What is the correct way to extend Material UI ListItem?

I’m using TypeScript 3.4.5 and Material UI 4.2 and with the following piece of code:

interface MyItemProps {
    name: string;
    value: string;

function Item({ name, value, ...props }: ListItemProps<'li', MyItemProps>): ReactElement {
    return (
        <ListItem {...props} className="item">
            <ListItemText primary={name} secondary={value || '-'} />

I’m getting Type 'boolean' is not assignable to type 'true' error. Why?

I’ve been looking into the type definitions for ListItem, but I can’t figure out what’s going on:

export interface ListItemTypeMap<P, D extends React.ElementType> {
  props: P & {
    alignItems?: 'flex-start' | 'center';
    autoFocus?: boolean;
    button?: boolean;
    ContainerComponent?: React.ElementType<React.HTMLAttributes<HTMLDivElement>>;
    ContainerProps?: React.HTMLAttributes<HTMLDivElement>;
    dense?: boolean;
    disabled?: boolean;
    disableGutters?: boolean;
    divider?: boolean;
    focusVisibleClassName?: string;
    selected?: boolean;
  defaultComponent: D;
  classKey: ListItemClassKey;

declare const ListItem: OverridableComponent<ListItemTypeMap<{ button?: false }, 'li'>> &
  ExtendButtonBase<ListItemTypeMap<{ button: true }, 'div'>>;

export type ListItemClassKey =
  | 'root'
  | 'container'
  | 'focusVisible'
  | 'default'
  | 'dense'
  | 'disabled'
  | 'divider'
  | 'gutters'
  | 'button'
  | 'secondaryAction'
  | 'selected';

export type ListItemProps<D extends React.ElementType = 'li', P = {}> = OverrideProps<
  ListItemTypeMap<P, D>,

export default ListItem;

The only thing that comes to my mind is “type widening”, but I don’t really know what’s happening and why.

Could somebody please explain what’s going on? Most importantly, what is the correct way of extending a Material UI component?

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