all: improve C++ static analyzers

src/util/membuffer.cpp

@@ -306,9 +306,13 @@ TEST_CASE("MemBuffer global overloads") {
     mb.clear();
     mb4.clear();
     CHECK(memcmp(mb, "\x00", 1) == 0);
+    // NOLINTNEXTLINE(bugprone-unused-return-value)
     CHECK_THROWS(memcmp(mb, "\x00\x00", 2));
+    // NOLINTNEXTLINE(bugprone-unused-return-value)
     CHECK_THROWS(memcmp("\x00\x00", mb, 2));
+    // NOLINTNEXTLINE(bugprone-unused-return-value)
     CHECK_THROWS(memcmp(mb, mb4, 2));
+    // NOLINTNEXTLINE(bugprone-unused-return-value)
     CHECK_THROWS(memcmp(mb4, mb, 2));
     CHECK_NOTHROW(memset(mb, 255, 1));
     CHECK_THROWS(memset(mb, 254, 2));

src/util/util.cpp

@@ -265,7 +265,9 @@ void upx_memswap(void *a, void *b, size_t n) {
         char *x = (char *) a;
         char *y = (char *) b;
         do {
-            char tmp = *x;
+            // strange clang-analyzer-15 false positive when compiling in Debug mode
+            // clang-analyzer-core.uninitialized.Assign
+            char tmp = *x; // NOLINT(*core.uninitialized.Assign) // bogus clang-analyzer warning
             *x++ = *y;
             *y++ = tmp;
         } while (--n != 0);

src/util/util.h

@@ -150,9 +150,9 @@ using OwningPointer = T *;
 
 #else
 
-// simple class with just a number of no-ops
+// also works: a simple class with just a number of no-ops
 template <class T>
-struct OwningPointer {
+struct OwningPointer final {
     static_assert(std::is_class_v<T>); // UPX convention
     typedef typename std::add_lvalue_reference<T>::type reference;
     typedef typename std::add_lvalue_reference<const T>::type const_reference;
@@ -167,7 +167,7 @@ struct OwningPointer {
     inline pointer operator->() noexcept { return ptr; }
     inline const_pointer operator->() const noexcept { return ptr; }
 };
-// overload mem_clear()
+// must overload mem_clear()
 template <class T>
 inline void mem_clear(OwningPointer<T> object) noexcept {
     mem_clear((T *) object);