Given a def id and a parent impl def id, this checks if the parent
def id (modulo modules) correspond to the def id of the parent impl definition.
Given a path and a parent impl def id, this checks if the if parent resolution
def id correspond to the def id of the parent impl definition.
Return a βerror message-ableβ ident for the last segment of the Path
Return for a given Path
the span until the last args
Compute the Span
and visual representation for the Self
we want to point at;
It follows part of the actual logic of non-local, and if possible return the least
amount possible for the span and representation.
Given a Ty
we check if the (outermost) type is local.