internal/lsp: add completions of unimported std lib pkgs

Unimported packages may be suggested as completion items. Since these
are not yet imported, they should be ranked lower than other candidates.

They also require an additional import statement to be valid, which is
provided as an AdditionalTextEdit.

Adding this import does not use astutil.AddNamedImport, to avoid
editing the current ast and work even if there are errors. Additionally,
it can be hard to determine what changes need to be made to the source
document from the ast, as astutil.AddNamedImport includes a merging
pass. Instead, the completion item simply adds another import
declaration.

Change-Id: Icbde226d843bd49ee3713cafcbd5299d51530695
Reviewed-on: https://go-review.googlesource.com/c/tools/+/190338
Run-TryBot: Suzy Mueller <suzmue@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Rebecca Stambler <rstambler@golang.org>
13 files changed
tree: 0f8e09fc7dc86e151705eee866b728994782fc64
  1. benchmark/
  2. blog/
  3. cmd/
  4. container/
  5. cover/
  6. go/
  7. godoc/
  8. gopls/
  9. imports/
  10. internal/
  11. playground/
  12. present/
  13. refactor/
  14. .gitattributes
  15. .gitignore
  16. AUTHORS
  17. codereview.cfg
  18. CONTRIBUTING.md
  19. CONTRIBUTORS
  20. go.mod
  21. go.sum
  22. LICENSE
  23. PATENTS
  24. README.md
README.md

Go Tools

This subrepository holds the source for various packages and tools that support the Go programming language.

Some of the tools, godoc and vet for example, are included in binary Go distributions.

Others, including the Go guru and the test coverage tool, can be fetched with go get.

Packages include a type-checker for Go and an implementation of the Static Single Assignment form (SSA) representation for Go programs.

Download/Install

The easiest way to install is to run go get -u golang.org/x/tools/.... You can also manually git clone the repository to $GOPATH/src/golang.org/x/tools.

Report Issues / Send Patches

This repository uses Gerrit for code changes. To learn how to submit changes to this repository, see https://golang.org/doc/contribute.html.

The main issue tracker for the tools repository is located at https://github.com/golang/go/issues. Prefix your issue with “x/tools/(your subdir):” in the subject line, so it is easy to find.