Fix DenseSet::ConstIterator typedefs

[bmoody]

Summary

Fix DenseSet::ConstIterator pointer/reference typedefs to be const

[dblaikie]

Thanks for the fix! (optionally, could put some static_asserts in the DenseSet unit test to validate that these changes have been made (is_const<...> etc)

[bmoody]

I don't have commit access, you're welcome to commit on my behalf. Thanks!

llvm/trunk/include/llvm/ADT/DenseSet.h

public:
   class ConstIterator {
     typename MapTy::const_iterator I;
     friend class DenseSet;
     friend class Iterator;
 
   public:
     using difference_type = typename MapTy::const_iterator::difference_type;
     using value_type = ValueT;
-    using pointer = value_type *;
-    using reference = value_type &;
+    using pointer = const value_type *;
+    using reference = const value_type &;
     using iterator_category = std::forward_iterator_tag;
 
     ConstIterator() = default;
     ConstIterator(const Iterator &B) : I(B.I) {}
     ConstIterator(const typename MapTy::const_iterator &i) : I(i) {}
 
     const ValueT &operator*() const { return I->getFirst(); }
     const ValueT *operator->() const { return &I->getFirst(); }

llvm/trunk/unittests/ADT/DenseSetTest.cpp

 #include "llvm/ADT/DenseSet.h"
 #include "gtest/gtest.h"
 #include <type_traits>
 
 using namespace llvm;
 
 namespace {
 
+static_assert(std::is_const<std::remove_pointer<
+                  DenseSet<int>::const_iterator::pointer>::type>::value,
+              "Iterator pointer type should be const");
+static_assert(std::is_const<std::remove_reference<
+                  DenseSet<int>::const_iterator::reference>::type>::value,
+              "Iterator reference type should be const");
+
 // Test hashing with a set of only two entries.
 TEST(DenseSetTest, DoubleEntrySetTest) {
   llvm::DenseSet<unsigned> set(2);
   set.insert(0);
   set.insert(1);
   // Original failure was an infinite loop in this call:
   EXPECT_EQ(0u, set.count(2));
 }