// Implementation

// Avoid excessive type-checking times due to quadratic termlist operations.
const maxTermCount = 100

// parseUnion parses uexpr as a union of expressions.
// The result is a Union type, or Typ[Invalid] for some errors.
func parseUnion(check *Checker, uexpr ast.Expr) Type {
	blist, tlist := flattenUnion(nil, uexpr)
	assert(len(blist) == len(tlist)-1)

	var terms []*Term

	var u Type

// Implementation

// Avoid excessive type-checking times due to quadratic termlist operations.
const maxTermCount = 100

// parseUnion parses uexpr as a union of expressions.
// The result is a Union type, or Typ[Invalid] for some errors.
func parseUnion(check *Checker, uexpr syntax.Expr) Type {
	blist, tlist := flattenUnion(nil, uexpr)
	assert(len(blist) == len(tlist)-1)

	var terms []*Term

	var u Type

			ityp.embedPos = new([]syntax.Pos)
		}
		*ityp.embedPos = append(*ityp.embedPos, pos)
	}

	for _, f := range iface.MethodList {
		if f.Name == nil {
			addEmbedded(atPos(f.Type), parseUnion(check, f.Type))
			continue
		}
		// f.Name != nil

		// We have a method with name f.Name.
		name := f.Name.Value
		if name == "_" {

			ityp.embedPos = new([]token.Pos)
		}
		*ityp.embedPos = append(*ityp.embedPos, pos)
	}

	for _, f := range iface.Methods.List {
		if len(f.Names) == 0 {
			addEmbedded(f.Type.Pos(), parseUnion(check, f.Type))
			continue
		}
		// f.Name != nil

		// We have a method with name f.Names[0].
		name := f.Names[0]
		if name.Name == "_" {