Auto merge of #33532 - jseyfried:mutable_lowering_context, r=nrc

Clean up `hir::lowering`

Clean up `hir::lowering`:
 - give lowering functions mutable access to the lowering context
 - refactor the `lower_*` functions and other functions that take a lowering context into methods
 - simplify the API that `hir::lowering` exposes to `driver`
 - other miscellaneous cleanups

r? @nrc

diff --cc src/librustc_driver/driver.rs
Simple merge

diff --cc src/librustc_metadata/astencode.rs
index 6da2e5b17a5e8ebd8d45381fa27a4bfe37b3840c,2a847c4c19538c20f86447de3a8964e75761b566..ad0e8e1c37623a9f03de6fabf74e1ba84df2977b
--- 1/src/librustc_metadata/astencode.rs
--- 2/src/librustc_metadata/astencode.rs
+++ b/src/librustc_metadata/astencode.rs
@@@ -57,10 -57,10 +57,10 @@@ use rustc_serialize::{Encodable, Encode
  #[cfg(test)] use syntax::parse;
  #[cfg(test)] use syntax::ast::NodeId;
  #[cfg(test)] use rustc::hir::print as pprust;
- #[cfg(test)] use rustc::hir::lowering::{lower_item, LoweringContext, DummyResolver};
+ #[cfg(test)] use rustc::hir::lowering::{LoweringContext, DummyResolver};
  
  struct DecodeContext<'a, 'b, 'tcx: 'a> {
 -    tcx: &'a TyCtxt<'tcx>,
 +    tcx: TyCtxt<'a, 'tcx, 'tcx>,
      cdata: &'b cstore::crate_metadata,
      from_id_range: IdRange,
      to_id_range: IdRange,

diff --cc src/librustdoc/test.rs
Simple merge