Rename const_view to const_slice
Renamed mut_view to mut_slice

This reverts commit a8f039a0.

correct handling of moves for struct-record update.

Part of #3678.  Fixes #2828, #3904, #4719.

This reverts commit a4250a96.

This is not the cause of the nonexhaustive-match failure.

This reverts commit 8e643525.

LinearMap is quite a bit faster, and is fully owned/sendable without
requiring copies. The older std::map also doesn't use explicit self and
relies on mutable fields.

Make the closure take two arguments instead of a single `path_entry`
struct; remove the `path_entry` type. This eliminates a bad copy.

specifically:

freevars::freevar_entry
ty::{field_ty,AutoAdjustment,AutoRef}
mod::{method_param,method_map_entry}

def-id we have, so that the inliner can distinguish between external and
internal def-ids.  Also add some comments explaining the distinction!

Fixes #4516.

r=graydon

Revert "librustc: Make unqualified identifier searches terminate at the nearest module scope. r=tjc"

This reverts commit a8d37af2.

~20% perf win for trans on -O0, with other minor improvements across the board.
No effect on -O2.

librustc: Encode language items into a special lookup table. 9% improvement in hello world compile time.

librustc: Terminate name searches at the nearest module scope for paths that contain at least two components. r=graydon

and rename "class" to "struct" everywhere possible (except local
vars, I was too lazy for that) -- that is why this commit is so
big.

No review, just dead code removal and renaming.

Closes #3515

Closes #4076