[libcxx] [test] Fix MSVC warnings, null pointer deref.

[STL_MSFT]

Summary

[libcxx] [test] Fix MSVC warnings, null pointer deref.

test/std/algorithms/alg.modifying.operations/alg.generate/generate_n.pass.cpp
Silence MSVC warning C4244. This is expected when passing
floating-point values for size.

test/std/utilities/template.bitset/bitset.members/to_ullong.pass.cpp
test/std/utilities/template.bitset/bitset.members/to_ulong.pass.cpp
Avoid MSVC "warning C4293: '<<': shift count negative or too big,
undefined behavior". MSVC sees (1ULL << N) and warns - being guarded
by const bool canFit is insufficient. A small change to the code
avoids the warning without the need for a pragma.

Remove a spurious printf() declaration from to_ullong.pass.cpp.

Change ULL to UL in to_ulong.pass.cpp. The ULL suffix was
probably copy-pasted.

test/std/utilities/tuple/tuple.general/ignore.pass.cpp
Use LIBCPP_STATIC_ASSERT for consistency with other files.

test/support/container_test_types.h
Fix a null pointer dereference, found by MSVC /analyze
warning C6011 "Dereferencing NULL pointer 'm_expected_args'."

[mclow.lists]

Avoid MSVC "warning C4293: '<<': shift count negative or too big, undefined behavior".
MSVC sees (1ULL << N) and warns - being guarded by const bool canFit is insufficient.

Your compiler needs to either (a) get much smarter about its warnings, or (b) stop warning about this. It's just WRONG here.

[mclow.lists]

These look fine to me. Thanks for the attention to detail.

test/std/algorithms/alg.modifying.operations/alg.generate/generate_n.pass.cpp

 // <algorithm>
 
 // template<class Iter, IntegralLike Size, Callable Generator>
 //   requires OutputIterator<Iter, Generator::result_type>
 //         && CopyConstructible<Generator>
 //   void
 //   generate_n(Iter first, Size n, Generator gen);
 
+#ifdef _MSC_VER
+#pragma warning(disable: 4244) // conversion from 'const double' to 'int', possible loss of data
+#endif
+
 #include <algorithm>
 #include <cassert>
 
 #include "test_macros.h"
 #include "test_iterators.h"
 #include "user_defined_integral.hpp"
 
 struct gen_test

test/std/utilities/template.bitset/bitset.members/to_ullong.pass.cpp

 //===----------------------------------------------------------------------===//
 //
 //                     The LLVM Compiler Infrastructure
 //
 // This file is dual licensed under the MIT and the University of Illinois Open
 // Source Licenses. See LICENSE.TXT for details.
 //
 //===----------------------------------------------------------------------===//
 
 // test unsigned long long to_ullong() const;
-extern "C" int printf(const char *, ...);
 
 #include <bitset>
 #include <algorithm>
 #include <type_traits>
 #include <climits>
 #include <cassert>
 
 template <std::size_t N>
void test_to_ullong()
     {
         unsigned long long j = tests[i];
         std::bitset<N> v(j);
         assert(j == v.to_ullong());
     }
     { // test values bigger than can fit into the bitset
     const unsigned long long val = 0x55AAAAFFFFAAAA55ULL;
     const bool canFit = N < sizeof(unsigned long long) * CHAR_BIT;
-    const unsigned long long mask = canFit ? (1ULL << N) - 1 : (unsigned long long)(-1);
+    const unsigned long long mask = canFit ? (1ULL << (canFit ? N : 0)) - 1 : (unsigned long long)(-1); // avoid compiler warnings
     std::bitset<N> v(val);
     assert(v.to_ullong() == (val & mask)); // we shouldn't return bit patterns from outside the limits of the bitset.
     }
 }
 
 int main()
 {
 //     test_to_ullong<0>();

test/std/utilities/template.bitset/bitset.members/to_ulong.pass.cpp

void test_to_ulong()
     for (std::size_t i = 0; i < sizeof(tests)/sizeof(tests[0]); ++i)
     {
         std::size_t j = tests[i];
         std::bitset<N> v(j);
         assert(j == v.to_ulong());
     }
 
     { // test values bigger than can fit into the bitset
-    const unsigned long val = 0x5AFFFFA5ULL;
+    const unsigned long val = 0x5AFFFFA5UL;
     const bool canFit = N < sizeof(unsigned long) * CHAR_BIT;
-    const unsigned long mask = canFit ? (1ULL << N) - 1 : (unsigned long)(-1);
+    const unsigned long mask = canFit ? (1UL << (canFit ? N : 0)) - 1 : (unsigned long)(-1); // avoid compiler warnings
     std::bitset<N> v(val);
     assert(v.to_ulong() == (val & mask)); // we shouldn't return bit patterns from outside the limits of the bitset.
     }
 }
 
 int main()
 {
     test_to_ulong<0>();

test/std/utilities/tuple/tuple.general/ignore.pass.cpp

 int main() {
     {
         constexpr auto& ignore_v = std::ignore;
         ((void)ignore_v);
     }
     {
         static_assert(test_ignore_constexpr(), "");
     }
-#if defined(_LIBCPP_VERSION)
     {
-        static_assert(std::is_trivial<decltype(std::ignore)>::value, "");
+        LIBCPP_STATIC_ASSERT(std::is_trivial<decltype(std::ignore)>::value, "");
     }
-#endif
 }

test/support/container_test_types.h

void clear() {
     m_expected_args = nullptr;
     m_expected_count = -1;
   }
 
   // Check for and consume an expected construction added by 'expect'.
   // Return true if the construction was expected and false otherwise.
   // This should only be called by 'Allocator.construct'.
   bool check(detail::TypeID const& tid) {
-    if (!m_expected_args)
+    if (!m_expected_args) {
       assert(m_allow_unchecked);
+      return m_allow_unchecked;
+    }
     bool res = *m_expected_args == tid;
     if (m_expected_count == -1 || --m_expected_count == -1)
       m_expected_args = nullptr;
     return res;
   }
 
   // Return true iff there is an unchecked construction expression.
   bool unchecked() {