Method interfaceType

syntax/parser.go:1469–1530

InterfaceType = "interface" "{" { ( MethodDecl | EmbeddedElem | TypeList ) ";" } "}" . TypeList = "type" Type { "," Type } . TODO(gri) remove TypeList syntax if we accept #45346

()

// TypeList      = "type" Type { "," Type } .
// TODO(gri) remove TypeList syntax if we accept #45346
func (p *parser) interfaceType() *InterfaceType {
	if trace {
		defer p.trace("interfaceType")()
	}

	typ := new(InterfaceType)
	typ.pos = p.pos()

	p.want(_Interface)
	p.asyncList(_Lbrace, _Semi, _Rbrace, func() bool {
		switch p.tok {
		case _Name:
			f := p.methodDecl()
			if f.Name == nil && p.allowGenerics() {
				f = p.embeddedElem(f)
			}
			typ.MethodList = append(typ.MethodList, f)
			return false

		case _Lparen:
			// TODO(gri) Need to decide how to adjust this restriction.
			p.syntaxError("cannot parenthesize embedded type")
			f := new(Field)
			f.pos = p.pos()
			p.next()
			f.Type = p.qualifiedName(nil)
			p.want(_Rparen)
			typ.MethodList = append(typ.MethodList, f)
			return false

		case _Operator:
			if p.op == Tilde && p.allowGenerics() {
				typ.MethodList = append(typ.MethodList, p.embeddedElem(nil))
				return false
			}

		default:
			if p.allowGenerics() {
				pos := p.pos()
				if t := p.typeOrNil(); t != nil {
					f := new(Field)
					f.pos = pos
					f.Type = t
					typ.MethodList = append(typ.MethodList, p.embeddedElem(f))
					return false
				}
			}
		}

		if p.allowGenerics() {
			p.syntaxError("expecting method or embedded element")
			p.advance(_Semi, _Rbrace)
			return false
		}

		p.syntaxError("expecting method or interface name")
		p.advance(_Semi, _Rbrace)
		return false