Duplicated definitions lead to dangerous error about yomm2 HOT 1 CLOSED

ambiguous call for N5yorel5yomm26methodI11YoMm2_S_sayFNSt7__cxx1112basic_stringIcSt11char_traitsIcESaIcEEENS0_8virtual_IRK9CharacterEEENS0_6policy23hash_factors_in_globalsEEE(7Warrior)
Aborted (core dumped)

ambiguous call for yorel::yomm2::method<YoMm2_S_say, std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > (yorel::yomm2::virtual_<Character const&>), yorel::yomm2::policy::hash_factors_in_globals>(Warrior)

ambiguous call for method<say, basic_string<char, char_traits<char>, allocator<char> > (virtual_<Character const&>)>(Warrior)

jll@euclid:~/dev/yomm2$ YOMM2_TRACE=1 /home/jll/dev/yomm2/build/tests/lab 2>&1 | dev/yomm2filt 
Static class info:
  0x55681c6adbd0 Character (Character(0x55681c6adbd0))  
  0x55681c6adc10 Warrior (Character(0x55681c6adbd0), Warrior(0x55681c6adc10))  
  0x55681c6adbe0 Dog (Character(0x55681c6adbd0), Dog(0x55681c6adbe0))  
Inheritance:
  Dog
    bases:      (Character)
    derived:    ()
    covariant_classes: (Dog)
  Warrior
    bases:      (Character)
    derived:    ()
    covariant_classes: (Warrior)
  Character
    bases:      ()
    derived:    (Dog, Warrior)
    covariant_classes: (Warrior, Dog, Character)
Methods:
  method<say, basic_string<char, char_traits<char>, allocator<char> > (virtual_<Character const&>)> (Character(0x55681c6adbd0))
    (const Warrior& long long)
    (const Warrior& long long)
    (const Character& long long)
Layering classes...
  Character
  Dog Warrior
Allocating slots...
  method<say, basic_string<char, char_traits<char>, allocator<char> > (virtual_<Character const&>)>#0: slot 0
    Character Dog Warrior    
Building dispatch table for method<say, basic_string<char, char_traits<char>, allocator<char> > (virtual_<Character const&>)>
  make groups for param #0, class Character
    specs applicable to Warrior
      (const Character& long long)
      (const Warrior& long long)
      (const Warrior& long long)
      -> mask: 111
    specs applicable to Dog
      (const Character& long long)
      -> mask: 001
    specs applicable to Character
      (const Character& long long)
      -> mask: 001
  groups for dim 0:
    group 0/0 mask 001
      Dog(0x55681c6adbe0)
      Character(0x55681c6adbd0)
    group 0/1 mask 111
      Warrior(0x55681c6adc10)
  assigning specs
    group 0/0 mask 001
      Dog(0x55681c6adbe0)
      Character(0x55681c6adbd0)
    select best of:
      (const Character& long long)
    -> (const Character& long long) pf = 0x55681c66dcf0
    group 0/1 mask 111
      Warrior(0x55681c6adc10)
    select best of:
      (const Character& long long)
      (const Warrior& long long)
      (const Warrior& long long)
      ambiguous
  0 not implemented, 1 ambiguities, concrete only: 0, 0
  assigning next
    (const Character& long long):
      for next, select best:
    -> none
    (const Warrior& long long):
      for next, select best:
        (const Character& long long)
    -> (const Character& long long)
    (const Warrior& long long):
      for next, select best:
        (const Character& long long)
    -> (const Character& long long)
Finding hash factor for 3 ti*
trying with M = 2, 4 buckets
found 6814184542283810107 after 1 attempts and 0.018717 msecs
   5 control table
   9 mtbl for Dog: 0x55681c820dc8
  10 mtbl for Warrior: 0x55681c820dd0
  11 mtbl for Character: 0x55681c820e38
Initializing global vector at 0x55681c820de0
   0 pointer to control table
   1 hash table
   5 control table
   9 method<say, basic_string<char, char_traits<char>, allocator<char> > (virtual_<Character const&>)>
   9 mtbl for Dog: 0x55681c820e28
  10 mtbl for Warrior: 0x55681c820e30
  11 mtbl for Character: 0x55681c820e38
  12 end
Optimizing
  method<say, basic_string<char, char_traits<char>, allocator<char> > (virtual_<Character const&>)>
Warrior mtbl[0] = 0x55681c66f8d0 (function)
Dog mtbl[0] = 0x55681c66dcf0 (function)
Character mtbl[0] = 0x55681c66dcf0 (function)
0 not implemented, 1 ambiguities, concrete only: 0, 0
Finished
ambiguous call for method<say, basic_string<char, char_traits<char>, allocator<char> > (virtual_<Character const&>)>(Warrior)