Closes#3083.
This takes a similar approach to #5797 where a set is present on the `tcx` of used mutable definitions. Everything is by default warned about, and analyses must explicitly add mutable definitions to this set so they're not warned about.
Most of this was pretty straightforward, although there was one caveat that I ran into when implementing it. Apparently when the old modes are used (or maybe `legacy_modes`, I'm not sure) some different code paths are taken to cause spurious warnings to be issued which shouldn't be issued. I'm not really sure how modes even worked, so I was having a lot of trouble tracking this down. I figured that because they're a legacy thing that I'd just de-mode the compiler so that the warnings wouldn't be a problem anymore (or at least for the compiler).
Other than that, the entire compiler compiles without warnings of unused mutable variables. To prevent bad warnings, #5965 should be landed (which in turn is waiting on #5963) before landing this. I figured I'd stick it out for review anyway though.
This implements #5158. Currently it takes the command line args and the crate map. Since it doesn't take a `main` function pointer, you can't actually start the runtime easily, but that seems to be a shim to allow the current `rust_start` function to call into main.
However, you can do an end-run round the io library and do this:
```rust
use core::libc::{write, c_int, c_void, size_t, STDOUT_FILENO};
#[start]
fn my_start(_argc:int, _argv: **u8, _crate_map: *u8) -> int {
do str::as_buf("Hello World!\n") |s,len| {
unsafe {
write(STDOUT_FILENO, s as *c_void, len as size_t);
}
}
return 0;
}
```
Which is the most basic "Hello World" you can do in rust without starting up the runtime (though that has quite a lot to do with the fact that `core::io` uses `@` everywhere...)
signature. In a nutshell, the idea is to (1) report an error if, for
a region pointer `'a T`, the lifetime `'a` is longer than any
lifetimes that appear in `T` (in other words, if a borrowed pointer
outlives any portion of its contents) and then (2) use this to assume
that in a function like `fn(self: &'a &'b T)`, the relationship `'a <=
'b` holds. This is needed for #5656. Fixes#5728.
This leaves the default lint modes at `warn`, but now the unused variable and dead assignment warnings are configurable on a per-item basis. As described in #3266, this just involved carrying around a couple ids to pass over to `span_lint`. I personally would prefer to keep the `_` prefix as well.
This closes#3266.
bare function store (which is not in fact a kind of value) but rather
ty::TraitRef. Removes many uses of fail!() and other telltale signs of
type-semantic mismatch.
cc #4183 (not a fix, but related)
I believe this patch incorporates all expected syntax changes from extern
function reform (#3678). You can now write things like:
extern "<abi>" fn foo(s: S) -> T { ... }
extern "<abi>" mod { ... }
extern "<abi>" fn(S) -> T
The ABI for foreign functions is taken from this syntax (rather than from an
annotation). We support the full ABI specification I described on the mailing
list. The correct ABI is chosen based on the target architecture.
Calls by pointer to C functions are not yet supported, and the Rust type of
crust fns is still *u8.
Before it wouldn't warn about unused imports in the list if something in the list was used. These commits fix that case, add a test, and remove all unused imports in lists of imports throughout the compiler.
Before, if anything in a list was used, the entire list was considered to be
used. This corrects this and also warns on a span of the actual unused import
instead of the entire list.
Impose a limit so that the typo suggester only shows reasonable
suggestions (i.e. don't suggest `args` when the error is `foobar`).
A tiny bit of progress on #2281.
