message: lint, require alt prop
diff: import React from 'react'
  import PropTypes from 'prop-types'
  -import classnames from 'classnames'
  import styled from 'react-emotion'
  import {themeGet} from 'styled-system'
  -import {withSystemProps, COMMON} from './system-props'
  +import {withSystemProps} from './system-props'
  const Avatar = styled(AvatarImage)`
  display: inline-block;
  overflow: hidden; // Ensure page layout in Firefox should images fail to load
  line-height: ${themeGet('lineHeights.condensedUltra', 1)};
  vertical-align: middle;
  - ${borderRadius}
  - ${childStyles}
  + ${borderRadius};
  + ${childStyles};
  `
  const getBackgroundColor = themeGet('colors.white', '#fff')
  -function AvatarImage({isChild, size, ...rest}) {
  - return <img width={size} height={size} {...rest} />
  +function AvatarImage({alt, size, ...rest}) {
  + delete rest.isChild
  + return <img alt={alt} width={size} height={size} {...rest} />
  }
  function borderRadius({isChild, size}) {
  - const small = (isChild === true || size <= 24)
  + const small = isChild === true || size <= 24
  return {
  borderRadius: small ? '2px' : '3px'
  }
  @@ -44,7 +44,7 @@ Avatar.defaultProps = {
  }
  Avatar.propTypes = {
  - alt: PropTypes.string,
  + alt: PropTypes.string.isRequired,
  isChild: PropTypes.bool,
  size: PropTypes.number,
  src: PropTypes.string
  