Resolution:
This could be caused by the presence of a YIELDING phrase in the method header for an ASYNC-VOID method. In any case, correct the code; then recompile.
Example:
In the following example, an illegal YIELDING phrase is used in the method header for an ASYNC-VOID method.
class-id A. method-id MethodAsync async-void yielding ret as string. end method. end class.