There is already a fancy completion that writes the entire if err != nil { ... } for you. Do you see it? For example, completing at *HERE* below:

func foo() (int, error) {
  i, err := foo()
  if*HERE*
}

@muirdm Yes, It is same thing in the first case, but I think the latter two will still provide some convenience.
And i find that the rr and reterrr are the same postfix completion, so we can just focus on the latter two scenarios

@findleyr What do you think of this proposal? The pattern of error handle will not change anytime soon, so I think it's very valuable.

Change https://go.dev/cl/550455 mentions this issue: gopls/internal/lsp/source/completion: support postfix completion (rr, varCheckErr)

@rogeryk I think this makes sense. I'll review your CL -- thanks!

(although I'm not sure about varCheckErr -- let's discuss on the CL).

In discussion on https://go.dev/cl/550455, we have settled on the more consistent snippet names iferr and variferr. I believe iferr is consistent with the preexisting vscode-go snippet: microsoft/vscode-go#1549 (comment).

@findleyr
Gerrit can't seem to send images, so I'll use a gif here to explain why the specified placeholder tabstop is needed.
Look at the pictures below, when I modify "err", all "err" variables are modified at the same time. This requires us to specify the same tabstops for all "err"

There is another confusing point, and I will explain it here.There is a nested tabstop in "variferr"

		{{- if eq ($a.TypeName $v.Type) "error" -}}
			{{$errName | $a.SpecifiedPlaceholder (len $a.Tuple) |
				$a.SpecifiedPlaceholder ($a.Inc (len $a.Tuple))}}
		{{- else -}}

		{{- if eq ($a.TypeName $v.Type) "error" -}}
			{{$errName | $a.SpecifiedPlaceholder 1 | $a.SpecifiedPlaceholder 2}}
		{{- else -}}

This is because sometimes we want to return err directly, and sometimes we want to wrap the err. So an additional tabstops is needed to modify the last returned err. Look the below picture.

@rogeryk that's very cool, and I didn't know it worked that way. Thank you for the explanation.