spec: wording about nil maps is confusing

[Sajmani]

One line in the Go spec says:
  A nil map is equivalent to an empty map except that no elements may be added.

That led me to believe that deletion from a nil map should work.  But another line in
the spec says:
  If the element m[k] does not exist, delete is a no-op. Calling delete with a nil map causes a run-time panic.

While this is clear, it appears to contradict the first statement.  Can we improve the
first statement?

[rsc]

Comment 1:

Or maybe we should make deletion from a nil-map a no-op. I keep having
to code around that.
Russ

[robpike]

Comment 2:

Labels changed: added priority-soon, removed priority-triage.

Status changed to Accepted.

[griesemer]

Comment 4:

Owner changed to @griesemer.

[rsc]

Comment 5:

I suggest we resolve this by defining deletion from a nil map to be the same as deletion
from an empty map: a no-op.

[rsc]

Comment 6:

Labels changed: added size-m.

[griesemer]

Comment 7:

This issue was closed by revision a9a49fe.

Status changed to Fixed.