## Tools {#tools}

### Go command {#go-command}

Setting the `GOROOT_FINAL` environment variable no longer has an effect
([#62047](/issue/62047)).
Distributions that install the `go` command to a location other than
`$GOROOT/bin/go` should install a symlink instead of relocating
or copying the `go` binary.

<!-- go.dev/issue/34208, CL 563137, CL 586095 -->
The new `go` `env` `-changed` flag causes the command to print only

-- .info --
{"Version":"v1.0.1"}
-- .mod --
// no longer deprecated
module example.com/undeprecated

go 1.17
-- go.mod --
// no longer deprecated
module example.com/undeprecated

go 1.17
-- undeprecated.go --
package undeprecated

-- cmd/a/a.go --
package main

import "fmt"

imported normally and vendored by the standard library.

Vendored packages are internally renamed with a "vendor/" prefix
to preserve the invariant that all packages have distinct paths.
This is necessary to avoid compiler and linker conflicts. Adding
a "vendor/" prefix also maintains the invariant that standard
library packages begin with a dotless path element.

The module requirements of std and cmd do not influence version

# If we combine a Go 1.16 go.sum file...
go mod tidy -go=1.16

# ...with a Go 1.17 go.mod file...
cp go.mod.orig go.mod

# ...then Go 1.17 no longer works. 😞
! go list -deps -test -f $MODFMT all

go install example.com/deprecated/a/cmd/a@v1.0.0
stderr '^go: module example.com/deprecated/a is deprecated: in example.com/deprecated/a@v1.9.0$'

# 'go install pkg@version' does not show a deprecation message if the module is no longer
# deprecated in its latest version, even if the module is deprecated in its current version.
go install example.com/undeprecated/cmd/a@v1.0.0
! stderr 'module.*is deprecated'

-- m/go.mod --
module m

On Windows, [Readlink] no longer tries to normalize volumes
to drive letters, which was not always even possible.
This behavior is controlled by the `winreadlinkvolume` setting.
For Go 1.23, it defaults to `winreadlinkvolume=1`.

)

-- d1/go.mod --
module example.net/deleted

go 1.17
-- d1/deleted.go --
package deleted
-- d2/go.mod --
module example.net/deleted

go 1.17
-- d2/README --
There is no longer a Go package here.

-- lazy/go.mod --
module example.net/lazy

go 1.17

require example.net/pruned v0.1.0
-- lazy/lazy.go --
package lazy

-- pruned/go.mod --
module example.net/pruned

stderr '^go: module example.com/deprecated/a is deprecated: in example.com/deprecated/a@v1.9.0$'
stdout '^a@v1.0.0$'

# 'go run pkg@version' does not show a deprecation message if the module is no longer
# deprecated in its latest version, even if the module is deprecated in its current version.
go run example.com/undeprecated/cmd/a@v1.0.0
! stderr 'module.*is deprecated'

-- m/go.mod --
module m

go 1.16

## Assembler {#assembler}

## Linker {#linker}

<!-- go.dev/issue/67401, CL 585556, CL 587220, and many more -->
The linker now disallows using a `//go:linkname` directive to refer to
internal symbols in the standard library (including the runtime) that
are not marked with `//go:linkname` on their definitions.
Similarly, the linker disallows references to such symbols from assembly
code.

On Windows, [EvalSymlinks] no longer evaluates mount points,
which was a source of many inconsistencies and bugs.
This behavior is controlled by the `winsymlink` setting.
For Go 1.23, it defaults to `winsymlink=1`.
Previous versions default to `winsymlink=0`.

On Windows, [EvalSymlinks] no longer tries to normalize
volumes to drive letters, which was not always even possible.
This behavior is controlled by the `winreadlinkvolume` setting.