Make GHCi print the entire result of an interactive 'bind' statement

Suppose

  foo :: Int -> IO (Maybe Int, Bool)

Then here's a GHCi interaction:

Prelude> foo 3
(Just 3,True)           -- Entire result printed
Prelude> (Just x, _) <- foo 3
3                       -- Value of x printed
Prelude> (Just x, y) <- foo 3
                        -- Nothing at all printed
Prelude> (_, _) <- foo 3
                        -- Nothing at all printed
Prelude> 

GHCi prints the result of a bind, p <- e, if and only if the pattern p binds exactly one variable. This is a bit odd; you get no info if it binds more than one.

A different and simpler behaviour would be to print the entire result every time. That is, all the commands above would print (Just 3, True).

I'm recording this ticket so that we remember the suggestion. I don't know for sure if it's a good one. Add comments if you have an opinion

Trac metadata

Trac field	Value
Version	6.6.1
Type	FeatureRequest
TypeOfFailure	OtherFailure
Priority	normal
Resolution	Unresolved
Component	Compiler
Test case
Differential revisions
BlockedBy
Related
Blocking
CC
Operating system	Unknown
Architecture	Unknown