Allow variables be assigned to other types if they are implicitly castable

src/Binder/BoundVariables/BoundScope.cpp

@@ -101,9 +101,13 @@ namespace Porygon::Binder {
         } else {
             // Assigning
             auto var = this->GetVariable(exists, identifier);
-            if (var->GetType()->operator!=(type)) {
+            auto t= var->GetType();
+            if (t->operator!=(type)) {
+                auto castResult = type->CastableTo(t, false);
+                if (castResult == CastResult::InvalidCast){
                     return VariableAssignment(VariableAssignmentResult::VariableDefinedWithDifferentType, nullptr);
                 }
+            }
             return VariableAssignment(VariableAssignmentResult::Ok, new BoundVariableKey(identifier, exists, false, type));
         }
     }