Index: src/ResolvExpr/Resolver.cc
===================================================================
--- src/ResolvExpr/Resolver.cc	(revision 4b97770cddc6c963b957ff9691018b2a164df9af)
+++ src/ResolvExpr/Resolver.cc	(revision 6138d0f75a1531a2f79bd02da26e6696c38ac53d)
@@ -155,5 +155,5 @@
 		} // if
 		#endif
-		assertf( finder.get_alternatives().size() == 1, "findSingleExpression: must have exactly one alternative at the end." );
+		assertf( finder.get_alternatives().size() == 1, "findSingleExpression: must have exactly one alternative at the end: (%zd) %s", finder.get_alternatives().size(), toString( untyped ).c_str() );
 		Alternative &choice = finder.get_alternatives().front();
 		Expression *newExpr = choice.expr->clone();