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

Summary: Re-land r362766 after it was reverted in r362823.

Reviewers: jhenderson, dsanders, aaron.ballman, MatzeB, lhames, dblaikie

Reviewed By: dblaikie

Subscribers: smeenai, mgrang, mgorny, dexonsmith, kristina, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D62369

llvm-svn: 362835

1 files changed, 0 insertions, 15 deletions

diff --git a/llvm/unittests/ADT/StringMapTest.cpp b/llvm/unittests/ADT/StringMapTest.cpp
index 841b5153935..4038d4d3d2f 100644
--- a/llvm/unittests/ADT/StringMapTest.cpp
+++ b/llvm/unittests/ADT/StringMapTest.cpp
@@ -7,7 +7,6 @@
 //===----------------------------------------------------------------------===//
 
 #include "llvm/ADT/StringMap.h"
-#include "llvm/ADT/StringSet.h"
 #include "llvm/ADT/Twine.h"
 #include "llvm/Support/DataTypes.h"
 #include "gtest/gtest.h"
@@ -284,20 +283,6 @@ 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) {}