This currently requires workarounds for the borrow checker not being flow-sensitive for `LinearMap` and `TrieMap`, but it can already be expressed for `TreeMap` and `SmallIntMap` without that.
Kills some warnings, and implements str::each_char_reverse so that it actually iterates. The test case wasn't detecting a failure, since the loop body was never executed.
The reasoning for doing it this way is that it's much easier to transition method-by-method to the `Map` API than trying to do the migration all at once.
I found an issue unrelated to my changes in one of the run-fail tests - if it uses `LinearMap`, it still fails but exits with 0. I xfailed it for now and opened [an issue](https://github.com/mozilla/rust/issues/5512), because it's not caused by these changes.
This makes the `trim` and `substr` functions return a slice instead of an `~str`, and removes the unnecessary `Trimmable` trait (`StrSlice` already contains the same functionality).
Also moves the `ToStr` implementations for the three str types into the str module in anticipation of further untangling.
Adds an assert_eq! macro that asserts that its two arguments are equal. Error messages can therefore be somewhat more informative than a simple assert, because the error message includes "expected" and "given" values.
A slice now always refers to something that returns an borrowed pointer, views don't exist anymore. If you want to have an explictit copy of a slice, use `to_owned()`
For bootstrapping purposes, this commit does not remove all uses of
the keyword "pure" -- doing so would cause the compiler to no longer
bootstrap due to some syntax extensions ("deriving" in particular).
Instead, it makes the compiler ignore "pure". Post-snapshot, we can
remove "pure" from the language.
There are quite a few (~100) borrow check errors that were essentially
all the result of mutable fields or partial borrows of `@mut`. Per
discussions with Niko I think we want to allow partial borrows of
`@mut` but detect obvious footguns. We should also improve the error
message when `@mut` is erroneously reborrowed.
