Proposed resolution (February, 2019):

Change _N4868_.6.4.1 [basic.scope.declarative] paragraph 4 as follows:

Given a set of declarations in a single declarative region, each of which specifies the same unqualified name,

• they shall all refer to the same entity, or all refer to functions and function templates; or

• exactly one declaration shall declare a class name or enumeration name that is not a typedef name and the other declarations shall all refer to the same variable, non-static data member, or enumerator, or all refer to functions and function templates; in this case the class name or enumeration name is hidden (_N4868_.6.4.10 [basic.scope.hiding]). [Note: A structured binding (9.6 [dcl.struct.bind]), namespace name (9.8 [basic.namespace]), or a class template name (Clause 13 [temp]) must be unique in its declarative region (9.8.3 [namespace.alias], Clause 13 [temp]). —end note]

Notes from the April, 2017 teleconference:

Structured bindings have no C compatibility implications, so the tag/nontag treatment need not apply.

[Accepted as a DR at the February, 2019 meeting.]

The current wording is not clear regarding examples like the following:

  struct A { int x; } a;
  struct B {} b; template<int> int &get(const B&);
  struct C {}; int c[1];
  auto [A] = a; // ok? 
  auto [B] = b; // ok? 
  auto [C] = c; // ok?