"do" no longer works when value is ignored

[redfish64]

https://gist.github.com/redfish64/c15272748a802d2bbd29b9855c655343

test : Maybe ()
test =
  do
    pure 'x'
    pure ()

doesn't compile with:

- + Errors (1)
 `-- LearnBug.idr line 16 col 4:
     While processing right hand side of test. Can't find an implementation for Applicative ?f.
     
     LearnBug.idr:16:5--16:13
      12 | 
      13 | test : Maybe ()
      14 | test =
      15 |   do
      16 |     pure 'x'
               ^^^^^^^^

This started occurring after commit: d2eeb7c
I believe part of the reason is that, Prelude/Interfaces.idr was changed as follows:

[nix-shell:~/Idris2]$ git diff d2eeb7ce867cf3bbfa49b45123e9c18964fe64ae~1 d2eeb7ce867cf3bbfa49b45123e9c18964fe64ae libs/prelude/Prelude/Interfaces.idr 
diff --git a/libs/prelude/Prelude/Interfaces.idr b/libs/prelude/Prelude/Interfaces.idr
index ea844768..62f8cf0f 100644
--- a/libs/prelude/Prelude/Interfaces.idr
+++ b/libs/prelude/Prelude/Interfaces.idr
@@ -197,7 +197,7 @@ public export
 
 ||| Sequencing of effectful composition
 public export
-(>>) : (Monad m) => m a -> m b -> m b
+(>>) : Monad m => m () -> Lazy (m b) -> m b
 a >> b = a >>= \_ => b
 
 ||| Left-to-right Kleisli composition of monads.

but there are a lot of changes in that commit, so I'm not sure how this would be fixed.

[stefan-hoeck]

As far as I know, that was intentional (see #1095). Use ignore, to explicitly throw away the result of a computation:

do ignore $ pure 'x'