imports incorrectly marked as unused when augmenting the module it was imported from in .d.ts file
#54042
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Working as Intended
The behavior described is the intended behavior; this is not a bug
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Module exports are implicitly in scope inside a module augmentation, so the import literally is unused. Demonstration of this fact: import { Program as Program2 } from 'typescript'
declare module 'typescript' {
// No error
export const foo: Program;
// No error
export const bar: ScriptKind;
} |
RyanCavanaugh
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the
Working as Intended
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@RyanCavanaugh i thought that too, but removing the import caused an error: declare module 'typescript' {
export const foo: Program // Cannot find name 'Program'. (2304)
}but playing around with it more i noticed that adding an |
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This issue has been marked 'Working as Intended' and has seen no recent activity. It has been automatically closed for house-keeping purposes. |
Krinkle
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Jan 9, 2025
Workarounds for TypeScript shortcomings: * `@typedef` can't be namespaced in JS files, thus mandating awkward constructs like `/** @import { Logger } from './qtap.js' */`. * There is no way to apply a type to a `catch` clause in JS files. The workaround is to re-assign it to a local variable and type that like `catch (e) { /* @type {any} */ const err = e;`. * There is no way to disable type checking for an entire block, function, or otherwise multiple lines, thus mandating lots of `// @ts-ignore` lines for the same problem, or to move the code out into a separate file where the entire file is ignored (as I ended up doing for client.js). Reported 8y ago, microsoft/TypeScript#19573. * `@types/node` lacks Error.code or Error.stack definitinos, thus regularly requiring use of the above workarounds. Reported 3y ago, DefinitelyTyped/DefinitelyTyped#59692. * The `noUnusedLocals` rule is broken, making a paradoxal claim. ``` /** @import { Logger } from './qtap.js' */ /** * @param {Logger} logger */ ``` The above makes sense, and passes, until noUnusedLocals is enabled. Then it fails: ``` error TS6133: 'Logger' is declared but its value is never read. /** @import { Logger } from './qtap.js' */ ``` Removing the import, of course, causes a more severe error instead: ``` error TS2304: Cannot find name 'Logger'. * @param {Logger} logger ``` Reported 2y ago, closed as wontfix. microsoft/TypeScript#54042 * The `noUnusedParameters` errors on unused arguments before arguments that are required and used. It appears to be unconfigurable and thus serves no purpose. Leave disabled in favor of ESLint no-unused-vars.
Krinkle
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to qunitjs/qtap
that referenced
this issue
Jan 11, 2025
Workarounds for TypeScript shortcomings: * `@typedef` can't be namespaced in JS files, thus mandating awkward constructs like `/** @import { Logger } from './qtap.js' */`. * There is no way to apply a type to a `catch` clause in JS files. The workaround is to re-assign it to a local variable and type that like `catch (e) { /* @type {any} */ const err = e;`. * There is no way to disable type checking for an entire block, function, or otherwise multiple lines, thus mandating lots of `// @ts-ignore` lines for the same problem, or to move the code out into a separate file where the entire file is ignored (as I ended up doing for client.js). Reported 8y ago, microsoft/TypeScript#19573. * `@types/node` lacks Error.code or Error.stack definitinos, thus regularly requiring use of the above workarounds. Reported 3y ago, DefinitelyTyped/DefinitelyTyped#59692. * The `noUnusedLocals` rule is broken, making a paradoxal claim. ``` /** @import { Logger } from './qtap.js' */ /** * @param {Logger} logger */ ``` The above makes sense, and passes, until noUnusedLocals is enabled. Then it fails: ``` error TS6133: 'Logger' is declared but its value is never read. /** @import { Logger } from './qtap.js' */ ``` Removing the import, of course, causes a more severe error instead: ``` error TS2304: Cannot find name 'Logger'. * @param {Logger} logger ``` Reported 2y ago, closed as wontfix. microsoft/TypeScript#54042 * The `noUnusedParameters` errors on unused arguments before arguments that are required and used. It appears to be unconfigurable and thus serves no purpose. Leave disabled in favor of ESLint no-unused-vars. * The `noImplicitAny: false` setting, while ostensibly turning some checks off, makes array behaviour more strict, changing default from `any[]` to an awkward `never[]`. Reported 5y ago, https://stackoverflow.com/a/57563877/319266 ``` const seen = { plan: null, asserts: [] }; p.on('assert', function (result) { //> error TS2345: Argument of type 'any' is not assignable to parameter of type 'never'. seen.asserts.push(result); }) ```
Krinkle
added a commit
to qunitjs/qtap
that referenced
this issue
Jan 25, 2025
Workarounds for TypeScript shortcomings: * `@typedef` can't be namespaced in JS files, thus mandating awkward constructs like `/** @import { Logger } from './qtap.js' */`. * There is no way to apply a type to a `catch` clause in JS files. The workaround is to re-assign it to a local variable and type that like `catch (e) { /* @type {any} */ const err = e;`. * There is no way to disable type checking for an entire block, function, or otherwise multiple lines, thus mandating lots of `// @ts-ignore` lines for the same problem, or to move the code out into a separate file where the entire file is ignored (as I ended up doing for client.js). Reported 8y ago, microsoft/TypeScript#19573. * `@types/node` lacks Error.code or Error.stack definitinos, thus regularly requiring use of the above workarounds. Reported 3y ago, DefinitelyTyped/DefinitelyTyped#59692. * The `noUnusedLocals` rule is broken, making a paradoxal claim. ``` /** @import { Logger } from './qtap.js' */ /** * @param {Logger} logger */ ``` The above makes sense, and passes, until noUnusedLocals is enabled. Then it fails: ``` error TS6133: 'Logger' is declared but its value is never read. /** @import { Logger } from './qtap.js' */ ``` Removing the import, of course, causes a more severe error instead: ``` error TS2304: Cannot find name 'Logger'. * @param {Logger} logger ``` Reported 2y ago, closed as wontfix. microsoft/TypeScript#54042 * The `noUnusedParameters` errors on unused arguments before arguments that are required and used. It appears to be unconfigurable and thus serves no purpose. Leave disabled in favor of ESLint no-unused-vars. * The `noImplicitAny: false` setting, while ostensibly turning some checks off, makes array behaviour more strict, changing default from `any[]` to an awkward `never[]`. Reported 5y ago, https://stackoverflow.com/a/57563877/319266 ``` const seen = { plan: null, asserts: [] }; p.on('assert', function (result) { //> error TS2345: Argument of type 'any' is not assignable to parameter of type 'never'. seen.asserts.push(result); }) ```
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Bug Report
🔎 Search Terms
unused import augment module
🕗 Version & Regression Information
5.1.0-dev.20230427
⏯ Playground Link
Playground link with relevant code
💻 Code
🙁 Actual behavior
🙂 Expected behavior
no warning
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