Sema: Don't crash when variable is redefined as a constexpr function

We have a diagnostic describing that constexpr changed in C++14 when
compiling in C++11 mode.  While doing this, it examines the previous
declaration and assumes that it is a function.  However it is possible,
in the context of error recovery, for this to not be the case.

llvm-svn: 225518

1 files changed, 5 insertions, 0 deletions

diff --git a/clang/test/SemaCXX/constant-expression-cxx11.cpp b/clang/test/SemaCXX/constant-expression-cxx11.cpp
index d8f6f0876a8..14c0ae320d7 100644
--- a/clang/test/SemaCXX/constant-expression-cxx11.cpp
+++ b/clang/test/SemaCXX/constant-expression-cxx11.cpp
@@ -1979,3 +1979,8 @@ namespace PR21859 {
   constexpr int Fun() { return; } // expected-error {{non-void constexpr function 'Fun' should return a value}}
   constexpr int Var = Fun(); // expected-error {{constexpr variable 'Var' must be initialized by a constant expression}}
 }
+
+struct InvalidRedef {
+  int f; // expected-note{{previous definition is here}}
+  constexpr int f(void); // expected-error{{redefinition of 'f'}} expected-warning{{will not be implicitly 'const'}}
+};