borrow = *elem << (uint::bits - n_bits);
The code above contains a bug that the value of the right operand of the shift operator exceeds the size of the left operand,
because sizeof(*elem) == 32, and 0 <= n_bits < 32 in 64bit architecture.
If `--opt-level` option is not given to rustc, the code above runs as if the right operand is `(uint::bits - n_bits) % 32`,
but if --opt-level is given, `borrow` is always zero.
I wonder why this bug is not catched in the libstd's testsuite (I try the `rustc --test --opt-level=2 bigint.rs` before fixing the bug,
but the unittest passes normally.)
The existing adaptors like `map` in the `iter` module are very flawed because they only work for `BaseIter` implementations. There are many internal iterator implementations in the standard library like the set methods (`difference`, `symmetric_difference`, `intersection`, `union`) and the `range` functions that only share the `for` loop protocol in common.
The internal iterator adaptors should be implemented to work on any implementation of that protocol, rather than just a method called `each` taking `&self`.
This just moves `iter.rs` to `old_iter.rs` and begins work on documenting and implementing a nicer module.
before this change, the parser would parse 14.a() as a method call, but
would parse 14.ø() as the floating-point number 14. followed by a function
call. This is because it was checking is_alpha, rather than ident_start,
and was therefore wrong with respect to unicode.
In principle, it seems like a nice idea to abstract over the two
functions that parse blocks (one with inner attrs allowed, one not).
However, the existing one wound up making things more complex than
just having two separate functions, especially after the obsolete
syntax is (will be) removed.
prec.rs no longer had much to do with precedence; the token->binop
function fits better in token.rs, and the one-liner defining the
precedence of 'as' can go next to the other precedence stuff in
ast_util.rs
r? @brson mkdir_recursive creates a directory as well as any of its
parent directories that don't exist already. Seems like a useful
thing to have in core.
(Or r? anyone who gets to it first.)
