commit 7c0525f22978c0a67c3a74385d9f06dff8db0268
author Muir Manders <muir@mnd.rs> Fri Jul 31 22:40:50 2020 -0700
committer Rebecca Stambler <rstambler@golang.org> Sat Aug 15 16:17:26 2020 +0000
tree 74b88f5377e76ef6c4cd0b6b1ea25d4facfbf499
parent 9882f1d1823da58283ff91ebbec3f7c0cc27cddc

internal/lsp/source: improve func literal completions

When a signature doesn't name its params, we make up param
names when generating a corresponding func literal:

    var f func(myType) // no param name
    f = fun<> // completes to "func(mt myType) {}"

Previously we would abbreviate named types and fall back to "_" for
builtins or repeated names. We would require placeholders to be
enabled when using "_" so the user could name the param easily. That
left users that don't use placeholders with no completion at all in
this case.

I made the following improvements:
- Generate a name for all params. For builtin types we use the first
  letter, e.g. "i" for "int", "s" for "[]string". If a name is
  repeated, we append incrementing numeric suffixes. For example,
  "func(int, int32)" becomes "func(i1 int, i2 int32").
- No longer require placeholders to be enabled in any case.
- Fix handling of alias types so the param name and type name are
  based on the alias, not the aliasee.

I also tweaked formatVarType to qualify packages using a
types.Qualifier. I needed it to respect a qualifier that doesn't
qualify anything so I could format e.g. "http.Response" as just
"Response" to come up with param names.

Fixes golang/go#38416.

Change-Id: I0ce8a0a4e2485dda41a0aa696d9fd48bea595869
Reviewed-on: https://go-review.googlesource.com/c/tools/+/246262
Run-TryBot: Rebecca Stambler <rstambler@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Rebecca Stambler <rstambler@golang.org>