What version of Go are you using (go version)?

1.15.6 / gopls 0.6.0

Does this issue reproduce with the latest release?

yes

What operating system and processor architecture are you using (go env)?

linux/amd64

Description

A problem I frequently encounter using gopls is that if the completion target depends on code defined in the same file but after the cursor position, the completion is non-functional unless the expression is extremely simple.

Here are some concrete examples using vscode.

If the type S is defined before the current function and I start typing a range statement, completion works fine:

If the type S is defined after the current function and I start typing a range statement, completion is not useful (it suggests some irrelevant packages):

An if expression has the same problem:

But if I only type a simple s., completion works:

I understand that the problem of trying to parse partial (i.e., broken) code is, in the general case, impossible. But doing a passable job in the typical cases seems important. ISTM that a heuristic as simple as "try parsing the code after deleting the line that the cursor is on" would cover the examples I showed here and most of the instances I notice day to day.

I looked for an existing issue as best I could with GH issue search but didn't find anything.