improve collapse-handling

include/engine/api/route_api.hpp

@@ -144,6 +144,7 @@ class RouteAPI : public BaseAPI
                 guidance::trimShortSegments(steps, leg_geometry);
                 leg.steps = guidance::postProcess(std::move(steps));
                 leg.steps = guidance::collapseTurns(std::move(leg.steps));
+                leg.steps = guidance::buildIntersections(std::move(leg.steps));
                 leg.steps = guidance::assignRelativeLocations(std::move(leg.steps),
                                                               leg_geometry,
                                                               phantoms.source_phantom,

include/engine/guidance/post_processing.hpp

@@ -37,6 +37,9 @@ std::vector<RouteStep> assignRelativeLocations(std::vector<RouteStep> steps,
                                                const PhantomNode &source_node,
                                                const PhantomNode &target_node);
 
+// collapse suppressed instructions remaining into intersections array
+std::vector<RouteStep> buildIntersections(std::vector<RouteStep> steps);
+
 // remove steps invalidated by post-processing
 std::vector<RouteStep> removeNoTurnInstructions(std::vector<RouteStep> steps);