Cannot infer generic argument type from passed callback

TypeScript Version: 3.4.0-dev.201xxxxx

Search Terms:

infer, parameter, argument, callback, function

Code

function inferArguments<T>(callback: ((t: T) => void)) {
  return callback;
}

function noop(){}

const explicit = inferArguments(({a = noop}: {a: Function}) => {});
explicit({a: noop}); // OK!
explicit({a: false}); // Expected error - Got one!

const implicit = inferArguments(({a = noop}) => {});
implicit({a: noop}); // OK!
implicit({a: false}); // Expected error - No Error!

Expected behavior:
Both function calls with ({a: false}) should cause a type error

Actual behavior:
Only the function call with the explicit typing causes a type error

Playground Link

Related Issues: #30975 Looks similar but seems different since there should be a clear way for inference to work in this case

Note that Parameters is correctly able to extract the correct types for such a construct as seen in this bit of code:

function noop() { }
function callback({ a = noop }) { }
let args: Parameters<typeof callback>;
args[0].a as Function

This appears to be an error with inline callback functions used in this fashion

Riproduci i casi espliciti e impliciti nel TypeScript Playground collegato, quindi confronta i tipi dei parametri della callback inferiti e il comportamento di Parameters. L'issue non indica alcun file del repository né alcun test; il lavoro è completato quando entrambe le chiamate che usano {a: false} producono errori di tipo, mentre i casi noop validi continuano a essere accettati.