error[E0277]: the trait bound `T: HeapSize` is not satisfied
 --> tests/ui/fail-derive-generic.rs:3:10
  |
3 |   #[derive(HeapSize)]
  |            ^^^^^^^^ the trait `HeapSize` is not implemented for `T`
4 |   pub struct G1<T> {
5 | /     #[heap_size]
6 | |     pub a: T,
  | |____________- required by a bound introduced by this call
  |
help: consider restricting type parameter `T`
  |
4 | pub struct G1<T: heapsz::HeapSize> {
  |                ++++++++++++++++++