Invalid cast in CrossCheck

[fm-117]

Describe the bug
An InvalidCastException is thrown for some programs in the CrossChecker if included copy contains nodes that are not DataDescription.

To Reproduce
Main program:

       IDENTIFICATION DIVISION.
       PROGRAM-ID. DVZZMFT3.
       DATA DIVISION.
       WORKING-STORAGE SECTION.
       01 sometable.
       EXEC SQL
          INCLUDE somecopy
       END-EXEC.
       PROCEDURE DIVISION.
           GOBACK
           .
       END PROGRAM DVZZMFT3.

Included copy:

           EXEC SQL DECLARE Table1 TABLE
           ( Table1_Champ1 CHAR(1) NOT NULL,
             Table1_Champ2 CHAR(4) NOT NULL
           ) END-EXEC.

           05 table1-record.                                           
              10 table1-champ1 PIC X(1).
              10 table1-champ2 PIC X(4).

Exception will be thrown from here:

TypeCobol/TypeCobol/Compiler/Diagnostics/CrossChecker.cs

Line 497 in 9861cc3

DiagnosticUtils.AddError(dataDescription, $"Cannot include copy {nextSibling.CodeElement?.FirstCopyDirective.TextName} " +

Expected behavior
No exception ! The CrossCheck should be able to handle any code coming from a copy although it would make it harder to detect level inconsistencies as originally intended.

[fm-117]

After reviewing the example, it appears there are in fact 2 bugs:

• the CrossChecker does not properly check the type of nextSibling before attempting cast
• the real problem is that we should not even attempt to cast because parent node 01 somedate should have children

In the current implementation, EXEC nodes reset the current level and in the example EXEC SQL DECLARE... become a child of WORKING STORAGE SECTION, and thus sibling of 01 somedate and 05 table1-record. It is ok to attach the EXEC to its aprent section but this should not affect the level for the following DataDescription nodes.