Fix #9438 by converting a panic to an error message

Previously, GHC was quite eager to panic whenever it was fed
an archive file when `DYNAMIC_GHC_PROGRAMS=YES`. This ought to be an
explicit error message instead, so this patch accomplishes just that.

Test Plan: make test TEST=T14708

Reviewers: Phyx, hvr, bgamari

Reviewed By: Phyx

Subscribers: thomie, carter

GHC Trac Issues: #9438, #14708, #15032

Differential Revision: https://phabricator.haskell.org/D4589

1 files changed, 13 insertions, 2 deletions

diff --git a/compiler/ghci/Linker.hs b/compiler/ghci/Linker.hs
index a91df323ce..8d0338a9dd 100644
--- a/compiler/ghci/Linker.hs
+++ b/compiler/ghci/Linker.hs
@@ -71,7 +71,10 @@ import System.Win32.Info (getSystemDirectory)
 
 import Exception
 
-import Foreign (Ptr) -- needed for 2nd stage
+-- needed for 2nd stage
+#if STAGE >= 2
+import Foreign (Ptr)
+#endif
 
 {- **********************************************************************
 
@@ -504,9 +507,17 @@ preloadLib hsc_env lib_paths framework_paths pls lib_spec = do
        = do b <- doesFileExist name
             if not b then return False
                      else do if dynamicGhc
-                                 then panic "Loading archives not supported"
+                                 then throwGhcExceptionIO $
+                                      CmdLineError dynamic_msg
                                  else loadArchive hsc_env name
                              return True
+      where
+        dynamic_msg = unlines
+          [ "User-specified static library could not be loaded ("
+            ++ name ++ ")"
+          , "Loading static libraries is not supported in this configuration."
+          , "Try using a dynamic library instead."
+          ]
 
 
 {- **********************************************************************