1 // PR c++/66635
2 // { dg-do compile { target c++11 } }
3 
4 #include <cassert>
5 
6 struct Foo {
FooFoo7     constexpr Foo(const unsigned i) : val(i) {}
8     constexpr Foo operator-(const Foo &rhs) const {
9       return assert(val >= rhs.val), Foo(val - rhs.val); // { dg-error "call to non-.constexpr." }
10     }
11     unsigned val;
12 };
13 
14 constexpr Foo foo(Foo(1) - Foo(2)); // { dg-message "in .constexpr. expansion of " }
15