The span labels for associated types and consts were hardcoded to `Foo`
rather than substituting the name of the trait.

This also normalizes the wording for associated methods', traits', and
consts' span labels.

Fixes rust-lang#36428.

the `InvocationCollector` and `PlaceholderExpander` folds.

only assign node ids during monotonic expansion.

…ay that is stable across compilation sessions and crate boundaries.

This is done by creating a little space on the stack. Hokey, but it's
the simplest fix I can see.

…ation

This flag is a debugging measure designed to detect cases where we start
a snapshot, create type variables, register obligations involving those
type variables in the fulfillment cx, and then have to unroll the
snapshot, leaving "dangling type variables" behind.  HOWEVER, in some
cases the flag is wrong. In particular, we sometimes create a
"mini-fulfilment-cx" in which we enroll obligations. As long as this
fulfillment cx is fully drained before we return, this is not a problem,
as there won't be any escaping obligations in the main cx. So we add a
fn to save/restore the flag.

[T]'s Index implementation is normally not used for indexing, instead
the compiler supplied indexing is used.

Use the compiler supplied version in Index/IndexMut.

This removes an inconsistency:

Compiler supplied bound check failures look like this:

thread 'main' panicked at 'index out of bounds: the len is 3 but the index is 4'

If you convince Rust to use the Index impl for slices, bounds check
failure looks like this instead:

thread 'main' panicked at 'assertion failed: index < self.len()'

The latter is used if you for example use Index generically::

   use std::ops::Index;
   fn foo<T: ?Sized>(x: &T) where T: Index<usize> { &x[4]; }

   foo(&[1, 2, 3][..])

Improve shallow `Clone` deriving

`Copy` unions now support `#[derive(Clone)]`.
Less code is generated for `#[derive(Clone, Copy)]`.
+
Unions now support `#[derive(Eq)]`.
Less code is generated for `#[derive(Eq)]`.

---
Example of code reduction:
```
enum E {
	A { a: u8, b: u16 },
	B { c: [u8; 100] },
}
```
Before:
```
fn clone(&self) -> E {
    match (&*self,) {
        (&E::A { a: ref __self_0, b: ref __self_1 },) => {
            ::std::clone::assert_receiver_is_clone(&(*__self_0));
            ::std::clone::assert_receiver_is_clone(&(*__self_1));
            *self
        }
        (&E::B { c: ref __self_0 },) => {
            ::std::clone::assert_receiver_is_clone(&(*__self_0));
            *self
        }
    }
}
```
After:
```
fn clone(&self) -> E {
    {
        let _: ::std::clone::AssertParamIsClone<u8>;
        let _: ::std::clone::AssertParamIsClone<u16>;
        let _: ::std::clone::AssertParamIsClone<[u8; 100]>;
        *self
    }
}
```

All the matches are removed, bound assertions are more lightweight.
`let _: Checker<CheckMe>;`, unlike `checker(&check_me);`, doesn't have to be translated by rustc_trans and then inlined by LLVM, it doesn't even exist in MIR, this means faster compilation.

---
Union impls are generated like this:
```
union U {
	a: u8,
	b: u16,
	c: [u8; 100],
}
```
```
fn clone(&self) -> U {
    {
        let _: ::std::clone::AssertParamIsCopy<Self>;
        *self
    }
}
```

Fixes rust-lang#36043
cc @durka
r? @alexcrichton

Delete stray ` character in error message.

…bounds, r=eddyb

Fix indeterminism in ty::TraitObject representation.

Make sure that projection bounds in `ty::TraitObject` are sorted in a way that is stable across compilation sessions and crate boundaries.

This PR
+  moves `DefPathHashes` up into `librustc` so it can be used there to create a stable sort key for `DefId`s,
+ changes `PolyExistentialProjection::sort_key()` to take advantage of the above,
+ and removes the unused `PolyProjectionPredicate::sort_key()` and `ProjectionTy::sort_key()` methods.

Fixes rust-lang#36155

fix "X is not a member of trait Y" span labels

Fixes rust-lang#36428.

Assign node ids during macro expansion

After this PR,
 - The `ExtCtxt` can access `resolve`'s `Resolver` through the trait object `ext::base::Resolver`.
  - The `Resolver` trait object can load macros and replaces today's `MacroLoader` trait object.
  - The macro expander uses the `Resolver` trait object to resolve macro invocations.
 - The macro expander assigns node ids and builds the `Resolver`'s `macros_at_scope` map.
   - This is groundwork for merging import resolution and expansion.
 - Performance of expansion together with node id assignment improves by ~5%.

**EDIT:** Since Github is reordering the commits, here is `git log`:
 - b54e1e3: Differentiate between monotonic and non-monotonic expansion and only assign node ids during monotonic expansion.
 - 78c0039: Expand generated test harnesses and macro registries.
 - f3c2dca: Remove scope placeholders from the crate root.
 - c86c8d4: Perform node id assignment and `macros_at_scope` construction during the `InvocationCollector` and `PlaceholderExpander` folds.
 - 72a6369: Move macro resolution into `librustc_resolve`.
 - 20b43b2: Rewrite the unit tests in `ext/expand.rs` as a `compile-fail` test.
 - a9821e1: Refactor `ExtCtxt` to use a `Resolver` instead of a `MacroLoader`.
 - 60440b2: Refactor `noop_fold_stmt_kind` out of `noop_fold_stmt`.
 - 50f94f6: Avoid needless reexpansions.

r? @nrc

…crichton

Use primitive indexing in slice's Index/IndexMut

[T]'s Index implementation is normally not used for indexing, instead
the compiler supplied indexing is used.

Use the compiler supplied version in Index/IndexMut.

This removes an inconsistency:

Compiler supplied bound check failures look like this:

thread 'main' panicked at 'index out of bounds: the len is 3 but the index is 4'

If you convince Rust to use the Index impl for slices, bounds check
failure looks like this instead:

thread 'main' panicked at 'assertion failed: index < self.len()'

The latter is used if you for example use Index generically:

```rust
use std::ops::Index;
fn foo<T: ?Sized>(x: &T) where T: Index<usize> { &x[4]; }

foo(&[1, 2, 3][..])
```

invoke drop glue with a ptr to (data, meta)

This is done by creating a little space on the stack. Hokey, but it's the simplest fix I can see, and I am in "kill regressions" mode right now.

Fixes rust-lang#35546

r? @eddyb

clear obligations-added flag with nested fulfillcx

This flag is a debugging measure designed to detect cases where we start
a snapshot, create type variables, register obligations involving those
type variables in the fulfillment cx, and then have to unroll the
snapshot, leaving "dangling type variables" behind.  HOWEVER, in some
cases the flag is wrong. In particular, we sometimes create a
"mini-fulfilment-cx" in which we enroll obligations. As long as this
fulfillment cx is fully drained before we return, this is not a problem,
as there won't be any escaping obligations in the main cx. So we add a
fn to save/restore the flag.

Fixes rust-lang#36053.

r? @arielb1

… r=alexcrichton

Add checked operation methods to Duration

Addresses rust-lang#35774.