src/test/ui/inference/cannot-infer-closure.stderr

   1 error[E0282]: type annotations needed for the closure `fn((), ()) -> Result<(), _>`
   2   --> $DIR/cannot-infer-closure.rs:4:9
   3    |
   4 LL |         Ok(b)
   5    |         ^^ cannot infer type for type parameter `E` declared on the enum `Result`
   6    |
   7 help: give this closure an explicit return type without `_` placeholders
   8    |
   9 LL |     let x = |a: (), b: ()| -> Result<(), _> {
  10    |                            ++++++++++++++++
  11
  12 error: aborting due to previous error
  13
  14 For more information about this error, try `rustc --explain E0282`.