Question InvalidProgramException: Invalid IL code

So I'm getting an InvalidProgramException on the following code snippets. Basically, I have a class

Descriptor

and a derived class

Descriptor_Number

, and I can't seem to call the method in the

Descriptor_Number

from a MonoBehaviour.

I tried several methods of casting, and neither worked.

What is going wrong here? The code compiles just fine. (There's more going on, of course, but these seem to be the relevant bits).

The full text of the error is:
"InvalidProgramException: Invalid IL code in Descriptor_Number:Increase (): IL_0026: stloc.1", and it triggers on the line noted below in the code.

EDIT: Cleaned up the code from the original post for better clarity. Same problems, though.

Code (CSharp):

1. public class Descriptor : IComparable<Descriptor>, IEquatable<Descriptor>
2. {
3.    // Stuff goes here
4. }
5.  
6. public class Descriptor_Number : Descriptor
7. {
8.     public string Value { get; set; } // There's more here, but for simplicity...
9.  
10.     // Increment Value
11.     public void Increase()
12.     {
13.         // Code goes here, but is never reached
14.     }
15.  
16.     // Decrement Value
17.     public void Decrease()
18.     {
19.         // Code goes here, but is never reached
20.     }
21. }
22.  
23.  
24. public abstract class MiniDescrListPanel : Monobehaviour
25. {
26.     protected Descriptor descriptor = null; // Later, a Descriptor_Number is stored here.
27. }
28.  
29. // Attached to a GameObject. Methods are assigned to UI objects via the Inspector
30. public class MiniDescrListPanel_Number : MiniDescrListPanel
31. {
32.     InputField valueInput = null; // Set to an InputField text object elsewhere
33.  
34.     // Called when a new value is entered in the InputField
35.     public void InputText_Edit(string text)
36.     {
37.         if (descriptor is Descriptor_Number dn)
38.         {
39.             dn.Value = text; // Setting this property works just fine
40.         }
41.     }
42.  
43.     // A "+" button calls this method, assigned via the inspector
44.     public void IncreaseButton_Click()
45.     {
46.         if (descriptor is Descriptor_Number dn)
47.         {
48.             dn.Increase(); // THIS IS WHERE THE ERROR OCCURS
49.             valueInput.text = dn.Value; // This line is never reached
50.         }
51.     }
52.  
53.     // A "-" button calls this method, assigned via the inspector
54.     public void DecreaseButton_Click()
55.     {
56.         if (descriptor is Descriptor_Number dn)
57.         {
58.             dn.Decrease(); // This triggers the same problem
59.             valueInput.text = dn.Value; // Not reached
60.         }
61.     }
62. }
63.  

Referenced in some older comments:

Spoiler: Originally posted code

Code (CSharp):

1. public class MiniDescrListPanel_Number : MonoBehaviour
2. {
3.    // assigned a value of type Descriptor_Number in another method
4.    protected Descriptor descriptor = null;
5.    // assigned in another method
6.    InputField valueInput = null;
7.  
8.     // triggered by end edit event in an InputField Text object, works fine.
9.     public void InputText_Edit(string text)
10.     {
11.         if (!(descriptor is Descriptor_Number))
12.             return;
13.         (descriptor as Descriptor_Number).Value = text;
14.     }
15.  
16.     // triggered by a button click event, assigned in the inspector
17.     public void IncreaseButton_Click()
18.     {
19.         Descriptor_Number descrNumber = descriptor as Descriptor_Number;
20.         if (descrNumber != null)
21.         {
22.             descrNumber.Increase();  // this call triggers the InvalidProgramException
23.             valueInput.text = descrNumber.Value;
24.         }
25.     }
26.  
27.    // similar to Increase(), but tries a different method, same problem
28.    public void DecreaseButton_Click()
29.     {
30.        // wish I could use (descriptor is not Descriptor_Number, but Unity doesn't like that format)
31.        if (!(descriptor is Descriptor_Number))
32.             return;
33.  
34.         (descriptor as Descriptor_Number).Decrease(); // this call triggers the InvalidProgramException
35.         valueInput.text = (descriptor as Descriptor_Number).Value;
36.     }
37. }
38.  
39. public class Descriptor{}
40. public class Descriptor_Number : Descriptor
41. {
42.    public string Value {get; set;}
43.    public void Increase() {} // increases the Descriptor_Number.Value
44.    public void Decrease() {} // Decreases the Descriptor_Number.Value
45. }
46.  

 

I'm not sure about the InvalidProgramException, but there is a simpler and cleaner way to do what you're doing.

Code (CSharp):

1. if (descriptor is Descriptor_Number dn)) {
2.     dn.Decrease();
3.     valueInput.text = dn.Value;
4. }

These probably also need to change (surprised this is not a compile error):

Code (CSharp):

1.    public void Increase {} // increases the Descriptor_Number.Value
2.    public void Decrease{} // Decreases the Descriptor_Number.Value

to

Code (CSharp):

1.    public void Increase() {} // increases the Descriptor_Number.Value
2.    public void Decrease() {} // Decreases the Descriptor_Number.Value

 

Are you talking about

System.Data.Services.Client.Descriptor

?

If so, on my Unity 2021, System.Data.Services does not exist.

 

No, Descriptor is a custom class.

 

I do like that syntax better, thanks! I knew there was something not quite as nice as it should be.

Unfortunately the console is rejecting it:

InvalidProgramException: Invalid IL code in Descriptor_Number:Increase (): IL_0026: stloc.1 ​

Oh, goodness, yes, those would have produced a compile error. Thankfully, the code that appeared in the OP was not my actual code, just snippets of it. (Also edited the OP to remove that distraction.)

 

The exception you're getting is very strange. Normally it is something you would only expect to see when generating code at runtime using the System.Reflection.Emit namespace or something similar. Are you doing anything like that?

 

No, nothing like that. I wish I was talented enough to get into that kind of trouble.

 

Still having this issue: I was hoping an update might fix it.

Here's the best simplified version of what's going on:

Code (CSharp):

1.  
2. public class Descriptor : IComparable<Descriptor>, IEquatable<Descriptor>
3. {
4.    // Stuff goes here
5. }
6.  
7. public class Descriptor_Number : Descriptor
8. {
9.     public string Value { get; set; } // There's more here, but for simplicity...
10.  
11.     // Increment Value
12.     public void Increase()
13.     {
14.         // Code goes here, but is never reached
15.     }
16.  
17.     // Decrement Value
18.     public void Decrease()
19.     {
20.         // Code goes here, but is never reached
21.     }
22. }
23.  
24.  
25. public abstract class MiniDescrListPanel : Monobehaviour
26. {
27.     protected Descriptor descriptor = null; // Later, a Descriptor_Number is stored here.
28. }
29.  
30. // Attached to a GameObject. Methods are assigned to UI objects via the Inspector
31. public class MiniDescrListPanel_Number : MiniDescrListPanel
32. {
33.     InputField valueInput = null; // Set to an InputField text object elsewhere
34.  
35.     // Called when a new value is entered in the InputField
36.     public void InputText_Edit(string text)
37.     {
38.         if (descriptor is Descriptor_Number dn)
39.         {
40.             dn.Value = text; // Setting this property works just fine
41.         }
42.     }
43.  
44.     // A "+" button calls this method, assigned via the inspector
45.     public void IncreaseButton_Click()
46.     {
47.         if (descriptor is Descriptor_Number dn)
48.         {
49.             dn.Increase(); // THIS IS WHERE THE ERROR OCCURS
50.             valueInput.text = dn.Value; // This line is never reached
51.         }
52.     }
53.  
54.     // A "-" button calls this method, assigned via the inspector
55.     public void DecreaseButton_Click()
56.     {
57.         if (descriptor is Descriptor_Number dn)
58.         {
59.             dn.Decrease(); // This triggers the same problem
60.             valueInput.text = dn.Value; // Not reached
61.         }
62.     }
63. }
64.  

 

Found the issue!

Unity was balking at calling the

Increase()

method, because the method contained something it didn't know how to compile, the new-fangled null-coalescing operator from C# 8.0:

(

decimal? nums[]

)

Code (CSharp):

1. // Increment Value
2.     public void Increase()
3.     {
4.         if (nums[(int)NumIndex.Increment] != null)
5.         {
6.             //nums[(int)NumIndex.Value] ??= 0; // COMMENTING OUT THIS CODE ALLOWS THE REST TO RUN
7.             nums[(int)NumIndex.Value] += nums[(int)NumIndex.Increment];
8.             Clamp(ref nums[(int)NumIndex.Value]);
9.         }
10.     }

The longer form, however, works as intended.

Code (CSharp):

1. // Increment Value
2.     public void Increase()
3.     {
4.         if (nums[(int)NumIndex.Increment] != null)
5.         {
6.             if (nums[(int)NumIndex.Value] is null)
7.                 nums[(int)NumIndex.Value] = 0;
8.             nums[(int)NumIndex.Value] += nums[(int)NumIndex.Increment];
9.             Clamp(ref nums[(int)NumIndex.Value]);
10.         }
11.     }