error[E0308]: mismatched types
  --> $DIR/issue-12552.rs:6:5
   |
LL |   match t {
   |         - this expression has type `Result<_, {integer}>`
LL |     Some(k) => match k {
   |     ^^^^^^^ expected `Result<_, {integer}>`, found `Option<_>`
   |
   = note: expected enum `Result<_, {integer}>`
              found enum `Option<_>`
help: try wrapping the pattern in `Ok`
   |
LL |     Ok(Some(k)) => match k {
   |     +++       +

error[E0308]: mismatched types
  --> $DIR/issue-12552.rs:9:5
   |
LL |   match t {
   |         - this expression has type `Result<_, {integer}>`
...
LL |     None => ()
   |     ^^^^ expected `Result<_, {integer}>`, found `Option<_>`
   |
   = note: expected enum `Result<_, {integer}>`
              found enum `Option<_>`
help: try wrapping the pattern in `Ok`
   |
LL |     Ok(None) => ()
   |     +++    +

error: aborting due to 2 previous errors

For more information about this error, try `rustc --explain E0308`.