```rust
struct S;
impl S {
    pub hello_method(&self) {
        println!("Hello");
    }
}
fn main() { S.hello_method(); }
```

```rust
error: can't qualify macro invocation with `pub`
 --> file.rs:3:4
  |
3 |     pub hello_method(&self) {
  |     ^^^-            - expected `!` here for a macro invocation
  |        |
  |        did you mean to write `fn` here for a method declaration?
  |
  = help: try adjusting the macro to put `pub` inside the invocation
```

The place_back was likely put into block with `T: Clone` bound by mistake.

LLVM has a bug - PR32488 - where it fails to deduplicate allocas in some
circumstances. The function `start_new_block` has allocas totalling 1216
bytes, and when LLVM inlines several copies of that function into
the recursive function `expr::into`, that function's stack space usage
goes into tens of kiBs, causing stack overflows.

Mark `start_new_block` as inline(never) to keep it from being inlined,
getting stack usage under control.

Fixes rust-lang#40493.
Fixes rust-lang#40573.

- Prefer simpler constructs instead of going through &mut I's Iterator
  implementation.

SIG_ERR is defined as 'pub const SIG_ERR: sighandler_t = !0 as sighandler_t;'

* Store capacity_mask instead of capacity
* Move bucket index into RawBucket
* Bucket index is now always within [0..table_capacity)
* Clone RawTable using RawBucket
* Simplify iterators by moving logic into RawBuckets
* Make retain aware of the number of elements

When the user select more than one target to generate rustlibs for, rustbuild will only install the host one.

This patch fixes it, more info in rust-lang#39235 (comment)

This commit shrinks the size of the aforementioned table from
2,102 bytes to 1,197 bytes. This is achieved by an observation that
most u16 entries are common in its upper byte. Specifically:

- SINGLETONS now uses two tables, one for (upper byte, lower count)
  and another for a series of lower bytes. For each upper byte given
  number of lower bytes are read and compared.

- NORMAL now uses a variable length format for the count of "true"
  codepoints and "false" codepoints (one byte with MSB unset, or
  two big-endian bytes with the first MSB set).

The code size and relative performance roughly remains same as this
commit tries to optimize for both. The new table and algorithm has
been verified for the equivalence to older ones.

Fixes other targets rustlibs installation

When the user select more than one target to generate rustlibs for, rustbuild will only install the host one.

This patch fixes it, more info in rust-lang#39235 (comment)

Simplify HashMap Bucket interface

> Simplify HashMap Bucket interface
>
> * Store capacity_mask instead of capacity
> * Move bucket index into RawBucket
> * Valid bucket index is now always within [0..table_capacity)
> * Simplify iterators by moving logic into RawBuckets
> * Clone RawTable using RawBucket
> * Make retain aware of the number of elements

The idea was to put idx in RawBucket instead of the other Bucket types and simplify next() and prev() as much as possible. The rest was a side-effect of that change, except maybe the last 2.

This change makes iteration and other next/prev() heavy operations noticeably faster. Clone is way faster.

```
➜  hashmap2 git:(adapt) ✗ cargo benchcmp pre:: adp:: bench.txt
 name                        pre:: ns/iter  adp:: ns/iter  diff ns/iter   diff %
 clone_10_000                74,364         39,736              -34,628  -46.57%
 grow_100_000                8,343,553      8,233,785          -109,768   -1.32%
 grow_10_000                 817,825        723,958             -93,867  -11.48%
 grow_big_value_100_000      18,418,979     17,906,186         -512,793   -2.78%
 grow_big_value_10_000       1,219,242      1,103,334          -115,908   -9.51%
 insert_1000                 74,546         58,343              -16,203  -21.74%
 insert_100_000              6,743,770      6,238,017          -505,753   -7.50%
 insert_10_000               798,079        719,123             -78,956   -9.89%
 insert_1_000_000            275,215,605    266,975,875      -8,239,730   -2.99%
 insert_int_bigvalue_10_000  1,517,387      1,419,838           -97,549   -6.43%
 insert_str_10_000           316,179        278,896             -37,283  -11.79%
 insert_string_10_000        770,927        747,449             -23,478   -3.05%
 iter_keys_100_000           386,099        333,104             -52,995  -13.73%
 iterate_100_000             387,320        355,707             -31,613   -8.16%
 lookup_100_000              206,757        193,063             -13,694   -6.62%
 lookup_100_000_unif         219,366        193,180             -26,186  -11.94%
 lookup_1_000_000            206,456        205,716                -740   -0.36%
 lookup_1_000_000_unif       659,934        629,659             -30,275   -4.59%
 lru_sim                     20,194,334     18,442,149       -1,752,185   -8.68%
 merge_shuffle               1,168,044      1,063,055          -104,989   -8.99%
```

Note 2: I may have messed up porting the diff, let's see what CI says.

…r, r=alexcrichton

Reduce a table used for `Debug` impl of `str`.

This commit shrinks the size of the aforementioned table from 2,102 bytes to 1,197 bytes. This is achieved by an observation that most `u16` entries are common in its upper byte. Specifically:

- `SINGLETONS` now uses two tables, one for (upper byte, lower count) and another for a series of lower bytes. For each upper byte given number of lower bytes are read and compared.

- `NORMAL` now uses a variable length format for the count of "true" codepoints and "false" codepoints (one byte with MSB unset, or two big-endian bytes with the first MSB set).

The code size and relative performance roughly remains same as this commit tries to optimize for both. The new table and algorithm has been verified for the equivalence to older ones.

In my x86-64 macOS laptop with `rustc 1.17.0-nightly (0aeb9c1 2017-03-15)`, `-C opt-level=3 -C lto` gives the following:

* The old routine compiles to 2,102 bytes of data and 416 bytes of code.
* The new routine compiles to 1,197 bytes of data and 448 bytes of code.

Counting a number of all printable Unicode scalar values (128,003, if you wonder) by filtering `0..0x110000` with `std::char::from_u32` and `is_printable` took 50±7ms for both. This can be surprising as the new routine *has* to do more calculations; this is partly explained by the fact that a linear search of `SINGLETONS` has been replaced by *two* linear searches for upper and lower bytes, which greatly reduces the iteration count.

Identify missing item category in `impl`s

```rust
struct S;
impl S {
    pub hello_method(&self) {
        println!("Hello");
    }
}
fn main() { S.hello_method(); }
```

```rust
error: missing `fn` for method declaration
 --> file.rs:3:4
  |
3 |     pub hello_method(&self) {
  |        ^ missing `fn`
```

Fix rust-lang#40006. r? @pnkfelix CC @jonathandturner @GuillaumeGomez

…chton

Allow using Vec::<T>::place_back for T: !Clone

The place_back was likely put into block with `T: Clone` bound by mistake.

… r=alexcrichton

Add a note about overflow for fetch_add/fetch_sub

Fixes rust-lang#40916
Fixes rust-lang#34618

r? @steveklabnik

Add ptr::offset_to

This PR adds a method to calculate the signed distance (in number of elements) between two pointers. The resulting value can then be passed to `offset` to get one pointer from the other. This is similar to pointer subtraction in C/C++.

There are 2 special cases:

- If the distance is not a multiple of the element size then the result is rounded towards zero. (in C/C++ this is UB)
-  ZST return `None`, while normal types return `Some(isize)`. This forces the user to handle the ZST case in unsafe code. (C/C++ doesn't have ZSTs)

…hton

mark build::cfg::start_new_block as inline(never)

LLVM has a bug - [PR32488](https://bugs.llvm.org//show_bug.cgi?id=32488) - where it fails to deduplicate allocas in some
circumstances. The function `start_new_block` has allocas totalling 1216
bytes, and when LLVM inlines several copies of that function into
the recursive function `expr::into`, that function's stack space usage
goes into tens of kiBs, causing stack overflows.

Mark `start_new_block` as inline(never) to keep it from being inlined,
getting stack usage under control.

Fixes rust-lang#40493.
Fixes rust-lang#40573.

r? @eddyb

Let .rev()'s find use the underlying rfind and vice versa

- Connect the plumbing in an obvious way from Rev's find → underlying rfind and vice versa
- A style change in the provided implementation for Iterator::rfind, using simple next_back when it is enough

…pls, r=estebank

Make 'overlapping_inherent_impls' lint a hard error

This is ought to be implemented in PR rust-lang#40728. Unfortunately, when I rebased the PR to resolve merge conflict, the "hard error" code disappeared. This PR complements the initial PR.

Now the following rust code gives the following error:
```rust
struct Foo;

impl Foo {
    fn id() {}
}

impl Foo {
    fn id() {}
}

fn main() {}
```
```
error[E0592]: duplicate definitions with name `id`
 --> /home/topecongiro/test.rs:4:5
  |
4 |     fn id() {}
  |     ^^^^^^^^^^ duplicate definitions for `id`
...
8 |     fn id() {}
  |     ---------- other definition for `id`

error: aborting due to previous error
```

Replace magic number with readable sig constant

SIG_ERR is defined as 'pub const SIG_ERR: sighandler_t = !0 as sighandler_t;'

…excrichton

[T]::rsplit() and rsplit_mut(), rust-lang#41020