[GHC] #10411: Neighbour let-bindings are not reported as relevant

[GHC]

#10411: Neighbour let-bindings are not reported as relevant
-------------------------------------+-------------------------------------
        Reporter:  Feuerbach         |                   Owner:
            Type:  bug               |                  Status:  new
        Priority:  normal            |               Milestone:
       Component:  Compiler          |                 Version:  7.10.1
      Resolution:                    |                Keywords:
Operating System:  Unknown/Multiple  |            Architecture:
 Type of failure:  None/Unknown      |  Unknown/Multiple
      Blocked By:                    |               Test Case:
 Related Tickets:                    |                Blocking:
                                     |  Differential Revisions:
-------------------------------------+-------------------------------------

Comment (by simonpj):

 GHC reports an enclosing binding as "relevant" if its type mentions a type
 variable used in the type of the hole.  Here we have `b :: forall t1.t1`,
 whereas `a::Bool`.  So `a` is not mentioned as relevant.

 You obviously wish that it was.  How could we define "relevant" better?

 Simon

--
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/10411#comment:1>
GHC <http://www.haskell.org/ghc/>
The Glasgow Haskell Compiler