TypeScript/tests/cases/compiler/indexSignatureAndMappedType.ts
2017-08-07 13:59:52 -07:00

36 lines
764 B
TypeScript

// @strict: true
// @declaration: true
// A mapped type { [P in K]: X }, where K is a generic type, is related to
// { [key: string]: Y } if X is related to Y.
function f1<T, K extends string>(x: { [key: string]: T }, y: Record<K, T>) {
x = y;
y = x; // Error
}
function f2<T>(x: { [key: string]: T }, y: Record<string, T>) {
x = y;
y = x;
}
function f3<T, U, K extends string>(x: { [key: string]: T }, y: Record<K, U>) {
x = y; // Error
y = x; // Error
}
// Repro from #14548
type Dictionary = {
[key: string]: string;
};
interface IBaseEntity {
name: string;
properties: Dictionary;
}
interface IEntity<T extends string> extends IBaseEntity {
properties: Record<T, string>;
}