all: minor updates

src/check/dt_cxxlib.cpp

@@ -27,6 +27,7 @@
 // lots of tests (and probably quite a number of redundant tests)
 // modern compilers will optimize away much of this code
 
+#if 0 // TODO later
 // libc++ hardenining
 #if defined(__clang__) && defined(__clang_major__) && (__clang_major__ + 0 >= 18)
 #if DEBUG
@@ -40,6 +41,7 @@
 #define _LIBCPP_ENABLE_ASSERTIONS 1
 #endif
 #endif
+#endif // TODO later
 
 #include "../headers.h"
 #include <vector>

src/check/dt_impl.cpp

@@ -28,6 +28,7 @@
 // doctest support code implementation
 **************************************************************************/
 
+#if 0 // TODO later
 // libc++ hardenining
 #if defined(__clang__) && defined(__clang_major__) && (__clang_major__ + 0 >= 18)
 #if DEBUG
@@ -41,6 +42,7 @@
 #define _LIBCPP_ENABLE_ASSERTIONS 1
 #endif
 #endif
+#endif // TODO later
 
 #if defined(__has_include)
 #if __has_include(<features.h>)

src/check/dt_xspan.cpp

@@ -242,7 +242,7 @@ TEST_CASE("basic xspan usage") {
 }
 
 TEST_CASE("xspan array access") {
-    constexpr size_t N = 16;
+    const size_t N = 16;
     char buf[N];
     memset(buf, 0, sizeof(buf));
     XSPAN_0_VAR(char, c0, buf, sizeof(buf));
@@ -254,6 +254,7 @@ TEST_CASE("xspan array access") {
         cp[i] += 1;
     for (size_t i = 0; i != N; ++i)
         cs[i] += 1;
+#if __cplusplus >= 201103L
     for (auto ptr = c0; ptr != c0 + N; ++ptr)
         *ptr += 1;
     for (auto ptr = c0 + 0; ptr < c0 + N; ++ptr)
@@ -266,6 +267,7 @@ TEST_CASE("xspan array access") {
         *ptr += 1;
     for (auto ptr = cs + 0; ptr < cs + N; ++ptr)
         *ptr += 1;
+#endif
 }
 
 /*************************************************************************
@@ -685,6 +687,9 @@ TEST_CASE("Span subspan") {
     CHECK((as + 2).subspan(0, -2)[0] == 0);
     CHECK_THROWS(as.subspan(1, 0)[0]);
     CHECK_THROWS(as.subspan(1, 1)[-1]);
+    CHECK(as.subspan(1)[0] == 1);
+    CHECK(as.subspan(2)[0] == 2);
+    CHECK(as.subspan(3)[0] == 3);
 }
 
 TEST_CASE("Span constness") {