[commit: ghc] master: Fix parsing constructors containing dots; fixes trac #4891 (9330f8d)

[Ian Lynagh]

Repository : ssh://darcs.haskell.org//srv/darcs/ghc

On branch  : master

http://hackage.haskell.org/trac/ghc/changeset/9330f8d055e9e1113cecbf4e57b9f6a750fe0291

>---------------------------------------------------------------

commit 9330f8d055e9e1113cecbf4e57b9f6a750fe0291
Author: Ian Lynagh <igloo at earth.li>
Date:   Sun Apr 3 15:23:38 2011 +0100

    Fix parsing constructors containing dots; fixes trac #4891

>---------------------------------------------------------------

 compiler/ghci/Linker.lhs |   11 +++++++++--
 1 files changed, 9 insertions(+), 2 deletions(-)

diff --git a/compiler/ghci/Linker.lhs b/compiler/ghci/Linker.lhs
index bd0bb35..eaf4521 100644
--- a/compiler/ghci/Linker.lhs
+++ b/compiler/ghci/Linker.lhs
@@ -245,10 +245,17 @@ dataConInfoPtrToName x = do
          where
          (modWords, occWord) = ASSERT (length rest1 > 0) (parseModOcc [] (tail rest1))
       parseModOcc :: [[Word8]] -> [Word8] -> ([[Word8]], [Word8])
-      parseModOcc acc str
+      -- We only look for dots if str could start with a module name,
+      -- i.e. if it starts with an upper case character.
+      -- Otherwise we might think that "X.:->" is the module name in
+      -- "X.:->.+", whereas actually "X" is the module name and
+      -- ":->.+" is a constructor name.
+      parseModOcc acc str@(c : _)
+       | isUpper $ chr $ fromIntegral c
          = case break (== dot) str of
               (top, []) -> (acc, top)
-              (top, _:bot) -> parseModOcc (top : acc) bot
+              (top, _ : bot) -> parseModOcc (top : acc) bot
+      parseModOcc acc str = (acc, str)
        
 -- | Get the 'HValue' associated with the given name.
 --