You can use this module with the following in your ~/.xmonad/xmonad.hs:

 import XMonad.Actions.MessageFeedback

You can then use this module's functions wherever an action is expected.

Note that most functions in this module have a return type of X Bool whereas configuration options will expect a X () action. For example, the key binding

 -- Shrink the master area of a tiled layout, or move the focused window
 -- to the left in a WindowArranger-based layout
 ((modKey, xK_Left), tryMessage Shrink (MoveLeft 50))

is mis-typed. For this reason, this module provides alternatives (ending with an underscore, e.g. tryMessage_) that discard their result and return an X (). For example, to correct the previous example:

 ((modKey, xK_Left), tryMessage_ Shrink (MoveLeft 50))