Microsoft/TypeScript
View on GitHub'this' implicitly has type 'any' in a function used within a conditional expression
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#54,723 opened on Jun 21, 2023
BugDomain: This-TypingHelp Wanted
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Description
Bug Report
🔎 Search Terms
this any implicit 2683 widen
🕗 Version & Regression Information
- This is the behavior in every version I tried
⏯ Playground Link
Playground link with relevant code
💻 Code
// @strict: true
interface State {
value: string;
matches(value: string): boolean;
}
declare function macthesState(state: { value: string }, value: string): boolean;
declare function isState(state: unknown): state is State;
// this doesn't work
function test(config: unknown, prevConfig: unknown) {
if (isState(config)) {
return {
...config,
matches: isState(prevConfig)
? prevConfig.matches
: function (value: string) {
return macthesState(this, value);
},
};
}
return config;
}
// this works
function test2(config: State) {
return {
...config,
matches: function (value: string) {
return macthesState(this, value);
},
};
}
🙁 Actual behavior
'this' implicitly has type 'any' because it does not have a type annotation.(2683)
🙂 Expected behavior
inferred this type