Closed as not planned
Description
🔎 Search Terms
- type narrowing
- return type never
- error
- throw
- method
- chaining
- error 7027
🕗 Version & Regression Information
- This is the behavior in every version I tried, and I reviewed the FAQ for any entries relating to return type
never
⏯ Playground Link
💻 Code
const throwError = (message: string): never => {
throw new Error(message);
}
type Thrower = typeof throwError;
const errorContext = {
throwError
};
type ErrorContext = typeof errorContext;
const test1 = (thrower: Thrower) => {
throw new Error('foo');
// following code results in 7027 "unreachable code detected" as expected
console.log('bar');
};
const test2 = (thrower: Thrower) => {
thrower('foo');
// following code results in 7027 "unreachable code detected" as expected
console.log('bar');
};
const test3 = (errorContext: ErrorContext) => {
errorContext.throwError('foo');
// following code does NOT result in 7027, although the code is unreachable at runtime
console.log('bar');
};🙁 Actual behavior
If a function that returns never is a method, it does not result in error 7027 "unreachable code detected" or any
expected type-narrowing for subsequent code when called.
🙂 Expected behavior
Any code after a call to a function that always returns never should result in error 7027 "unreachable code detected" and any expected type-narrowing regardless of whether that function is method or a standalone function.
Additional information about the issue
No response