error[E0277]: the trait bound `(): ~const Tr` is not satisfied
  --> $DIR/default-method-body-is-const-same-trait-ck.rs:8:12
   |
LL |         ().a()
   |            ^ the trait `~const Tr` is not implemented for `()`
   |
note: the trait `Tr` is implemented for `()`, but that implementation is not `const`
  --> $DIR/default-method-body-is-const-same-trait-ck.rs:8:12
   |
LL |         ().a()
   |            ^
help: consider introducing a `where` clause, but there might be an alternative better way to express this requirement
   |
LL | pub trait Tr where (): ~const Tr {
   |              +++++++++++++++++++

error: aborting due to previous error

For more information about this error, try `rustc --explain E0277`.