xref: /llvm-project/clang/test/SemaCXX/conditional-expr.cpp (revision c54cf7373f916aa7d3c1e1c70656cb1b4b601c05)
1 // RUN: %clang_cc1 -fsyntax-only -verify -faccess-control -std=c++0x -Wsign-compare %s
2 
3 // C++ rules for ?: are a lot stricter than C rules, and have to take into
4 // account more conversion options.
5 // This test runs in C++0x mode for the contextual conversion of the condition.
6 
7 struct ToBool { explicit operator bool(); };
8 
9 struct B;
10 struct A { A(); A(const B&); }; // expected-note 2 {{candidate constructor}}
11 struct B { operator A() const; }; // expected-note 2 {{candidate function}}
12 struct I { operator int(); };
13 struct J { operator I(); };
14 struct K { operator double(); };
15 typedef void (*vfn)();
16 struct F { operator vfn(); };
17 struct G { operator vfn(); };
18 
19 struct Base {
20   int trick();
21   A trick() const;
22   void fn1();
23 };
24 struct Derived : Base {
25   void fn2();
26 };
27 struct Convertible { operator Base&(); };
28 struct Priv : private Base {}; // expected-note 4 {{'private' inheritance specifier here}}
29 struct Mid : Base {};
30 struct Fin : Mid, Derived {};
31 typedef void (Derived::*DFnPtr)();
32 struct ToMemPtr { operator DFnPtr(); };
33 
34 struct BadDerived;
35 struct BadBase { operator BadDerived&(); };
36 struct BadDerived : BadBase {};
37 
38 struct Fields {
39   int i1, i2, b1 : 3, b2 : 3;
40 };
41 struct MixedFields {
42   int i;
43   volatile int vi;
44   const int ci;
45   const volatile int cvi;
46 };
47 struct MixedFieldsDerived : MixedFields {
48 };
49 
50 enum Enum { EVal };
51 
52 struct Ambig {
53   operator short(); // expected-note 2 {{candidate function}}
54   operator signed char(); // expected-note 2 {{candidate function}}
55 };
56 
57 void test()
58 {
59   // This function tests C++0x 5.16
60 
61   // p1 (contextually convert to bool)
62   int i1 = ToBool() ? 0 : 1;
63 
64   // p2 (one or both void, and throwing)
65   i1 ? throw 0 : throw 1;
66   i1 ? test() : throw 1;
67   i1 ? throw 0 : test();
68   i1 ? test() : test();
69   i1 = i1 ? throw 0 : 0;
70   i1 = i1 ? 0 : throw 0;
71   i1 ? 0 : test(); // expected-error {{right operand to ? is void, but left operand is of type 'int'}}
72   i1 ? test() : 0; // expected-error {{left operand to ? is void, but right operand is of type 'int'}}
73   (i1 ? throw 0 : i1) = 0; // expected-error {{expression is not assignable}}
74   (i1 ? i1 : throw 0) = 0; // expected-error {{expression is not assignable}}
75 
76   // p3 (one or both class type, convert to each other)
77   // b1 (lvalues)
78   Base base;
79   Derived derived;
80   Convertible conv;
81   Base &bar1 = i1 ? base : derived;
82   Base &bar2 = i1 ? derived : base;
83   Base &bar3 = i1 ? base : conv;
84   Base &bar4 = i1 ? conv : base;
85   // these are ambiguous
86   BadBase bb;
87   BadDerived bd;
88   (void)(i1 ? bb : bd); // expected-error {{conditional expression is ambiguous; 'struct BadBase' can be converted to 'struct BadDerived' and vice versa}}
89   (void)(i1 ? bd : bb); // expected-error {{conditional expression is ambiguous}}
90   // curiously enough (and a defect?), these are not
91   // for rvalues, hierarchy takes precedence over other conversions
92   (void)(i1 ? BadBase() : BadDerived());
93   (void)(i1 ? BadDerived() : BadBase());
94 
95   // b2.1 (hierarchy stuff)
96   const Base constret();
97   const Derived constder();
98   // should use const overload
99   A a1((i1 ? constret() : Base()).trick());
100   A a2((i1 ? Base() : constret()).trick());
101   A a3((i1 ? constret() : Derived()).trick());
102   A a4((i1 ? Derived() : constret()).trick());
103   // should use non-const overload
104   i1 = (i1 ? Base() : Base()).trick();
105   i1 = (i1 ? Base() : Base()).trick();
106   i1 = (i1 ? Base() : Derived()).trick();
107   i1 = (i1 ? Derived() : Base()).trick();
108   // should fail: const lost
109   (void)(i1 ? Base() : constder()); // expected-error {{incompatible operand types ('struct Base' and 'struct Derived const')}}
110   (void)(i1 ? constder() : Base()); // expected-error {{incompatible operand types ('struct Derived const' and 'struct Base')}}
111 
112   Priv priv;
113   Fin fin;
114   (void)(i1 ? Base() : Priv()); // expected-error{{conversion from 'struct Priv' to inaccessible base class 'struct Base'}}
115   (void)(i1 ? Priv() : Base()); // expected-error{{error: conversion from 'struct Priv' to inaccessible base class 'struct Base'}}
116   (void)(i1 ? Base() : Fin()); // expected-error{{ambiguous conversion from derived class 'struct Fin' to base class 'struct Base'}}
117   (void)(i1 ? Fin() : Base()); // expected-error{{ambiguous conversion from derived class 'struct Fin' to base class 'struct Base'}}
118   (void)(i1 ? base : priv); // expected-error {{conversion from 'struct Priv' to inaccessible base class 'struct Base'}}
119   (void)(i1 ? priv : base); // expected-error {{conversion from 'struct Priv' to inaccessible base class 'struct Base'}}
120   (void)(i1 ? base : fin); // expected-error {{ambiguous conversion from derived class 'struct Fin' to base class 'struct Base'}}
121   (void)(i1 ? fin : base); // expected-error {{ambiguous conversion from derived class 'struct Fin' to base class 'struct Base'}}
122 
123   // b2.2 (non-hierarchy)
124   i1 = i1 ? I() : i1;
125   i1 = i1 ? i1 : I();
126   I i2(i1 ? I() : J());
127   I i3(i1 ? J() : I());
128   // "the type [it] woud have if E2 were converted to an rvalue"
129   vfn pfn = i1 ? F() : test;
130   pfn = i1 ? test : F();
131   (void)(i1 ? A() : B()); // expected-error {{conversion from 'struct B' to 'struct A' is ambiguous}}
132   (void)(i1 ? B() : A()); // expected-error {{conversion from 'struct B' to 'struct A' is ambiguous}}
133   (void)(i1 ? 1 : Ambig()); // expected-error {{conversion from 'struct Ambig' to 'int' is ambiguous}}
134   (void)(i1 ? Ambig() : 1); // expected-error {{conversion from 'struct Ambig' to 'int' is ambiguous}}
135   // By the way, this isn't an lvalue:
136   &(i1 ? i1 : i2); // expected-error {{address expression must be an lvalue or a function designator}}
137 
138   // p4 (lvalue, same type)
139   Fields flds;
140   int &ir1 = i1 ? flds.i1 : flds.i2;
141   (i1 ? flds.b1 : flds.i2) = 0;
142   (i1 ? flds.i1 : flds.b2) = 0;
143   (i1 ? flds.b1 : flds.b2) = 0;
144 
145   // p5 (conversion to built-in types)
146   // GCC 4.3 fails these
147   double d1 = i1 ? I() : K();
148   pfn = i1 ? F() : G();
149   DFnPtr pfm;
150   pfm = i1 ? DFnPtr() : &Base::fn1;
151   pfm = i1 ? &Base::fn1 : DFnPtr();
152 
153   // p6 (final conversions)
154   i1 = i1 ? i1 : ir1;
155   int *pi1 = i1 ? &i1 : 0;
156   pi1 = i1 ? 0 : &i1;
157   i1 = i1 ? i1 : EVal; // expected-warning {{operands of ? are integers of different signs}} ??
158   i1 = i1 ? EVal : i1; // expected-warning {{operands of ? are integers of different signs}} ??
159   d1 = i1 ? 'c' : 4.0;
160   d1 = i1 ? 4.0 : 'c';
161   Base *pb = i1 ? (Base*)0 : (Derived*)0;
162   pb = i1 ? (Derived*)0 : (Base*)0;
163   pfm = i1 ? &Base::fn1 : &Derived::fn2;
164   pfm = i1 ? &Derived::fn2 : &Base::fn1;
165   pfm = i1 ? &Derived::fn2 : 0;
166   pfm = i1 ? 0 : &Derived::fn2;
167   const int (MixedFieldsDerived::*mp1) =
168     i1 ? &MixedFields::ci : &MixedFieldsDerived::i;
169   const volatile int (MixedFields::*mp2) =
170     i1 ? &MixedFields::ci : &MixedFields::cvi;
171   (void)(i1 ? &MixedFields::ci : &MixedFields::vi);
172   // Conversion of primitives does not result in an lvalue.
173   &(i1 ? i1 : d1); // expected-error {{address expression must be an lvalue or a function designator}}
174 
175   (void)&(i1 ? flds.b1 : flds.i1); // expected-error {{address of bit-field requested}}
176   (void)&(i1 ? flds.i1 : flds.b1); // expected-error {{address of bit-field requested}}
177 
178 
179   unsigned long test0 = 5;
180   test0 = test0 ? (long) test0 : test0; // expected-warning {{operands of ? are integers of different signs}}
181   test0 = test0 ? (int) test0 : test0; // expected-warning {{operands of ? are integers of different signs}}
182   test0 = test0 ? (short) test0 : test0; // expected-warning {{operands of ? are integers of different signs}}
183   test0 = test0 ? test0 : (long) test0; // expected-warning {{operands of ? are integers of different signs}}
184   test0 = test0 ? test0 : (int) test0; // expected-warning {{operands of ? are integers of different signs}}
185   test0 = test0 ? test0 : (short) test0; // expected-warning {{operands of ? are integers of different signs}}
186   test0 = test0 ? test0 : (long) 10;
187   test0 = test0 ? test0 : (int) 10;
188   test0 = test0 ? test0 : (short) 10;
189   test0 = test0 ? (long) 10 : test0;
190   test0 = test0 ? (int) 10 : test0;
191   test0 = test0 ? (short) 10 : test0;
192 
193   test0 = test0 ? EVal : test0;
194   test0 = test0 ? EVal : (int) test0; // expected-warning {{operands of ? are integers of different signs}}
195 
196   // Note the thing that this does not test: since DR446, various situations
197   // *must* create a separate temporary copy of class objects. This can only
198   // be properly tested at runtime, though.
199 }
200