Implement LWG#2688: 'clamp misses preconditions and has extraneous condition on result'. We already did this, just added tests

llvm-svn: 274252

2 files changed, 135 insertions, 4 deletions

diff --git a/libcxx/test/std/algorithms/alg.sorting/alg.clamp/clamp.comp.pass.cpp b/libcxx/test/std/algorithms/alg.sorting/alg.clamp/clamp.comp.pass.cpp
index 7067227119c..3fec12b6b53 100644
--- a/libcxx/test/std/algorithms/alg.sorting/alg.clamp/clamp.comp.pass.cpp
+++ b/libcxx/test/std/algorithms/alg.sorting/alg.clamp/clamp.comp.pass.cpp
@@ -18,6 +18,20 @@
 #include <functional>
 #include <cassert>
 
+struct Tag {
+    Tag() : val(0), tag("Default") {}
+    Tag(int a, const char *b) : val(a), tag(b) {}
+    ~Tag() {}
+        
+    int val;
+    const char *tag;
+    };
+    
+bool eq(const Tag& rhs, const Tag& lhs) { return rhs.val == lhs.val && rhs.tag == lhs.tag; }
+// bool operator==(const Tag& rhs, const Tag& lhs) { return rhs.val == lhs.val; }
+bool comp (const Tag& rhs, const Tag& lhs) { return rhs.val <  lhs.val; }
+
+
 template <class T, class C>
 void
 test(const T& v, const T& lo, const T& hi, C c, const T& x)
@@ -48,7 +62,60 @@ int main()
     test(x, y, z, std::greater<int>(), y);
     test(y, x, z, std::greater<int>(), y);
     }
-#if _LIBCPP_STD_VER > 11
+
+    {
+//  If they're all the same, we should get the value back.
+    Tag x{0, "Zero-x"};
+    Tag y{0, "Zero-y"};
+    Tag z{0, "Zero-z"};
+    assert(eq(std::clamp(x, y, z, comp), x));
+    assert(eq(std::clamp(y, x, z, comp), y));
+    }
+
+    {
+//  If it's the same as the lower bound, we get the value back.
+    Tag x{0, "Zero-x"};
+    Tag y{0, "Zero-y"};
+    Tag z{1, "One-z"};
+    assert(eq(std::clamp(x, y, z, comp), x));
+    assert(eq(std::clamp(y, x, z, comp), y));
+    }
+
+    {
+//  If it's the same as the upper bound, we get the value back.
+    Tag x{1, "One-x"};
+    Tag y{0, "Zero-y"};
+    Tag z{1, "One-z"};
+    assert(eq(std::clamp(x, y, z, comp), x));
+    assert(eq(std::clamp(z, y, x, comp), z));
+    }
+
+    {
+//  If the value is between, we should get the value back
+    Tag x{1, "One-x"};
+    Tag y{0, "Zero-y"};
+    Tag z{2, "Two-z"};
+    assert(eq(std::clamp(x, y, z, comp), x));
+    assert(eq(std::clamp(y, x, z, comp), x));
+    }
+
+    {
+//  If the value is less than the 'lo', we should get the lo back.
+    Tag x{0, "Zero-x"};
+    Tag y{1, "One-y"};
+    Tag z{2, "Two-z"};
+    assert(eq(std::clamp(x, y, z, comp), y));
+    assert(eq(std::clamp(y, x, z, comp), y));
+    }
+    {
+//  If the value is greater than 'hi', we should get hi back.
+    Tag x{2, "Two-x"};
+    Tag y{0, "Zero-y"};
+    Tag z{1, "One-z"};
+    assert(eq(std::clamp(x, y, z, comp), z));
+    assert(eq(std::clamp(y, z, x, comp), z));
+    }
+
     {
     typedef int T;
     constexpr T x = 1;
@@ -57,5 +124,4 @@ int main()
     static_assert(std::clamp(x, y, z, std::greater<T>()) == y, "" );
     static_assert(std::clamp(y, x, z, std::greater<T>()) == y, "" );
     }
-#endif
 }
diff --git a/libcxx/test/std/algorithms/alg.sorting/alg.clamp/clamp.pass.cpp b/libcxx/test/std/algorithms/alg.sorting/alg.clamp/clamp.pass.cpp
index 2592f904fd2..779c41827c9 100644
--- a/libcxx/test/std/algorithms/alg.sorting/alg.clamp/clamp.pass.cpp
+++ b/libcxx/test/std/algorithms/alg.sorting/alg.clamp/clamp.pass.cpp
@@ -17,6 +17,19 @@
 #include <algorithm>
 #include <cassert>
 
+struct Tag {
+	Tag() : val(0), tag("Default") {}
+	Tag(int a, const char *b) : val(a), tag(b) {}
+	~Tag() {}
+		
+	int val;
+	const char *tag;
+	};
+	
+bool eq(const Tag& rhs, const Tag& lhs) { return rhs.val == lhs.val && rhs.tag == lhs.tag; }
+// bool operator==(const Tag& rhs, const Tag& lhs) { return rhs.val == lhs.val; }
+bool operator< (const Tag& rhs, const Tag& lhs) { return rhs.val <  lhs.val; }
+
 template <class T>
 void
 test(const T& a, const T& lo, const T& hi, const T& x)
@@ -47,7 +60,60 @@ int main()
     test(x, y, z, x);
     test(y, x, z, x);
     }
-#if _LIBCPP_STD_VER > 11
+
+    {
+//  If they're all the same, we should get the value back.
+    Tag x{0, "Zero-x"};
+    Tag y{0, "Zero-y"};
+    Tag z{0, "Zero-z"};
+    assert(eq(std::clamp(x, y, z), x));
+    assert(eq(std::clamp(y, x, z), y));
+    }
+
+    {
+//  If it's the same as the lower bound, we get the value back.
+    Tag x{0, "Zero-x"};
+    Tag y{0, "Zero-y"};
+    Tag z{1, "One-z"};
+    assert(eq(std::clamp(x, y, z), x));
+    assert(eq(std::clamp(y, x, z), y));
+    }
+
+    {
+//  If it's the same as the upper bound, we get the value back.
+    Tag x{1, "One-x"};
+    Tag y{0, "Zero-y"};
+    Tag z{1, "One-z"};
+    assert(eq(std::clamp(x, y, z), x));
+    assert(eq(std::clamp(z, y, x), z));
+    }
+
+    {
+//  If the value is between, we should get the value back
+    Tag x{1, "One-x"};
+    Tag y{0, "Zero-y"};
+    Tag z{2, "Two-z"};
+    assert(eq(std::clamp(x, y, z), x));
+    assert(eq(std::clamp(y, x, z), x));
+    }
+
+    {
+//  If the value is less than the 'lo', we should get the lo back.
+    Tag x{0, "Zero-x"};
+    Tag y{1, "One-y"};
+    Tag z{2, "Two-z"};
+    assert(eq(std::clamp(x, y, z), y));
+    assert(eq(std::clamp(y, x, z), y));
+    }
+    {
+//  If the value is greater than 'hi', we should get hi back.
+    Tag x{2, "Two-x"};
+    Tag y{0, "Zero-y"};
+    Tag z{1, "One-z"};
+    assert(eq(std::clamp(x, y, z), z));
+    assert(eq(std::clamp(y, z, x), z));
+    }
+
     {
     typedef int T;
     constexpr T x = 1;
@@ -56,5 +122,4 @@ int main()
     static_assert(std::clamp(x, y, z) == x, "" );
     static_assert(std::clamp(y, x, z) == x, "" );
     }
-#endif
 }