1 files changed, 1 insertions, 0 deletions
diff --git a/expr.h b/expr.h
index 8e1ee19a..8c110ad9 100644
--- a/expr.h
+++ b/expr.h
@@ -39,6 +39,7 @@ namespace ledger {
 DECLARE_EXCEPTION(parse_error, std::runtime_error);
 DECLARE_EXCEPTION(compile_error, std::runtime_error);
 DECLARE_EXCEPTION(calc_error, std::runtime_error);
+DECLARE_EXCEPTION(usage_error, std::runtime_error);
 
 class scope_t;
 class call_scope_t;