Implement disambiguation of base class members via a

nested-name-specifier. For example, this allows member access in
diamond-shaped hierarchies like:

  struct Base {
    void Foo();
    int Member;
  };

  struct D1 : public Base {};
  struct D2 : public Base {};

  struct Derived : public D1, public D2 { }

  void Test(Derived d) {
    d.Member = 17; // error: ambiguous cast from Derived to Base
    d.D1::Member = 17; // error: okay, modify D1's Base's Member
  }

Fixes PR5820 and <rdar://problem/7535045>. Also, eliminate some
redundancy between Sema::PerformObjectMemberConversion() and
Sema::PerformObjectArgumentInitialization() -- the latter now calls
the former.

llvm-svn: 97674

1 files changed, 63 insertions, 0 deletions

diff --git a/clang/test/CXX/class.derived/class.member.lookup/p8.cpp b/clang/test/CXX/class.derived/class.member.lookup/p8.cpp
new file mode 100644
index 00000000000..4d4acc3460e
--- /dev/null
+++ b/clang/test/CXX/class.derived/class.member.lookup/p8.cpp
@@ -0,0 +1,63 @@
+// RUN: %clang_cc1 -fsyntax-only -verify %s
+
+// FIXME: Access control checks
+
+namespace PR5820 {
+  // also <rdar://problem/7535045>
+  struct Base {
+    void Foo();
+    int Member;
+  };
+
+  struct D1 : public Base {};
+  struct D2 : public Base {};
+
+  struct Derived : public D1, public D2 {
+    void Inner();
+  };
+
+  void Test() {
+    Derived d;
+    d.D1::Foo();
+    d.D1::Member = 17;
+  }
+
+  void Derived::Inner() {
+    D1::Foo();
+    D1::Member = 42;
+    this->D1::Foo();
+    this->D1::Member = 42;
+  }
+}
+
+template<typename T>
+struct BaseT {
+  void Foo(); // expected-note{{found by ambiguous name lookup}}
+  int Member;
+};
+
+template<typename T> struct Derived1T : BaseT<T> { };
+template<typename T> struct Derived2T : BaseT<T> { };
+
+template<typename T>
+struct DerivedT : public Derived1T<T>, public Derived2T<T> {
+  void Inner();
+};
+
+template<typename T>
+void DerivedT<T>::Inner() {
+  Derived1T<T>::Foo();
+  Derived2T<T>::Member = 42;
+  this->Derived1T<T>::Foo();
+  this->Derived2T<T>::Member = 42;
+  this->Foo(); // expected-error{{non-static member 'Foo' found in multiple base-class subobjects of type 'BaseT<int>'}}
+}
+
+template<typename T>
+void Test(DerivedT<T> d) {
+  d.template Derived1T<T>::Foo();
+  d.template Derived2T<T>::Member = 17;
+  d.Inner(); // expected-note{{in instantiation}}
+}
+
+template void Test(DerivedT<int>);