Slightly more helpful panic message in DynFlags

diff --git a/compiler/main/DynFlags.hs b/compiler/main/DynFlags.hs
index e8b4f28..c147b15 100644 (file)
--- a/compiler/main/DynFlags.hs
+++ b/compiler/main/DynFlags.hs
@@ -578,7 +578,7 @@ defaultDynFlags =
         ghcUsagePath            = panic "defaultDynFlags: No ghciUsagePath",
         ghciUsagePath           = panic "defaultDynFlags: No ghciUsagePath",
         topDir                  = panic "defaultDynFlags: No topDir",
-        systemPackageConfig     = panic "defaultDynFlags: No systemPackageConfig",
+        systemPackageConfig     = panic  "no systemPackageConfig: call GHC.setSessionDynFlags",
         pgm_L                   = panic "defaultDynFlags: No pgm_L",
         pgm_P                   = panic "defaultDynFlags: No pgm_P",
         pgm_F                   = panic "defaultDynFlags: No pgm_F",