4 files changed, 25 insertions, 15 deletions
diff --git a/src/yuescript/yue_ast.h b/src/yuescript/yue_ast.h
index fa47559..6b2b7f8 100644
--- a/src/yuescript/yue_ast.h
+++ b/src/yuescript/yue_ast.h
@@ -302,14 +302,15 @@ AST_NODE(Switch)
 AST_END(Switch, "switch"sv)
 AST_NODE(Assignment)
-        ast_ptr<true, ExpList_t> expList;
+        ast_ptr<false, ExpList_t> expList;
        ast_ptr<true, Assign_t> assign;
        AST_MEMBER(Assignment, &expList, &assign)
 AST_END(Assignment, "assignment"sv)
 AST_NODE(IfCond)
-        ast_sel<true, Exp_t, Assignment_t> condition;
+        ast_ptr<true, Exp_t> condition;
-        AST_MEMBER(IfCond, &condition)
+        ast_ptr<false, Assignment_t> assignment;
+        AST_MEMBER(IfCond, &condition, &assignment)
 AST_END(IfCond, "if_cond"sv)
 AST_LEAF(IfType)
diff --git a/src/yuescript/yue_compiler.cpp b/src/yuescript/yue_compiler.cpp
index 69a028f..d37f911 100644
--- a/src/yuescript/yue_compiler.cpp
+++ b/src/yuescript/yue_compiler.cpp
@@ -75,7 +75,7 @@ static std::unordered_set<std::string> Metamethods = {
        "close"s // Lua 5.4
 };
-const std::string_view version = "0.20.7"sv;
+const std::string_view version = "0.21.0"sv;
 const std::string_view extension = "yue"sv;
 class CompileError : public std::logic_error {
@@ -3088,7 +3088,7 @@ private:
                for (auto it = nodes.rbegin(); it != nodes.rend(); ++it) {
                        ns.push_back(*it);
                        if (auto cond = ast_cast<IfCond_t>(*it)) {
-                                if (*it != nodes.front() && cond->condition.is<Assignment_t>()) {
+                                if (*it != nodes.front() && cond->assignment) {
                                        auto x = *it;
                                        auto newIf = x->new_ptr<If_t>();
                                        newIf->type.set(toAst<IfType_t>("if"sv, x));
@@ -3142,11 +3142,12 @@ private:
                                default: YUEE("AST node mismatch", node); break;
                        }
                }
-                auto asmt = ifCondPairs.front().first->condition.as<Assignment_t>();
+                auto firstIfCond = ifCondPairs.front().first;
+                auto asmt = firstIfCond->assignment.get();
                bool storingValue = false;
                ast_ptr<false, ExpListAssign_t> extraAssignment;
                if (asmt) {
-                        ast_ptr<false, ast_node> exp = asmt->expList->exprs.front();
+                        auto exp = firstIfCond->condition.get();
                        auto x = exp;
                        auto var = singleVariableFrom(exp, false);
                        if (var.empty() || isGlobal(var)) {
@@ -3164,11 +3165,12 @@ private:
                                                temp.push_back(indent() + "do"s + nll(asmt));
                                                pushScope();
                                        }
-                                        asmt->expList->exprs.pop_front();
                                        auto expList = toAst<ExpList_t>(desVar, x);
                                        auto assignment = x->new_ptr<ExpListAssign_t>();
-                                        for (auto expr : asmt->expList->exprs.objects()) {
+                                        if (asmt->expList) {
-                                                expList->exprs.push_back(expr);
+                                                for (auto expr : asmt->expList->exprs.objects()) {
+                                                        expList->exprs.push_back(expr);
+                                                }
                                        }
                                        assignment->expList.set(expList);
                                        assignment->action.set(asmt->assign);
@@ -3196,9 +3198,10 @@ private:
                                }
                                auto expList = x->new_ptr<ExpList_t>();
                                expList->exprs.push_back(exp);
-                                asmt->expList->exprs.pop_front();
+                                if (asmt->expList) {
-                                for (auto expr : asmt->expList->exprs.objects()) {
+                                        for (auto expr : asmt->expList->exprs.objects()) {
-                                        expList->exprs.push_back(expr);
+                                                expList->exprs.push_back(expr);
+                                        }
                                }
                                auto assignment = x->new_ptr<ExpListAssign_t>();
                                assignment->expList.set(expList);
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;
+        Assignment = -(',' >> space >> ExpList >> space) >> (':' >> Assign | and_('=') >> if_assignment_syntax_error);
-        IfCond = disable_chain_rule(disable_arg_table_block_rule(Assignment | Exp));
+        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;
diff --git a/src/yuescript/yue_parser.h b/src/yuescript/yue_parser.h
index 16b57b2..c3d5d7d 100644
--- a/src/yuescript/yue_parser.h
+++ b/src/yuescript/yue_parser.h
@@ -141,6 +141,7 @@ private:
        NONE_AST_RULE(invalid_interpolation_error);
        NONE_AST_RULE(confusing_unary_not_error);
        NONE_AST_RULE(table_key_pair_error);
+        NONE_AST_RULE(if_assignment_syntax_error);
        NONE_AST_RULE(inc_exp_level);
        NONE_AST_RULE(dec_exp_level);