src/test/ui/try-trait/option-to-result.stderr

   1 error[E0277]: the `?` operator can only be used on `Result`s, not `Option`s, in a function that returns `Result`
   2   --> $DIR/option-to-result.rs:5:6
   3    |
   4 LL | / fn test_result() -> Result<(),()> {
   5 LL | |     let a:Option<()> = Some(());
   6 LL | |     a?;
   7    | |      ^ use `.ok_or(...)?` to provide an error compatible with `Result<(), ()>`
   8 LL | |     Ok(())
   9 LL | | }
  10    | |_- this function returns a `Result`
  11    |
  12    = help: the trait `FromResidual<Option<Infallible>>` is not implemented for `Result<(), ()>`
  13 note: required by `from_residual`
  14   --> $SRC_DIR/core/src/ops/try_trait.rs:LL:COL
  15    |
  16 LL |     fn from_residual(residual: R) -> Self;
  17    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  18
  19 error[E0277]: the `?` operator can only be used on `Option`s, not `Result`s, in a function that returns `Option`
  20   --> $DIR/option-to-result.rs:11:6
  21    |
  22 LL | / fn test_option() -> Option<i32>{
  23 LL | |     let a:Result<i32, i32> = Ok(5);
  24 LL | |     a?;
  25    | |      ^ use `.ok()?` if you want to discard the `Result<Infallible, i32>` error information
  26 LL | |     Some(5)
  27 LL | | }
  28    | |_- this function returns an `Option`
  29    |
  30    = help: the trait `FromResidual<Result<Infallible, i32>>` is not implemented for `Option<i32>`
  31 note: required by `from_residual`
  32   --> $SRC_DIR/core/src/ops/try_trait.rs:LL:COL
  33    |
  34 LL |     fn from_residual(residual: R) -> Self;
  35    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  36
  37 error: aborting due to 2 previous errors
  38
  39 For more information about this error, try `rustc --explain E0277`.