The `each_line` function in `ReaderUtil` acts very differently to equivalent functions in Python, Ruby, Clojure etc. E.g. given a file `t` with contents `trailing\nnew line\n` and `n` containing `no trailing\nnew line`:
Rust:
```Rust
t: ~[~"trailing", ~"new line", ~""]
n: ~[~"no trailing", ~"new line"]
```
Python:
```Python
>>> open('t').readlines()
['trailing\n', 'new line\n']
>>> open('n').readlines()
['no trailing\n', 'new line']
```
Ruby:
```Ruby
irb(main):001:0> File.readlines('t')
=> ["trailing\n", "new line\n"]
irb(main):002:0> File.readlines('n')
=> ["no trailing\n", "new line"]
```
Clojure
```Clojure
user=> (read-lines "t")
("trailing" "new line")
user=> (read-lines "n")
("no trailing" "new line")
```
The extra string that rust includes at the end is inconsistent, and means that it is impossible to distinguish between the "real" empty line a file that ends `...\n\n`, and the "fake" one after the last `\n`.
The code attached makes Rust's `each_line` act like Clojure (and PHP, i.e. not including the `\n`), as well as adjusting `str::lines` to fix the trailing empty line problem.
Also, add a convenience `read_lines` method to read all the lines in a file into a vector.
Specifically, `lines` and `each_line` will not emit a trailing empty string
when given "...\n". Also, add `read_lines`, which just collects all of
`each_line` into a vector, and `split_*_no_trailing` which will is the
generalised version of `lines`.
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.
I've found that unused imports can often start cluttering a project after a long time, and it's very useful to keep them under control. I don't like how Go forces a compiler error by default and it can't be changed, but I certainly want to know about them so I think that a warn is a good default.
Now that the `unused_imports` lint option is a bit smarter, I think it's possible to change the default level to warn. This commit also removes all unused imports throughout the compiler and libraries (500+).
The only odd things that I ran into were that some `use` statements had to have `#[cfg(notest)]` or `#[cfg(test)]` based on where they were. The ones with `notest` were mostly in core for modules like `cmp` whereas `cfg(test)` was for tests that weren't part of a normal `mod test` module.
Issue #3869
review? @nikomatsakis
Convert all uses of vec::slice to vec::view Issue #3869
Rename const_view to const_slice
Renamed mut_view to mut_slice
Fix windows build error. `buf` is borrowed by the call to
`as_mut_buf()` and so we must invoke `slice()` outside of that
call.
