Closed
Description
π Version & Regression Information
- This is the behavior in every version I tried.
β― Playground Link
π» Code
function f1<T>(x: T & string | T & undefined) {
if (x) {
x; // Should narrow to T & string
}
}
function f2<T>(x: T & string | T & undefined) {
if (x !== undefined) {
x; // Should narrow to T & string
}
else {
x; // Should narrow to T & undefined
}
}
function f3<T>(x: T & string | T & number) {
if (typeof x === "string") {
x; // Should narrow to T & string
}
else {
x; // Should narrow to T & number
}
}
function f4<T>(x: T & 1 | T & 2) {
switch (x) {
case 1: x; break; // T & 1
case 2: x; break; // T & 2
default: x; // Should narrow to never
}
}
function f5<T extends string | number>(x: T & number) {
const t1 = x === "hello"; // Should be an error
}
π Actual behavior
No narrowing or errors where expected.
π Expected behavior
Narrowing and errors as indicated above.