The `inspect' verb had no coverage. The discriminating case is not a path
step, it is the frame: dev-inspect.flan gives `mark' to a global holding 99
and to a local of the OUTER frame holding a Point, so evaluating the name and
rooting at the frame answer differently and not even with the same type. One
`eval-expr' and one `inspect' of that name is the bug and the fix in a pair.
The slot index comes off the locals listing's fourth element rather than being
written as a literal, which exercises the field the editor depends on and
keeps the test from passing for the wrong reason if slot allocation shifts.
The rest is what a path can and cannot do: a struct field, an array element,
an option's payload and a union case's field — the last two having offsets but
no accessor form in the language — and four refusals, each checked for naming
the step and saying why. A `:path' of `nil' is read as the slot itself,
because Emacs has no other spelling for an empty list.
Two claims about the frame, since `stopped_frame' being shared is an assertion
about code rather than about behaviour until something proves it: the frame
whose body was redefined under it is refused, and so is the whole stack once
the program resumes.
Joseph Ferano
404c810958