[GHC] #14950: GHC 8.2.2: GHCi duplicates breakpoint range prompt

[GHC]

#14950: GHC 8.2.2: GHCi duplicates breakpoint range prompt
-------------------------------------+-------------------------------------
           Reporter:  lierdakil      |             Owner:  (none)
               Type:  bug            |            Status:  new
           Priority:  normal         |         Milestone:
          Component:  GHCi           |           Version:  8.2.2
           Keywords:                 |  Operating System:  Unknown/Multiple
       Architecture:                 |   Type of failure:  Other
  Unknown/Multiple                   |
          Test Case:                 |        Blocked By:
           Blocking:                 |   Related Tickets:
Differential Rev(s):                 |         Wiki Page:
-------------------------------------+-------------------------------------
 I think breakpoint range is being printed twice, once as part of prompt,
 and the second time by itself.

 To reproduce, create `test.hs` file like this:

 {{{#!hs
 module Test where

 test :: IO ()
 test = putStrLn "Hello, World!"
 }}}

 Then run the following GHCi session:
 {{{
 $ ghci test.hs
 GHCi, version 8.2.2: http://www.haskell.org/ghc/  :? for help
 [1 of 1] Compiling Test             ( test.hs, interpreted )
 Ok, one module loaded.
 *Test> :break test
 Breakpoint 0 activated at test.hs:4:8-31
 *Test> :trace test
 Stopped in Test.test, test.hs:4:8-31
 _result :: IO () = _
 [test.hs:4:8-31] [test.hs:4:8-31] *Test> :set prompt ""
 [test.hs:4:8-31]
 }}}

 Notice `[test.hs:4:8-31]` is printed twice, and is even printed when
 prompt is set to `""`.

-- 
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/14950>
GHC <http://www.haskell.org/ghc/>
The Glasgow Haskell Compiler