%prec( {a} < {b})%

%prec( {a} < {c})%

%prec( {b} < {c})%

%left_assoc( a, b, c)%

%right_assoc( d)%

Error (line 3, column 16) prec_anno conflict: c < a

a,b

b,c 'a'

Error (line 5, column 14) identifier has already other associativity 'b'

Error (line 5, column 16) identifier has already other associativity 'a'

Hint (line 5, column 20) repeated associative identifier 'd'