tree 75b35f52f394ddf3d8db52f922edf5f827ad9cac
parent d5732443393ee4383f2d5eb43f41d07efa846137
author Jonathan Amsterdam <jba@google.com> 1611356763 -0500
committer Jonathan Amsterdam <jba@google.com> 1611593526 +0000

internal/godoc/internal/doc: remove unused declarations from playable examples

When synthesizing the code for a playable example, we need to include
all the declared variables, types and functions that the example uses.
This CL makes sure we don't include more than we need.

If a declaration declared multiple names, like `var a, b int` or
```
var (
    a int
    b string
)
```
then we would include the entire declaration, even if the example only
used one of the variables.

Keep track the names actually used, and prune the unused ones from the
declarations.

For golang/go#43658

Change-Id: Ia9e88ecd6d4ea50bd07fad6dfba219bfcb512f0d
Reviewed-on: https://go-review.googlesource.com/c/pkgsite/+/285972
Trust: Jonathan Amsterdam <jba@google.com>
Run-TryBot: Jonathan Amsterdam <jba@google.com>
TryBot-Result: kokoro <noreply+kokoro@google.com>
Reviewed-by: Julie Qiu <julie@golang.org>