improve the comments on integer overflow safety
impl Buffer for ChanReader
fix stupid error
auto merge of #17983 : jakub-/rust/memoize-things, r=pcwalton
fix a failing test
auto merge of #17934 : pcwalton/rust/better-autoderef-fixup, r=pnkfelix

librustc: Improve method autoderef/deref/index behavior more, and enable IndexMut on mutable vectors.

This fixes a bug whereby the mutability fixups for method behavior were
not kicking in after autoderef failed to happen at any level. It also
adds support for `Index` to the fixer-upper.

Closes #12825.

r? @pnkfelix
shootout-reverse-complement: reimplement TwoSideIter using pointers
Add assume intrinsic

Adds an `assume` intrinsic that gets translated to llvm.assume. It is
used on a boolean expression and allows the optimizer to assume that
the expression is true.

This implements #18051.
auto merge of #18015 : jakub-/rust/issue-4201, r=pcwalton

Closes #4201.
auto merge of #18067 : mahkoh/rust/immutableintslice, r=alexcrichton

There is also a second commit that adds them to the prelude.
Improve documentation of assume intrinsic.
Removes useless confs from bitv.rs

Linked to #18009
Remove libdebug and update tests.
libsyntax: Remove all uses of {:?}.
librustc: Remove all uses of {:?}.
libstd: Remove all uses of {:?}.
liballoc: Remove all uses of {:?}.
librustdoc: Remove all uses of {:?}.
libcollections: Remove all uses of {:?}.
libnative: Remove all uses of {:?}.