r225518 - Sema: Don't crash when variable is redefined as a constexpr function

[David Majnemer]

Author: majnemer
Date: Fri Jan  9 04:33:23 2015
New Revision: 225518

URL: http://llvm.org/viewvc/llvm-project?rev=225518&view=rev
Log:
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.

Modified:
    cfe/trunk/lib/Sema/SemaDecl.cpp
    cfe/trunk/test/SemaCXX/constant-expression-cxx11.cpp

Modified: cfe/trunk/lib/Sema/SemaDecl.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/Sema/SemaDecl.cpp?rev=225518&r1=225517&r2=225518&view=diff
==============================================================================
--- cfe/trunk/lib/Sema/SemaDecl.cpp (original)
+++ cfe/trunk/lib/Sema/SemaDecl.cpp Fri Jan  9 04:33:23 2015
@@ -7885,7 +7885,7 @@ bool Sema::CheckFunctionDeclaration(Scop
       (MD->getTypeQualifiers() & Qualifiers::Const) == 0) {
     CXXMethodDecl *OldMD = nullptr;
     if (OldDecl)
-      OldMD = dyn_cast<CXXMethodDecl>(OldDecl->getAsFunction());
+      OldMD = dyn_cast_or_null<CXXMethodDecl>(OldDecl->getAsFunction());
     if (!OldMD || !OldMD->isStatic()) {
       const FunctionProtoType *FPT =
         MD->getType()->castAs<FunctionProtoType>();

Modified: cfe/trunk/test/SemaCXX/constant-expression-cxx11.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/test/SemaCXX/constant-expression-cxx11.cpp?rev=225518&r1=225517&r2=225518&view=diff
==============================================================================
--- cfe/trunk/test/SemaCXX/constant-expression-cxx11.cpp (original)
+++ cfe/trunk/test/SemaCXX/constant-expression-cxx11.cpp Fri Jan  9 04:33:23 2015
@@ -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'}}
+};