xref: /llvm-project/clang/test/SemaCXX/implicit-exception-spec.cpp (revision 433e05306fa0217598535211103641221b9021ce)
1 // RUN: %clang_cc1 -fsyntax-only -fcxx-exceptions -verify -std=c++11 -Wall %s
2 
3 template<bool b> struct ExceptionIf { static int f(); };
4 template<> struct ExceptionIf<false> { typedef int f; };
5 
6 // The exception specification of a defaulted default constructor depends on
7 // the contents of in-class member initializers. However, the in-class member
8 // initializers can depend on the exception specification of the constructor,
9 // since the class is considered complete within them. We reject any such cases.
10 namespace InClassInitializers {
11   // Noexcept::Noexcept() is implicitly declared as noexcept(false), because it
12   // directly invokes ThrowSomething(). However...
13   //
14   // If noexcept(Noexcept()) is false, then Noexcept() is a constant expression,
15   // so noexcept(Noexcept()) is true. But if noexcept(Noexcept()) is true, then
16   // Noexcept::Noexcept is not declared constexpr, therefore noexcept(Noexcept())
17   // is false.
18   bool ThrowSomething() noexcept(false);
19   struct ConstExpr {
20     bool b = noexcept(ConstExpr()) && ThrowSomething(); // expected-error {{exception specification is not available until end of class definition}}
21   };
22   // We can use it now.
23   bool w = noexcept(ConstExpr());
24 
25   // Much more obviously broken: we can't parse the initializer without already
26   // knowing whether it produces a noexcept expression.
27   struct TemplateArg {
28     int n = ExceptionIf<noexcept(TemplateArg())>::f(); // expected-error {{exception specification is not available until end of class definition}}
29   };
30   bool x = noexcept(TemplateArg());
31 
32   // And within a nested class.
33   struct Nested {
34     struct Inner {
35       int n = ExceptionIf<noexcept(Nested())>::f(); // expected-error {{exception specification is not available until end of class definition}}
36     } inner;
37   };
38   bool y = noexcept(Nested());
39   bool z = noexcept(Nested::Inner());
40 }
41 
42 namespace ExceptionSpecification {
43   struct Nested {
44     struct T {
45       T() noexcept(!noexcept(Nested())); // expected-error{{exception specification is not available until end of class definition}}
46     } t;
47   };
48 }
49 
50 namespace DefaultArgument {
51   struct Default {
52     struct T {
53       T(int = ExceptionIf<noexcept(Default())::f()); // expected-error {{call to implicitly-deleted default constructor}}
54     } t; // expected-note {{has no default constructor}}
55   };
56 }
57