MonoDevelop suddenly inexplicably warning all marked as error

This is a "pit" about MonoDevelop.

When we compile game scripts with MonoDevelop, we usually have a few caveats, which are generally harmless.

Does not affect the game run. But then, one day, MonoDevelop a psycho. Mark some warnings as errors, resulting in unity

The game cannot be run. To view the output information of the MonoDevelop, the following information is found:

Unhandled Exception:
Mono.CSharp.InternalErrorException:/player/playeranimationcontroller.cs (89,17): <errorillustration >C__ITERATOR39---> System.ArgumentException:Label not marked
At System.Reflection.Emit.ILGenerator.label_fixup () [0x00000] in <filename unknown>:0
At System.Reflection.Emit.MethodBuilder.fixup () [0x00000] in <filename unknown>:0

...

Well, errorillustration is a function that we write ourselves, look at the code of the function.

1 IEnumerator errorillustration ()2         {3             yield return NULL;4 5             if(false )6             {7                 yield return NULL;8 9             }Ten  One             yield  Break; A}

View Code

There is a unreachable code, is this the problem?

Try to remove this code, MonoDevelop actually back to normal,

It seems that if Ctrip has a unreachable code, it will cause the monodevelop to produce an internal exception.

MonoDevelop suddenly inexplicably warning all marked as error