e.g. chmod +w, checkout.
Also: add a TIPS section to the documentation.
LGTM=crawshaw
R=crawshaw, gri
CC=golang-codereviews
https://golang.org/cl/136780044
PackageInfo:
- deleted IsType
- inlined + deleted: ValueOf, TypeCaseVar, ImportSpecPkg
- on failure, TypeOf accessor now returns nil (was: panic)
go/ssa: avoid extra map lookups by using Uses or Defs directly when safe to do so,
and keeping the TypeAndValue around in expr0().
LGTM=gri
R=gri, pcc
CC=golang-codereviews
https://golang.org/cl/107650043