Repository navigation
False positive assignment error with generics when using --strictBindCallApply #28900
Description
TypeScript Version: 3.3.0-dev.20181207
Search Terms: bind generic strict
Code
class SomeClass {
constructor() {
this.genericMethod = this.genericMethod.bind(this);
// TS2322: Type '(callback: (p: {}) => {}) => void' is not
// assignable to type '<T>(callback: (p: T) => T) => void':
this.genericWithCallback = this.genericWithCallback.bind(this);
}
genericMethod<T>(p: T): void { }
genericWithCallback<T>(callback: (p: T) => T): void { }
}Compile with tsc TypeScriptIssue.ts --target es6 --strictBindCallApply
Expected behavior:
No compile error
Actual behavior:
error TS2322: Type '(callback: (p: {}) => {}) => void' is not assignable to type '<T>(callback: (p: T) => T) => void'.
Types of parameters 'callback' and 'callback' are incompatible.
Types of parameters 'p' and 'p' are incompatible.
Type '{}' is not assignable to type 'T'.
Playground Link: (no --strictBindCallApply flag available)
Related issues:
Activity
ahejlsberg commentedon Dec 7, 2018
This is a known and unfortunate design limitation. See comment here. We're thinking about ways to alleviate the issue.
ulrichb commentedon Dec 7, 2018
Anders Hejlsberg (@ahejlsberg) Ah, okay. Didn't find that. Thanks for the link. I'll leave this issue open for discoverability.