x/tools/gopls: order struct fields completions by definition

[golopot]

When I am writing a struct literal, I expect the completion suggestions to be ordered the same way as when it is defined. For example, if a struct has 4 fields, in order, key, content, start, end, I expect the the completion suggestions to be be ordered just like that, instead of alphabetically, like content, end, key, start.

Developers usually order fields purposefully, both in definition and struct literal. For example is it unnatural to write end before start, and it is conventional to put key as the first field. Therefore changing the suggestion order will make completion more ergonomic.

Example:

type Foo struct {
        key string
        content string
        start string
	end string
}

func main() {
	foo := Foo{
        <>
        // expects the first suggestion to be `key`
        // but got `content` instead 
	}
}

[gopherbot]

Change https://golang.org/cl/270777 mentions this issue: internal/lsp: order struct fields completions by definition