fix(type_checker): does not allow passing const to a nonconst, allow …

…passing nonconst to a const

compiler/src/compiler/type_checker.cpp

@@ -1111,6 +1111,7 @@ void type_checker::visit_const_stmt(const_stmt *obj) {
     auto match = type_match(obj->data_type_->args_[0], expression_dt, true);
     if (match.matched_) {
       placeholder = expression_data;
+      placeholder.datatype_ = obj->data_type_; // Set the correct data type
     } else {
       std::stringstream message{};
       message << "Constant '" << name << "' data type mismatch. ";
@@ -1150,6 +1151,10 @@ type_match_result type_checker::type_match(ykdatatype *required_datatype,
         required_datatype->auto_cast(provided_datatype, dt_pool_, false, true);
     if (castable != nullptr) { return type_match_result{"", true, true}; }
   }
+  // Pass a Type to a Const[Type] is allowed (becomes more restrictive)
+  if (primitive_or_obj && is_identical_type(required_datatype->const_unwrap(), provided_datatype)) {
+    return type_match_result{"", true, false};
+  }
   std::stringstream message{};
   message << "data type mismatch. Expected: ";
   message << required_datatype->as_string_simplified();

compiler/tests/test_type_checker.cpp

@@ -413,6 +413,28 @@ TEST_CASE(
       "    return 0",
       "Variable argument: 5 mismatches. Expected: int Provided: i64");
 }
+TEST_CASE("type checker: pass in a non constant structure to a const") {
+  test_typechecker_snippet_full_ok(
+      "class A:\n"
+      "    a: int\n"
+      "def afunc(a: Const[A]) -> None:\n"
+      "    pass\n"
+      "def main() -> int:\n"
+      "    myobj = A{a: 1}\n"
+      "    afunc(myobj)\n"
+      "    return 0");
+}
+TEST_CASE("type checker: pass in a constant structure object to a non const") {
+  test_typechecker_snippet_full(
+      "class A:\n"
+      "    a: int\n"
+      "def afunc(a: A) -> None:\n"
+      "    pass\n"
+      "def main() -> int:\n"
+      "    myobj: Const[A] = A{a: 1}\n"
+      "    afunc(myobj)\n"
+      "    return 0", "Parameter & argument 1 mismatches. Expected: A Provided: Const[A]");
+}
 TEST_CASE("type checker: func ptr call parameter and argument mismatches") {
   test_typechecker_snippet_full_ok("def fnc(a: int, b: int) -> None:\n"
                                    "    pass\n"