Flow errors with styled component ref prop

[sandgraham]

Flow errors when trying to pass a ref to a styled component.

// flow works
class Foo extends React.Component<any, any> {
  ref = React.createRef<HTMLInputElement>();
  render() {
    return <input ref={this.ref} />;
  }
}

// flow works
import {styled} from 'styletron-react';
const Input = styled('input', {});
class Boo extends React.Component<any, any> {
  ref = React.createRef<HTMLInputElement>();
  render() {
    return <Input $ref={this.ref} />;
  }
}

// code works, flow fails
import {styled} from 'styletron-react';
const Input = styled('input', {});
class Boo extends React.Component<any, any> {
  ref = React.createRef<HTMLInputElement>();
  render() {
    return <Input ref={this.ref} />; // flow complains about ref type
  }
}

Here is the flow error output:

Cannot create Input element because:
 • Either undefined [1] is incompatible with null [2] in property current of property ref.
 • Or a call signature declaring the expected parameter / return type is missing in object type [3] but exists in
   function type [4] in property ref.
 • Or object type [5] is not a React component.

        src/App.js
         22│   render() {
         23│     const Input = styled("input", {});
         24│     return (
         25│       <Input ref={this.ref} onChange={() => console.log(this.ref.current)} />
         26│     );
         27│   }
         28│ }

        /private/tmp/flow/flowlib_289644ca/react.js
    [4] 197│   | ((React$ElementRef<ElementType> | null) => mixed)
           :
 [3][2] 246│   ): {|current: null | T|};

        node_modules/styletron-react/src/types.js
 [1][5]  48│ export type StyletronComponent<Props> = StatelessFunctionalComponent<Props> & {
         49│   __STYLETRON__: any,
         50│ };

[KosGrillis]

Any workarounds for this?