On Friday, 31 July 2015 at 00:30:23 UTC, Jonathan M Davis wrote:
On Friday, 31 July 2015 at 00:07:43 UTC, Idan Arye wrote:
Thoughts?
Some unit test helpers for this sort of thing might be nice,
but I don't think that it really buys us much with this
particular case. You could just as easily do
unittest
{
foreach(T; TypeTuple!(ubyte, byte, ushort, short, uint,
int, ulong, long))
static assert(is(typeof(foo(T.init)));
}
and the code is basically as long as is with assertCompilesWith
- shorter even. The above example is longer due to not using an
alias for the integral types like you did, but if that same
alias were used, then it becomes
unittest
{
foreach(T; IntegerTypes)
static assert(is(typeof(foo(T.init)));
}
which isn't all that different than
unittest
{
assertCompilesWith!(IntegerTypes, (x) {
foo(x);
});
}
The resulting compilation errors are extremely different. With
your method we get:
/d391/f994.d(31): Error: static assert (is(typeof(__error))) is
false
which doesn't tell us what the problem is. With my method we get:
/d433/f500.d(25): Error: cannot implicitly convert expression (x)
of type ulong to int /d433/f500.d(31): Error: template instance
f500.foo!ulong error instantiating
And yes, a lot of "static stack trace" after that, but these too
lines tells us what the problem is and which template parameters
caused it.
Of course, if you just ran the function inside the foreach loop
you'd get nice error messages as well - but then you'd have to
write tests that actually run. Which is easy for numbers, because
they are all the same type of data with different sizes, but can
get tricky when you have more complex types, that differ more in
their behavior.
