Method: Deflate,
		Extra:  []byte(ts.Format(time.RFC3339Nano)), // missing tag and len, but Extra is best-effort parsing
	}
	h.SetModTime(ts)

	testValidHeader(&h, t)
}

func TestHeaderTooShort(t *testing.T) {
	h := FileHeader{
		Name:   "foo.txt",
		Method: Deflate,
		Extra:  []byte{zip64ExtraID}, // missing size and second half of tag, but Extra is best-effort parsing
	}
	testValidHeader(&h, t)
}

			context = ctxType
		} else {
			context = ctxExpr
		}
		f.walk(n.List, context, visit)
		f.walk(n.Body, ctxStmt, visit)
	case *ast.SwitchStmt:
		f.walk(n.Init, ctxStmt, visit)
		f.walk(&n.Tag, ctxExpr, visit)
		f.walk(n.Body, ctxSwitch, visit)
	case *ast.TypeSwitchStmt:
		f.walk(n.Init, ctxStmt, visit)
		f.walk(n.Assign, ctxStmt, visit)
		f.walk(n.Body, ctxTypeSwitch, visit)
	case *ast.CommClause:

pkg debug/dwarf, const TagCondition Tag
pkg debug/dwarf, const TagRvalueReferenceType = 66
pkg debug/dwarf, const TagRvalueReferenceType Tag
pkg debug/dwarf, const TagSharedType = 64
pkg debug/dwarf, const TagSharedType Tag
pkg debug/dwarf, const TagTemplateAlias = 67
pkg debug/dwarf, const TagTemplateAlias Tag
pkg debug/dwarf, const TagTypeUnit = 65
pkg debug/dwarf, const TagTypeUnit Tag

but are otherwise ignored.
</p>

<pre>
struct {
	x, y float64 ""  // an empty tag string is like an absent tag
	name string  "any string is permitted as a tag"
	_    [4]byte "ceci n'est pas un champ de structure"
}

// A struct corresponding to a TimeStamp protocol buffer.
// The tag strings define the protocol buffer field numbers;
// they follow the convention outlined by the reflect package.
struct {

pkg go/types, method (*StdSizes) Sizeof(Type) int64
pkg go/types, method (*Struct) Field(int) *Var
pkg go/types, method (*Struct) NumFields() int
pkg go/types, method (*Struct) String() string
pkg go/types, method (*Struct) Tag(int) string
pkg go/types, method (*Struct) Underlying() Type
pkg go/types, method (*Tuple) At(int) *Var
pkg go/types, method (*Tuple) Len() int
pkg go/types, method (*Tuple) String() string

pkg debug/dwarf, method (*UnsupportedType) String() string
pkg debug/dwarf, type UnsupportedType struct
pkg debug/dwarf, type UnsupportedType struct, embedded CommonType
pkg debug/dwarf, type UnsupportedType struct, Tag Tag
pkg debug/elf, type Symbol struct, Library string
pkg debug/elf, type Symbol struct, Version string
pkg encoding/csv, method (*ParseError) Unwrap() error
pkg encoding/json, method (*MarshalerError) Unwrap() error

but are otherwise ignored.
</p>

<pre>
struct {
	x, y float64 ""  // an empty tag string is like an absent tag
	name string  "any string is permitted as a tag"
	_    [4]byte "ceci n'est pas un champ de structure"
}

// A struct corresponding to a TimeStamp protocol buffer.
// The tag strings define the protocol buffer field numbers;
// they follow the convention outlined by the reflect package.
struct {

pkg syscall (netbsd-386), const RTAX_IFA = 5
pkg syscall (netbsd-386), const RTAX_IFP = 4
pkg syscall (netbsd-386), const RTAX_MAX = 9
pkg syscall (netbsd-386), const RTAX_NETMASK = 2
pkg syscall (netbsd-386), const RTAX_TAG = 8
pkg syscall (netbsd-386), const RTA_AUTHOR = 64
pkg syscall (netbsd-386), const RTA_BRD = 128
pkg syscall (netbsd-386), const RTA_DST = 1
pkg syscall (netbsd-386), const RTA_GATEWAY = 2

pkg syscall (netbsd-386), const RTAX_IFP ideal-int
pkg syscall (netbsd-386), const RTAX_MAX ideal-int
pkg syscall (netbsd-386), const RTAX_NETMASK ideal-int
pkg syscall (netbsd-386), const RTAX_TAG ideal-int
pkg syscall (netbsd-386), const RTA_AUTHOR ideal-int
pkg syscall (netbsd-386), const RTA_BRD ideal-int
pkg syscall (netbsd-386), const RTA_DST ideal-int
pkg syscall (netbsd-386), const RTA_GATEWAY ideal-int

		// Have to give it a name to simulate C "struct foo" references.
		tag := dt.StructName
		if dt.ByteSize < 0 && tag == "" { // opaque unnamed struct - should not be possible
			break
		}
		if tag == "" {
			tag = anonymousStructTag[dt]
			if tag == "" {
				tag = "__" + strconv.Itoa(tagGen)
				tagGen++
				anonymousStructTag[dt] = tag
			}
		} else if t.C.Empty() {
			t.C.Set(dt.Kind + " " + tag)