src/share/vm/code/dependencies.cpp

*** 880,889 ****
--- 880,897 ----
    // Current thread must be in VM (not native mode, as in CI):
    assert(must_be_in_vm(), "raw oops here");
    // Must not move the class hierarchy during this check:
    assert_locked_or_safepoint(Compile_lock);
  
+   int nof_impls = instanceKlass::cast(context_type)->nof_implementors();
+   if (nof_impls > 1) {
+     // Avoid this case: *I.m > { A.m, C }; B.m > C
+     // %%% Until this is fixed more systematically, bail out.
+     // See corresponding comment in find_witness_anywhere.
+     return context_type;
+   }
+ 
    assert(!is_participant(new_type), "only old classes are participants");
    if (participants_hide_witnesses) {
      // If the new type is a subtype of a participant, we are done.
      for (int i = 0; i < num_participants(); i++) {
        klassOop part = participant(i);