// Hack: we know that there are traits implementing Fn for &F
// where F:Fn and so forth. In the particular case of types
- // like `x: &mut FnMut()`, if there is a call `x()`, we would
- // normally translate to `FnMut::call_mut(&mut x, ())`, but
- // that winds up requiring `mut x: &mut FnMut()`. A little
- // over the top. The simplest fix by far is to just ignore
- // this case and deref again, so we wind up with
- // `FnMut::call_mut(&mut *x, ())`.
+ // like `f: &mut FnMut()`, if there is a call `f()`, we would
+ // normally translate to `FnMut::call_mut(&mut f, ())`, but
+ // that winds up potentially requiring the user to mark their
+ // variable as `mut` which feels unnecessary and unexpected.
+ //
+ // fn foo(f: &mut impl FnMut()) { f() }
+ // ^ without this hack `f` would have to be declared as mutable
+ //
+ // The simplest fix by far is to just ignore this case and deref again,
+ // so we wind up with `FnMut::call_mut(&mut *f, ())`.
ty::Ref(..) if autoderef.step_count() == 0 => {
return None;
}
// previously appeared within a `Binder<>` and hence would not
// have been normalized before.
let fn_sig = self.replace_bound_vars_with_fresh_vars(call_expr.span, infer::FnCall, fn_sig);
- let fn_sig = self.normalize_associated_types_in(call_expr.span, fn_sig);
+ let fn_sig = self.normalize(call_expr.span, fn_sig);
// Call the generic checker.
let expected_arg_tys = self.expected_inputs_for_expected_output(