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      1 // RUN: %clang_cc1 -fsyntax-only -std=c++11 -triple x86_64-apple-macosx10.6.7 -verify %s
      2 
      3 // Verify that narrowing conversions in initializer lists cause errors in C++0x
      4 // mode.
      5 
      6 void std_example() {
      7   int x = 999;  // x is not a constant expression
      8   const int y = 999;
      9   const int z = 99;
     10   char c1 = x;  // OK, though it might narrow (in this case, it does narrow)
     11   char c2{x};  // expected-error {{ cannot be narrowed }} expected-note {{override}}
     12   char c3{y};  // expected-error {{ cannot be narrowed }} expected-note {{override}} expected-warning {{changes value}}
     13   char c4{z};  // OK: no narrowing needed
     14   unsigned char uc1 = {5};  // OK: no narrowing needed
     15   unsigned char uc2 = {-1};  // expected-error {{ cannot be narrowed }} expected-note {{override}}
     16   unsigned int ui1 = {-1};  // expected-error {{ cannot be narrowed }} expected-note {{override}}
     17   signed int si1 =
     18     { (unsigned int)-1 };  // expected-error {{ cannot be narrowed }} expected-note {{override}}
     19   int ii = {2.0};  // expected-error {{ cannot be narrowed }} expected-note {{override}}
     20   float f1 { x };  // expected-error {{ cannot be narrowed }} expected-note {{override}}
     21   float f2 { 7 };  // OK: 7 can be exactly represented as a float
     22   int f(int);
     23   int a[] =
     24     { 2, f(2), f(2.0) };  // OK: the double-to-int conversion is not at the top level
     25 }
     26 
     27 // Test each rule individually.
     28 
     29 template<typename T>
     30 struct Agg {
     31   T t;
     32 };
     33 
     34 template<typename T>
     35 struct Convert {
     36   constexpr Convert(T v) : v(v) {}
     37   constexpr operator T() const { return v; }
     38   T v;
     39 };
     40 template<typename T> Convert<T> ConvertVar();
     41 
     42 // C++0x [dcl.init.list]p7: A narrowing conversion is an implicit conversion
     43 //
     44 // * from a floating-point type to an integer type, or
     45 
     46 void float_to_int() {
     47   Agg<char> a1 = {1.0F};  // expected-error {{type 'float' cannot be narrowed to 'char'}} expected-note {{override}}
     48   Agg<char> a2 = {1.0};  // expected-error {{ cannot be narrowed }} expected-note {{override}}
     49   Agg<char> a3 = {1.0L};  // expected-error {{ cannot be narrowed }} expected-note {{override}}
     50 
     51   float f = 1.0;
     52   double d = 1.0;
     53   long double ld = 1.0;
     54   Agg<char> a4 = {f};  // expected-error {{ cannot be narrowed }} expected-note {{override}}
     55   Agg<char> a5 = {d};  // expected-error {{ cannot be narrowed }} expected-note {{override}}
     56   Agg<char> a6 = {ld};  // expected-error {{ cannot be narrowed }} expected-note {{override}}
     57 
     58   Agg<char> ce1 = { Convert<float>(1.0) }; // expected-error {{type 'float' cannot be narrowed to 'char'}} expected-note {{override}}
     59   Agg<char> ce2 = { ConvertVar<double>() }; // expected-error {{type 'double' cannot be narrowed to 'char'}} expected-note {{override}}
     60 }
     61 
     62 // * from long double to double or float, or from double to float, except where
     63 //   the source is a constant expression and the actual value after conversion
     64 //   is within the range of values that can be represented (even if it cannot be
     65 //   represented exactly), or
     66 
     67 void shrink_float() {
     68   // These aren't constant expressions.
     69   float f = 1.0;
     70   double d = 1.0;
     71   long double ld = 1.0;
     72 
     73   // Variables.
     74   Agg<float> f1 = {f};  // OK  (no-op)
     75   Agg<float> f2 = {d};  // expected-error {{non-constant-expression cannot be narrowed from type 'double' to 'float'}} expected-note {{override}}
     76   Agg<float> f3 = {ld};  // expected-error {{ cannot be narrowed }} expected-note {{override}}
     77   // Exact constants.
     78   Agg<float> f4 = {1.0};  // OK  (double constant represented exactly)
     79   Agg<float> f5 = {1.0L};  // OK  (long double constant represented exactly)
     80   // Inexact but in-range constants.
     81   Agg<float> f6 = {0.1};  // OK (double constant in range but rounded)
     82   Agg<float> f7 = {0.1L};  // OK (long double constant in range but rounded)
     83   // Out of range constants.
     84   Agg<float> f8 = {1E50};  // expected-error {{constant expression evaluates to 1.000000e+50 which cannot be narrowed to type 'float'}} expected-note {{override}}
     85   Agg<float> f9 = {1E50L};  // expected-error {{ cannot be narrowed }} expected-note {{override}}
     86   // More complex constant expression.
     87   constexpr long double e40 = 1E40L, e30 = 1E30L, e39 = 1E39L;
     88   Agg<float> f10 = {e40 - 5 * e39 + e30 - 5 * e39};  // OK
     89 
     90   // Variables.
     91   Agg<double> d1 = {f};  // OK  (widening)
     92   Agg<double> d2 = {d};  // OK  (no-op)
     93   Agg<double> d3 = {ld};  // expected-error {{ cannot be narrowed }} expected-note {{override}}
     94   // Exact constant.
     95   Agg<double> d4 = {1.0L};  // OK  (long double constant represented exactly)
     96   // Inexact but in-range constant.
     97   Agg<double> d5 = {0.1L};  // OK (long double constant in range but rounded)
     98   // Out of range constant.
     99   Agg<double> d6 = {1E315L};  // expected-error {{ cannot be narrowed }} expected-note {{override}}
    100   // More complex constant expression.
    101   constexpr long double e315 = 1E315L, e305 = 1E305L, e314 = 1E314L;
    102   Agg<double> d7 = {e315 - 5 * e314 + e305 - 5 * e314};  // OK
    103 
    104   Agg<float> ce1 = { Convert<double>(1e300) }; // expected-error {{constant expression evaluates to 1.000000e+300 which cannot be narrowed to type 'float'}} expected-note {{override}}
    105   Agg<double> ce2 = { ConvertVar<long double>() }; // expected-error {{non-constant-expression cannot be narrowed from type 'long double' to 'double'}} expected-note {{override}}
    106 }
    107 
    108 // * from an integer type or unscoped enumeration type to a floating-point type,
    109 //   except where the source is a constant expression and the actual value after
    110 //   conversion will fit into the target type and will produce the original
    111 //   value when converted back to the original type, or
    112 void int_to_float() {
    113   // Not a constant expression.
    114   char c = 1;
    115 
    116   // Variables.  Yes, even though all char's will fit into any floating type.
    117   Agg<float> f1 = {c};  // expected-error {{ cannot be narrowed }} expected-note {{override}}
    118   Agg<double> f2 = {c};  // expected-error {{ cannot be narrowed }} expected-note {{override}}
    119   Agg<long double> f3 = {c};  // expected-error {{ cannot be narrowed }} expected-note {{override}}
    120 
    121   // Constants.
    122   Agg<float> f4 = {12345678};  // OK (exactly fits in a float)
    123   Agg<float> f5 = {123456789};  // expected-error {{ cannot be narrowed }} expected-note {{override}}
    124 
    125   Agg<float> ce1 = { Convert<int>(123456789) }; // expected-error {{constant expression evaluates to 123456789 which cannot be narrowed to type 'float'}} expected-note {{override}}
    126   Agg<double> ce2 = { ConvertVar<long long>() }; // expected-error {{non-constant-expression cannot be narrowed from type 'long long' to 'double'}} expected-note {{override}}
    127 }
    128 
    129 // * from an integer type or unscoped enumeration type to an integer type that
    130 //   cannot represent all the values of the original type, except where the
    131 //   source is a constant expression and the actual value after conversion will
    132 //   fit into the target type and will produce the original value when converted
    133 //   back to the original type.
    134 void shrink_int() {
    135   // Not a constant expression.
    136   short s = 1;
    137   unsigned short us = 1;
    138   Agg<char> c1 = {s};  // expected-error {{ cannot be narrowed }} expected-note {{override}}
    139   Agg<unsigned short> s1 = {s};  // expected-error {{ cannot be narrowed }} expected-note {{override}}
    140   Agg<short> s2 = {us};  // expected-error {{ cannot be narrowed }} expected-note {{override}}
    141 
    142   // "that cannot represent all the values of the original type" means that the
    143   // validity of the program depends on the relative sizes of integral types.
    144   // This test compiles with -m64, so sizeof(int)<sizeof(long)==sizeof(long
    145   // long).
    146   long l1 = 1;
    147   Agg<int> i1 = {l1};  // expected-error {{ cannot be narrowed }} expected-note {{override}}
    148   long long ll = 1;
    149   Agg<long> l2 = {ll};  // OK
    150 
    151   // Constants.
    152   Agg<char> c2 = {127};  // OK
    153   Agg<char> c3 = {300};  // expected-error {{ cannot be narrowed }} expected-note {{override}} expected-warning {{changes value}}
    154 
    155   Agg<int> i2 = {0x7FFFFFFFU};  // OK
    156   Agg<int> i3 = {0x80000000U};  // expected-error {{ cannot be narrowed }} expected-note {{override}}
    157   Agg<unsigned int> i4 = {-0x80000000L};  // expected-error {{ cannot be narrowed }} expected-note {{override}}
    158 
    159   // Bool is also an integer type, but conversions to it are a different AST
    160   // node.
    161   Agg<bool> b1 = {0};  // OK
    162   Agg<bool> b2 = {1};  // OK
    163   Agg<bool> b3 = {-1};  // expected-error {{ cannot be narrowed }} expected-note {{override}}
    164 
    165   // Conversions from pointers to booleans aren't narrowing conversions.
    166   Agg<bool> b = {&b1};  // OK
    167 
    168   Agg<short> ce1 = { Convert<int>(100000) }; // expected-error {{constant expression evaluates to 100000 which cannot be narrowed to type 'short'}} expected-note {{override}} expected-warning {{changes value from 100000 to -31072}}
    169   Agg<char> ce2 = { ConvertVar<short>() }; // expected-error {{non-constant-expression cannot be narrowed from type 'short' to 'char'}} expected-note {{override}}
    170 
    171   // Negative -> larger unsigned type.
    172   unsigned long long ll1 = { -1 }; // expected-error {{ -1 which cannot be narrowed}} expected-note {{override}}
    173   unsigned long long ll2 = { 1 }; // OK
    174   unsigned long long ll3 = { s }; // expected-error {{cannot be narrowed from type 'short'}} expected-note {{override}}
    175   unsigned long long ll4 = { us }; // OK
    176   unsigned long long ll5 = { ll }; // expected-error {{cannot be narrowed from type 'long long'}} expected-note {{override}}
    177   Agg<unsigned long long> ll6 = { -1 }; // expected-error {{ -1 which cannot be narrowed}} expected-note {{override}}
    178   Agg<unsigned long long> ll7 = { 18446744073709551615ULL }; // OK
    179   Agg<unsigned long long> ll8 = { __int128(18446744073709551615ULL) + 1 }; // expected-error {{ 18446744073709551616 which cannot be narrowed}} expected-note {{override}} expected-warning {{changes value}}
    180   signed char c = 'x';
    181   unsigned short usc1 = { c }; // expected-error {{non-constant-expression cannot be narrowed from type 'signed char'}} expected-note {{override}}
    182   unsigned short usc2 = { (signed char)'x' }; // OK
    183   unsigned short usc3 = { (signed char)-1 }; // expected-error {{ -1 which cannot be narrowed}} expected-note {{override}}
    184 }
    185 
    186 // Be sure that type- and value-dependent expressions in templates get the error
    187 // too.
    188 
    189 template<int I, typename T>
    190 void maybe_shrink_int(T t) {
    191   Agg<short> s1 = {t};  // expected-error {{ cannot be narrowed }} expected-note {{override}}
    192   Agg<short> s2 = {I};  // expected-error {{ cannot be narrowed }} expected-note {{override}} expected-warning {{changes value}}
    193   Agg<T> t2 = {700};  // expected-error {{ cannot be narrowed }} expected-note {{override}} expected-warning {{changes value}}
    194 }
    195 
    196 void test_template() {
    197   maybe_shrink_int<15>((int)3);  // expected-note {{in instantiation}}
    198   maybe_shrink_int<70000>((char)3);  // expected-note {{in instantiation}}
    199 }
    200 
    201 
    202 // We don't want qualifiers on the types in the diagnostic.
    203 
    204 void test_qualifiers(int i) {
    205   const int j = i;
    206   struct {const unsigned char c;} c1 = {j};  // expected-error {{from type 'int' to 'unsigned char' in}} expected-note {{override}}
    207   // Template arguments make it harder to avoid printing qualifiers:
    208   Agg<const unsigned char> c2 = {j};  // expected-error {{from type 'int' to 'const unsigned char' in}} expected-note {{override}}
    209 }
    210 
    211 // Test SFINAE checks.
    212 template<unsigned> struct Value { };
    213 
    214 template<typename T>
    215 int &check_narrowed(Value<sizeof((T){1.1})>);
    216 
    217 template<typename T>
    218 float &check_narrowed(...);
    219 
    220 void test_narrowed(Value<sizeof(int)> vi, Value<sizeof(double)> vd) {
    221   int &ir = check_narrowed<double>(vd);
    222   float &fr = check_narrowed<int>(vi);
    223 }
    224