p7-0x.cpp revision 4c3fc9b38d3723f73e4ded594cebf38c76f91d93
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 6void 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 29template<typename T> 30struct Agg { 31 T t; 32}; 33 34template<typename T> 35struct Convert { 36 constexpr Convert(T v) : v(v) {} 37 constexpr operator T() const { return v; } 38 T v; 39}; 40template<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 46void 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 67void 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 112void 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. 134void 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} 171 172// Be sure that type- and value-dependent expressions in templates get the error 173// too. 174 175template<int I, typename T> 176void maybe_shrink_int(T t) { 177 Agg<short> s1 = {t}; // expected-error {{ cannot be narrowed }} expected-note {{override}} 178 Agg<short> s2 = {I}; // expected-error {{ cannot be narrowed }} expected-note {{override}} expected-warning {{changes value}} 179 Agg<T> t2 = {700}; // expected-error {{ cannot be narrowed }} expected-note {{override}} expected-warning {{changes value}} 180} 181 182void test_template() { 183 maybe_shrink_int<15>((int)3); // expected-note {{in instantiation}} 184 maybe_shrink_int<70000>((char)3); // expected-note {{in instantiation}} 185} 186 187 188// We don't want qualifiers on the types in the diagnostic. 189 190void test_qualifiers(int i) { 191 const int j = i; 192 struct {const unsigned char c;} c1 = {j}; // expected-error {{from type 'int' to 'unsigned char' in}} expected-note {{override}} 193 // Template arguments make it harder to avoid printing qualifiers: 194 Agg<const unsigned char> c2 = {j}; // expected-error {{from type 'int' to 'const unsigned char' in}} expected-note {{override}} 195} 196