1 files changed, 7 insertions, 2 deletions

diff --git a/src/yuescript/yue_parser.cpp b/src/yuescript/yue_parser.cpp
index 2206686..5b97a25 100644
--- a/src/yuescript/yue_parser.cpp
+++ b/src/yuescript/yue_parser.cpp
@@ -114,6 +114,11 @@ YueParser::YueParser() {
                 return false;
         });
 
+        if_assignment_syntax_error = pl::user(true_(), [](const item_t& item) {
+                throw ParserError("use := for if-assignment expression"sv, item.begin);
+                return false;
+        });
+
         #define ensure(patt, finally) ((patt) >> (finally) | (finally) >> cut)
 
         #define key(str) (expr(str) >> not_alpha_num)
@@ -369,8 +374,8 @@ YueParser::YueParser() {
                         +space_break >> advance_match >> space >> SwitchCase >> switch_block >> pop_indent
                 ) >> switch_block;
 
-        Assignment = ExpList >> space >> Assign;
-        IfCond = disable_chain_rule(disable_arg_table_block_rule(Assignment | Exp));
+        Assignment = -(',' >> space >> ExpList >> space) >> (':' >> Assign | and_('=') >> if_assignment_syntax_error);
+        IfCond = disable_chain_rule(disable_arg_table_block_rule(Exp >> -(space >> Assignment)));
         if_else_if = -(line_break >> *space_break >> check_indent_match) >> space >> key("elseif") >> space >> IfCond >> space >> body_with("then");
         if_else = -(line_break >> *space_break >> check_indent_match) >> space >> key("else") >> space >> body;
         IfType = (expr("if") | "unless") >> not_alpha_num;