Comment # 8 on bug 1135254 from Richard Biener

So while

Supplements: (gdb and libstdc++6 = 9.1.1+r271995-lp151.18.1)

works in SLE15+

Supplements: packageand(gdb:libstdc++6=9.1.1+r271995-18.1)

does not seem to work on Leap 42.3 for example.  When doing zypper in
libstdc++6-gcc9 the pretty-printer package is not selected.  Note that
the Supplements above mentions the virtual package libstdc++6 the
libstdc++6-gcc9 package provides (and the system currently has
libstdc++6-gcc8 also providing it but in a non-matching version).

So my conclusion is for the SLE12 Toolchain module this split is
counter-productive since people will need to explicitely install
libstdc++6-pp-gcc9 to debug C++.

Michael - is the virtual package thing the issue here?  If so it might
in the end work (since the actual installed runtime _will_ have the
bare libstdc++6 name on the Toolchain module, just installing an
unsupported runtime would cause this issue).