If you have not used `--no-pointer-validate' to suppress validation, Makeinfo will check the validity of the final info file. Mostly, this means ensuring that nodes you have referenced really exist. Here is a complete list of what is checked:
Prev, Next or Up is a
reference to a node in this file (i.e., not an external reference such
as `(DIR)'), then the referenced node must exist.
Prev is different
than the node referenced by the Up, then the node referenced by
the Prev must have a Next which references this node.
Top must have an Up field.
Up must contain a reference to this node,
other than a Next reference. Obviously, this includes menu items
and followed references.
Next reference is not the same as the Next
reference of the Up reference, then the node referenced by
Next must have a Prev reference pointing back at this
node. This rule still allows the last node in a section to point to the
first node of the next chapter.