X-Git-Url: http://git.megacz.com/?p=ghc-hetmet.git;a=blobdiff_plain;f=compiler%2Fiface%2FMkIface.lhs;h=b11c1e0f48219f005b345b98f589d775fc79dcc2;hp=3c33647201dd34b582f4ba3f441ce9b0bc098c82;hb=c004ec62b41aa2137b5b5e298ca562609b0de92e;hpb=89cc39884310a8d1d60681a9c64f89f17848f17e

diff --git a/compiler/iface/MkIface.lhs b/compiler/iface/MkIface.lhs
index 3c33647..b11c1e0 100644
--- a/compiler/iface/MkIface.lhs
+++ b/compiler/iface/MkIface.lhs
@@ -704,15 +704,21 @@ computeChangedOccs ver_fn this_module old_usages eq_info
     -- return True if an external name has changed
     name_changed :: Name -> Bool
     name_changed nm
-        | Just ents <- lookupUFM usg_modmap (moduleName mod) 
-        = case lookupUFM ents parent_occ of
-                Nothing -> pprTrace "WARNING: computeChangedOccs" (ppr nm) $ False
-                Just v  -> v < new_version
+        | Just ents <- lookupUFM usg_modmap (moduleName mod),
+          Just v    <- lookupUFM ents parent_occ
+        = v < new_version
+        | modulePackageId mod == this_pkg
+        = WARN(True, ptext SLIT("computeChangedOccs") <+> ppr nm) True
+        -- should really be a panic, see #1959.  The problem is that the usages doesn't
+        -- contain all the names that might be referred to by unfoldings.  So as a
+        -- conservative workaround we just assume these names have changed.
         | otherwise = False -- must be in another package
       where
          mod = nameModule nm
          (parent_occ, new_version) = ver_fn nm
 
+    this_pkg = modulePackageId this_module
+
     -- Turn the usages from the old ModIface into a mapping
     usg_modmap = listToUFM [ (usg_name usg, listToUFM (usg_entities usg))
                            | usg <- old_usages ]
@@ -749,6 +755,11 @@ computeChangedOccs ver_fn this_module old_usages eq_info
 
 type OccIfaceEq = GenIfaceEq OccSet
 
+instance Outputable OccIfaceEq where
+  ppr Equal          = ptext SLIT("Equal")
+  ppr NotEqual       = ptext SLIT("NotEqual")
+  ppr (EqBut occset) = ptext SLIT("EqBut") <+> ppr (occSetElts occset)
+
 changedWrt :: OccSet -> OccIfaceEq -> Bool
 changedWrt so_far Equal        = False
 changedWrt so_far NotEqual     = True