private void CheckForAllowedSyntaxForConstantBinding(
            )
        {
            var child = _constantClause.ChildNodes().FirstOrDefault();

            if (child == null)
            {
                throw new DpdtException(
                          DpdtExceptionTypeEnum.InternalError,
                          $"Unknown error during validation a target in 'constant' binding."
                          );
            }

            var cconstant = _semanticModel.GetConstantValue(child);

            if (cconstant.HasValue)
            {
                //it's a true constant, keep going!
                return;
            }

            var ilsymbol = _semanticModel.GetSymbolInfo(child).Symbol;

            if (ilsymbol is null)
            {
                throw new DpdtException(
                          DpdtExceptionTypeEnum.InternalError,
                          $"Unknown error during validation a target in 'constant' binding."
                          );
            }

            if (ilsymbol.Kind != SymbolKind.Field)
            {
                throw new DpdtException(
                          DpdtExceptionTypeEnum.InternalError,
                          $"Unsupported type of 'constant' binding. Allowed compile-time constants, readonly fields and readonly static fields only."
                          );
            }

            var filsymbol = ilsymbol as IFieldSymbol;

            if (filsymbol is null)
            {
                throw new DpdtException(
                          DpdtExceptionTypeEnum.InternalError,
                          $"Unknown error during validation a target in 'constant' binding."
                          );
            }

            if (!filsymbol.IsReadOnly)
            {
                throw new DpdtException(
                          DpdtExceptionTypeEnum.InternalError,
                          $"Unsupported type of 'constant' binding. Allowed compile-time constants, readonly fields and readonly static fields only."
                          );
            }
        }