constexpr until we get to the end of the class definition. When that happens,
be sure to remember that the class actually does have a constexpr constructor.
This is a stopgap solution, which still doesn't cover the case of a class with
multiple copy constructors (only some of which are constexpr). We should be
performing constructor lookup when implicitly defining a constructor in order
to determine whether all constructors it invokes are constexpr.
llvm-svn: 158228
non-const reference parameter type if the class had any subobjects with deleted
copy constructors. This causes a rejects-valid if the class's copy constructor
is explicitly defaulted (as happens for some implementations of std::pair etc).
llvm-svn: 155218
Richard Smith