error[E0412]: cannot find type `Src` in this scope
  --> $DIR/unknown_src.rs:20:31
   |
LL |     assert::is_transmutable::<Src, Dst, Context>();
   |                               ^^^ not found in this scope
   |
help: you might be missing a type parameter
   |
LL | fn should_gracefully_handle_unknown_src<Src>() {
   |                                        +++++

error: aborting due to previous error

For more information about this error, try `rustc --explain E0412`.