Diagnosis
A field value node has no dependent node, or more than one dependentnode of an incorrect type.

Procedure
Combination rules for field value nodes:
- The field value node must have a node child.
- The node child must not be a field value node.
- The field value node is allowed no more than one node child if the
node child is of a decision operation, error operation, or subfeature
access type.
- A field value node for a main feature is also allowed no more than
one node child if the node child is of a program access type.
- If a main feature has field return, a field value node is allowed no
more than one node child if the node child is of the return value
type.
- Two node children are allowed if a node child contains a debugging
operation.
- If a main feature has table return, a maximum of 36 node children
are allowed if all of the node children contain return lines, or a
maximum of 35 return lines and just one debugging operation.
- A subfeature is allowed a maximum of 36 node children if they all
contain return lines or program accesses, or 35 and just one
debugging operation.