case last == nil:
						last = new(ast.ValueSpec) // make sure last exists
						inherited = false
					}
					check.arityMatch(s, last)
					f(constDecl{spec: s, iota: iota, typ: last.Type, init: last.Values, inherited: inherited})
				case token.VAR:
					check.arityMatch(s, nil)
					f(varDecl{s})
				default:
					check.errorf(s, InvalidSyntaxTree, "invalid token %s", d.Tok)
				}
			case *ast.TypeSpec:

		m = make(map[Object]bool)
		d.deps = m
	}
	m[obj] = true
}

// arityMatch checks that the lhs and rhs of a const or var decl
// have the appropriate number of names and init exprs. For const
// decls, init is the value spec providing the init exprs; for
// var decls, init is nil (the init exprs are in s in this case).
func (check *Checker) arityMatch(s, init *ast.ValueSpec) {
	l := len(s.Names)
	r := len(s.Values)
	if init != nil {

		// expr for each lhs variable, leading to duplicate work.
	}

	// check initialization
	if init == nil {
		if typ == nil {
			// error reported before by arityMatch
			obj.typ = Typ[Invalid]
		}
		return
	}

	if lhs == nil || len(lhs) == 1 {
		assert(lhs == nil || lhs[0] == obj)
		var x operand
		check.expr(newTarget(obj.typ, obj.name), &x, init)