error[E0609]: no field `0` on type `fn(char, u16) -> Foo {Foo}`
  --> $DIR/tuple-field.rs:12:15
   |
LL |     thing.bar.0;
   |     --------- ^
   |     |
   |     this is the constructor of a struct
   |
help: call the constructor
   |
LL |     (thing.bar)(_, _).0;
   |     +         +++++++

error: aborting due to previous error

For more information about this error, try `rustc --explain E0609`.