diff -r 7cc2d66a92a6 -r 517655a528fe lib/Tools/ghc
--- a/lib/Tools/ghc	Thu Nov 08 15:49:56 2018 +0100
+++ b/lib/Tools/ghc	Thu Nov 08 15:52:10 2018 +0100
@@ -5,7 +5,7 @@
 # DESCRIPTION: invoke Glasgow Haskell Compiler within the Isabelle environment
 
 if [ -d "$ISABELLE_STACK_ROOT" -a -n "$ISABELLE_GHC" ]; then
-  isabelle_stack ghc --resolver "$ISABELLE_STACK_RESOLVER" --compiler "$ISABELLE_GHC_VERSION" -- "$@"
+  isabelle_stack ghc -- "$@"
 else
   echo "Cannot execute ghc: missing Isabelle GHC setup" >&2
   exit 127