gcc libstdc++ built with -D_GLIBCXX_DEBUG includes in
std::array::operator[] an assertion of the form:
```
assert(index < size());
```
The valptridx allow_end_construction constructor, when given a
completely full array, will call operator[](size()), which causes the
assertion to fail. Rework the constructor to compute an end iterator
without using operator[]. valptridx allow_end_construction expects that
the resulting iterator may be the end iterator and shall not be
dereferenced.
Introduce a helper to obtain both the magnitude of a vector and the
corresponding normalized vector. Use it to capture both values as const
when possible.
`Multi_is_guided` is only enabled in one place. One code path set up
Guided_missile[] for the local player, and a different path handled
network players. Remove `Multi_is_guided` and rearrange such that a
single site handles both local and network players.
This is only used in the file where it is defined, so it can be inlined
even though the definition is not in a header. Enabling inlining
encourages gcc to see that the `operator new`/`operator delete` calls
are not mismatched.
clang-14 is detected as being able to optimize out unreachable paths,
but then triggers a build error reporting an unspecified invalid use
somewhere in multi.cpp.
Remove the static check, and rely on -Wsuggest-attribute=noreturn to
report any functions which are guaranteed to fail. This is a weaker
check, but over the course of development, the static check has been hit
rarely, if ever, so keeping it provides little value.
```
In file included from similar/main/multi.cpp:38:
In file included from common/main/game.h:32:
In file included from common/main/robot.h:34:
In file included from common/main/object.h:40:
common/include/valptridx.h:229:2: error: call to unsigned int valptridx<dcx::player>::check_index_range_size<valptridx<dcx::player>::index_range_exception, std::__1::less>(char const*, unsigned int, unsigned long, valptridx<dcx::player>::array_managed_type const*)::DXX_ALWAYS_ERROR_FUNCTION::dxx_trap_handle_index_range_error() declared with 'error' attribute: invalid index used in array subscript
DXX_VALPTRIDX_CHECK(Compare<std::size_t>()(s, array_size), handle_index_range_error, "invalid index used in array subscript", a, s);
^
common/include/valptridx.h:37:3: note: expanded from macro 'DXX_VALPTRIDX_CHECK'
DXX_VALPTRIDX_STATIC_CHECK(dxx_valptridx_check_success_condition, dxx_trap_##ERROR, FAILURE_STRING); \
^
common/include/valptridx.h:20:5: note: expanded from macro 'DXX_VALPTRIDX_STATIC_CHECK'
(DXX_ALWAYS_ERROR_FUNCTION(FAILURE_FUNCTION, FAILURE_STRING), 0) \
^
build/ulinux-clang++-14-64b10d04-ogl/dxxsconf.h:84:2: note: expanded from macro 'DXX_ALWAYS_ERROR_FUNCTION'
DXX_ALWAYS_ERROR_FUNCTION::F(); \
^
1 error generated.
```
Given this code:
```
enum class X : unsigned;
X a{1};
```
gdb has an unfortunate behavior of reporting "incomplete type" and
refusing to show the underlying value of `a`, even when `a` is in scope.
Adding `enum class X : unsigned {}` fixes this and allows gdb to show
the value.
Compiler error messages are generally better when reporting a misuse
that fails a requires() versus reporting a misuse that fails a
std::enable_if. In some cases, this also makes the code clearer, and
avoids the need for dummy template parameters as a place to invoke
std::enable_if.
