pkg go/ast, type Package //deprecated #52463
pkg go/ast, type Scope //deprecated #52463
pkg go/types, func NewAlias(*TypeName, Type) *Alias #63223
pkg go/types, func Unalias(Type) Type #63223
pkg go/types, method (*Alias) Obj() *TypeName #63223
pkg go/types, method (*Alias) String() string #63223
pkg go/types, method (*Alias) Underlying() Type #63223
pkg go/types, method (*Info) PkgNameOf(*ast.ImportSpec) *PkgName #62037

The [Alias] type now has an [Rhs] method that returns the type on the
right-hand side of its declaration: given `type A = B`, the `Rhs` of A

// aliasReplacer applies type aliases to earlier API files,
// to avoid misleading negative results.
// This makes all the references to os.FileInfo in go1.txt
// be read as if they said fs.FileInfo, since os.FileInfo is now an alias.
// If there are many of these, we could do a more general solution,
// but for now the replacer is fine.
var aliasReplacer = strings.NewReplacer(
	"os.FileInfo", "fs.FileInfo",
	"os.FileMode", "fs.FileMode",