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'Using Type Parameters in Generic Constraints' code error #13651
Description
TypeScript Version: 2.1.5
Code
Taken from 'Using Type Parameters in Generic Constraints' in the official docs
function copyFields<T extends U, U>(target: T, source: U): T {
for (let id in source) {
target[id] = source[id];
}
return target;
}
let x = { a: 1, b: 2, c: 3, d: 4 };
copyFields(x, { b: 10, d: 20 });Expected behavior:
Compiles.
Actual behavior:
error TS2322: Type 'U[keyof U]' is not assignable to type 'T[keyof U]'.
Type 'U' is not assignable to type 'T'.
Activity
gcnew commentedon Jan 24, 2017
I raised the documentation issue in #13023
Fix microsoft/TypeScript#13651: update generic extends example