Unable to generate sourcemap into a separate file #717

// rollup.config.js
export default {
    entry: 'src/main.js',
    format: 'iife',
    moduleName: 'RollupTest',
    dest: 'dist/bundle.js',
    sourceMap: true,
    sourceMapFile: 'dist/bundle.js.map',
    ...
}

// src/main.js
var foo = 42;

function main() {
    console.log(foo);
    return foo;
}

function woa() {
    return 5;
}

export default main;

var RollupTest = (function () {
    'use strict';

    var foo = 42;

    function main() {
        console.log(foo);
        return foo;
    }

    return main;

}());
//# sourceMappingURL=bundle.js.map