[Voted into the WP at the March, 2011 meeting as part of paper N3277.]

Proposed resolution (January, 2011):

1. Change 9.2.6 [dcl.constexpr] paragraph 3 as follows:

• ...

• its function-body shall be = delete or a compound-statement of the form

    { return expression ; }
  

• ...

2. Change 9.2.6 [dcl.constexpr] paragraph 4 as follows:

The definition of a constexpr constructor In the definition of a constexpr constructor, each of the parameter types shall be a literal type or a reference to a literal type. In addition, either its function-body shall be = delete or it shall satisfy the following constraints:

• each of its parameter types shall be a literal type or a reference to literal type;

• ...

The current requirements for constexpr functions do not permit a deleted constexpr function because the definition does not consist of a compound-statement containing just a return statement. However, it could be useful to allow this form in a case where a single piece of code is used in multiple configurations, in some of which the function is constexpr and others deleted; having to update all declarations of the function to remove the constexpr specifier is unnecessarily onerous.