Index: src/SymTab/Validate.cc
===================================================================
--- src/SymTab/Validate.cc	(revision 108f3cdb1c308290d06b0f98d2f61dcf43a681bc)
+++ src/SymTab/Validate.cc	(revision a0c7dc36aea9a9949803d2973e714ade8c8e51e8)
@@ -752,5 +752,5 @@
 
 		typedeclNames[ typeDecl->get_name() ] = typeDecl;
-		return Mutator::mutate( typeDecl );
+		return dynamic_cast<TypeDecl *>( Mutator::mutate( typeDecl ) );
 	}