Spec and Field names are declared as such by Type_Checker_m%Init_Symbols

Labels are declared by Type_Checker_m%Type_Checker, with the "tree" field
referencing the N_Spec tree node.

The N_Spec tree node is decorated with its S_... value from the
declaration table.

Subtree 2 of N_Value node in Line is decorated with the S_... of the label