// sequential fashion. Note that with each new declaration, we save
	// the existing environment and restore it when done; thus inTParamList
	// is true exactly only when we are in a specific type parameter list.
	assert(!check.inTParamList)
	check.inTParamList = true
	defer func() {
		check.inTParamList = false
	}()

	// Keep track of bounds for later validation.
	var bound Type
	for i, f := range list {

	// the existing environment and restore it when done; thus inTPList is
	// true exactly only when we are in a specific type parameter list.
	assert(!check.inTParamList)
	check.inTParamList = true
	defer func() {
		check.inTParamList = false
	}()

	index := 0
	for _, f := range list.List {
		var bound Type
		// NOTE: we may be able to assert that f.Type != nil here, but this is not

	iota          constant.Value            // value of iota in a constant declaration; nil otherwise
	errpos        syntax.Pos                // if valid, identifier position of a constant with inherited initializer
	inTParamList  bool                      // set if inside a type parameter list
	sig           *Signature                // function signature if inside a function; nil otherwise

	iota          constant.Value         // value of iota in a constant declaration; nil otherwise
	errpos        positioner             // if set, identifier position of a constant with inherited initializer
	inTParamList  bool                   // set if inside a type parameter list
	sig           *Signature             // function signature if inside a function; nil otherwise