Microsoft/TypeScript

No constituent of type 'Function | (T & Function)' is callable.

Open

#46,066 opened on Sep 26, 2021

View on GitHub
 (6 comments) (0 reactions) (0 assignees)TypeScript (6,726 forks)batch import
BugDomain: Error MessagesEffort: DifficultHelp Wanted

Repository metrics

Stars
 (48,455 stars)
PR merge metrics
 (Avg merge 6d 17h) (9 merged PRs in 30d)

Description

Bug Report

🔎 Search Terms

generic function union-type call-signatures

🕗 Version & Regression Information

  • This is a crash
  • This is the behavior in every version I tried, and I reviewed the FAQ for entries about Generics
  • I was unable to test this on prior versions because _______

⏯ Playground Link

Playground link with relevant code

💻 Code

type Test = <T>(fn: T | Function) => void;
const test: Test = (fn) => {
  return typeof fn === 'function' ? fn() : null;
};
// This expression is not callable.
// No constituent of type 'Function | (T & Function)' is callable.

🙁 Actual behavior

Compiler throw error: This expression is not callable. Not all constituents of type 'Function | (T & Function)' are callable.

🙂 Expected behavior

Compile success

because both 'Function | (T & Function)' are callable.

Contributor guide