r208157 causes:

markus@x4 skia % cat test.ii
struct A {
  A(int);
};
typedef struct {
  A format;
} B;

markus@x4 skia % g++ -std=c++11 -c test.ii
test.ii: In constructor ‘B::B()’:
test.ii:6:3: error: no matching function for call to ‘A::A()’
 } B;
   ^
test.ii:6:3: note: candidates are:
test.ii:2:3: note: A::A(int)
   A(int);
   ^
test.ii:2:3: note:   candidate expects 1 argument, 0 provided
test.ii:1:8: note: constexpr A::A(const A&)
 struct A {
        ^
test.ii:1:8: note:   candidate expects 1 argument, 0 provided
test.ii:1:8: note: constexpr A::A(A&&)
test.ii:1:8: note:   candidate expects 1 argument, 0 provided
test.ii: At global scope:
test.ii:4:16: note: synthesized method ‘B::B()’ first required here 
 typedef struct {
                ^