clang/test/SemaCXX/warn-bitfield-enum-conversion.cpp

   1 // RUN: %clang_cc1 -std=c++11 -triple x86_64-windows-msvc -verify %s -Wbitfield-enum-conversion
   2 // RUN: %clang_cc1 -std=c++11 -triple x86_64-linux -verify %s -Wbitfield-enum-conversion
   3
   4 enum TwoBits { Hi1 = 3 } two_bits;
   5 enum TwoBitsSigned { Lo2 = -2, Hi2 = 1 } two_bits_signed;
   6 enum ThreeBits { Hi3 = 7 } three_bits;
   7 enum ThreeBitsSigned { Lo4 = -4, Hi4 = 3 } three_bits_signed;
   8 enum TwoBitsFixed : unsigned { Hi5 = 3 } two_bits_fixed;
   9
  10 struct Foo {
  11   unsigned two_bits : 2;        // expected-note 2 {{widen this field to 3 bits}} expected-note 2 {{type signed}}
  12   int two_bits_signed : 2;      // expected-note 2 {{widen this field to 3 bits}} expected-note 1 {{type unsigned}}
  13   unsigned three_bits : 3;      // expected-note 2 {{type signed}}
  14   int three_bits_signed : 3;    // expected-note 1 {{type unsigned}}
  15
  16 #ifdef _WIN32
  17   // expected-note@+2 {{type unsigned}}
  18 #endif
  19   ThreeBits three_bits_enum : 3;
  20   ThreeBits four_bits_enum : 4;
  21 };
  22
  23 void f() {
  24   Foo f;
  25
  26   f.two_bits = two_bits;
  27   f.two_bits = two_bits_signed;            // expected-warning {{negative enumerators}}
  28   f.two_bits = three_bits;                 // expected-warning {{not wide enough}}
  29   f.two_bits = three_bits_signed;          // expected-warning {{negative enumerators}} expected-warning {{not wide enough}}
  30   f.two_bits = two_bits_fixed;
  31
  32   f.two_bits_signed = two_bits;            // expected-warning {{needs an extra bit}}
  33   f.two_bits_signed = two_bits_signed;
  34   f.two_bits_signed = three_bits;          // expected-warning {{not wide enough}}
  35   f.two_bits_signed = three_bits_signed;   // expected-warning {{not wide enough}}
  36
  37   f.three_bits = two_bits;
  38   f.three_bits = two_bits_signed;          // expected-warning {{negative enumerators}}
  39   f.three_bits = three_bits;
  40   f.three_bits = three_bits_signed;        // expected-warning {{negative enumerators}}
  41
  42   f.three_bits_signed = two_bits;
  43   f.three_bits_signed = two_bits_signed;
  44   f.three_bits_signed = three_bits;        // expected-warning {{needs an extra bit}}
  45   f.three_bits_signed = three_bits_signed;
  46
  47 #ifdef _WIN32
  48   // Enums on Windows are always implicitly 'int', which is signed, so you need
  49   // an extra bit to store values that set the MSB. This is not true on SysV
  50   // platforms like Linux.
  51   // expected-warning@+2 {{needs an extra bit}}
  52 #endif
  53   f.three_bits_enum = three_bits;
  54   f.four_bits_enum = three_bits;
  55
  56   // Explicit casts suppress the warning.
  57   f.two_bits = (unsigned)three_bits_signed;
  58   f.two_bits = static_cast<unsigned>(three_bits_signed);
  59 }