error: a union literal may set only one member, or several members of the same anonymous-struct arm — 'Overlay's members overlay the same storage
  --> examples/diagnostics/1191-diagnostics-union-literal-overlap.sx:11:19
   |
11 |     o : Overlay = .{ f = 3.14, i = 7 };   // ERROR: f and i overlay the same bytes
   |                   ^^^^^^^^^^^^^^^^^^^^