function get_global_keypath(node, scope) {
	let n = node;

	let joined = '';

	while (n.type === 'MemberExpression') {
		if (n.computed) return null;
		if (n.property.type !== 'Identifier') return null;
		joined = '.' + n.property.name + joined;
		n = n.object;
	}

	if (n.type === 'CallExpression' && n.callee.type === 'Identifier') {
		joined = '()' + joined;
		n = n.callee;
	}

	if (n.type !== 'Identifier') return null;

	const binding = scope.get(n.name);
	if (binding !== null) return null; // rune name, but references a variable or store

	return n.name + joined;
}
Returns the name of the rune if the given expression is a `CallExpression` using a rune.
@param {Expression | Super} node
@param {Scope} scope