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Type guard - type propagation #37339
Description
If I use variable which has type set via type guard in nested anonymous class - it becomes of type any.
TypeScript Version: 3.8.3
Search Terms: Type guard, type propagation
Code
function isError(error: Error | any): error is Error {
return error instanceof Error;
}
try {
throw new Error('test');
} catch(hookError) {
if(isError(hookError)) {
const errorHandler = class extends Error {
log() {
// hookError is any
console.log(hookError.message);
}
};
} else {
throw hookError;
}
}Expected behavior: hookError in console.log should have type Error
Actual behavior: hookError has type any
Related Issues: I think this #30557 could be same issue, but not sure
Activity
MartinJohns commentedon Mar 11, 2020
Most likely the same issue as #9998.
RyanCavanaugh commentedon Mar 11, 2020
In addition to #9998,
hookErrorhas typeany, andanys don't get narrowed by type guards. See other issues on annotatedcatchclause variables.typescript-bot commentedon Mar 14, 2020
This issue has been marked 'Working as Intended' and has seen no recent activity. It has been automatically closed for house-keeping purposes.