# dev.go2go branch

This branch provides an experimental go2go tool for testing the use of
the generics design draft.
This branch was published in 2020 and is no longer being maintained.
The [generics
proposal](https://go.googlesource.com/proposal/+/refs/heads/master/design/43651-type-parameters.md)
has [been accepted](https://golang.org/issue/43651) and development is
now focused on implementing the proposal in the ordinary Go tools.

## Original README

This branch contains a type checker and a translation tool for
experimentation with generics in Go.
This implements the [generics design draft](https://go.googlesource.com/proposal/+/refs/heads/master/design/go2draft-type-parameters.md).

You can build this branch [as
usual](https://golang.org/doc/install/source).
You can then use the new `go2go` tool.
Write your generic code in a file with the extension `.go2` instead of
`.go`.
Run it using `go tool go2go run x.go2`.
There are some sample packages in `cmd/go2go/testdata/go2path/src`.
You can see the full documentation for the tool by running `go doc
cmd/go2go`.

The `go2go` tool will look for `.go2` files using the environment variable `GO2PATH`.
You can find some useful packages that you might want to experiment with by
setting `GO2PATH=$GOROOT/src/cmd/go2go/testdata/go2path`.

If you find bugs in the updated type checker or in the translation
tool, they should be filed in the [standard Go issue
tracker](https://golang.org/issue).
Please start the issue title with `cmd/go2go`.
Note that the issue tracker should only be used for reporting bugs in
the tools, not for discussion of changes to the language.

Unlike typical dev branches, we do not intend any eventual merge of
this code into the master branch.
We will update it for bug fixes and change to the generic design
draft.
If a generics language proposal is accepted, it will be implemented in
the standard compiler, not via a translation tool.
The necessary changes to the go/* packages (go/ast, go/parser, and so
forth) may re-use code from this prototype but will follow the usual
code review process.