resolve(ident) {
        let ref, i, iz;

        assert(this.__isClosed(), "Scope should be closed.");
        assert(ident.type === Syntax.Identifier, "Target should be identifier.");
        for (i = 0, iz = this.references.length; i < iz; ++i) {
            ref = this.references[i];
            if (ref.identifier === ident) {
                return ref;
            }
        }
        return null;
    }
returns resolved {Reference}
@function Scope#resolve
@param {Espree.Identifier} ident identifier to be resolved.
@returns {Reference} reference