the function in pkg/src/index.ts allows you correctly infer types while in the pkg folder.
once built, the test-dep function imports the compiled version, and has issues with inference.
both pkg/src/index.ts and test-dep/index.ts use the function the same way, the way the typescript emitter keeps doesn't change the generic based on scope, all intermediate information is lost, because only the final U and the first T are used.
//...
deeper: <U extends Object>(child: U) => {
result: T & U & U & U & U & U & U & U & U;
deeper: <U extends Object>(child: U) => {
result: T & U & U & U & U & U & U & U & U & U;
deeper: <U extends Object>(child: U) => {
result: T & U & U & U & U & U & U & U & U & U & U;
deeper: <U extends Object>(child: U) => any;
};
};
};
//...