Previously, std.debug.assert would `@panic` in test builds,
if the assertion failed. Now, it's always `unreachable`.
This makes release mode test builds more accurately test
the actual code that will be run.
However this requires tests to call `std.testing.expect`
rather than `std.debug.assert` to make sure output is correct.
Here is the explanation of when to use either one, copied from
the assert doc comments:
Inside a test block, it is best to use the `std.testing` module
rather than assert, because assert may not detect a test failure
in ReleaseFast and ReleaseSafe mode. Outside of a test block, assert
is the correct function to use.
closes#1304
A few notes on the implementation:
- Any unsigned power of two integer type less than 64 bits in size is supported
as a Limb type.
- The algorithms used are kept simple for the moment. More complicated
algorithms are generally only more useful as integer sizes increase a
lot and I don't expect our current usage to be used for this purpose
just yet.
- All branches (practically) have been covered by tests.
See 986a2b3243/bench
for rough performance comparison numbers.
Closes#364.
