shift exponent too large in left shift

[mgudemann]

when supplying a carefully crafted GOTO, it is possible to have a left shift showing potentially undefined behavior, as more than bit-width bits are left shifted

  while(in.good())
  {
    unsigned char ch=in.get();
    res|=(size_t(ch&0x7f))<<shift_distance;
    shift_distance+=7;
    if((ch&0x80)==0) break;
  }

wrong_left_shift.zip

[tautschnig]

A check was added in #3116.