error[E0599]: no method named `test` found for reference `&impl T1` in the current scope
  --> $DIR/issue-99597.rs:11:7
   |
LL |     s.test();
   |       ^^^^ method not found in `&impl T1`
   |
   = help: items from traits can only be used if the type parameter is bounded by the trait
help: the following trait defines an item `test`, perhaps you need to restrict type parameter `impl T1` with it:
   |
LL | fn go(s: &(impl T1 + T2)) {
   |           +        +++++

error: aborting due to 1 previous error

For more information about this error, try `rustc --explain E0599`.