diff --git a/libcxx/src/filesystem/filesystem_common.h b/libcxx/src/filesystem/filesystem_common.h
index fe5c42f5e6d0b3..a7828ef38632d8 100644
--- a/libcxx/src/filesystem/filesystem_common.h
+++ b/libcxx/src/filesystem/filesystem_common.h
@@ -13,8 +13,9 @@
 #include "filesystem"
 #include "array"
 #include "chrono"
-#include "cstdlib"
 #include "climits"
+#include "cstdlib"
+#include "ctime"
 
 #include <unistd.h>
 #include <sys/stat.h>
@@ -47,7 +48,7 @@ static string format_string_imp(const char* msg, ...) {
   struct GuardVAList {
     va_list& target;
     bool active = true;
-    GuardVAList(va_list& target) : target(target), active(true) {}
+    GuardVAList(va_list& tgt) : target(tgt), active(true) {}
     void clear() {
       if (active)
         va_end(target);
@@ -134,50 +135,50 @@ path error_value<path>() {
 
 template <class T>
 struct ErrorHandler {
-  const char* func_name;
-  error_code* ec = nullptr;
-  const path* p1 = nullptr;
-  const path* p2 = nullptr;
+  const char* func_name_;
+  error_code* ec_ = nullptr;
+  const path* p1_ = nullptr;
+  const path* p2_ = nullptr;
 
   ErrorHandler(const char* fname, error_code* ec, const path* p1 = nullptr,
                const path* p2 = nullptr)
-      : func_name(fname), ec(ec), p1(p1), p2(p2) {
-    if (ec)
-      ec->clear();
+      : func_name_(fname), ec_(ec), p1_(p1), p2_(p2) {
+    if (ec_)
+      ec_->clear();
   }
 
-  T report(const error_code& m_ec) const {
-    if (ec) {
-      *ec = m_ec;
+  T report(const error_code& ec) const {
+    if (ec_) {
+      *ec_ = ec;
       return error_value<T>();
     }
-    string what = string("in ") + func_name;
-    switch (bool(p1) + bool(p2)) {
+    string what = string("in ") + func_name_;
+    switch (bool(p1_) + bool(p2_)) {
     case 0:
-      __throw_filesystem_error(what, m_ec);
+      __throw_filesystem_error(what, ec);
     case 1:
-      __throw_filesystem_error(what, *p1, m_ec);
+      __throw_filesystem_error(what, *p1_, ec);
     case 2:
-      __throw_filesystem_error(what, *p1, *p2, m_ec);
+      __throw_filesystem_error(what, *p1_, *p2_, ec);
     }
     _LIBCPP_UNREACHABLE();
   }
 
   template <class... Args>
-  T report(const error_code& m_ec, const char* msg, Args const&... args) const {
-    if (ec) {
-      *ec = m_ec;
+  T report(const error_code& ec, const char* msg, Args const&... args) const {
+    if (ec_) {
+      *ec_ = ec;
       return error_value<T>();
     }
     string what =
-        string("in ") + func_name + ": " + format_string(msg, args...);
-    switch (bool(p1) + bool(p2)) {
+        string("in ") + func_name_ + ": " + format_string(msg, args...);
+    switch (bool(p1_) + bool(p2_)) {
     case 0:
-      __throw_filesystem_error(what, m_ec);
+      __throw_filesystem_error(what, ec);
     case 1:
-      __throw_filesystem_error(what, *p1, m_ec);
+      __throw_filesystem_error(what, *p1_, ec);
     case 2:
-      __throw_filesystem_error(what, *p1, *p2, m_ec);
+      __throw_filesystem_error(what, *p1_, *p2_, ec);
     }
     _LIBCPP_UNREACHABLE();
   }
@@ -197,8 +198,8 @@ struct ErrorHandler {
 using chrono::duration;
 using chrono::duration_cast;
 
-using TimeSpec = struct ::timespec;
-using StatT = struct ::stat;
+using TimeSpec = std::timespec;
+using StatT = struct stat;
 
 template <class FileTimeT, class TimeT,
           bool IsFloat = is_floating_point<typename FileTimeT::rep>::value>
diff --git a/libcxx/test/libcxx/containers/gnu_cxx/hash_map.pass.cpp b/libcxx/test/libcxx/containers/gnu_cxx/hash_map.pass.cpp
index 38f06a214b20a6..20bfd9b5eea8c4 100644
--- a/libcxx/test/libcxx/containers/gnu_cxx/hash_map.pass.cpp
+++ b/libcxx/test/libcxx/containers/gnu_cxx/hash_map.pass.cpp
@@ -6,12 +6,9 @@
 //
 //===----------------------------------------------------------------------===//
 
-// Prevent emission of the deprecated warning.
-#ifdef __clang__
-#pragma clang diagnostic ignored "-W#warnings"
-#endif
-#ifdef __GNUC__
-#pragma GCC diagnostic ignored "-Wcpp"
+// Prevent <ext/hash_map> from generating deprecated warnings for this test.
+#if defined(__DEPRECATED)
+#   undef __DEPRECATED
 #endif
 
 #include <ext/hash_map>
diff --git a/libcxx/test/libcxx/containers/gnu_cxx/hash_map_name_lookup.pass.cpp b/libcxx/test/libcxx/containers/gnu_cxx/hash_map_name_lookup.pass.cpp
index 31e877eda82267..a88a219a9af3e7 100644
--- a/libcxx/test/libcxx/containers/gnu_cxx/hash_map_name_lookup.pass.cpp
+++ b/libcxx/test/libcxx/containers/gnu_cxx/hash_map_name_lookup.pass.cpp
@@ -6,20 +6,18 @@
 //
 //===----------------------------------------------------------------------===//
 
-// Prevent emission of the deprecated warning.
-#ifdef __clang__
-#pragma clang diagnostic ignored "-W#warnings"
-#endif
-#ifdef __GNUC__
-#pragma GCC diagnostic push "-Wcpp"
-#endif
-
 // Poison the std:: names we might use inside __gnu_cxx to ensure they're
 // properly qualified.
 struct allocator;
 struct pair;
 struct equal_to;
 struct unique_ptr;
+
+// Prevent <ext/hash_map> from generating deprecated warnings for this test.
+#if defined(__DEPRECATED)
+#   undef __DEPRECATED
+#endif
+
 #include <ext/hash_map>
 
 #include "test_macros.h"
diff --git a/libcxx/test/libcxx/containers/gnu_cxx/hash_set.pass.cpp b/libcxx/test/libcxx/containers/gnu_cxx/hash_set.pass.cpp
index eb982cca048ccf..c5c37af539831f 100644
--- a/libcxx/test/libcxx/containers/gnu_cxx/hash_set.pass.cpp
+++ b/libcxx/test/libcxx/containers/gnu_cxx/hash_set.pass.cpp
@@ -6,12 +6,9 @@
 //
 //===----------------------------------------------------------------------===//
 
-// Prevent emission of the deprecated warning.
-#ifdef __clang__
-#pragma clang diagnostic ignored "-W#warnings"
-#endif
-#ifdef __GNUC__
-#pragma GCC diagnostic ignored "-Wcpp"
+// Prevent <ext/hash_set> from generating deprecated warnings for this test.
+#if defined(__DEPRECATED)
+#   undef __DEPRECATED
 #endif
 
 #include <ext/hash_set>
diff --git a/libcxx/test/libcxx/containers/gnu_cxx/hash_set_name_lookup.pass.cpp b/libcxx/test/libcxx/containers/gnu_cxx/hash_set_name_lookup.pass.cpp
index 6e50137ceb7163..83283dc1dc2975 100644
--- a/libcxx/test/libcxx/containers/gnu_cxx/hash_set_name_lookup.pass.cpp
+++ b/libcxx/test/libcxx/containers/gnu_cxx/hash_set_name_lookup.pass.cpp
@@ -6,20 +6,18 @@
 //
 //===----------------------------------------------------------------------===//
 
-// Prevent emission of the deprecated warning.
-#ifdef __clang__
-#pragma clang diagnostic ignored "-W#warnings"
-#endif
-#ifdef __GNUC__
-#pragma GCC diagnostic ignored "-Wcpp"
-#endif
-
 // Poison the std:: names we might use inside __gnu_cxx to ensure they're
 // properly qualified.
 struct allocator;
 struct pair;
 struct equal_to;
 struct unique_ptr;
+
+// Prevent <ext/hash_set> from generating deprecated warnings for this test.
+#if defined(__DEPRECATED)
+#   undef __DEPRECATED
+#endif
+
 #include <ext/hash_set>
 
 #include "test_macros.h"
diff --git a/libcxx/test/libcxx/containers/sequences/deque/spare_block_handling.pass.cpp b/libcxx/test/libcxx/containers/sequences/deque/spare_block_handling.pass.cpp
index 6b4fcfcb1cf8f3..3b90464b729782 100644
--- a/libcxx/test/libcxx/containers/sequences/deque/spare_block_handling.pass.cpp
+++ b/libcxx/test/libcxx/containers/sequences/deque/spare_block_handling.pass.cpp
@@ -53,18 +53,18 @@ static_assert(BlockSize<LargeT>::value == 16, "");
 
 const auto& AllocBytes = malloc_allocator_base::outstanding_bytes;
 
-template <class DT>
+template <class Deque>
 struct PrintOnFailure {
-   explicit PrintOnFailure(DT const& d) : d(&d) {}
+   explicit PrintOnFailure(Deque const& deque) : deque_(&deque) {}
 
   ~PrintOnFailure() {
     if (::rapid_cxx_test::get_reporter().current_failure().type
         != ::rapid_cxx_test::failure_type::none) {
-      print(*d);
+      print(*deque_);
     }
   }
 private:
-  const DT* d;
+  const Deque* deque_;
 
   PrintOnFailure(PrintOnFailure const&) = delete;
 };
diff --git a/libcxx/test/libcxx/include_as_c.sh.cpp b/libcxx/test/libcxx/include_as_c.sh.cpp
index 04b044bee8753c..60e0a26ed57689 100644
--- a/libcxx/test/libcxx/include_as_c.sh.cpp
+++ b/libcxx/test/libcxx/include_as_c.sh.cpp
@@ -10,6 +10,10 @@
 // We're building as C, so this test doesn't work when building with modules.
 // UNSUPPORTED: -fmodules
 
+// GCC complains about unrecognized arguments because we're compiling the
+// file as C, but we're passing C++ flags on the command-line.
+// UNSUPPORTED: gcc
+
 // Test that the C wrapper headers can be included when compiling them as C.
 
 // NOTE: It's not common or recommended to have libc++ in the header search
diff --git a/libcxx/test/std/algorithms/alg.nonmodifying/alg.search/search.pass.cpp b/libcxx/test/std/algorithms/alg.nonmodifying/alg.search/search.pass.cpp
index cb1bd1cf40e98e..b4b841f273c46f 100644
--- a/libcxx/test/std/algorithms/alg.nonmodifying/alg.search/search.pass.cpp
+++ b/libcxx/test/std/algorithms/alg.nonmodifying/alg.search/search.pass.cpp
@@ -58,12 +58,12 @@ struct MySearcher {
 
 namespace User {
 struct S {
-    S(int x) : x(x) {}
-    int x;
+    S(int x) : x_(x) {}
+    int x_;
 };
 bool operator==(S lhs, S rhs)
 {
-    return lhs.x == rhs.x;
+    return lhs.x_ == rhs.x_;
 }
 template <class T, class U>
 void make_pair(T&&, U&&) = delete;
diff --git a/libcxx/test/std/containers/container.adaptors/priority.queue/priqueue.cons.alloc/ctor_alloc.pass.cpp b/libcxx/test/std/containers/container.adaptors/priority.queue/priqueue.cons.alloc/ctor_alloc.pass.cpp
index 59547203b49b75..07b4f46e65dea4 100644
--- a/libcxx/test/std/containers/container.adaptors/priority.queue/priqueue.cons.alloc/ctor_alloc.pass.cpp
+++ b/libcxx/test/std/containers/container.adaptors/priority.queue/priqueue.cons.alloc/ctor_alloc.pass.cpp
@@ -28,11 +28,11 @@ struct test
     explicit test(const test_allocator<int>& a) : base(a) {}
     test(const value_compare& comp, const test_allocator<int>& a)
         : base(comp, c, a) {}
-    test(const value_compare& comp, const container_type& c,
-        const test_allocator<int>& a) : base(comp, c, a) {}
+    test(const value_compare& comp, const container_type& container,
+        const test_allocator<int>& a) : base(comp, container, a) {}
 #if TEST_STD_VER >= 11
-    test(const value_compare& comp, container_type&& c,
-         const test_allocator<int>& a) : base(comp, std::move(c), a) {}
+    test(const value_compare& comp, container_type&& container,
+         const test_allocator<int>& a) : base(comp, std::move(container), a) {}
     test(test&& q, const test_allocator<int>& a) : base(std::move(q), a) {}
 #endif
     test_allocator<int> get_allocator() {return c.get_allocator();}
diff --git a/libcxx/test/std/containers/container.adaptors/priority.queue/priqueue.cons.alloc/ctor_comp_alloc.pass.cpp b/libcxx/test/std/containers/container.adaptors/priority.queue/priqueue.cons.alloc/ctor_comp_alloc.pass.cpp
index 40f6bc473c7a77..87b9ada9b703c6 100644
--- a/libcxx/test/std/containers/container.adaptors/priority.queue/priqueue.cons.alloc/ctor_comp_alloc.pass.cpp
+++ b/libcxx/test/std/containers/container.adaptors/priority.queue/priqueue.cons.alloc/ctor_comp_alloc.pass.cpp
@@ -26,13 +26,13 @@ struct test
     typedef typename base::value_compare value_compare;
 
     explicit test(const test_allocator<int>& a) : base(a) {}
-    test(const value_compare& comp, const test_allocator<int>& a)
-        : base(comp, a) {}
-    test(const value_compare& comp, const container_type& c,
-        const test_allocator<int>& a) : base(comp, c, a) {}
+    test(const value_compare& compare, const test_allocator<int>& a)
+        : base(compare, a) {}
+    test(const value_compare& compare, const container_type& container,
+        const test_allocator<int>& a) : base(compare, container, a) {}
 #if TEST_STD_VER >= 11
-    test(const value_compare& comp, container_type&& c,
-         const test_allocator<int>& a) : base(comp, std::move(c), a) {}
+    test(const value_compare& compare, container_type&& container,
+         const test_allocator<int>& a) : base(compare, std::move(container), a) {}
     test(test&& q, const test_allocator<int>& a) : base(std::move(q), a) {}
 #endif
     test_allocator<int> get_allocator() {return c.get_allocator();}
diff --git a/libcxx/test/std/containers/container.adaptors/priority.queue/priqueue.cons.alloc/ctor_comp_cont_alloc.pass.cpp b/libcxx/test/std/containers/container.adaptors/priority.queue/priqueue.cons.alloc/ctor_comp_cont_alloc.pass.cpp
index 1f3dd7fbd1679f..afec7713967995 100644
--- a/libcxx/test/std/containers/container.adaptors/priority.queue/priqueue.cons.alloc/ctor_comp_cont_alloc.pass.cpp
+++ b/libcxx/test/std/containers/container.adaptors/priority.queue/priqueue.cons.alloc/ctor_comp_cont_alloc.pass.cpp
@@ -37,13 +37,13 @@ struct test
     typedef typename base::value_compare value_compare;
 
     explicit test(const test_allocator<int>& a) : base(a) {}
-    test(const value_compare& comp, const test_allocator<int>& a)
-        : base(comp, a) {}
-    test(const value_compare& comp, const container_type& c,
-        const test_allocator<int>& a) : base(comp, c, a) {}
+    test(const value_compare& compare, const test_allocator<int>& a)
+        : base(compare, a) {}
+    test(const value_compare& compare, const container_type& container,
+        const test_allocator<int>& a) : base(compare, container, a) {}
 #if TEST_STD_VER >= 11 // testing rvalue constructor
-    test(const value_compare& comp, container_type&& c,
-         const test_allocator<int>& a) : base(comp, std::move(c), a) {}
+    test(const value_compare& compare, container_type&& container,
+         const test_allocator<int>& a) : base(compare, std::move(container), a) {}
     test(test&& q, const test_allocator<int>& a) : base(std::move(q), a) {}
 #endif
     test_allocator<int> get_allocator() {return c.get_allocator();}
diff --git a/libcxx/test/std/containers/container.adaptors/priority.queue/priqueue.cons.alloc/ctor_comp_rcont_alloc.pass.cpp b/libcxx/test/std/containers/container.adaptors/priority.queue/priqueue.cons.alloc/ctor_comp_rcont_alloc.pass.cpp
index 3956f9b974e619..7ddb5f4d5a3c0b 100644
--- a/libcxx/test/std/containers/container.adaptors/priority.queue/priqueue.cons.alloc/ctor_comp_rcont_alloc.pass.cpp
+++ b/libcxx/test/std/containers/container.adaptors/priority.queue/priqueue.cons.alloc/ctor_comp_rcont_alloc.pass.cpp
@@ -37,13 +37,13 @@ struct test
     typedef typename base::value_compare value_compare;
 
     explicit test(const test_allocator<int>& a) : base(a) {}
-    test(const value_compare& comp, const test_allocator<int>& a)
-        : base(comp, a) {}
-    test(const value_compare& comp, const container_type& c,
-        const test_allocator<int>& a) : base(comp, c, a) {}
+    test(const value_compare& compare, const test_allocator<int>& a)
+        : base(compare, a) {}
+    test(const value_compare& compare, const container_type& container,
+        const test_allocator<int>& a) : base(compare, container, a) {}
 #if TEST_STD_VER >= 11 // testing rvalue ctor
-    test(const value_compare& comp, container_type&& c,
-         const test_allocator<int>& a) : base(comp, std::move(c), a) {}
+    test(const value_compare& compare, container_type&& container,
+         const test_allocator<int>& a) : base(compare, std::move(container), a) {}
     test(test&& q, const test_allocator<int>& a) : base(std::move(q), a) {}
 #endif
     test_allocator<int> get_allocator() {return c.get_allocator();}
diff --git a/libcxx/test/std/containers/container.adaptors/priority.queue/priqueue.cons.alloc/ctor_copy_alloc.pass.cpp b/libcxx/test/std/containers/container.adaptors/priority.queue/priqueue.cons.alloc/ctor_copy_alloc.pass.cpp
index 152030ff5546a4..77c9989e91c51d 100644
--- a/libcxx/test/std/containers/container.adaptors/priority.queue/priqueue.cons.alloc/ctor_copy_alloc.pass.cpp
+++ b/libcxx/test/std/containers/container.adaptors/priority.queue/priqueue.cons.alloc/ctor_copy_alloc.pass.cpp
@@ -36,10 +36,10 @@ struct test
     typedef typename base::value_compare value_compare;
 
     explicit test(const test_allocator<int>& a) : base(a) {}
-    test(const value_compare& comp, const test_allocator<int>& a)
-        : base(comp, c, a) {}
-    test(const value_compare& comp, const container_type& c,
-         const test_allocator<int>& a) : base(comp, c, a) {}
+    test(const value_compare& compare, const test_allocator<int>& a)
+        : base(compare, c, a) {}
+    test(const value_compare& compare, const container_type& container,
+         const test_allocator<int>& a) : base(compare, container, a) {}
     test(const test& q, const test_allocator<int>& a) : base(q, a) {}
     test_allocator<int> get_allocator() {return c.get_allocator();}
 
diff --git a/libcxx/test/std/containers/container.adaptors/priority.queue/priqueue.cons.alloc/ctor_move_alloc.pass.cpp b/libcxx/test/std/containers/container.adaptors/priority.queue/priqueue.cons.alloc/ctor_move_alloc.pass.cpp
index a707946fa0d105..c1c05808606ab7 100644
--- a/libcxx/test/std/containers/container.adaptors/priority.queue/priqueue.cons.alloc/ctor_move_alloc.pass.cpp
+++ b/libcxx/test/std/containers/container.adaptors/priority.queue/priqueue.cons.alloc/ctor_move_alloc.pass.cpp
@@ -41,12 +41,12 @@ struct test
     typedef typename base::value_compare value_compare;
 
     explicit test(const test_allocator<int>& a) : base(a) {}
-    test(const value_compare& comp, const test_allocator<int>& a)
-        : base(comp, c, a) {}
-    test(const value_compare& comp, const container_type& c,
-        const test_allocator<int>& a) : base(comp, c, a) {}
-    test(const value_compare& comp, container_type&& c,
-         const test_allocator<int>& a) : base(comp, std::move(c), a) {}
+    test(const value_compare& compare, const test_allocator<int>& a)
+        : base(compare, c, a) {}
+    test(const value_compare& compare, const container_type& container,
+        const test_allocator<int>& a) : base(compare, container, a) {}
+    test(const value_compare& compare, container_type&& container,
+         const test_allocator<int>& a) : base(compare, std::move(container), a) {}
     test(test&& q, const test_allocator<int>& a) : base(std::move(q), a) {}
     test_allocator<int> get_allocator() {return c.get_allocator();}
 
diff --git a/libcxx/test/std/containers/container.adaptors/priority.queue/priqueue.cons/deduct.pass.cpp b/libcxx/test/std/containers/container.adaptors/priority.queue/priqueue.cons/deduct.pass.cpp
index bc01a8af37f3d5..c4f5375bad45a0 100644
--- a/libcxx/test/std/containers/container.adaptors/priority.queue/priqueue.cons/deduct.pass.cpp
+++ b/libcxx/test/std/containers/container.adaptors/priority.queue/priqueue.cons/deduct.pass.cpp
@@ -108,12 +108,12 @@ int main(int, char**)
 //  has to match the type of the one used by the underlying container
     typedef long double T;
     typedef std::greater<T> Comp;
-    typedef test_allocator<T> A;
-    typedef std::deque<T, A> Cont;
+    typedef test_allocator<T> Alloc;
+    typedef std::deque<T, Alloc> Cont;
 
     Cont c{2,3,0,1};
     std::priority_queue<T, Cont, Comp> source(Comp(), c);
-    std::priority_queue pri(source, A(2)); // queue(queue &, allocator)
+    std::priority_queue pri(source, Alloc(2)); // queue(queue &, allocator)
     static_assert(std::is_same_v<decltype(pri)::value_type, T>, "");
     static_assert(std::is_same_v<decltype(pri)::container_type, Cont>, "");
     assert(pri.size() == 4);
diff --git a/libcxx/test/std/containers/container.adaptors/queue/queue.cons.alloc/ctor_alloc.pass.cpp b/libcxx/test/std/containers/container.adaptors/queue/queue.cons.alloc/ctor_alloc.pass.cpp
index 8d916f767718aa..197256051dc3ac 100644
--- a/libcxx/test/std/containers/container.adaptors/queue/queue.cons.alloc/ctor_alloc.pass.cpp
+++ b/libcxx/test/std/containers/container.adaptors/queue/queue.cons.alloc/ctor_alloc.pass.cpp
@@ -23,9 +23,9 @@ struct test
     typedef std::queue<int, std::deque<int, test_allocator<int> > > base;
 
     explicit test(const test_allocator<int>& a) : base(a) {}
-    test(const container_type& c, const test_allocator<int>& a) : base(c, a) {}
+    test(const container_type& container, const test_allocator<int>& a) : base(container, a) {}
 #if TEST_STD_VER >= 11
-    test(container_type&& c, const test_allocator<int>& a) : base(std::move(c), a) {}
+    test(container_type&& container, const test_allocator<int>& a) : base(std::move(container), a) {}
     test(test&& q, const test_allocator<int>& a) : base(std::move(q), a) {}
 #endif
     test_allocator<int> get_allocator() {return c.get_allocator();}
diff --git a/libcxx/test/std/containers/container.adaptors/queue/queue.cons.alloc/ctor_container_alloc.pass.cpp b/libcxx/test/std/containers/container.adaptors/queue/queue.cons.alloc/ctor_container_alloc.pass.cpp
index 56272064fc22fd..674fc6c243f0fc 100644
--- a/libcxx/test/std/containers/container.adaptors/queue/queue.cons.alloc/ctor_container_alloc.pass.cpp
+++ b/libcxx/test/std/containers/container.adaptors/queue/queue.cons.alloc/ctor_container_alloc.pass.cpp
@@ -36,9 +36,9 @@ struct test
     typedef std::queue<int, C> base;
 
     explicit test(const test_allocator<int>& a) : base(a) {}
-    test(const container_type& c, const test_allocator<int>& a) : base(c, a) {}
+    test(const container_type& container, const test_allocator<int>& a) : base(container, a) {}
 #if TEST_STD_VER >= 11
-    test(container_type&& c, const test_allocator<int>& a) : base(std::move(c), a) {}
+    test(container_type&& container, const test_allocator<int>& a) : base(std::move(container), a) {}
     test(test&& q, const test_allocator<int>& a) : base(std::move(q), a) {}
 #endif
     test_allocator<int> get_allocator() {return c.get_allocator();}
diff --git a/libcxx/test/std/containers/container.adaptors/queue/queue.cons.alloc/ctor_queue_alloc.pass.cpp b/libcxx/test/std/containers/container.adaptors/queue/queue.cons.alloc/ctor_queue_alloc.pass.cpp
index 38ba6f7c4a7c20..a9107f25822dc9 100644
--- a/libcxx/test/std/containers/container.adaptors/queue/queue.cons.alloc/ctor_queue_alloc.pass.cpp
+++ b/libcxx/test/std/containers/container.adaptors/queue/queue.cons.alloc/ctor_queue_alloc.pass.cpp
@@ -38,7 +38,7 @@ struct test
     typedef typename base::container_type container_type;
 
     explicit test(const allocator_type& a) : base(a) {}
-    test(const container_type& c, const allocator_type& a) : base(c, a) {}
+    test(const container_type& container, const allocator_type& a) : base(container, a) {}
     test(const test& q, const allocator_type& a) : base(q, a) {}
     allocator_type get_allocator() {return this->c.get_allocator();}
 };
diff --git a/libcxx/test/std/containers/container.adaptors/queue/queue.cons.alloc/ctor_rcontainer_alloc.pass.cpp b/libcxx/test/std/containers/container.adaptors/queue/queue.cons.alloc/ctor_rcontainer_alloc.pass.cpp
index 8c6b88a651b8c7..5e78c33df8bbc6 100644
--- a/libcxx/test/std/containers/container.adaptors/queue/queue.cons.alloc/ctor_rcontainer_alloc.pass.cpp
+++ b/libcxx/test/std/containers/container.adaptors/queue/queue.cons.alloc/ctor_rcontainer_alloc.pass.cpp
@@ -42,8 +42,8 @@ struct test
     typedef typename base::container_type container_type;
 
     explicit test(const allocator_type& a) : base(a) {}
-    test(const container_type& c, const allocator_type& a) : base(c, a) {}
-    test(container_type&& c, const allocator_type& a) : base(std::move(c), a) {}
+    test(const container_type& container, const allocator_type& a) : base(container, a) {}
+    test(container_type&& container, const allocator_type& a) : base(std::move(container), a) {}
     test(test&& q, const allocator_type& a) : base(std::move(q), a) {}
     allocator_type get_allocator() {return this->c.get_allocator();}
 };
diff --git a/libcxx/test/std/containers/container.adaptors/queue/queue.cons.alloc/ctor_rqueue_alloc.pass.cpp b/libcxx/test/std/containers/container.adaptors/queue/queue.cons.alloc/ctor_rqueue_alloc.pass.cpp
index b19538394536be..b0604ced6163fa 100644
--- a/libcxx/test/std/containers/container.adaptors/queue/queue.cons.alloc/ctor_rqueue_alloc.pass.cpp
+++ b/libcxx/test/std/containers/container.adaptors/queue/queue.cons.alloc/ctor_rqueue_alloc.pass.cpp
@@ -42,8 +42,8 @@ struct test
     typedef typename base::container_type container_type;
 
     explicit test(const allocator_type& a) : base(a) {}
-    test(const container_type& c, const allocator_type& a) : base(c, a) {}
-    test(container_type&& c, const allocator_type& a) : base(std::move(c), a) {}
+    test(const container_type& container, const allocator_type& a) : base(container, a) {}
+    test(container_type&& container, const allocator_type& a) : base(std::move(container), a) {}
     test(test&& q, const allocator_type& a) : base(std::move(q), a) {}
     allocator_type get_allocator() {return this->c.get_allocator();}
 };
diff --git a/libcxx/test/std/containers/container.adaptors/queue/queue.cons/deduct.pass.cpp b/libcxx/test/std/containers/container.adaptors/queue/queue.cons/deduct.pass.cpp
index 484aa51b5d9fb3..738a3a17016386 100644
--- a/libcxx/test/std/containers/container.adaptors/queue/queue.cons/deduct.pass.cpp
+++ b/libcxx/test/std/containers/container.adaptors/queue/queue.cons/deduct.pass.cpp
@@ -75,14 +75,14 @@ int main(int, char**)
 //  This one is odd - you can pass an allocator in to use, but the allocator
 //  has to match the type of the one used by the underlying container
     typedef short T;
-    typedef test_allocator<T> A;
-    typedef std::deque<T, A> C;
+    typedef test_allocator<T> Alloc;
+    typedef std::deque<T, Alloc> Container;
 
-    C c{0,1,2,3};
-    std::queue<T, C> source(c);
-    std::queue que(source, A(2)); // queue(queue &, allocator)
+    Container c{0,1,2,3};
+    std::queue<T, Container> source(c);
+    std::queue que(source, Alloc(2)); // queue(queue &, allocator)
     static_assert(std::is_same_v<decltype(que)::value_type, T>, "");
-    static_assert(std::is_same_v<decltype(que)::container_type, C>, "");
+    static_assert(std::is_same_v<decltype(que)::container_type, Container>, "");
     assert(que.size() == 4);
     assert(que.back() == 3);
     }
diff --git a/libcxx/test/std/containers/container.adaptors/stack/stack.cons.alloc/ctor_alloc.pass.cpp b/libcxx/test/std/containers/container.adaptors/stack/stack.cons.alloc/ctor_alloc.pass.cpp
index 9fb09b158dfbcf..8ec90a50aa8095 100644
--- a/libcxx/test/std/containers/container.adaptors/stack/stack.cons.alloc/ctor_alloc.pass.cpp
+++ b/libcxx/test/std/containers/container.adaptors/stack/stack.cons.alloc/ctor_alloc.pass.cpp
@@ -23,9 +23,9 @@ struct test
     typedef std::stack<int, std::deque<int, test_allocator<int> > > base;
 
     explicit test(const test_allocator<int>& a) : base(a) {}
-    test(const container_type& c, const test_allocator<int>& a) : base(c, a) {}
+    test(const container_type& cont, const test_allocator<int>& a) : base(cont, a) {}
 #if TEST_STD_VER >= 11
-    test(container_type&& c, const test_allocator<int>& a) : base(std::move(c), a) {}
+    test(container_type&& cont, const test_allocator<int>& a) : base(std::move(cont), a) {}
     test(test&& q, const test_allocator<int>& a) : base(std::move(q), a) {}
 #endif
     test_allocator<int> get_allocator() {return c.get_allocator();}
diff --git a/libcxx/test/std/containers/container.adaptors/stack/stack.cons.alloc/ctor_container_alloc.pass.cpp b/libcxx/test/std/containers/container.adaptors/stack/stack.cons.alloc/ctor_container_alloc.pass.cpp
index b0c6f4fcac7927..05e48eecb6adb1 100644
--- a/libcxx/test/std/containers/container.adaptors/stack/stack.cons.alloc/ctor_container_alloc.pass.cpp
+++ b/libcxx/test/std/containers/container.adaptors/stack/stack.cons.alloc/ctor_container_alloc.pass.cpp
@@ -36,9 +36,9 @@ struct test
     typedef std::stack<int, C> base;
 
     explicit test(const test_allocator<int>& a) : base(a) {}
-    test(const container_type& c, const test_allocator<int>& a) : base(c, a) {}
+    test(const container_type& cont, const test_allocator<int>& a) : base(cont, a) {}
 #if TEST_STD_VER >= 11
-    test(container_type&& c, const test_allocator<int>& a) : base(std::move(c), a) {}
+    test(container_type&& cont, const test_allocator<int>& a) : base(std::move(cont), a) {}
     test(test&& q, const test_allocator<int>& a) : base(std::move(q), a) {}
 #endif
     test_allocator<int> get_allocator() {return c.get_allocator();}
diff --git a/libcxx/test/std/containers/container.adaptors/stack/stack.cons.alloc/ctor_copy_alloc.pass.cpp b/libcxx/test/std/containers/container.adaptors/stack/stack.cons.alloc/ctor_copy_alloc.pass.cpp
index 1ca3cdbaa2d5a4..499a3fd2cbf4f9 100644
--- a/libcxx/test/std/containers/container.adaptors/stack/stack.cons.alloc/ctor_copy_alloc.pass.cpp
+++ b/libcxx/test/std/containers/container.adaptors/stack/stack.cons.alloc/ctor_copy_alloc.pass.cpp
@@ -38,7 +38,7 @@ struct test
     typedef typename base::container_type container_type;
 
     explicit test(const allocator_type& a) : base(a) {}
-    test(const container_type& c, const allocator_type& a) : base(c, a) {}
+    test(const container_type& cont, const allocator_type& a) : base(cont, a) {}
     test(const test& q, const allocator_type& a) : base(q, a) {}
     allocator_type get_allocator() {return this->c.get_allocator();}
 };
diff --git a/libcxx/test/std/containers/container.adaptors/stack/stack.cons.alloc/ctor_rcontainer_alloc.pass.cpp b/libcxx/test/std/containers/container.adaptors/stack/stack.cons.alloc/ctor_rcontainer_alloc.pass.cpp
index d975983edd0bb0..eb3a1ac1bf67c8 100644
--- a/libcxx/test/std/containers/container.adaptors/stack/stack.cons.alloc/ctor_rcontainer_alloc.pass.cpp
+++ b/libcxx/test/std/containers/container.adaptors/stack/stack.cons.alloc/ctor_rcontainer_alloc.pass.cpp
@@ -42,8 +42,8 @@ struct test
     typedef typename base::container_type container_type;
 
     explicit test(const allocator_type& a) : base(a) {}
-    test(const container_type& c, const allocator_type& a) : base(c, a) {}
-    test(container_type&& c, const allocator_type& a) : base(std::move(c), a) {}
+    test(const container_type& cont, const allocator_type& a) : base(cont, a) {}
+    test(container_type&& cont, const allocator_type& a) : base(std::move(cont), a) {}
     test(test&& q, const allocator_type& a) : base(std::move(q), a) {}
     allocator_type get_allocator() {return this->c.get_allocator();}
 };
diff --git a/libcxx/test/std/containers/container.adaptors/stack/stack.cons.alloc/ctor_rqueue_alloc.pass.cpp b/libcxx/test/std/containers/container.adaptors/stack/stack.cons.alloc/ctor_rqueue_alloc.pass.cpp
index 7d9d84a6dcdb6a..849ad046898a7e 100644
--- a/libcxx/test/std/containers/container.adaptors/stack/stack.cons.alloc/ctor_rqueue_alloc.pass.cpp
+++ b/libcxx/test/std/containers/container.adaptors/stack/stack.cons.alloc/ctor_rqueue_alloc.pass.cpp
@@ -42,8 +42,8 @@ struct test
     typedef typename base::container_type container_type;
 
     explicit test(const allocator_type& a) : base(a) {}
-    test(const container_type& c, const allocator_type& a) : base(c, a) {}
-    test(container_type&& c, const allocator_type& a) : base(std::move(c), a) {}
+    test(const container_type& cont, const allocator_type& a) : base(cont, a) {}
+    test(container_type&& cont, const allocator_type& a) : base(std::move(cont), a) {}
     test(test&& q, const allocator_type& a) : base(std::move(q), a) {}
     allocator_type get_allocator() {return this->c.get_allocator();}
 };
diff --git a/libcxx/test/std/containers/container.adaptors/stack/stack.cons/deduct.pass.cpp b/libcxx/test/std/containers/container.adaptors/stack/stack.cons/deduct.pass.cpp
index 5769d9210b357e..fb211f6570d774 100644
--- a/libcxx/test/std/containers/container.adaptors/stack/stack.cons/deduct.pass.cpp
+++ b/libcxx/test/std/containers/container.adaptors/stack/stack.cons/deduct.pass.cpp
@@ -78,14 +78,14 @@ int main(int, char**)
 //  This one is odd - you can pass an allocator in to use, but the allocator
 //  has to match the type of the one used by the underlying container
     typedef short T;
-    typedef test_allocator<T> A;
-    typedef std::deque<T, A> C;
+    typedef test_allocator<T> Alloc;
+    typedef std::deque<T, Alloc> Container;
 
-    C c{0,1,2,3};
-    std::stack<T, C> source(c);
-    std::stack stk(source, A(2)); // stack(stack &, allocator)
+    Container c{0,1,2,3};
+    std::stack<T, Container> source(c);
+    std::stack stk(source, Alloc(2)); // stack(stack &, allocator)
     static_assert(std::is_same_v<decltype(stk)::value_type, T>, "");
-    static_assert(std::is_same_v<decltype(stk)::container_type, C>, "");
+    static_assert(std::is_same_v<decltype(stk)::container_type, Container>, "");
     assert(stk.size() == 4);
     assert(stk.top() == 3);
     }
diff --git a/libcxx/test/std/depr/depr.c.headers/stdlib_h.pass.cpp b/libcxx/test/std/depr/depr.c.headers/stdlib_h.pass.cpp
index be436475b9b680..295f51807d41f2 100644
--- a/libcxx/test/std/depr/depr.c.headers/stdlib_h.pass.cpp
+++ b/libcxx/test/std/depr/depr.c.headers/stdlib_h.pass.cpp
@@ -137,18 +137,21 @@ int main(int, char**)
                   "");
 #endif
 
+    void* pv = 0;
+    void (*handler)() = 0;
+    int (*comp)(void const*, void const*) = 0;
     static_assert((std::is_same<decltype(calloc(0,0)), void*>::value), "");
     static_assert((std::is_same<decltype(free(0)), void>::value), "");
     static_assert((std::is_same<decltype(malloc(0)), void*>::value), "");
     static_assert((std::is_same<decltype(realloc(0,0)), void*>::value), "");
     static_assert((std::is_same<decltype(abort()), void>::value), "");
-    static_assert((std::is_same<decltype(atexit(0)), int>::value), "");
+    static_assert((std::is_same<decltype(atexit(handler)), int>::value), "");
     static_assert((std::is_same<decltype(exit(0)), void>::value), "");
     static_assert((std::is_same<decltype(_Exit(0)), void>::value), "");
     static_assert((std::is_same<decltype(getenv("")), char*>::value), "");
     static_assert((std::is_same<decltype(system("")), int>::value), "");
-    static_assert((std::is_same<decltype(bsearch(0,0,0,0,0)), void*>::value), "");
-    static_assert((std::is_same<decltype(qsort(0,0,0,0)), void>::value), "");
+    static_assert((std::is_same<decltype(bsearch(pv,pv,0,0,comp)), void*>::value), "");
+    static_assert((std::is_same<decltype(qsort(pv,0,0,comp)), void>::value), "");
     static_assert((std::is_same<decltype(abs(0)), int>::value), "");
     static_assert((std::is_same<decltype(labs((long)0)), long>::value), "");
     static_assert((std::is_same<decltype(llabs((long long)0)), long long>::value), "");
diff --git a/libcxx/test/std/input.output/file.streams/c.files/cstdio.pass.cpp b/libcxx/test/std/input.output/file.streams/c.files/cstdio.pass.cpp
index bae82fec69b020..f3883868195288 100644
--- a/libcxx/test/std/input.output/file.streams/c.files/cstdio.pass.cpp
+++ b/libcxx/test/std/input.output/file.streams/c.files/cstdio.pass.cpp
@@ -92,25 +92,27 @@ int main(int, char**)
     std::size_t s = 0;
     char* cp = 0;
     std::va_list va;
+    void const* vp = 0;
     ((void)fp); // Prevent unused warning
     ((void)fpos); // Prevent unused warning
     ((void)s); // Prevent unused warning
     ((void)cp); // Prevent unused warning
     ((void)va); // Prevent unused warning
+    ((void)vp); // Prevent unused warning
     static_assert((std::is_same<decltype(std::fclose(fp)), int>::value), "");
     static_assert((std::is_same<decltype(std::fflush(fp)), int>::value), "");
     static_assert((std::is_same<decltype(std::setbuf(fp,cp)), void>::value), "");
-    static_assert((std::is_same<decltype(std::vfprintf(fp,"",va)), int>::value), "");
+    static_assert((std::is_same<decltype(std::vfprintf(fp," ",va)), int>::value), "");
     static_assert((std::is_same<decltype(std::fprintf(fp," ")), int>::value), "");
-    static_assert((std::is_same<decltype(std::fscanf(fp,"")), int>::value), "");
+    static_assert((std::is_same<decltype(std::fscanf(fp," ")), int>::value), "");
     static_assert((std::is_same<decltype(std::snprintf(cp,0," ")), int>::value), "");
     static_assert((std::is_same<decltype(std::sprintf(cp," ")), int>::value), "");
-    static_assert((std::is_same<decltype(std::sscanf("","")), int>::value), "");
-    static_assert((std::is_same<decltype(std::vfprintf(fp,"",va)), int>::value), "");
-    static_assert((std::is_same<decltype(std::vfscanf(fp,"",va)), int>::value), "");
+    static_assert((std::is_same<decltype(std::sscanf(""," ")), int>::value), "");
+    static_assert((std::is_same<decltype(std::vfprintf(fp," ",va)), int>::value), "");
+    static_assert((std::is_same<decltype(std::vfscanf(fp," ",va)), int>::value), "");
     static_assert((std::is_same<decltype(std::vsnprintf(cp,0," ",va)), int>::value), "");
     static_assert((std::is_same<decltype(std::vsprintf(cp," ",va)), int>::value), "");
-    static_assert((std::is_same<decltype(std::vsscanf("","",va)), int>::value), "");
+    static_assert((std::is_same<decltype(std::vsscanf(""," ",va)), int>::value), "");
     static_assert((std::is_same<decltype(std::fgetc(fp)), int>::value), "");
     static_assert((std::is_same<decltype(std::fgets(cp,0,fp)), char*>::value), "");
     static_assert((std::is_same<decltype(std::fputc(0,fp)), int>::value), "");
@@ -119,7 +121,7 @@ int main(int, char**)
     static_assert((std::is_same<decltype(std::putc(0,fp)), int>::value), "");
     static_assert((std::is_same<decltype(std::ungetc(0,fp)), int>::value), "");
     static_assert((std::is_same<decltype(std::fread((void*)0,0,0,fp)), std::size_t>::value), "");
-    static_assert((std::is_same<decltype(std::fwrite((const void*)0,0,0,fp)), std::size_t>::value), "");
+    static_assert((std::is_same<decltype(std::fwrite(vp,0,0,fp)), std::size_t>::value), "");
 #ifndef _LIBCPP_HAS_NO_FGETPOS_FSETPOS
     static_assert((std::is_same<decltype(std::fgetpos(fp, &fpos)), int>::value), "");
 #endif
@@ -149,7 +151,7 @@ int main(int, char**)
     static_assert((std::is_same<decltype(std::gets(cp)), char*>::value), "");
 #endif
     static_assert((std::is_same<decltype(std::scanf(" ")), int>::value), "");
-    static_assert((std::is_same<decltype(std::vscanf("",va)), int>::value), "");
+    static_assert((std::is_same<decltype(std::vscanf(" ",va)), int>::value), "");
 #endif
 
 #ifndef _LIBCPP_HAS_NO_STDOUT
diff --git a/libcxx/test/std/input.output/filesystems/fs.op.funcs/fs.op.last_write_time/last_write_time.pass.cpp b/libcxx/test/std/input.output/filesystems/fs.op.funcs/fs.op.last_write_time/last_write_time.pass.cpp
index d3841f5406c8e2..f4a9210a137659 100644
--- a/libcxx/test/std/input.output/filesystems/fs.op.funcs/fs.op.last_write_time/last_write_time.pass.cpp
+++ b/libcxx/test/std/input.output/filesystems/fs.op.funcs/fs.op.last_write_time/last_write_time.pass.cpp
@@ -17,10 +17,11 @@
 //                      std::error_code& ec) noexcept;
 
 #include "filesystem_include.h"
-#include <type_traits>
 #include <chrono>
 #include <cstdio>
 #include <cstdlib>
+#include <ctime>
+#include <type_traits>
 
 #include "test_macros.h"
 #include "rapid-cxx-test.h"
@@ -32,8 +33,8 @@
 
 using namespace fs;
 
-using TimeSpec = struct ::timespec;
-using StatT = struct ::stat;
+using TimeSpec = std::timespec;
+using StatT = struct stat;
 
 using Sec = std::chrono::duration<file_time_type::rep>;
 using Hours = std::chrono::hours;
diff --git a/libcxx/test/std/input.output/iostream.format/input.streams/istream.unformatted/sync.pass.cpp b/libcxx/test/std/input.output/iostream.format/input.streams/istream.unformatted/sync.pass.cpp
index ff22e9876f553b..bc808fb69caedd 100644
--- a/libcxx/test/std/input.output/iostream.format/input.streams/istream.unformatted/sync.pass.cpp
+++ b/libcxx/test/std/input.output/iostream.format/input.streams/istream.unformatted/sync.pass.cpp
@@ -111,6 +111,7 @@ int main(int, char**)
         assert( is.bad());
         assert(!is.eof());
         assert( is.fail());
+        assert(threw);
     }
     {
         throwing_testbuf<wchar_t> sb(L" 123456789");
@@ -125,6 +126,7 @@ int main(int, char**)
         assert( is.bad());
         assert(!is.eof());
         assert( is.fail());
+        assert(threw);
     }
 #endif
 
diff --git a/libcxx/test/std/iterators/iterator.container/ssize.pass.cpp b/libcxx/test/std/iterators/iterator.container/ssize.pass.cpp
index a26663b1dcdfcd..f077e977a35f2f 100644
--- a/libcxx/test/std/iterators/iterator.container/ssize.pass.cpp
+++ b/libcxx/test/std/iterators/iterator.container/ssize.pass.cpp
@@ -23,12 +23,14 @@
 
 #include "test_macros.h"
 
+// Ignore warning about std::numeric_limits comparisons being tautological.
+#ifdef __GNUC__
+#pragma GCC diagnostic ignored "-Wtype-limits"
+#endif
 
 struct short_container {
     uint16_t size() const { return 60000; } // not noexcept
-    };
-
-
+};
 
 template<typename C>
 void test_container(C& c)
diff --git a/libcxx/test/std/language.support/support.dynamic/destroying_delete_t_declaration.pass.cpp b/libcxx/test/std/language.support/support.dynamic/destroying_delete_t_declaration.pass.cpp
index 6dcfbe8cd97ab1..b98af1bfe1e45f 100644
--- a/libcxx/test/std/language.support/support.dynamic/destroying_delete_t_declaration.pass.cpp
+++ b/libcxx/test/std/language.support/support.dynamic/destroying_delete_t_declaration.pass.cpp
@@ -46,7 +46,6 @@ int main(int, char**) {
   static_assert(std::is_default_constructible<std::destroying_delete_t>::value, "");
   static_assert(!test_convertible<std::destroying_delete_t>(), "");
   constexpr std::destroying_delete_t dd{};
-  static_assert((dd, true), "");
   static_assert(&dd != &std::destroying_delete, "");
   static_assert(test_constexpr(std::destroying_delete), "");
   return 0;
diff --git a/libcxx/test/std/language.support/support.initlist/support.initlist.access/access.pass.cpp b/libcxx/test/std/language.support/support.initlist/support.initlist.access/access.pass.cpp
index 4a793bc59f252b..695001008ed1b1 100644
--- a/libcxx/test/std/language.support/support.initlist/support.initlist.access/access.pass.cpp
+++ b/libcxx/test/std/language.support/support.initlist/support.initlist.access/access.pass.cpp
@@ -53,7 +53,7 @@ struct B
 
 int main(int, char**)
 {
-    A test1 = {3, 2, 1};
+    A test1 = {3, 2, 1}; (void)test1;
 #if TEST_STD_VER > 11
     constexpr B test2 = {3, 2, 1};
     (void)test2;
diff --git a/libcxx/test/std/language.support/support.initlist/support.initlist.range/begin_end.pass.cpp b/libcxx/test/std/language.support/support.initlist/support.initlist.range/begin_end.pass.cpp
index 1015467f320dbb..335a8ef5a427e8 100644
--- a/libcxx/test/std/language.support/support.initlist/support.initlist.range/begin_end.pass.cpp
+++ b/libcxx/test/std/language.support/support.initlist/support.initlist.range/begin_end.pass.cpp
@@ -51,7 +51,7 @@ struct B
 
 int main(int, char**)
 {
-    A test1 = {3, 2, 1};
+    A test1 = {3, 2, 1}; (void)test1;
 #if TEST_STD_VER > 11
     constexpr B test2 = {3, 2, 1};
     (void)test2;
diff --git a/libcxx/test/std/language.support/support.runtime/cstdlib.pass.cpp b/libcxx/test/std/language.support/support.runtime/cstdlib.pass.cpp
index 72a3cf8d33a9a3..668213f84838c6 100644
--- a/libcxx/test/std/language.support/support.runtime/cstdlib.pass.cpp
+++ b/libcxx/test/std/language.support/support.runtime/cstdlib.pass.cpp
@@ -124,18 +124,21 @@ int main(int, char**)
         (std::is_same<decltype(std::aligned_alloc(1, 0)), void*>::value), "");
 #endif
 
+    void* pv = 0;
+    void (*handler)() = 0;
+    int (*comp)(void const*, void const*) = 0;
     static_assert((std::is_same<decltype(std::calloc(0,0)), void*>::value), "");
     static_assert((std::is_same<decltype(std::free(0)), void>::value), "");
     static_assert((std::is_same<decltype(std::malloc(0)), void*>::value), "");
     static_assert((std::is_same<decltype(std::realloc(0,0)), void*>::value), "");
     static_assert((std::is_same<decltype(std::abort()), void>::value), "");
-    static_assert((std::is_same<decltype(std::atexit(0)), int>::value), "");
+    static_assert((std::is_same<decltype(std::atexit(handler)), int>::value), "");
     static_assert((std::is_same<decltype(std::exit(0)), void>::value), "");
     static_assert((std::is_same<decltype(std::_Exit(0)), void>::value), "");
     static_assert((std::is_same<decltype(std::getenv("")), char*>::value), "");
     static_assert((std::is_same<decltype(std::system("")), int>::value), "");
-    static_assert((std::is_same<decltype(std::bsearch(0,0,0,0,0)), void*>::value), "");
-    static_assert((std::is_same<decltype(std::qsort(0,0,0,0)), void>::value), "");
+    static_assert((std::is_same<decltype(std::bsearch(pv,pv,0,0,comp)), void*>::value), "");
+    static_assert((std::is_same<decltype(std::qsort(pv,0,0,comp)), void>::value), "");
     static_assert((std::is_same<decltype(std::abs(0)), int>::value), "");
     static_assert((std::is_same<decltype(std::abs((long)0)), long>::value), "");
     static_assert((std::is_same<decltype(std::abs((long long)0)), long long>::value), "");
diff --git a/libcxx/test/std/language.support/support.runtime/ctime.pass.cpp b/libcxx/test/std/language.support/support.runtime/ctime.pass.cpp
index fb744c5001e924..df827793a12827 100644
--- a/libcxx/test/std/language.support/support.runtime/ctime.pass.cpp
+++ b/libcxx/test/std/language.support/support.runtime/ctime.pass.cpp
@@ -45,7 +45,7 @@ int main(int, char**)
     static_assert((std::is_same<decltype(std::mktime(&tm)), std::time_t>::value), "");
     static_assert((std::is_same<decltype(std::time(&t)), std::time_t>::value), "");
 #if TEST_STD_VER > 14 && defined(TEST_HAS_TIMESPEC_GET)
-    static_assert((std::is_same<decltype(std::timespec_get(nullptr, 0)), int>::value), "");
+    static_assert((std::is_same<decltype(std::timespec_get(&tmspec, 0)), int>::value), "");
 #endif
 #ifndef _LIBCPP_HAS_NO_THREAD_UNSAFE_C_FUNCTIONS
     static_assert((std::is_same<decltype(std::asctime(&tm)), char*>::value), "");
diff --git a/libcxx/test/std/localization/locale.categories/category.monetary/locale.moneypunct/money_base.pass.cpp b/libcxx/test/std/localization/locale.categories/category.monetary/locale.moneypunct/money_base.pass.cpp
index 5ebf0e8caf91d5..fb39976b5649a8 100644
--- a/libcxx/test/std/localization/locale.categories/category.monetary/locale.moneypunct/money_base.pass.cpp
+++ b/libcxx/test/std/localization/locale.categories/category.monetary/locale.moneypunct/money_base.pass.cpp
@@ -29,7 +29,7 @@ int main(int, char**)
     static_assert(std::money_base::sign == 3, "");
     static_assert(std::money_base::value == 4, "");
     static_assert(sizeof(std::money_base::pattern) == 4, "");
-    std::money_base::pattern p;
+    std::money_base::pattern p; (void)p;
     p.field[0] = std::money_base::none;
 
   return 0;
diff --git a/libcxx/test/std/numerics/numarray/template.valarray/valarray.unary/not.pass.cpp b/libcxx/test/std/numerics/numarray/template.valarray/valarray.unary/not.pass.cpp
index 1abc5112cb60d1..714402602c4879 100644
--- a/libcxx/test/std/numerics/numarray/template.valarray/valarray.unary/not.pass.cpp
+++ b/libcxx/test/std/numerics/numarray/template.valarray/valarray.unary/not.pass.cpp
@@ -38,7 +38,7 @@ int main(int, char**)
         std::valarray<bool> v2 = !(v + v);
         assert(v2.size() == v.size());
         for (std::size_t i = 0; i < v2.size(); ++i)
-            assert(v2[i] == !(2 * v[i]));
+            assert(v2[i] == !(v[i] + v[i]));
     }
 
   return 0;
diff --git a/libcxx/test/std/utilities/memory/allocator.traits/allocator.traits.members/construct.pass.cpp b/libcxx/test/std/utilities/memory/allocator.traits/allocator.traits.members/construct.pass.cpp
index 10e8879012fcc3..38e24fdc5db445 100644
--- a/libcxx/test/std/utilities/memory/allocator.traits/allocator.traits.members/construct.pass.cpp
+++ b/libcxx/test/std/utilities/memory/allocator.traits/allocator.traits.members/construct.pass.cpp
@@ -36,13 +36,13 @@ struct B
 {
     typedef T value_type;
 
-    TEST_CONSTEXPR_CXX20 B(int& count) : count(count) {}
+    TEST_CONSTEXPR_CXX20 B(int& count) : count_(count) {}
 
 #if TEST_STD_VER >= 11
     template <class U, class ...Args>
     TEST_CONSTEXPR_CXX20 void construct(U* p, Args&& ...args)
     {
-        ++count;
+        ++count_;
 #if TEST_STD_VER > 17
         std::construct_at(p, std::forward<Args>(args)...);
 #else
@@ -51,7 +51,7 @@ struct B
     }
 #endif
 
-    int& count;
+    int& count_;
 };
 
 struct A0
diff --git a/libcxx/test/std/utilities/memory/allocator.traits/allocator.traits.members/deallocate.pass.cpp b/libcxx/test/std/utilities/memory/allocator.traits/allocator.traits.members/deallocate.pass.cpp
index fd066b97b0f5da..2f153eedc6fcd0 100644
--- a/libcxx/test/std/utilities/memory/allocator.traits/allocator.traits.members/deallocate.pass.cpp
+++ b/libcxx/test/std/utilities/memory/allocator.traits/allocator.traits.members/deallocate.pass.cpp
@@ -27,16 +27,16 @@ struct A
 {
     typedef T value_type;
 
-    TEST_CONSTEXPR_CXX20 A(int& called) : called(called) {}
+    TEST_CONSTEXPR_CXX20 A(int& called) : called_(called) {}
 
     TEST_CONSTEXPR_CXX20 void deallocate(value_type* p, std::size_t n)
     {
         assert(p == &storage);
         assert(n == 10);
-        ++called;
+        ++called_;
     }
 
-    int& called;
+    int& called_;
 
     value_type storage;
 };
diff --git a/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.assign/auto_ptr_Y.pass.cpp b/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.assign/auto_ptr_Y.pass.cpp
index 20902be0ca9727..9621434dc36926 100644
--- a/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.assign/auto_ptr_Y.pass.cpp
+++ b/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.assign/auto_ptr_Y.pass.cpp
@@ -38,7 +38,7 @@ struct A
     static int count;
 
     A() {++count;}
-    A(const A&) {++count;}
+    A(const A& other) : B(other) {++count;}
     ~A() {--count;}
 };
 
diff --git a/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.assign/shared_ptr.pass.cpp b/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.assign/shared_ptr.pass.cpp
index 75f58e4411fab0..47b5190aecd185 100644
--- a/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.assign/shared_ptr.pass.cpp
+++ b/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.assign/shared_ptr.pass.cpp
@@ -37,7 +37,7 @@ struct A
     static int count;
 
     A() {++count;}
-    A(const A&) {++count;}
+    A(const A& other) : B(other) {++count;}
     ~A() {--count;}
 };
 
diff --git a/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.assign/shared_ptr_Y.pass.cpp b/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.assign/shared_ptr_Y.pass.cpp
index 6fd4c8e074232f..7e23e62bff19a0 100644
--- a/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.assign/shared_ptr_Y.pass.cpp
+++ b/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.assign/shared_ptr_Y.pass.cpp
@@ -35,7 +35,7 @@ struct A
     static int count;
 
     A() {++count;}
-    A(const A&) {++count;}
+    A(const A& other) : B(other) {++count;}
     ~A() {--count;}
 };
 
diff --git a/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.assign/shared_ptr_Y_rv.pass.cpp b/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.assign/shared_ptr_Y_rv.pass.cpp
index 4a9b97ebfb2d2a..b86cfd4cf0b443 100644
--- a/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.assign/shared_ptr_Y_rv.pass.cpp
+++ b/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.assign/shared_ptr_Y_rv.pass.cpp
@@ -37,7 +37,7 @@ struct A
     static int count;
 
     A() {++count;}
-    A(const A&) {++count;}
+    A(const A& other) : B(other) {++count;}
     ~A() {--count;}
 };
 
diff --git a/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.assign/shared_ptr_rv.pass.cpp b/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.assign/shared_ptr_rv.pass.cpp
index 7e8bccb3b90508..9dc51068140e5f 100644
--- a/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.assign/shared_ptr_rv.pass.cpp
+++ b/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.assign/shared_ptr_rv.pass.cpp
@@ -37,7 +37,7 @@ struct A
     static int count;
 
     A() {++count;}
-    A(const A&) {++count;}
+    A(const A& other) : B(other) {++count;}
     ~A() {--count;}
 };
 
diff --git a/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.assign/unique_ptr_Y.pass.cpp b/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.assign/unique_ptr_Y.pass.cpp
index 349fbec746f1c9..0096897ee07e65 100644
--- a/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.assign/unique_ptr_Y.pass.cpp
+++ b/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.assign/unique_ptr_Y.pass.cpp
@@ -35,7 +35,7 @@ struct A
     static int count;
 
     A() {++count;}
-    A(const A&) {++count;}
+    A(const A& other) : B(other) {++count;}
     ~A() {--count;}
 };
 
diff --git a/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.cast/const_pointer_cast.pass.cpp b/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.cast/const_pointer_cast.pass.cpp
index 588a79f9b07f60..d0da8c1124c9fc 100644
--- a/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.cast/const_pointer_cast.pass.cpp
+++ b/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.cast/const_pointer_cast.pass.cpp
@@ -35,7 +35,7 @@ struct A
     static int count;
 
     A() {++count;}
-    A(const A&) {++count;}
+    A(const A& other) : B(other) {++count;}
     ~A() {--count;}
 };
 
diff --git a/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.cast/dynamic_pointer_cast.pass.cpp b/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.cast/dynamic_pointer_cast.pass.cpp
index 6059ff8b562fef..7a8041ee13c829 100644
--- a/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.cast/dynamic_pointer_cast.pass.cpp
+++ b/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.cast/dynamic_pointer_cast.pass.cpp
@@ -37,7 +37,7 @@ struct A
     static int count;
 
     A() {++count;}
-    A(const A&) {++count;}
+    A(const A& other) : B(other) {++count;}
     ~A() {--count;}
 };
 
diff --git a/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.cast/static_pointer_cast.pass.cpp b/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.cast/static_pointer_cast.pass.cpp
index 8f8dadea0d48d3..6449f72251d924 100644
--- a/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.cast/static_pointer_cast.pass.cpp
+++ b/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.cast/static_pointer_cast.pass.cpp
@@ -35,7 +35,7 @@ struct A
     static int count;
 
     A() {++count;}
-    A(const A&) {++count;}
+    A(const A& other) : B(other) {++count;}
     ~A() {--count;}
 };
 
diff --git a/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.const/auto_ptr.pass.cpp b/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.const/auto_ptr.pass.cpp
index 00b1a596facbe2..f1ffba637b3452 100644
--- a/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.const/auto_ptr.pass.cpp
+++ b/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.const/auto_ptr.pass.cpp
@@ -38,7 +38,7 @@ struct A
     static int count;
 
     A() {++count;}
-    A(const A&) {++count;}
+    A(const A& other) : B(other) {++count;}
     ~A() {--count;}
 };
 
diff --git a/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.const/shared_ptr_Y.pass.cpp b/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.const/shared_ptr_Y.pass.cpp
index 6f770ef0dd2cba..62eb5eba1809db 100644
--- a/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.const/shared_ptr_Y.pass.cpp
+++ b/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.const/shared_ptr_Y.pass.cpp
@@ -35,7 +35,7 @@ struct A
     static int count;
 
     A() {++count;}
-    A(const A&) {++count;}
+    A(const A& other) : B(other) {++count;}
     ~A() {--count;}
 };
 
diff --git a/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.const/shared_ptr_Y_rv.pass.cpp b/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.const/shared_ptr_Y_rv.pass.cpp
index 67d158d9f706c3..9e47293b37169d 100644
--- a/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.const/shared_ptr_Y_rv.pass.cpp
+++ b/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.const/shared_ptr_Y_rv.pass.cpp
@@ -37,7 +37,7 @@ struct A
     static int count;
 
     A() {++count;}
-    A(const A&) {++count;}
+    A(const A& other) : B(other) {++count;}
     ~A() {--count;}
 };
 
diff --git a/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.const/unique_ptr.pass.cpp b/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.const/unique_ptr.pass.cpp
index 3cbaf5e1edf6e5..398c64ee6d74a7 100644
--- a/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.const/unique_ptr.pass.cpp
+++ b/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.const/unique_ptr.pass.cpp
@@ -37,7 +37,7 @@ struct A
     static int count;
 
     A() {++count;}
-    A(const A&) {++count;}
+    A(const A& other) : B(other) {++count;}
     ~A() {--count;}
 };
 
diff --git a/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.const/weak_ptr.pass.cpp b/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.const/weak_ptr.pass.cpp
index 9174f39be37bd4..4859f81049335f 100644
--- a/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.const/weak_ptr.pass.cpp
+++ b/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.const/weak_ptr.pass.cpp
@@ -34,7 +34,7 @@ struct A
     static int count;
 
     A() {++count;}
-    A(const A&) {++count;}
+    A(const A& other) : B(other) {++count;}
     ~A() {--count;}
 };
 
diff --git a/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.mod/reset.pass.cpp b/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.mod/reset.pass.cpp
index 55c22414d63a3d..0d175d40d7ff61 100644
--- a/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.mod/reset.pass.cpp
+++ b/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.mod/reset.pass.cpp
@@ -34,7 +34,7 @@ struct A
     static int count;
 
     A() {++count;}
-    A(const A&) {++count;}
+    A(const A& other) : B(other) {++count;}
     ~A() {--count;}
 };
 
diff --git a/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.mod/reset_pointer.pass.cpp b/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.mod/reset_pointer.pass.cpp
index 789013fdaac95f..d2e6c9f0de2e58 100644
--- a/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.mod/reset_pointer.pass.cpp
+++ b/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.mod/reset_pointer.pass.cpp
@@ -34,7 +34,7 @@ struct A
     static int count;
 
     A() {++count;}
-    A(const A&) {++count;}
+    A(const A& other) : B(other) {++count;}
     ~A() {--count;}
 };
 
diff --git a/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.mod/reset_pointer_deleter.pass.cpp b/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.mod/reset_pointer_deleter.pass.cpp
index c337e19257736c..f4944db727d0c7 100644
--- a/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.mod/reset_pointer_deleter.pass.cpp
+++ b/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.mod/reset_pointer_deleter.pass.cpp
@@ -34,7 +34,7 @@ struct A
     static int count;
 
     A() {++count;}
-    A(const A&) {++count;}
+    A(const A& other) : B(other) {++count;}
     ~A() {--count;}
 };
 
diff --git a/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.mod/reset_pointer_deleter_allocator.pass.cpp b/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.mod/reset_pointer_deleter_allocator.pass.cpp
index 2724e35fbef9ee..481284016835d6 100644
--- a/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.mod/reset_pointer_deleter_allocator.pass.cpp
+++ b/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.mod/reset_pointer_deleter_allocator.pass.cpp
@@ -35,7 +35,7 @@ struct A
     static int count;
 
     A() {++count;}
-    A(const A&) {++count;}
+    A(const A& other) : B(other) {++count;}
     ~A() {--count;}
 };
 
diff --git a/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.weak/util.smartptr.weak.assign/shared_ptr_Y.pass.cpp b/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.weak/util.smartptr.weak.assign/shared_ptr_Y.pass.cpp
index f899dc4262514b..86624478f40f53 100644
--- a/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.weak/util.smartptr.weak.assign/shared_ptr_Y.pass.cpp
+++ b/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.weak/util.smartptr.weak.assign/shared_ptr_Y.pass.cpp
@@ -35,7 +35,7 @@ struct A
     static int count;
 
     A() {++count;}
-    A(const A&) {++count;}
+    A(const A& other) : B(other) {++count;}
     ~A() {--count;}
 };
 
diff --git a/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.weak/util.smartptr.weak.assign/weak_ptr.pass.cpp b/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.weak/util.smartptr.weak.assign/weak_ptr.pass.cpp
index ae166a5662659b..c722dd0de262dc 100644
--- a/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.weak/util.smartptr.weak.assign/weak_ptr.pass.cpp
+++ b/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.weak/util.smartptr.weak.assign/weak_ptr.pass.cpp
@@ -35,7 +35,7 @@ struct A
     static int count;
 
     A() {++count;}
-    A(const A&) {++count;}
+    A(const A& other) : B(other) {++count;}
     ~A() {--count;}
 };
 
diff --git a/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.weak/util.smartptr.weak.assign/weak_ptr_Y.pass.cpp b/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.weak/util.smartptr.weak.assign/weak_ptr_Y.pass.cpp
index 257e5ef189eb90..9da2fd75fbf269 100644
--- a/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.weak/util.smartptr.weak.assign/weak_ptr_Y.pass.cpp
+++ b/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.weak/util.smartptr.weak.assign/weak_ptr_Y.pass.cpp
@@ -35,7 +35,7 @@ struct A
     static int count;
 
     A() {++count;}
-    A(const A&) {++count;}
+    A(const A& other) : B(other) {++count;}
     ~A() {--count;}
 };
 
diff --git a/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.weak/util.smartptr.weak.const/shared_ptr_Y.pass.cpp b/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.weak/util.smartptr.weak.const/shared_ptr_Y.pass.cpp
index 24f57d3449fb31..3b66e9ae27fadc 100644
--- a/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.weak/util.smartptr.weak.const/shared_ptr_Y.pass.cpp
+++ b/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.weak/util.smartptr.weak.const/shared_ptr_Y.pass.cpp
@@ -35,7 +35,7 @@ struct A
     static int count;
 
     A() {++count;}
-    A(const A&) {++count;}
+    A(const A& other) : B(other) {++count;}
     ~A() {--count;}
 };
 
diff --git a/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.weak/util.smartptr.weak.const/weak_ptr.pass.cpp b/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.weak/util.smartptr.weak.const/weak_ptr.pass.cpp
index 658b233c41c7b1..179c2f5928a4d9 100644
--- a/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.weak/util.smartptr.weak.const/weak_ptr.pass.cpp
+++ b/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.weak/util.smartptr.weak.const/weak_ptr.pass.cpp
@@ -36,7 +36,7 @@ struct A
     static int count;
 
     A() {++count;}
-    A(const A&) {++count;}
+    A(const A& other) : B(other) {++count;}
     ~A() {--count;}
 };
 
diff --git a/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.weak/util.smartptr.weak.const/weak_ptr_Y.pass.cpp b/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.weak/util.smartptr.weak.const/weak_ptr_Y.pass.cpp
index 478af1e1b5a961..3fd447356cd77d 100644
--- a/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.weak/util.smartptr.weak.const/weak_ptr_Y.pass.cpp
+++ b/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.weak/util.smartptr.weak.const/weak_ptr_Y.pass.cpp
@@ -36,7 +36,7 @@ struct A
     static int count;
 
     A() {++count;}
-    A(const A&) {++count;}
+    A(const A& other) : B(other) {++count;}
     ~A() {--count;}
 };
 
diff --git a/libcxx/test/std/utilities/meta/meta.trans/meta.trans.other/result_of11.pass.cpp b/libcxx/test/std/utilities/meta/meta.trans/meta.trans.other/result_of11.pass.cpp
index 2cc90f28d85510..35abfa9cbeaeb3 100644
--- a/libcxx/test/std/utilities/meta/meta.trans/meta.trans.other/result_of11.pass.cpp
+++ b/libcxx/test/std/utilities/meta/meta.trans/meta.trans.other/result_of11.pass.cpp
@@ -17,6 +17,12 @@
 #include <utility>
 #include "test_macros.h"
 
+// Ignore warnings about volatile in parameters being deprecated.
+// We know it is, but we still have to test it.
+#ifdef __GNUC__
+#pragma GCC diagnostic ignored "-Wvolatile"
+#endif
+
 struct wat
 {
     wat& operator*() { return *this; }
diff --git a/libcxx/test/std/utilities/optional/optional.object/optional.object.ctor/rvalue_T.pass.cpp b/libcxx/test/std/utilities/optional/optional.object/optional.object.ctor/rvalue_T.pass.cpp
index fc19d52e0de2b3..521706d74eefdf 100644
--- a/libcxx/test/std/utilities/optional/optional.object/optional.object.ctor/rvalue_T.pass.cpp
+++ b/libcxx/test/std/utilities/optional/optional.object/optional.object.ctor/rvalue_T.pass.cpp
@@ -138,15 +138,10 @@ int main(int, char**)
     }
 #ifndef TEST_HAS_NO_EXCEPTIONS
     {
-        struct Z {
-            Z(int) {}
-            Z(Z&&) {throw 6;}
-        };
-        typedef Z T;
         try
         {
-            T t(3);
-            optional<T> opt(std::move(t));
+            Z z(3);
+            optional<Z> opt(std::move(z));
             assert(false);
         }
         catch (int i)
diff --git a/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.dltr/unique.ptr.dltr.dflt/convert_ctor.pass.cpp b/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.dltr/unique.ptr.dltr.dflt/convert_ctor.pass.cpp
index 83a5f3132e7846..d4c00f46748f97 100644
--- a/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.dltr/unique.ptr.dltr.dflt/convert_ctor.pass.cpp
+++ b/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.dltr/unique.ptr.dltr.dflt/convert_ctor.pass.cpp
@@ -30,7 +30,7 @@ struct B
 {
     static int count;
     B() {++count;}
-    B(const B&) {++count;}
+    B(const B& other) : A(other) {++count;}
     virtual ~B() {--count;}
 };
 
diff --git a/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.special/eq.pass.cpp b/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.special/eq.pass.cpp
index 0d0ac2709b7c3a..6bd1451212dc0d 100644
--- a/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.special/eq.pass.cpp
+++ b/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.special/eq.pass.cpp
@@ -39,7 +39,7 @@ struct B
 {
     static int count;
     B() {++count;}
-    B(const B&) {++count;}
+    B(const B& other) : A(other) {++count;}
     virtual ~B() {--count;}
 };
 
diff --git a/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.special/rel.pass.cpp b/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.special/rel.pass.cpp
index bc411ca545c29c..b8f1c4b91c12f5 100644
--- a/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.special/rel.pass.cpp
+++ b/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.special/rel.pass.cpp
@@ -47,7 +47,7 @@ struct B
 {
     static int count;
     B() {++count;}
-    B(const B&) {++count;}
+    B(const B& other) : A(other) {++count;}
     virtual ~B() {--count;}
 };
 
diff --git a/libcxx/test/std/utilities/template.bitset/bitset.cons/char_ptr_ctor.pass.cpp b/libcxx/test/std/utilities/template.bitset/bitset.cons/char_ptr_ctor.pass.cpp
index ee6405bde1e724..58549b94e0d385 100644
--- a/libcxx/test/std/utilities/template.bitset/bitset.cons/char_ptr_ctor.pass.cpp
+++ b/libcxx/test/std/utilities/template.bitset/bitset.cons/char_ptr_ctor.pass.cpp
@@ -36,12 +36,12 @@ void test_char_pointer_ctor()
     }
 
     {
-    const char str[] ="1010101010";
+    const char str[] = "1010101010";
     std::bitset<N> v(str);
-    std::size_t M = std::min<std::size_t>(N, 10);
+    std::size_t M = std::min<std::size_t>(v.size(), 10);
     for (std::size_t i = 0; i < M; ++i)
         assert(v[i] == (str[M - 1 - i] == '1'));
-    for (std::size_t i = 10; i < N; ++i)
+    for (std::size_t i = 10; i < v.size(); ++i)
         assert(v[i] == false);
     }
 }
diff --git a/libcxx/test/std/utilities/template.bitset/bitset.cons/default.pass.cpp b/libcxx/test/std/utilities/template.bitset/bitset.cons/default.pass.cpp
index bb5de6b18c72ff..a59427bdd061eb 100644
--- a/libcxx/test/std/utilities/template.bitset/bitset.cons/default.pass.cpp
+++ b/libcxx/test/std/utilities/template.bitset/bitset.cons/default.pass.cpp
@@ -13,17 +13,13 @@
 
 #include "test_macros.h"
 
-#if defined(TEST_COMPILER_C1XX)
-#pragma warning(disable: 6294) // Ill-defined for-loop:  initial condition does not satisfy test.  Loop body not executed.
-#endif
-
 template <std::size_t N>
 void test_default_ctor()
 {
     {
         TEST_CONSTEXPR std::bitset<N> v1;
         assert(v1.size() == N);
-        for (std::size_t i = 0; i < N; ++i)
+        for (std::size_t i = 0; i < v1.size(); ++i)
             assert(v1[i] == false);
     }
 #if TEST_STD_VER >= 11
diff --git a/libcxx/test/std/utilities/template.bitset/bitset.cons/ull_ctor.pass.cpp b/libcxx/test/std/utilities/template.bitset/bitset.cons/ull_ctor.pass.cpp
index 4697d8bd380a48..2f5c066221da67 100644
--- a/libcxx/test/std/utilities/template.bitset/bitset.cons/ull_ctor.pass.cpp
+++ b/libcxx/test/std/utilities/template.bitset/bitset.cons/ull_ctor.pass.cpp
@@ -25,10 +25,10 @@ void test_val_ctor()
     {
         TEST_CONSTEXPR std::bitset<N> v(0xAAAAAAAAAAAAAAAAULL);
         assert(v.size() == N);
-        std::size_t M = std::min<std::size_t>(N, 64);
+        std::size_t M = std::min<std::size_t>(v.size(), 64);
         for (std::size_t i = 0; i < M; ++i)
             assert(v[i] == ((i & 1) != 0));
-        for (std::size_t i = M; i < N; ++i)
+        for (std::size_t i = M; i < v.size(); ++i)
             assert(v[i] == false);
     }
 #if TEST_STD_VER >= 11
diff --git a/libcxx/test/std/utilities/template.bitset/bitset.members/right_shift_eq.pass.cpp b/libcxx/test/std/utilities/template.bitset/bitset.members/right_shift_eq.pass.cpp
index a103f37585851a..a32f602d0c03b9 100644
--- a/libcxx/test/std/utilities/template.bitset/bitset.members/right_shift_eq.pass.cpp
+++ b/libcxx/test/std/utilities/template.bitset/bitset.members/right_shift_eq.pass.cpp
@@ -25,7 +25,7 @@ void test_right_shift() {
             std::bitset<N> v2 = v1;
             v1 >>= s;
             for (std::size_t i = 0; i < v1.size(); ++i)
-                if (i + s < N)
+                if (i + s < v1.size())
                     assert(v1[i] == v2[i + s]);
                 else
                     assert(v1[i] == 0);
diff --git a/libcxx/test/std/utilities/time/date.time/ctime.pass.cpp b/libcxx/test/std/utilities/time/date.time/ctime.pass.cpp
index da16c85e7cd566..8ad3cca4758e08 100644
--- a/libcxx/test/std/utilities/time/date.time/ctime.pass.cpp
+++ b/libcxx/test/std/utilities/time/date.time/ctime.pass.cpp
@@ -51,7 +51,7 @@ int main(int, char**)
     static_assert((std::is_same<decltype(std::mktime(&tm)), std::time_t>::value), "");
     static_assert((std::is_same<decltype(std::time(&t)), std::time_t>::value), "");
 #if TEST_STD_VER > 14 && defined(TEST_HAS_TIMESPEC_GET)
-    static_assert((std::is_same<decltype(std::timespec_get(nullptr, 0)), int>::value), "");
+    static_assert((std::is_same<decltype(std::timespec_get(&tmspec, 0)), int>::value), "");
 #endif
 #ifndef _LIBCPP_HAS_NO_THREAD_UNSAFE_C_FUNCTIONS
     static_assert((std::is_same<decltype(std::asctime(&tm)), char*>::value), "");
diff --git a/libcxx/test/std/utilities/time/time.cal/time.cal.day/time.cal.day.members/ctor.pass.cpp b/libcxx/test/std/utilities/time/time.cal/time.cal.day/time.cal.day.members/ctor.pass.cpp
index bd03d512ba5c2d..63a68d5748516c 100644
--- a/libcxx/test/std/utilities/time/time.cal/time.cal.day/time.cal.day.members/ctor.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.cal/time.cal.day/time.cal.day.members/ctor.pass.cpp
@@ -39,8 +39,8 @@ int main(int, char**)
 
     for (unsigned i = 0; i <= 255; ++i)
     {
-        day day(i);
-        assert(static_cast<unsigned>(day) == i);
+        day d(i);
+        assert(static_cast<unsigned>(d) == i);
     }
 
   return 0;
diff --git a/libcxx/test/std/utilities/time/time.cal/time.cal.day/time.cal.day.members/decrement.pass.cpp b/libcxx/test/std/utilities/time/time.cal/time.cal.day/time.cal.day.members/decrement.pass.cpp
index 032f9289fb0537..fd15b98b25f7d2 100644
--- a/libcxx/test/std/utilities/time/time.cal/time.cal.day/time.cal.day.members/decrement.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.cal/time.cal.day/time.cal.day.members/decrement.pass.cpp
@@ -43,10 +43,10 @@ int main(int, char**)
 
     for (unsigned i = 10; i <= 20; ++i)
     {
-        day day(i);
-        assert(static_cast<unsigned>(--day) == i - 1);
-        assert(static_cast<unsigned>(day--) == i - 1);
-        assert(static_cast<unsigned>(day)   == i - 2);
+        day d(i);
+        assert(static_cast<unsigned>(--d) == i - 1);
+        assert(static_cast<unsigned>(d--) == i - 1);
+        assert(static_cast<unsigned>(d)   == i - 2);
     }
 
   return 0;
diff --git a/libcxx/test/std/utilities/time/time.cal/time.cal.day/time.cal.day.members/increment.pass.cpp b/libcxx/test/std/utilities/time/time.cal/time.cal.day/time.cal.day.members/increment.pass.cpp
index f7ba56427811bd..f11021b35f4dc3 100644
--- a/libcxx/test/std/utilities/time/time.cal/time.cal.day/time.cal.day.members/increment.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.cal/time.cal.day/time.cal.day.members/increment.pass.cpp
@@ -43,10 +43,10 @@ int main(int, char**)
 
     for (unsigned i = 10; i <= 20; ++i)
     {
-        day day(i);
-        assert(static_cast<unsigned>(++day) == i + 1);
-        assert(static_cast<unsigned>(day++) == i + 1);
-        assert(static_cast<unsigned>(day)   == i + 2);
+        day d(i);
+        assert(static_cast<unsigned>(++d) == i + 1);
+        assert(static_cast<unsigned>(d++) == i + 1);
+        assert(static_cast<unsigned>(d)   == i + 2);
     }
 
   return 0;
diff --git a/libcxx/test/std/utilities/time/time.cal/time.cal.day/time.cal.day.members/plus_minus_equal.pass.cpp b/libcxx/test/std/utilities/time/time.cal/time.cal.day/time.cal.day.members/plus_minus_equal.pass.cpp
index a23477e7f80b06..723ab2af14d1c7 100644
--- a/libcxx/test/std/utilities/time/time.cal/time.cal.day/time.cal.day.members/plus_minus_equal.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.cal/time.cal.day/time.cal.day.members/plus_minus_equal.pass.cpp
@@ -47,11 +47,11 @@ int main(int, char**)
 
     for (unsigned i = 0; i <= 10; ++i)
     {
-        day day(i);
-        assert(static_cast<unsigned>(day += days{22}) == i + 22);
-        assert(static_cast<unsigned>(day)             == i + 22);
-        assert(static_cast<unsigned>(day -= days{12}) == i + 10);
-        assert(static_cast<unsigned>(day)             == i + 10);
+        day d(i);
+        assert(static_cast<unsigned>(d += days{22}) == i + 22);
+        assert(static_cast<unsigned>(d)             == i + 22);
+        assert(static_cast<unsigned>(d -= days{12}) == i + 10);
+        assert(static_cast<unsigned>(d)             == i + 10);
     }
 
   return 0;
diff --git a/libcxx/test/std/utilities/time/time.cal/time.cal.day/time.cal.day.nonmembers/literals.pass.cpp b/libcxx/test/std/utilities/time/time.cal/time.cal.day/time.cal.day.nonmembers/literals.pass.cpp
index aba50a61ead6de..61de53b7acd503 100644
--- a/libcxx/test/std/utilities/time/time.cal/time.cal.day/time.cal.day.nonmembers/literals.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.cal/time.cal.day/time.cal.day.nonmembers/literals.pass.cpp
@@ -30,7 +30,7 @@ int main(int, char**)
     static_assert( 7d == day(7), "");
     day d1 = 4d;
     assert (d1 == day(4));
-}
+    }
 
     {
     using namespace std::literals;
diff --git a/libcxx/test/std/utilities/time/time.cal/time.cal.month/time.cal.month.members/decrement.pass.cpp b/libcxx/test/std/utilities/time/time.cal/time.cal.month/time.cal.month.members/decrement.pass.cpp
index 49e877be2eaf05..56711227771d6f 100644
--- a/libcxx/test/std/utilities/time/time.cal/time.cal.month/time.cal.month.members/decrement.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.cal/time.cal.month/time.cal.month.members/decrement.pass.cpp
@@ -44,10 +44,10 @@ int main(int, char**)
 
     for (unsigned i = 10; i <= 20; ++i)
     {
-        month month(i);
-        assert(static_cast<unsigned>(--month) == i - 1);
-        assert(static_cast<unsigned>(month--) == i - 1);
-        assert(static_cast<unsigned>(month)   == i - 2);
+        month m(i);
+        assert(static_cast<unsigned>(--m) == i - 1);
+        assert(static_cast<unsigned>(m--) == i - 1);
+        assert(static_cast<unsigned>(m)   == i - 2);
     }
 
   return 0;
diff --git a/libcxx/test/std/utilities/time/time.cal/time.cal.month/time.cal.month.members/increment.pass.cpp b/libcxx/test/std/utilities/time/time.cal/time.cal.month/time.cal.month.members/increment.pass.cpp
index 96701c11332bae..af61d3442c3af3 100644
--- a/libcxx/test/std/utilities/time/time.cal/time.cal.month/time.cal.month.members/increment.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.cal/time.cal.month/time.cal.month.members/increment.pass.cpp
@@ -43,10 +43,10 @@ int main(int, char**)
 
     for (unsigned i = 0; i <= 10; ++i)
     {
-        month month(i);
-        assert(static_cast<unsigned>(++month) == i + 1);
-        assert(static_cast<unsigned>(month++) == i + 1);
-        assert(static_cast<unsigned>(month)   == i + 2);
+        month m(i);
+        assert(static_cast<unsigned>(++m) == i + 1);
+        assert(static_cast<unsigned>(m++) == i + 1);
+        assert(static_cast<unsigned>(m)   == i + 2);
     }
 
   return 0;
diff --git a/libcxx/test/std/utilities/time/time.cal/time.cal.month/time.cal.month.members/plus_minus_equal.pass.cpp b/libcxx/test/std/utilities/time/time.cal/time.cal.month/time.cal.month.members/plus_minus_equal.pass.cpp
index f73e4179b15456..848a96a9b73f7c 100644
--- a/libcxx/test/std/utilities/time/time.cal/time.cal.month/time.cal.month.members/plus_minus_equal.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.cal/time.cal.month/time.cal.month.members/plus_minus_equal.pass.cpp
@@ -46,22 +46,22 @@ int main(int, char**)
 
     for (unsigned i = 1; i <= 10; ++i)
     {
-        month month(i);
+        month m(i);
         int exp = i + 10;
         while (exp > 12)
             exp -= 12;
-        assert(static_cast<unsigned>(month += months{10}) == static_cast<unsigned>(exp));
-        assert(static_cast<unsigned>(month)               == static_cast<unsigned>(exp));
+        assert(static_cast<unsigned>(m += months{10}) == static_cast<unsigned>(exp));
+        assert(static_cast<unsigned>(m)               == static_cast<unsigned>(exp));
     }
 
     for (unsigned i = 1; i <= 10; ++i)
     {
-        month month(i);
+        month m(i);
         int exp = i - 9;
         while (exp < 1)
             exp += 12;
-        assert(static_cast<unsigned>(month -= months{ 9}) == static_cast<unsigned>(exp));
-        assert(static_cast<unsigned>(month)               == static_cast<unsigned>(exp));
+        assert(static_cast<unsigned>(m -= months{ 9}) == static_cast<unsigned>(exp));
+        assert(static_cast<unsigned>(m)               == static_cast<unsigned>(exp));
     }
 
   return 0;
diff --git a/libcxx/test/std/utilities/time/time.cal/time.cal.year/time.cal.year.members/ctor.pass.cpp b/libcxx/test/std/utilities/time/time.cal/time.cal.year/time.cal.year.members/ctor.pass.cpp
index 0c8605a69fc064..b32325aabcb22a 100644
--- a/libcxx/test/std/utilities/time/time.cal/time.cal.year/time.cal.year.members/ctor.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.cal/time.cal.year/time.cal.year.members/ctor.pass.cpp
@@ -39,8 +39,8 @@ int main(int, char**)
 
     for (int i = 0; i <= 2550; i += 7)
     {
-        year year(i);
-        assert(static_cast<int>(year) == i);
+        year yr(i);
+        assert(static_cast<int>(yr) == i);
     }
 
   return 0;
diff --git a/libcxx/test/std/utilities/time/time.cal/time.cal.year/time.cal.year.members/decrement.pass.cpp b/libcxx/test/std/utilities/time/time.cal/time.cal.year/time.cal.year.members/decrement.pass.cpp
index 7add59448d105a..1857a38eb3356c 100644
--- a/libcxx/test/std/utilities/time/time.cal/time.cal.year/time.cal.year.members/decrement.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.cal/time.cal.year/time.cal.year.members/decrement.pass.cpp
@@ -43,10 +43,10 @@ int main(int, char**)
 
     for (int i = 11000; i <= 11020; ++i)
     {
-        year year(i);
-        assert(static_cast<int>(--year) == i - 1);
-        assert(static_cast<int>(year--) == i - 1);
-        assert(static_cast<int>(year)   == i - 2);
+        year yr(i);
+        assert(static_cast<int>(--yr) == i - 1);
+        assert(static_cast<int>(yr--) == i - 1);
+        assert(static_cast<int>(yr)   == i - 2);
     }
 
   return 0;
diff --git a/libcxx/test/std/utilities/time/time.cal/time.cal.year/time.cal.year.members/increment.pass.cpp b/libcxx/test/std/utilities/time/time.cal/time.cal.year/time.cal.year.members/increment.pass.cpp
index 2db5eea6c54a3c..9407683404233a 100644
--- a/libcxx/test/std/utilities/time/time.cal/time.cal.year/time.cal.year.members/increment.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.cal/time.cal.year/time.cal.year.members/increment.pass.cpp
@@ -43,10 +43,10 @@ int main(int, char**)
 
     for (int i = 11000; i <= 11020; ++i)
     {
-        year year(i);
-        assert(static_cast<int>(++year) == i + 1);
-        assert(static_cast<int>(year++) == i + 1);
-        assert(static_cast<int>(year)   == i + 2);
+        year yr(i);
+        assert(static_cast<int>(++yr) == i + 1);
+        assert(static_cast<int>(yr++) == i + 1);
+        assert(static_cast<int>(yr)   == i + 2);
     }
 
   return 0;
diff --git a/libcxx/test/std/utilities/time/time.cal/time.cal.year/time.cal.year.members/plus_minus.pass.cpp b/libcxx/test/std/utilities/time/time.cal/time.cal.year/time.cal.year.members/plus_minus.pass.cpp
index 0307bab8a5b5c7..f351083ec1d2e8 100644
--- a/libcxx/test/std/utilities/time/time.cal/time.cal.year/time.cal.year.members/plus_minus.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.cal/time.cal.year/time.cal.year.members/plus_minus.pass.cpp
@@ -42,9 +42,9 @@ int main(int, char**)
 
     for (int i = 10000; i <= 10020; ++i)
     {
-        year year(i);
-        assert(static_cast<int>(+year) ==  i);
-        assert(static_cast<int>(-year) == -i);
+        year yr(i);
+        assert(static_cast<int>(+yr) ==  i);
+        assert(static_cast<int>(-yr) == -i);
     }
 
   return 0;
diff --git a/libcxx/test/std/utilities/time/time.cal/time.cal.year/time.cal.year.members/plus_minus_equal.pass.cpp b/libcxx/test/std/utilities/time/time.cal/time.cal.year/time.cal.year.members/plus_minus_equal.pass.cpp
index e71c5ea96bfc2a..f3236318281da6 100644
--- a/libcxx/test/std/utilities/time/time.cal/time.cal.year/time.cal.year.members/plus_minus_equal.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.cal/time.cal.year/time.cal.year.members/plus_minus_equal.pass.cpp
@@ -47,11 +47,11 @@ int main(int, char**)
 
     for (int i = 10000; i <= 10020; ++i)
     {
-        year year(i);
-        assert(static_cast<int>(year += years{10}) == i + 10);
-        assert(static_cast<int>(year)              == i + 10);
-        assert(static_cast<int>(year -= years{ 9}) == i +  1);
-        assert(static_cast<int>(year)              == i +  1);
+        year yr(i);
+        assert(static_cast<int>(yr += years{10}) == i + 10);
+        assert(static_cast<int>(yr)              == i + 10);
+        assert(static_cast<int>(yr -= years{ 9}) == i +  1);
+        assert(static_cast<int>(yr)              == i +  1);
     }
 
   return 0;
diff --git a/libcxx/test/std/utilities/time/time.duration/time.duration.special/max.pass.cpp b/libcxx/test/std/utilities/time/time.duration/time.duration.special/max.pass.cpp
index 58de66a01583d3..dadd47bb7741c3 100644
--- a/libcxx/test/std/utilities/time/time.duration/time.duration.special/max.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.duration/time.duration.special/max.pass.cpp
@@ -27,14 +27,14 @@ void test()
     ASSERT_NOEXCEPT(       std::chrono::duration_values<typename D::rep>::max());
 #endif
     {
-    typedef typename D::rep Rep;
-    Rep max_rep = std::chrono::duration_values<Rep>::max();
+    typedef typename D::rep DRep;
+    DRep max_rep = std::chrono::duration_values<DRep>::max();
     assert(D::max().count() == max_rep);
     }
 #if TEST_STD_VER >= 11
     {
-    typedef typename D::rep Rep;
-    constexpr Rep max_rep = std::chrono::duration_values<Rep>::max();
+    typedef typename D::rep DRep;
+    constexpr DRep max_rep = std::chrono::duration_values<DRep>::max();
     static_assert(D::max().count() == max_rep, "");
     }
 #endif
diff --git a/libcxx/test/std/utilities/time/time.duration/time.duration.special/min.pass.cpp b/libcxx/test/std/utilities/time/time.duration/time.duration.special/min.pass.cpp
index 9b0113b2980de4..1f4660a1d62652 100644
--- a/libcxx/test/std/utilities/time/time.duration/time.duration.special/min.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.duration/time.duration.special/min.pass.cpp
@@ -27,14 +27,14 @@ void test()
     ASSERT_NOEXCEPT(       std::chrono::duration_values<typename D::rep>::min());
 #endif
     {
-    typedef typename D::rep Rep;
-    Rep min_rep = std::chrono::duration_values<Rep>::min();
+    typedef typename D::rep DRep;
+    DRep min_rep = std::chrono::duration_values<DRep>::min();
     assert(D::min().count() == min_rep);
     }
 #if TEST_STD_VER >= 11
     {
-    typedef typename D::rep Rep;
-    constexpr Rep min_rep = std::chrono::duration_values<Rep>::min();
+    typedef typename D::rep DRep;
+    constexpr DRep min_rep = std::chrono::duration_values<DRep>::min();
     static_assert(D::min().count() == min_rep, "");
     }
 #endif
diff --git a/libcxx/test/std/utilities/time/time.duration/time.duration.special/zero.pass.cpp b/libcxx/test/std/utilities/time/time.duration/time.duration.special/zero.pass.cpp
index 34a05b5f0715f8..a3f535071d7a98 100644
--- a/libcxx/test/std/utilities/time/time.duration/time.duration.special/zero.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.duration/time.duration.special/zero.pass.cpp
@@ -26,14 +26,14 @@ void test()
     ASSERT_NOEXCEPT(       std::chrono::duration_values<typename D::rep>::zero());
 #endif
     {
-    typedef typename D::rep Rep;
-    Rep zero_rep = std::chrono::duration_values<Rep>::zero();
+    typedef typename D::rep DRep;
+    DRep zero_rep = std::chrono::duration_values<DRep>::zero();
     assert(D::zero().count() == zero_rep);
     }
 #if TEST_STD_VER >= 11
     {
-    typedef typename D::rep Rep;
-    constexpr Rep zero_rep = std::chrono::duration_values<Rep>::zero();
+    typedef typename D::rep DRep;
+    constexpr DRep zero_rep = std::chrono::duration_values<DRep>::zero();
     static_assert(D::zero().count() == zero_rep, "");
     }
 #endif
diff --git a/libcxx/test/std/utilities/utility/forward/move.pass.cpp b/libcxx/test/std/utilities/utility/forward/move.pass.cpp
index 64d4911a3395db..e04aa138b57258 100644
--- a/libcxx/test/std/utilities/utility/forward/move.pass.cpp
+++ b/libcxx/test/std/utilities/utility/forward/move.pass.cpp
@@ -76,19 +76,19 @@ int main(int, char**)
         assert(copy_ctor == 0);
         assert(move_ctor == 0);
 
-        A a2 = a;
+        A a2 = a; (void)a2;
         assert(copy_ctor == 1);
         assert(move_ctor == 0);
 
-        A a3 = std::move(a);
+        A a3 = std::move(a); (void)a3;
         assert(copy_ctor == 1);
         assert(move_ctor == 1);
 
-        A a4 = ca;
+        A a4 = ca; (void)a4;
         assert(copy_ctor == 2);
         assert(move_ctor == 1);
 
-        A a5 = std::move(ca);
+        A a5 = std::move(ca); (void)a5;
         assert(copy_ctor == 3);
         assert(move_ctor == 1);
     }
diff --git a/libcxx/test/support/debug_mode_helper.h b/libcxx/test/support/debug_mode_helper.h
index c0cdac12033363..fdda3d77e5055c 100644
--- a/libcxx/test/support/debug_mode_helper.h
+++ b/libcxx/test/support/debug_mode_helper.h
@@ -43,8 +43,8 @@ struct DebugInfoMatcher {
   static constexpr const char* any_msg = "*";
 
   constexpr DebugInfoMatcher() : is_empty(true), msg(any_msg, __builtin_strlen(any_msg)), file(any_file, __builtin_strlen(any_file)), line(any_line) { }
-  constexpr DebugInfoMatcher(const char* msg, const char* file = any_file, int line = any_line)
-    : is_empty(false), msg(msg, __builtin_strlen(msg)), file(file, __builtin_strlen(file)), line(line) {}
+  constexpr DebugInfoMatcher(const char* msg_, const char* file_ = any_file, int line_ = any_line)
+    : is_empty(false), msg(msg_, __builtin_strlen(msg_)), file(file_, __builtin_strlen(file_)), line(line_) {}
 
   bool Matches(std::__libcpp_debug_info const& got) const {
     assert(!empty() && "empty matcher");
diff --git a/libcxx/test/support/filesystem_test_helper.h b/libcxx/test/support/filesystem_test_helper.h
index 2841b67fde9531..1cf6bff870067e 100644
--- a/libcxx/test/support/filesystem_test_helper.h
+++ b/libcxx/test/support/filesystem_test_helper.h
@@ -599,19 +599,19 @@ struct ExceptionChecker {
   const char* func_name;
   std::string opt_message;
 
-  explicit ExceptionChecker(std::errc first_err, const char* func_name,
+  explicit ExceptionChecker(std::errc first_err, const char* fun_name,
                             std::string opt_msg = {})
-      : expected_err{first_err}, num_paths(0), func_name(func_name),
+      : expected_err{first_err}, num_paths(0), func_name(fun_name),
         opt_message(opt_msg) {}
   explicit ExceptionChecker(fs::path p, std::errc first_err,
-                            const char* func_name, std::string opt_msg = {})
+                            const char* fun_name, std::string opt_msg = {})
       : expected_err(first_err), expected_path1(p), num_paths(1),
-        func_name(func_name), opt_message(opt_msg) {}
+        func_name(fun_name), opt_message(opt_msg) {}
 
   explicit ExceptionChecker(fs::path p1, fs::path p2, std::errc first_err,
-                            const char* func_name, std::string opt_msg = {})
+                            const char* fun_name, std::string opt_msg = {})
       : expected_err(first_err), expected_path1(p1), expected_path2(p2),
-        num_paths(2), func_name(func_name), opt_message(opt_msg) {}
+        num_paths(2), func_name(fun_name), opt_message(opt_msg) {}
 
   void operator()(fs::filesystem_error const& Err) {
     TEST_CHECK(ErrorIsImp(Err.code(), {expected_err}));
diff --git a/libcxx/test/support/unique_ptr_test_helper.h b/libcxx/test/support/unique_ptr_test_helper.h
index 5f56f7123ea448..1613ad197457eb 100644
--- a/libcxx/test/support/unique_ptr_test_helper.h
+++ b/libcxx/test/support/unique_ptr_test_helper.h
@@ -27,7 +27,7 @@ int A::count = 0;
 struct B : public A {
   static int count;
   B() { ++count; }
-  B(const B&) { ++count; }
+  B(const B& other) : A(other) { ++count; }
   virtual ~B() { --count; }
 };