diff --git a/liblll/CodeFragment.cpp b/liblll/CodeFragment.cpp
index 0f8f26061..0ba072a4c 100644
--- a/liblll/CodeFragment.cpp
+++ b/liblll/CodeFragment.cpp
@@ -587,7 +587,7 @@ void CodeFragment::constructOperation(sp::utree const& _t, CompilerState& _s)
 		else if (us.find_first_of("1234567890") != 0 && us.find_first_not_of("QWERTYUIOPASDFGHJKLZXCVBNM1234567890_") == string::npos)
 			m_asm.append((u256)varAddress(s));
 		else
-			error<InvalidOperation>();
+			error<InvalidOperation>("Unsupported keyword: '" + us + "'");
 	}
 }