PR43519: don't inject a diagnostic when constant-evaulation of a

pointer-to-member call can't determine a callee.

We will have produced a diagnostic already if the callee is known to be
unevaluatable, and diagnosing here rejects valid code during potential
constant expression checking.

llvm-svn: 373553

diff --git a/clang/lib/AST/ExprConstant.cpp b/clang/lib/AST/ExprConstant.cpp
index 33b0380..908e801 100644 (file)
--- a/clang/lib/AST/ExprConstant.cpp
+++ b/clang/lib/AST/ExprConstant.cpp
@@ -6845,8 +6845,11 @@ public:
         HasQualifier = ME->hasQualifier();
       } else if (const BinaryOperator *BE = dyn_cast<BinaryOperator>(Callee)) {
         // Indirect bound member calls ('.*' or '->*').
-        Member = dyn_cast_or_null<CXXMethodDecl>(
-            HandleMemberPointerAccess(Info, BE, ThisVal, false));
+        const ValueDecl *D =
+            HandleMemberPointerAccess(Info, BE, ThisVal, false);
+        if (!D)
+          return false;
+        Member = dyn_cast<CXXMethodDecl>(D);
         if (!Member)
           return Error(Callee);
         This = &ThisVal;

diff --git a/clang/test/SemaCXX/constant-expression-cxx11.cpp b/clang/test/SemaCXX/constant-expression-cxx11.cpp
index bd7094f..27ad0f6 100644 (file)
--- a/clang/test/SemaCXX/constant-expression-cxx11.cpp
+++ b/clang/test/SemaCXX/constant-expression-cxx11.cpp
@@ -1108,6 +1108,11 @@ namespace MemberPointer {
   static_assert((int Derived::*)(int Mid<0>::*)&Mid<0>::n !=
                 (int Derived::*)(int Mid<1>::*)&Mid<1>::n, "");
   static_assert(&Mid<0>::n == (int Mid<0>::*)&Base::n, "");
+
+  constexpr int apply(const A &a, int (A::*f)() const) {
+    return (a.*f)();
+  }
+  static_assert(apply(A(2), &A::f) == 5, "");
 }
 
 namespace ArrayBaseDerived {