go install example.com/cmd/a@v1.0.0 example.com/cmd/nomatch...@v1.0.0
stderr '^go: warning: "example.com/cmd/nomatch\.\.\." matched no packages$'

# If a wildcard matches only non-main packages, we should see a different warning.
go install example.com/cmd/err...@v1.0.0
stderr '^go: warning: "example.com/cmd/err\.\.\." matched only non-main packages$'

Vendoring in std and cmd
========================

The Go command maintains copies of external packages needed by the
standard library in the src/vendor and src/cmd/vendor directories.

There are two modules, std and cmd, defined in src/go.mod and
src/cmd/go.mod. When a package outside std or cmd is imported
by a package inside std or cmd, the import path is interpreted
as if it had a "vendor/" prefix. For example, within "crypto/tls",

! go run example.com/cmd/err@v1.0.0
stderr '^package example.com/cmd/err is not a main package$'


# 'go run pkg@version' should report errors if the module contains
# replace or exclude directives.
go mod download example.com/cmd@v1.0.0-replace
! go run example.com/cmd/a@v1.0.0-replace
cmp stderr replace-err

go mod download example.com/cmd@v1.0.0-exclude
! go run example.com/cmd/a@v1.0.0-exclude

by any [`//go:build` constraints](https://pkg.go.dev/cmd/go#hdr-Build_constraints)
in the file.)

For example, it will report a diagnostic for a reference to the
`reflect.TypeFor` function (introduced in go1.22) from a file in a
module whose go.mod file specifies `go 1.21`.

### Cgo {#cgo}

<!-- go.dev/issue/66456 -->
[cmd/cgo] supports the new `-ldflags` flag for passing flags to the C linker.

-- .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"

-- .mod --
// Deprecated: in v1.0.0
module example.com/undeprecated

go 1.17
-- go.mod --
// Deprecated: in v1.0.0
module example.com/undeprecated

go 1.17
-- undeprecated.go --
package undeprecated

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

import "fmt"

module cmd

go 1.23

require (
	github.com/google/pprof v0.0.0-20240528025155-186aa0362fba
	golang.org/x/arch v0.8.0
	golang.org/x/build v0.0.0-20240603162849-5dfbda438323
	golang.org/x/mod v0.18.0
	golang.org/x/sync v0.7.0
	golang.org/x/sys v0.21.0
	golang.org/x/telemetry v0.0.0-20240603224550-f2b69109f79b
	golang.org/x/term v0.20.0
	golang.org/x/tools v0.21.1-0.20240604144337-208808308b70
)

require (

a few x/tools CLs tagged and deleted the golang.org/x/tools/cmd/guru command per accepted proposal https://go.dev/issue/65880; an unreleased change and not something that's in scope of Go 1.23 release notes
CL 580076 - seemingly internal cmd/go change to propagate module information for accepted proposal https://go.dev/issue/66315; doesn't seem to warrant a release note

-- .info --
{"Version":"v1.0.0"}
-- .mod --
module example.com/deprecated/a

go 1.17
-- go.mod --
module example.com/deprecated/a

go 1.17
-- a.go --
package a

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

import "fmt"

module example.com/deprecated/a

go 1.17
-- go.mod --
// Deprecated: in example.com/deprecated/a@v1.9.0
module example.com/deprecated/a

go 1.17
-- a.go --
package a

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

import "fmt"