### New unique package

The new [unique] package provides facilities for
canonicalizing values (like "interning" or "hash-consing").

Any value of comparable type may be canonicalized with the new
`Make[T]` function, which produces a reference to a canonical copy of
the value in the form of a `Handle[T]`.
Two `Handle[T]` are equal if and only if the values used to produce the
handles are equal, allowing programs to deduplicate values and reduce

The new [ParseCookie] function parses a Cookie header value and
returns all the cookies which were set in it. Since the same cookie
name can appear multiple times the returned Values can contain
more than one value for a given key.

The new [ParseSetCookie] function parses a Set-Cookie header value and

	}
	newPath, newVersion, err := parsePathVersionOptional("new", new, true)
	if err != nil {
		base.Fatalf("go: -replace=%s: %v", arg, err)
	}
	if newPath == new && !modfile.IsDirectoryPath(new) {
		base.Fatalf("go: -replace=%s: unversioned new path must be local directory", arg)
	}

	workedits = append(workedits, func(f *modfile.WorkFile) {

  a new slice.
- [AppendSeq](/pkg/slices#AppendSeq) appends values from an iterator to
  an existing slice.
- [Sorted](/pkg/slices#Sorted) collects values from an iterator into a
  new slice, and then sorts the slice.
- [SortedFunc](/pkg/slices#SortedFunc) is like `Sorted` but with a
  comparison function.
- [SortedStableFunc](/pkg/slices#SortedStableFunc) is like `SortFunc`
  but uses a stable sort algorithm.

func asNamed(t Type) *Named {
	n, _ := Unalias(t).(*Named)
	return n
}

// newAlias creates a new Alias type with the given type name and rhs.
// rhs must not be nil.
func (check *Checker) newAlias(obj *TypeName, rhs Type) *Alias {
	assert(rhs != nil)
	a := new(Alias)
	a.obj = obj
	a.orig = a
	a.fromRHS = rhs
	if obj.typ == nil {
		obj.typ = a
	}

// the timestamps/paths of the objects; this makes it
// difficult/impossible to support reproducible builds. Since we try
// hard to maintain build reproducibility for Go, the APIs here
// compute a new UUID (based on the Go build ID) and write it to the
// final executable generated by the external linker.

import (
	"cmd/internal/notsha256"
	"debug/macho"
	"io"
	"os"
	"unsafe"
)

a large open-source code corpus remain supported.
Any new references to standard library internal symbols will be disallowed.

A linker command line flag `-checklinkname=0` can be used to disable
this check, for debugging and experimenting purposes.

<!-- CL 473495 -->
When building a dynamically linked ELF binary (including PIE binary), the

<!-- This is a new package; covered in 6-stdlib/3-structs.md. -->...

The new [Request.CookiesNamed] method retrieves all cookies that match the given name....

### New structs package

The new [structs] package provides
types for struct fields that modify properties of
the containing struct type such as memory layout.

In this release, the only such type is
[`HostLayout`](/pkg/structs#HostLayout)
which indicates that a structure with a field of that
type has a layout that conforms to host platform