error[E0282]: type annotations needed
  --> $DIR/auto-trait-selection.rs:15:16
   |
LL |     if false { is_trait(foo()) } else { Default::default() }
   |                ^^^^^^^^ cannot infer type of the type parameter `T` declared on the function `is_trait`
   |
help: consider specifying the generic arguments
   |
LL |     if false { is_trait::<T, U>(foo()) } else { Default::default() }
   |                        ++++++++

error: aborting due to 1 previous error

For more information about this error, try `rustc --explain E0282`.