message: trans_fn: Use replace() instead of new() + swap()
diff: @@ -20,8 +20,7 @@ pub(crate) fn trans_fn<'tcx, B: Backend + 'static>(
  let mut func_ctx = FunctionBuilderContext::new();
  cx.cached_context.clear();
  - let mut func = Function::new();
  - std::mem::swap(&mut cx.cached_context.func, &mut func);
  + let mut func = std::mem::replace(&mut cx.cached_context.func, Function::new());
  func.name = ExternalName::user(0, func_id.as_u32());
  func.signature = sig;
  func.collect_debug_info();
  