Added a type checking rule for the Main Machine

Src/PCompiler/CompilerCore/TypeChecker/ModuleSystemTypeChecker.cs

@@ -4,6 +4,7 @@
 using Plang.Compiler.TypeChecker.AST;
 using Plang.Compiler.TypeChecker.AST.Declarations;
 using Plang.Compiler.TypeChecker.AST.ModuleExprs;
+using Plang.Compiler.TypeChecker.Types;
 
 namespace Plang.Compiler.TypeChecker
 {
@@ -189,13 +190,21 @@ internal void CheckSafetyTest(SafetyTest test)
                     $"test module is not closed with respect to created interfaces; interface {@interface.First().Name} is created but not implemented inside the module");
             }
 
-            //check that the test module main machine exists
+            // check that the test module main machine exists
             var hasMainMachine = test.ModExpr.ModuleInfo.InterfaceDef.Values.Any(m => m.Name == test.Main && !m.IsSpec);
             if (!hasMainMachine)
             {
                 throw handler.NoMain(test.SourceLocation,
                     $"machine {test.Main} does not exist in the test module");
             }
+
+            // make sure that the main machine does not take a parameter as input
+            globalScope.Get(test.Main, out Machine main);
+            if (!main.PayloadType.Equals(PrimitiveType.Null))
+            {
+                throw handler.NoMain(test.SourceLocation,
+                    $"main machine {test.Main} cannot take an input parameter in the entry function of the start state.");
+            }
         }
 
         internal void CheckImplementationDecl(Implementation impl)

Tst/RegressionTests/Feature1SMLevelDecls/Correct/EntryNamedFunction/EntryNamedFunction.p

@@ -1,21 +1,20 @@
-
-/* PSrc/FrontDesk.p */
 type tRoomInfo = (roomNumber: int, isAvailable: bool);
 
 
 machine Main {
-    var rooms: map[int, tRoomInfo];
+    start state Init {
+        entry {
+            new m1(default(map[int, tRoomInfo]));
+        }
+    }
+}
 
+machine m1 {
     start state Init {
         entry Init_Entry;
-        exit {
-            assert true;
-        }
     }
 
     fun Init_Entry(initialRooms: map[int, tRoomInfo]) {
-        new Main(default(map[int, tRoomInfo]));
+        assert true;
     }
-}
-
-
+}

Tst/RegressionTests/Feature1SMLevelDecls/StaticError/StartMachineNullParam/StartMachineNullParam.p

@@ -0,0 +1,8 @@
+machine Main {
+    start state Init {
+        entry (payload: int) {};
+        exit {
+            assert true;
+        }
+    }
+}