react/no-unused-proptype false positive

[georeith]

The following is considered an error for the props a and b:

import React from 'react';

export default function SomeComponent(props) {
    const callback = () => {
        props.a(props.b);
    };

    const anotherCallback = () => {};

    return (
        <SomeOtherComponent
            name={props.c}
            callback={callback}
        />
    );
}

SomeComponent.propTypes = {
    a: React.PropTypes.func.isRequired,
    b: React.PropTypes.string.isRequired,
    c: React.PropTypes.string.isRequired,
};

Removing the line const anotherCallback = () => {}; fixes the false positive.
The following does not trigger an error:

import React from 'react';

export default function SomeComponent(props) {
    const callback = () => {
        props.a(props.b);
    };

    return (
        <SomeOtherComponent
            name={props.c}
            callback={callback}
        />
    );
}

SomeComponent.propTypes = {
    a: React.PropTypes.func.isRequired,
    b: React.PropTypes.string.isRequired,
    c: React.PropTypes.string.isRequired,
};

[jseminck]

I have been taking a look at this issue as I wanted to familiarize myself with the codebase a little bit. I managed to reproduce the issue through tests, and found a fix for it. Though I have no idea if the fix is valid or not. It does not break any other tests, though.

I will make a PR with the fix later today or tomorrow. Then anyone more experienced with the code can take a look. Even if my fix is not correct it might help someone else figure out what the issue really is.

For clarification, this also works (declaring anotherCallback before callback):

export default function SomeComponent(props) {
    const anotherCallback = () => {};

    const callback = () => {
        props.a(props.b);
    };

    return (
        <SomeOtherComponent
            name={props.c}
            callback={callback}
        />
    );
}

SomeComponent.propTypes = {
    a: React.PropTypes.func.isRequired,
    b: React.PropTypes.string.isRequired,
    c: React.PropTypes.string.isRequired,
};

[ljharb]

Thanks, good to start somewhere.

[ljharb]

I believe this may be fixed with #1218. Please reopen after the next release if not.