{{ path(app.request.attributes.get('_route'),
app.request.attributes.get('_route_params')) }}
If you want to read it into a view variable:
{% set currentPath = path(app.request.attributes.get('_route'),
app.request.attributes.get('_route_params')) %}
The app global view variable contains all sorts of useful shortcuts, such as app.session and app.security.token.user, that reference the services you might use in a controller.