[GHC] #14456: Windows runtime linker failure with icuuc

[GHC]

#14456: Windows runtime linker failure with icuuc
-------------------------------------+-------------------------------------
           Reporter:  RyanGlScott    |             Owner:  (none)
               Type:  bug            |            Status:  new
           Priority:  normal         |         Milestone:
          Component:  Runtime        |           Version:  8.2.1
  System (Linker)                    |
           Keywords:                 |  Operating System:  Windows
       Architecture:                 |   Type of failure:  GHCi crash
  Unknown/Multiple                   |
          Test Case:                 |        Blocked By:
           Blocking:                 |   Related Tickets:
Differential Rev(s):                 |         Wiki Page:
-------------------------------------+-------------------------------------
 First, install `mingw-w64-x86_64-icu` (I'm using version 58.2-2):

 {{{
 $ pacman -S mingw-w64-x86_64-icu
 }}}

 Now take this file:

 {{{#!hs
 module Main where

 import Data.Int
 import Foreign

 foreign import ccall "ucnv_getMaxCharSize_58"
   c_ucnv_getMaxCharSize :: Ptr () -> IO Int8

 main :: IO ()
 main = c_ucnv_getMaxCharSize nullPtr >>= print
 }}}

 GHC is able to compile this successfully:

 {{{
 $ ghc -licuuc Bug2.hs
 [1 of 1] Compiling Main             ( Bug2.hs, Bug2.o )
 Linking Bug2.exe ...
 }}}

 But GHCi is unable to accomplish the same thing:

 {{{
 $ runghc -licuuc Bug2.hs
 ghc.exe: ^^ Could not load 'ucnv_getMaxCharSize_58', dependency
 unresolved. See top entry above.

 Bug2.hs:
 ByteCodeLink: can't find label
 During interactive linking, GHCi couldn't find the following symbol:
   ucnv_getMaxCharSize_58
 This may be due to you not asking GHCi to load extra object files,
 archives or DLLs needed by your current session.  Restart GHCi, specifying
 the missing library using the -L/path/to/object/dir and -lmissinglibname
 flags, or simply by naming the relevant files on the GHCi command line.
 Alternatively, this link failure might indicate a bug in GHCi.
 If you suspect the latter, please send a bug report to:
   glasgow-haskell-bugs at haskell.org
 }}}

 Phyx- and I discussed this briefly on IRC. He suspected that the fact that
 `C:\Windows\System32` now contains its own copy of `icuuc.dll` is
 contributing to the issue.

-- 
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/14456>
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