error[E0277]: `T` cannot be sent between threads safely
  --> $DIR/builtin-superkinds-double-superkind.rs:6:24
   |
LL | trait Foo : Send+Sync { }
   |             ---- required by this bound in `Foo`
LL | 
LL | impl <T: Sync+'static> Foo for (T,) { }
   |                        ^^^ `T` cannot be sent between threads safely
   |
   = note: required because it appears within the type `(T,)`
help: consider further restricting this bound
   |
LL | impl <T: Sync+'static + std::marker::Send> Foo for (T,) { }
   |                       ^^^^^^^^^^^^^^^^^^^

error[E0277]: `T` cannot be shared between threads safely
  --> $DIR/builtin-superkinds-double-superkind.rs:9:16
   |
LL | trait Foo : Send+Sync { }
   |                  ---- required by this bound in `Foo`
...
LL | impl <T: Send> Foo for (T,T) { }
   |                ^^^ `T` cannot be shared between threads safely
   |
   = note: required because it appears within the type `(T, T)`
help: consider further restricting this bound
   |
LL | impl <T: Send + std::marker::Sync> Foo for (T,T) { }
   |               ^^^^^^^^^^^^^^^^^^^

error: aborting due to 2 previous errors

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