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