}

func (u *Union) Len() int         { return len(u.terms) }
func (u *Union) Term(i int) *Term { return u.terms[i] }

func (u *Union) Underlying() Type { return u }
func (u *Union) String() string   { return TypeString(u, nil) }

// A Term represents a term in a Union.
type Term term

// NewTerm returns a new union term.
func NewTerm(tilde bool, typ Type) *Term { return &Term{tilde, typ} }

					return allTermlist
				}
				xi = u1
				used[j] = true // xj is now unioned into xi - ignore it in future iterations
			}
		}
		rl = append(rl, xi)
	}
	return rl
}

// union returns the union xl ∪ yl.
func (xl termlist) union(yl termlist) termlist {
	return append(xl, yl...).norm()
}

// intersect returns the intersection xl ∩ yl.
func (xl termlist) intersect(yl termlist) termlist {

				t = nil // ∅ term
			}
			terms = termlist{(*term)(t)}
		}
		// The type set of a union expression is the union
		// of the type sets of each term.
		allTerms = allTerms.union(terms)
		if len(allTerms) > maxTermCount {
			if check != nil {
				check.errorf(atPos(pos), InvalidUnion, "cannot handle more than %d union terms (implementation limitation)", maxTermCount)
			}
			unionSets[utyp] = &invalidTypeSet

// license that can be found in the LICENSE file.

// Test that the error message for an unrepresentable typedef in a
// union appears on the right line. This test is only run if the size
// of long double is larger than 64.

package main

/*
typedef long double             Float128;

typedef struct SV {
    union {
        Float128         float128;
    } value;
} SV;
*/
import "C"

type ts struct {

	},
	{
		// Check a pointer to a union if the union has any
		// pointer fields.
		name:    "union1",
		c:       `typedef union { char **p; unsigned long i; } u29; void f29(u29 *pu) {}`,
		imports: []string{"unsafe"},
		body:    `var b C.char; p := &b; C.f29((*C.u29)(unsafe.Pointer(&p)))`,
		fail:    true,
	},
	{
		// Don't check a pointer to a union if the union does
		// not have any pointer fields.

//go:build ignore

package main

// This file tests that when cgo -godefs sees a struct with a field
// that is an anonymous union, the first field in the union is
// promoted to become a field of the struct.  See issue 6677 for
// background.

/*
typedef struct {
	union {
		long l;
		int c;
	};
} t;
*/
import "C"

// Input for cgo -godefs.

// contains reports whether [lo:hi] is completely within sr.
func (sr shadowRange) contains(lo, hi int64) bool {
	return lo >= sr.lo() && hi <= sr.hi()
}

// merge returns the union of sr and [lo:hi].
// merge is allowed to return something smaller than the union.
func (sr shadowRange) merge(lo, hi int64) shadowRange {
	if lo < 0 || hi > 0xffff {
		// Ignore offsets that are too large or small.
		return sr
	}

		w.typ(t.base)

	case *Tuple:
		w.tuple(t, false)

	case *Signature:
		w.string("func")
		w.signature(t)

	case *Union:
		// Unions only appear as (syntactic) embedded elements
		// in interfaces and syntactically cannot be empty.
		if t.Len() == 0 {
			w.error("empty union")
			break
		}
		for i, t := range t.terms {
			if i > 0 {
				w.string(termSep)
			}
			if t.tilde {
				w.byte('~')

		return x.variadic == y.variadic &&
			c.identical(x.params, yparams, p) &&
			c.identical(x.results, yresults, p)

	case *Union:
		if y, _ := y.(*Union); y != nil {
			// TODO(rfindley): can this be reached during type checking? If so,
			// consider passing a type set map.
			unionSets := make(map[*Union]*_TypeSet)
			xset := computeUnionTypeSet(nil, unionSets, nopos, x)
			yset := computeUnionTypeSet(nil, unionSets, nopos, y)

// struct_foo becomes "struct foo", and similarly for
// union and enum.
func cname(s string) string {
	if t, ok := nameToC[s]; ok {
		return t
	}

	if strings.HasPrefix(s, "struct_") {
		return "struct " + s[len("struct_"):]
	}
	if strings.HasPrefix(s, "union_") {
		return "union " + s[len("union_"):]
	}
	if strings.HasPrefix(s, "enum_") {
		return "enum " + s[len("enum_"):]
	}