Rollup merge of #36438 - jseyfried:node_ids_in_expansion, r=nrc

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`:
 - b54e1e399741579612f13e2df98a25ea9447989d: Differentiate between monotonic and non-monotonic expansion and only assign node ids during monotonic expansion.
 - 78c00398780db6f59ebf43e765fa9368dad436d2: Expand generated test harnesses and macro registries.
 - f3c2dca3539e6edc745f9c91898cb97d281865c1: Remove scope placeholders from the crate root.
 - c86c8d41a26b2037e80c9fd028a59313a78b3a66: Perform node id assignment and `macros_at_scope` construction during the `InvocationCollector` and `PlaceholderExpander` folds.
 - 72a636975fc5d0bb4af45af7bdd97987cc722a6a: Move macro resolution into `librustc_resolve`.
 - 20b43b23230ce063ccf99a4841d85790ad311bdf: Rewrite the unit tests in `ext/expand.rs` as a `compile-fail` test.
 - a9821e1658240bb2c056f260a4b6bc9789301fae: Refactor `ExtCtxt` to use a `Resolver` instead of a `MacroLoader`.
 - 60440b226d2f70bdae803443ff7ad2e2af2c9b10: Refactor `noop_fold_stmt_kind` out of `noop_fold_stmt`.
 - 50f94f6c95c944f08c4af264f48260e42efefd47: Avoid needless reexpansions.

r? @nrc

1 files changed, 2 insertions, 7 deletions

diff --git a/src/libsyntax_ext/deriving/mod.rs b/src/libsyntax_ext/deriving/mod.rs
index fcbce363890..6162beb80ec 100644
--- a/src/libsyntax_ext/deriving/mod.rs
+++ b/src/libsyntax_ext/deriving/mod.rs
@@ -11,8 +11,7 @@
 //! The compiler code necessary to implement the `#[derive]` extensions.
 
 use syntax::ast::{self, MetaItem};
-use syntax::ext::base::{Annotatable, ExtCtxt, SyntaxEnv};
-use syntax::ext::base::MultiModifier;
+use syntax::ext::base::{Annotatable, ExtCtxt};
 use syntax::ext::build::AstBuilder;
 use syntax::feature_gate;
 use syntax::codemap;
@@ -89,7 +88,7 @@ fn allow_unstable(cx: &mut ExtCtxt, span: Span, attr_name: &str) -> Span {
     }
 }
 
-fn expand_derive(cx: &mut ExtCtxt,
+pub fn expand_derive(cx: &mut ExtCtxt,
                  span: Span,
                  mitem: &MetaItem,
                  annotatable: Annotatable)
@@ -243,10 +242,6 @@ fn expand_derive(cx: &mut ExtCtxt,
 
 macro_rules! derive_traits {
     ($( $name:expr => $func:path, )+) => {
-        pub fn register_all(env: &mut SyntaxEnv) {
-            env.insert(intern("derive"), MultiModifier(Box::new(expand_derive)));
-        }
-
         pub fn is_builtin_trait(name: &str) -> bool {
             match name {
                 $( $name )|+ => true,