Re: constexpr keyword is unnecessary

Kaz Kylheku <643-408-1753@kylheku.com> writes:

[...]

"I think truncation does not happen" is here logically equivalent to
the specific condition that ch is in the range 0 to UCHAR_MAX.
>
That can be asserted:
>
  assert (0 <= ch && ch <= UCHAR_MAX);
>
If ch has the type unsigned char, then this condition is always
true.
>
We can think about a warning like that "controlling expression of
assert unconditionally true due to range of types", but it serves no
purpose.  There is nothing wrong with asserting something that is
always true.
>
When assertions are enabled, the compiler can use their predicates
to reason about the code and not warn about conditions that are
precluded by assertions being true.
>
You will find that this already happens in today's compilers,
and not due to assert being treated specially.  The assertion
translates into something like
>
  if (!(0 <= ch && ch <= UCHAR_MAX)) do {
    __assert_fail("0 <= ch && ch <= UCHAR_MAX", "foo.c", 42);
  } while (0)
>
where __assert_fail is annotated a function which does not return.

Invoking assert() emphatically does not expand into any such
statement.  The C standard requires the assert macro to expand to
a void expression.