P0962R1: only use the member form of 'begin' and 'end' in a range-based

for loop if both members exist.

This resolves a DR whereby an errant 'begin' or 'end' member in a base
class could result in a derived class not being usable as a range with
non-member 'begin' and 'end'.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@342925 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 57 insertions, 2 deletions

diff --git a/test/CXX/stmt.stmt/stmt.iter/stmt.ranged/p1.cpp b/test/CXX/stmt.stmt/stmt.iter/stmt.ranged/p1.cpp
index 473c8b62ba..f42fc9b6e5 100644
--- a/test/CXX/stmt.stmt/stmt.iter/stmt.ranged/p1.cpp
+++ b/test/CXX/stmt.stmt/stmt.iter/stmt.ranged/p1.cpp
@@ -150,9 +150,9 @@ void g() {
   struct NoEnd {
     null_t begin();
   };
-  for (auto u : NoBegin()) { // expected-error {{range type 'NoBegin' has 'end' member but no 'begin' member}}
+  for (auto u : NoBegin()) { // expected-error {{no viable 'begin' function available}}
   }
-  for (auto u : NoEnd()) { // expected-error {{range type 'NoEnd' has 'begin' member but no 'end' member}} 
+  for (auto u : NoEnd()) { // expected-error {{no viable 'end' function available}}
   }
 
   struct NoIncr {
@@ -271,3 +271,58 @@ namespace rdar13712739 {
 
   template void foo(const int&); // expected-note{{in instantiation of function template specialization}}
 }
+
+namespace p0962r1 {
+  namespace NA {
+    struct A {
+      void begin();
+    };
+    int *begin(A);
+    int *end(A);
+  }
+
+  namespace NB {
+    struct B {
+      void end();
+    };
+    int *begin(B);
+    int *end(B);
+  }
+
+  namespace NC {
+    struct C {
+      void begin();
+    };
+    int *begin(C);
+  }
+
+  namespace ND {
+    struct D {
+      void end();
+    };
+    int *end(D);
+  }
+
+  namespace NE {
+    struct E {
+      void begin(); // expected-note {{member is not a candidate because range type 'p0962r1::NE::E' has no 'end' member}}
+    };
+    int *end(E);
+  }
+
+  namespace NF {
+    struct F {
+      void end(); // expected-note {{member is not a candidate because range type 'p0962r1::NF::F' has no 'begin' member}}
+    };
+    int *begin(F);
+  }
+
+  void use(NA::A a, NB::B b, NC::C c, ND::D d, NE::E e, NF::F f) {
+    for (auto x : a) {}
+    for (auto x : b) {}
+    for (auto x : c) {} // expected-error {{no viable 'end' function}}
+    for (auto x : d) {} // expected-error {{no viable 'begin' function}}
+    for (auto x : e) {} // expected-error {{no viable 'begin' function}}
+    for (auto x : f) {} // expected-error {{no viable 'end' function}}
+  }
+}