forbid exprlist appears in the left part of update statement.

1 files changed, 1 insertions, 0 deletions

diff --git a/src/MoonP/moon_compiler.cpp b/src/MoonP/moon_compiler.cpp
index e015939..0a5babe 100644
--- a/src/MoonP/moon_compiler.cpp
+++ b/src/MoonP/moon_compiler.cpp
@@ -1239,6 +1239,7 @@ private:
                 auto action = assignment->action.get();
                 switch (action->getId()) {
                         case "Update"_id: {
+                                if (expList->exprs.size() > 1) throw std::logic_error(debugInfo("Can not apply update to multiple values."sv, expList));
                                 auto update = static_cast<Update_t*>(action);
                                 auto leftExp = static_cast<Exp_t*>(expList->exprs.objects().front());
                                 auto leftValue = singleValueFrom(leftExp);