1 files changed, 2 insertions, 1 deletions
diff --git a/tuplr.cpp b/tuplr.cpp
index 7dd3e9b..5aaf54a 100644
--- a/tuplr.cpp
+++ b/tuplr.cpp
@@ -250,7 +250,8 @@ eval(CEnv& cenv, const string& name, istream& is)
 			result->constrain(cenv.tenv, c); // Constrain types
 			cenv.tsubst = Subst::compose(cenv.tsubst, TEnv::unify(c)); // Solve type constraints
 			resultType = cenv.type(result);
-			result->lift(cenv); // Lift functions
+			if (resultType->concrete())
+				result->lift(cenv); // Lift functions
 			exprs.push_back(make_pair(exp, result));
 
 			// Add definitions as GC roots