Revert "[ADT] Enable set_difference() to be used on StringSet"

This reverts commit 0bddef79019a23ab14fcdb27028e55e484674c88, it was
causing ASan failures on the sanitizer bots:
http://lab.llvm.org:8011/builders/sanitizer-x86_64-linux-fast/builds/32800

llvm-svn: 362823

1 files changed, 15 insertions, 0 deletions

diff --git a/llvm/unittests/ADT/StringMapTest.cpp b/llvm/unittests/ADT/StringMapTest.cpp
index 4038d4d3d2f..841b5153935 100644
--- a/llvm/unittests/ADT/StringMapTest.cpp
+++ b/llvm/unittests/ADT/StringMapTest.cpp
@@ -7,6 +7,7 @@
 //===----------------------------------------------------------------------===//
 
 #include "llvm/ADT/StringMap.h"
+#include "llvm/ADT/StringSet.h"
 #include "llvm/ADT/Twine.h"
 #include "llvm/Support/DataTypes.h"
 #include "gtest/gtest.h"
@@ -283,6 +284,20 @@ TEST_F(StringMapTest, IterMapKeys) {
   EXPECT_EQ(Expected, Keys);
 }
 
+TEST_F(StringMapTest, IterSetKeys) {
+  StringSet<> Set;
+  Set.insert("A");
+  Set.insert("B");
+  Set.insert("C");
+  Set.insert("D");
+
+  auto Keys = to_vector<4>(Set.keys());
+  llvm::sort(Keys);
+
+  SmallVector<StringRef, 4> Expected = {"A", "B", "C", "D"};
+  EXPECT_EQ(Expected, Keys);
+}
+
 // Create a non-default constructable value
 struct StringMapTestStruct {
   StringMapTestStruct(int i) : i(i) {}