lsp/completion: support completing to Elem() types

For array, slice, maps and chan candidates, we now support
transforming them to their element type in completions. For example:

    var m map[string]int
    var _ int = m<>

At <> we complete to "m[]" because we see that the map value type
matches our expected type.

Fixes golang/go#46045.

Change-Id: Ibee088550193a53744f93217cc365f67f301ae90
Run-TryBot: Muir Manders <>
gopls-CI: kokoro <>
TryBot-Result: Go Bot <>
Trust: Cherry Mui <>
Reviewed-by: Robert Findley <>
6 files changed
tree: 5d5210c718a7af9c7e09a2afa446040f57ad0d82
  1. .gitattributes
  2. .gitignore
  3. .prettierrc
  10. benchmark/
  11. blog/
  12. cmd/
  13. codereview.cfg
  14. container/
  15. copyright/
  16. cover/
  17. go.mod
  18. go.sum
  19. go/
  20. godoc/
  21. gopls/
  22. imports/
  23. internal/
  24. playground/
  25. present/
  26. refactor/
  27. txtar/

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.


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

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This repository uses prettier to format JS and CSS files.

The version of prettier used is 1.18.2.

It is encouraged that all JS and CSS code be run through this before submitting a change. However, it is not a strict requirement enforced by CI.

Report Issues / Send Patches

This repository uses Gerrit for code changes. To learn how to submit changes to this repository, see

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