error: vtable entries for `<S as D>`: [
           MetadataDropInPlace,
           MetadataSize,
           MetadataAlign,
           Method(<S as A>::foo_a),
           Method(<S as B>::foo_b),
           Method(<S as C>::foo_c),
           TraitVPtr(<S as C>),
           Method(<S as D>::foo_d),
       ]
  --> $DIR/vtable-diamond.rs:21:1
   |
LL | trait D: B + C {
   | ^^^^^^^^^^^^^^

error: vtable entries for `<S as C>`: [
           MetadataDropInPlace,
           MetadataSize,
           MetadataAlign,
           Method(<S as A>::foo_a),
           Method(<S as C>::foo_c),
       ]
  --> $DIR/vtable-diamond.rs:15:1
   |
LL | trait C: A {
   | ^^^^^^^^^^

error: aborting due to 2 previous errors