id	summary	reporter	owner	description	type	status	priority	milestone	component	version	resolution	keywords	cc
7788	validator should accept some kinds of way overlaps	A_Pirard	team	"A convenient and sensible way to map ways is to
- map the waterways in one thread at layer -2
- overlap culverts and bridges at layer -1
- map roads in one thread at layer 0
- overlap road/railway tunnels at level 1

convenient: obviously easier not to have to tag many way segments all the same[[BR]]
sensible: for example, 
- a tunnel is not the river, it's something around it
- a bridge is concrete under continued tarmac
in fact, the way runs uninterrupted.

Hence, JOSM should allow such overlap combinations and forbid others.
Or, even more simply, it should allow them because they're not at the same level=layer.

Note that it should be supported to map an overlapping segment even of the same kind and layer to add or modify a tag on a short distance.  Say turn a tarmac road to cobblestone for 100m with overlap=cobblestone.
"	enhancement	new	normal		Core	latest			A_Pirard