### Compilation failed:

error: 16: operator '=' can not operate on arrays (or structs containing arrays)
void assign_A() { a1 = a2; }
                  ^^^^^^^
error: 17: operator '=' can not operate on arrays (or structs containing arrays)
void assign_S() { s1 = s2; }
                  ^^^^^^^
error: 18: operator '=' can not operate on arrays (or structs containing arrays)
void assign_T() { t1 = t2; }
                  ^^^^^^^
error: 21: functions may not return structs containing arrays
S return_S() { return s1; }
^^^^^^^^^^^^
error: 22: functions may not return structs containing arrays
T return_T() { return t1; }
^^^^^^^^^^^^
error: 24: operator '==' can not operate on arrays (or structs containing arrays)
bool equals_A()    { return a1 == a2; }
                            ^^^^^^^^
error: 25: operator '==' can not operate on arrays (or structs containing arrays)
bool equals_S()    { return s1 == s2; }
                            ^^^^^^^^
error: 26: operator '==' can not operate on arrays (or structs containing arrays)
bool equals_T()    { return t1 == t2; }
                            ^^^^^^^^
error: 28: operator '!=' can not operate on arrays (or structs containing arrays)
bool notequals_A() { return a1 != a2; }
                            ^^^^^^^^
error: 29: operator '!=' can not operate on arrays (or structs containing arrays)
bool notequals_S() { return s1 != s2; }
                            ^^^^^^^^
error: 30: operator '!=' can not operate on arrays (or structs containing arrays)
bool notequals_T() { return t1 != t2; }
                            ^^^^^^^^
error: 32: operator ',' can not operate on arrays (or structs containing arrays)
void sequence_A() { a1, a2; }
                    ^^^^^^
error: 33: operator ',' can not operate on arrays (or structs containing arrays)
void sequence_S() { s1, s2; }
                    ^^^^^^
error: 34: operator ',' can not operate on arrays (or structs containing arrays)
void sequence_T() { t1, t2; }
                    ^^^^^^
error: 36: ternary operator result may not be an array (or struct containing an array)
int ternary_A(bool b) { return (b ? a1 : a2)    [0]; }
                                ^^^^^^^^^^^
error: 37: ternary operator result may not be an array (or struct containing an array)
int ternary_S(bool b) { return (b ? s1 : s2)  .x[0]; }
                                ^^^^^^^^^^^
error: 38: ternary operator result may not be an array (or struct containing an array)
int ternary_T(bool b) { return (b ? t1 : t2).s.x[0]; }
                                ^^^^^^^^^^^
17 errors