x/tools/gopls/internal/analysis/modernize: minmax doesn't work with return statements

[dominikh]

gopls isn't emitting any diagnostics for the following code:

func Mymin(a, b int) int {
	if a < b {
		return a
	} else {
		return b
	}
}

but it could suggest replacing the if/else with return min(a, b).

[Jorropo]

Also

func Mymin(a, b int) int {
	if a < b {
		return a
	}
	return b
}

[adonovan]

I agree this would be a good feature, but it is surprisingly fiddly to get even these elementary transformations right. (Witness the number of issues filed about minmax.) I wish we had good abstractions for generalizing these patterns, so that minmax could share logic with the slicescontains modernizer, which handles a variety of control flow patterns including {return false} and {x=false; break}.