code review 7493048: cmd/vet: diagnose unreachable code

cmd/vet: diagnose unreachable code

[rsc, 2013-03-22 21:26:50]

Hello golang-dev@googlegroups.com,

I'd like you to review this change to
https://code.google.com/p/go/

[r, 2013-03-22 21:33:21]

LGTM but think about the name

https://codereview.appspot.com/7493048/diff/5001/src/cmd/vet/deadcode.go
File src/cmd/vet/deadcode.go (right):

https://codereview.appspot.com/7493048/diff/5001/src/cmd/vet/deadcode.go#newc...
src/cmd/vet/deadcode.go:1: package main
copyright and explanatory comment missing.

https://codereview.appspot.com/7493048/diff/5001/src/cmd/vet/deadcode.go#newc...
src/cmd/vet/deadcode.go:18: // checkDead checks a function body for dead code.
not sure whether i like 'dead' as the adjective here, since that term
usually covers a much larger scope, so to speak, but 'unreachable' is worse.
'dead' is ok if nothing better comes to mind.

https://codereview.appspot.com/7493048/diff/5001/src/cmd/vet/deadcode.go#newc...
src/cmd/vet/deadcode.go:195: if ok && name.Name == "panic" && name.Obj == nil {
there could be a local panic, but i guess this is good enough absent go/types

[rsc, 2013-03-22 21:46:17]

https://codereview.appspot.com/7493048/diff/5001/src/cmd/vet/deadcode.go
File src/cmd/vet/deadcode.go (right):

https://codereview.appspot.com/7493048/diff/5001/src/cmd/vet/deadcode.go#newc...
src/cmd/vet/deadcode.go:1: package main
On 2013/03/22 21:33:21, r wrote:
> copyright and explanatory comment missing.

Done.

https://codereview.appspot.com/7493048/diff/5001/src/cmd/vet/deadcode.go#newc...
src/cmd/vet/deadcode.go:18: // checkDead checks a function body for dead code.
On 2013/03/22 21:33:21, r wrote:
> not sure whether i like 'dead' as the adjective here, since that term
> usually covers a much larger scope, so to speak, but 'unreachable' is worse.
> 'dead' is ok if nothing better comes to mind.

I called the flag -unreachable, so changed this to checkUnreachable. Leaving the
other dead references that are purely within this file.

https://codereview.appspot.com/7493048/diff/5001/src/cmd/vet/deadcode.go#newc...
src/cmd/vet/deadcode.go:195: if ok && name.Name == "panic" && name.Obj == nil {
On 2013/03/22 21:33:21, r wrote:
> there could be a local panic, but i guess this is good enough absent go/types

This code handles that correctly. If there were a local panic, name.Obj would be
non-nil.

[rsc, 2013-03-22 21:46:49]

*** Submitted as https://code.google.com/p/go/source/detail?r=c61a75775ab6 ***

cmd/vet: diagnose unreachable code

R=golang-dev, r
CC=golang-dev
https://codereview.appspot.com/7493048