There were still some mentions of `~[T]` and `~T`, mostly in comments and debugging statements. I tried to do my best to preserve meaning, but I might have gotten some wrong-- I'm happy to fix anything :)
Fixes the problem in #16974 with unhelpful error messages when accidentally using the wrong syntax for the `crate_type="lib"` attribute. The attribute syntax error now shows up instead of "main function not found".
If the user intended to set the crate_type to "lib" but accidentally used
incorrect syntax such as `#![crate_type(lib)]`, the compilation would fail with
"main function not found". This made it hard to locate the source of the
problem, since the failure would cause the warning about the incorrect
attribute not to be shown.
This change is worrisome to me, both because:
1. I thought the rules in RFC 599 imply that the `Box<Trait>` without `'static`
in the first case would expand to the second case, but their behaviors
here differ. And,
2. The explicit handling of `'static` should mean `dropck` has no application
here and thus we should have seen no change to the expected error messages.
Nonetheless, the error messages changed.
The error message was misleading, so I adjusted it, and I also added the long diagnostics for this error (resolves one point in #24407).
I was unsure about how to phrase the error message. Is “generic parameter binding” the correct term for this?
The [UnsafeCell documentation says it is undefined behavior](http://doc.rust-lang.org/nightly/std/cell/struct.UnsafeCell.html), so people shouldn't do it.
This happened to catch one case in libstd that was doing this, and I switched that to use an UnsafeCell internally.
Closes#13146
[breaking-change] Technically breaking, since code that had been using
these transmutes before will no longer compile. However, it was
undefined behavior, so really, it's a good thing. Fixing your code would
require some re-working to use an UnsafeCell instead.
Closes#13146
typeck: Make sure casts from other types to fat pointers are illegal
Fixes ICEs where non-fat pointers and scalars are cast to fat pointers,
Fixes#21397Fixes#22955Fixes#23237Fixes#24100
The new functionality being tested here is that a drop impl bounded by
`UserDefined` does not cause dropck to inject its conservative
constraints on region inference.
Closes#17841.
The majority of the work should be done, e.g. trait and inherent impls, different forms of UFCS syntax, defaults, and cross-crate usage. It's probably enough to replace the constants in `f32`, `i8`, and so on, or close to good enough.
There is still some significant functionality missing from this commit:
- ~~Associated consts can't be used in match patterns at all. This is simply because I haven't updated the relevant bits in the parser or `resolve`, but it's *probably* not hard to get working.~~
- Since you can't select an impl for trait-associated consts until partway through type-checking, there are some problems with code that assumes that you can check constants earlier. Associated consts that are not in inherent impls cause ICEs if you try to use them in array sizes or match ranges. For similar reasons, `check_static_recursion` doesn't check them properly, so the stack goes ka-blooey if you use an associated constant that's recursively defined. That's a bit trickier to solve; I'm not entirely sure what the best approach is yet.
- Dealing with consts associated with type parameters will raise some new issues (e.g. if you have a `T: Int` type parameter and want to use `<T>::ZERO`). See rust-lang/rfcs#865.
- ~~Unused associated consts don't seem to trigger the `dead_code` lint when they should. Probably easy to fix.~~
Also, this is the first time I've been spelunking in rustc to such a large extent, so I've probably done some silly things in a couple of places.
An actual typeck error is the cause of many failed compilations but an
unrelated bug is being reported instead. It is triggered because a typeck
error is presumably not yet identified during compiler execution, which
would normally bypass an invariant in the presence of other errors. In
this particular situation, we delay the reporting of the bug until
abort_if_errors().
Closes#23827, closes#24356, closes#23041, closes#22897, closes#23966,
closes#24013, and closes#23729
**There is at least one situation where this bug may still be genuinely
triggered (#23437).**
As part of the audit for #22820 the following duplicate feature
gate tests were removed:
* `box_patterns`
* `simd_ffi`
These tests for `box_patterns` and `simd_ffi` were added in #23578,
however there were existing tests in #20723 and #21233 respectively.
r? @nrc
