[GHC] #1084: Improve coalescing of dynamic breakpoints in the ghci debugger

[GHC]

#1084: Improve coalescing of dynamic breakpoints in the ghci debugger
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    Reporter:  mnislaih     |       Owner:         
        Type:  task         |      Status:  new    
    Priority:  normal       |   Milestone:  6.8    
   Component:  GHCi         |     Version:  6.6    
    Severity:  normal       |    Keywords:         
  Difficulty:  Easy (1 hr)  |    Testcase:         
Architecture:  Unknown      |          Os:  Unknown
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(or disable it altogether)

 Right now coalescing of breakpoints works at instrumentation time by:
  1. Not inserting a breakpoint if there are no local bindings in the site
  1. Removing adjacent breakpoints, i.e. removing one of them (not
 implemented yet)
  1. adhoc case: if we are about to insert a breakpoint but the
 subexpresion is a HsLet, then don't.

 Proposal is to disable cases 1 and 3 and implement case 2 using rewriting
 rules.

-- 
Ticket URL: <http://hackage.haskell.org/trac/ghc/ticket/1084>
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