time}	_{4.32s (± 1.93%)}	_{4.31s (± 1.60%)}	_~	_4.21s	_4.38s	_{p=0.470 n=6}
_{Total Time}	_{68.96s (± 0.16%)}	_{68.96s (± 0.39%)}	_~	_68.63s	_69.29s	_{p=0.810 n=6}
_{self-compiler - node (v18.15.0, x64)}
_Errors	₀	₀	_~	_~	_~	_{p=1.000 n=6}
_Symbols	_262,624	_262,625	_{+1 (+ 0.00%)}	_~	_~	_{p=0.001 n=6}
_Types	_106,695	_106,695	_~	_~	_~	_{p=1.000 n=6}
_{Memory used}	_{440,851k (± 0.01%)}	_{440,784k (± 0.02%)}	_~	_440,628k	_440,897k	_{p=0.471 n=6}
_{Parse Time}	_{3.56s (± 1.19%)}	_{3.52s (± 0.66%)}	_~	_3.49s	_3.54s	_{p=0.107 n=6}
_{Bind Time}	_{1.31s (± 0.57%)}	_{1.31s (± 0.79%)}	_~	_1.30s	_1.33s	_{p=0.931 n=6}
_{Check Time}	_{19.03s (± 0.36%)}	_{18.94s (± 0.31%)}	_~	_18.87s	_19.03s	_{p=0.077 n=6}
_{Emit Time}	_{1.54s (± 0.71%)}	_{1.54s (± 0.53%)}	_~	_1.52s	_1.54s	_{p=0.389 n=6}
_{Total Time}	_{25.44s (± 0.22%)}	_{25.31s (± 0.29%)}	_{-0.13s (- 0.50%)}	_25.21s	_25.39s	_{p=0.013 n=6}
_{ts-pre-modules - node (v18.15.0, x64)}
_Errors	₇₀	₇₀	_~	_~	_~	_{p=1.000 n=6}
_Symbols	_226,095	_226,095	_~	_~	_~	_{p=1.000 n=6}
_Types	_94,488	_94,488	_~	_~	_~	_{p=1.000 n=6}
_{Memory used}	_{371,651k (± 0.01%)}	_{371,746k (± 0.04%)}	_~	_371,643k	_371,933k	_{p=0.575 n=6}
_{Parse Time}	_{2.91s (± 1.16%)}	_{2.89s (± 1.11%)}	_~	_2.85s	_2.93s	_{p=0.125 n=6}
_{Bind Time}	_{1.60s (± 1.33%)}	_{1.59s (± 0.51%)}	_~	_1.58s	_1.60s	_{p=0.677 n=6}
_{Check Time}	_{16.52s (± 0.50%)}	_{16.48s (± 0.17%)}	_~	_16.45s	_16.52s	_{p=0.873 n=6}
_{Emit Time}	_{0.00s (±244.70%)}	_0.00s	_~	_~	_~	_{p=0.405 n=6}
_{Total Time}	_{21.03s (± 0.59%)}	_{20.96s (± 0.20%)}	_~	_20.91s	_21.02s	_{p=0.630 n=6}
_{vscode - node (v18.15.0, x64)}
_Errors	₃	₃	_~	_~	_~	_{p=1.000 n=6}
_Symbols	_3,238,966	_3,238,966	_~	_~	_~	_{p=1.000 n=6}
_Types	_1,115,494	_1,115,494	_~	_~	_~	_{p=1.000 n=6}
_{Memory used}	_{3,306,731k (± 0.01%)}	_{3,306,843k (± 0.01%)}	_~	_3,306,321k	_3,307,138k	_{p=0.470 n=6}
_{Parse Time}	_{14.20s (± 0.16%)}	_{14.18s (± 0.49%)}	_~	_14.11s	_14.31s	_{p=0.294 n=6}
_{Bind Time}	_{4.59s (± 2.63%)}	_{4.65s (± 2.93%)}	_~	_4.53s	_4.84s	_{p=0.373 n=6}
_{Check Time}	_{88.19s (± 1.33%)}	_{89.66s (± 2.27%)}	_~	_87.12s	_92.27s	_{p=0.575 n=6}
_{Emit Time}	_{27.92s (± 1.83%)}	_{27.75s (± 1.96%)}	_~	_27.27s	_28.69s	_{p=0.422 n=6}
_{Total Time}	_{134.90s (± 1.22%)}	_{136.24s (± 1.60%)}	_~	_133.45s	_139.68s	_{p=0.298 n=6}
_{webpack - node (v18.15.0, x64)}
_Errors	₀	₀	_~	_~	_~	_{p=1.000 n=6}
_Symbols	_291,595	_291,595	_~	_~	_~	_{p=1.000 n=6}
_Types	_118,971	_118,971	_~	_~	_~	_{p=1.000 n=6}
_{Memory used}	_{445,325k (± 0.02%)}	_{445,429k (± 0.02%)}	_~	_445,308k	_445,560k	_{p=0.128 n=6}
_{Parse Time}	_{4.10s (± 0.93%)}	_{4.10s (± 1.33%)}	_~	_4.03s	_4.20s	_{p=1.000 n=6}
_{Bind Time}	_{1.76s (± 0.46%)}	_{1.78s (± 1.48%)}	_~	_1.74s	_1.82s	_{p=0.157 n=6}
_{Check Time}	_{18.77s (± 0.28%)}	_{18.79s (± 0.48%)}	_~	_18.70s	_18.91s	_{p=0.688 n=6}
_{Emit Time}	_0.00s	_0.00s	_~	_~	_~	_{p=1.000 n=6}
_{Total Time}	_{24.64s (± 0.30%)}	_{24.67s (± 0.54%)}	_~	_24.56s	_24.90s	_{p=1.000 n=6}
_{xstate-main - node (v18.15.0, x64)}
_Errors	₅	₅	_~	_~	_~	_{p=1.000 n=6}
_Symbols	_555,050	_555,050	_~	_~	_~	_{p=1.000 n=6}
_Types	_186,115	_186,115	_~	_~	_~	_{p=1.000 n=6}
_{Memory used}	_{493,942k (± 0.01%)}	_{493,927k (± 0.01%)}	_~	_493,888k	_493,972k	_{p=0.748 n=6}
_{Parse Time}	_{2.76s (± 0.23%)}	_{2.77s (± 0.40%)}	_~	_2.76s	_2.79s	_{p=0.081 n=6}
_{Bind Time}	_{0.96s (± 0.78%)}	_{0.96s (± 0.57%)}	_~	_0.96s	_0.97s	_{p=0.137 n=6}
_{Check Time}	_{16.26s (± 0.25%)}	_{16.25s (± 0.37%)}	_~	_16.19s	_16.34s	_{p=0.810 n=6}
_{Emit Time}	_0.00s	_0.00s	_~	_~	_~	_{p=1.000 n=6}
_{Total Time}	_{19.98s (± 0.21%)}	_{19.99s (± 0.29%)}	_~	_19.92s	_20.06s	_{p=1.000 n=6}

System info unknown

Hosts

node (v18.15.0, x64)

Scenarios

Compiler-Unions - node (v18.15.0, x64)
angular-1 - node (v18.15.0, x64)
mui-docs - node (v18.15.0, x64)
self-build-src - node (v18.15.0, x64)
self-build-src-public-api - node (v18.15.0, x64)
self-compiler - node (v18.15.0, x64)
ts-pre-modules - node (v18.15.0, x64)
vscode - node (v18.15.0, x64)
webpack - node (v18.15.0, x64)
xstate-main - node (v18.15.0, x64)

_Benchmark	_Name	_Iterations
_Current	_pr	₆
_Baseline	_baseline	₆

Developer Information:

Download Benchmarks

typescript-bot · 2025-01-13T20:49:25Z

@jakebailey Here are the results of running the top 400 repos with tsc comparing main and refs/pull/60921/merge:

Everything looks good!

jakebailey · 2025-01-17T18:13:12Z

Looking at the playground, I believe this does fix #58368, yes.

Before: Playground Link
After: Playground Link

jakebailey · 2025-01-17T18:28:11Z

src/compiler/binder.ts

+            if (isJSDocImportTag(node)) {
+                return;
+            }


Why is the import tag special here?

Also, this early return will leave inAssignmentPattern in a bad state, so I think it's better to skip the steps below that are broken with import tags if needed, or maybe there's something else wrong otherwise.

@jakebailey thanks for the feedback. These changes are open for discussion :). This applies to the case when we have

/** @import { Foo } from 'foo' */ function foo() {}

The function acts as a container that holds locals, including the symbol Foo. Since this symbol is unused (and doesn't have an exportSymbol like the typedef does), the checker triggers an error.

if (.... local.exportSymbol) { return; }

Perhaps the container for the import tag should be treated like a SourceFile...

ContainerFlags.IsContainer | ContainerFlags.IsControlFlowContainer | ContainerFlags.HasLocals;

Anyway, I’d be grateful for any ideas or suggestions regarding this case. thanks

Mainly, I'm trying to understand why import tags have to be special cased, but other JSDoc "declarations" don't.

fix(60908): avoid binding jsdocimport children to the jsdoc host cont…

7d1ed12

…ainer

typescript-bot added For Uncommitted Bug PR for untriaged, rejected, closed or missing bug For Backlog Bug PRs that fix a backlog bug and removed For Uncommitted Bug PR for untriaged, rejected, closed or missing bug labels Jan 6, 2025

a-tarasyuk marked this pull request as ready for review January 10, 2025 20:42

add additional tests

49cdbda

typescript-bot assigned sandersn Jan 17, 2025

typescript-bot added the For Milestone Bug PRs that fix a bug with a specific milestone label Jan 17, 2025

jakebailey reviewed Jan 17, 2025

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fix(60908): Unexpected "'Type' is declared but its value is never read." error with jsdoc @import syntax #60921

fix(60908): Unexpected "'Type' is declared but its value is never read." error with jsdoc @import syntax #60921

a-tarasyuk commented Jan 6, 2025 •

edited by jakebailey

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fix(60908): Unexpected "'Type' is declared but its value is never read." error with jsdoc @import syntax #60921

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fix(60908): Unexpected "'Type' is declared but its value is never read." error with jsdoc @import syntax #60921

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a-tarasyuk commented Jan 6, 2025 •

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