Issue

I don't think the proposed=* tag is being interpreted correctly for foot, bike or car. In the example below, a mapper had used it to indicate that the road was tertiary but there was a plan/proposal to upgrade it to a B-road at some point. OSRM pruned way 1156793083 from the map, so it is not routable.

It could be argued that a road with both highway=tertiary and proposed=* is non-standard, however I believe it should still be routable. There will be many instances when a perfectly usable road is planned to be upgraded or turned into something else.

It should only be highway=proposed that is pruned, and in that case, the additional tag proposed=* isn't very relevant.

Steps to reproduce

The road in question has since been fixed, but the issue can be replicated by simply creating a highway with tags:
highway=tertiary and proposed=secondary and attempting to plan a route using the default foot/bike/car profiles.

Likely, any highway=* and proposed=* will exhibit similar behaviour.

Specifications

N/A