Collect library features from non-exported macros

Author: petrochenkov

src/librustc/hir/lowering.rs

@@ -90,6 +90,7 @@ pub struct LoweringContext<'a> {
     impl_items: BTreeMap<hir::ImplItemId, hir::ImplItem>,
     bodies: BTreeMap<hir::BodyId, hir::Body>,
     exported_macros: Vec<hir::MacroDef>,
+    non_exported_macro_attrs: Vec<ast::Attribute>,
 
     trait_impls: BTreeMap<DefId, Vec<hir::HirId>>,
 
@@ -252,6 +253,7 @@ pub fn lower_crate(
         trait_impls: BTreeMap::new(),
         modules: BTreeMap::new(),
         exported_macros: Vec::new(),
+        non_exported_macro_attrs: Vec::new(),
         catch_scopes: Vec::new(),
         loop_scopes: Vec::new(),
         is_in_loop_condition: false,
@@ -662,6 +664,7 @@ impl<'a> LoweringContext<'a> {
             attrs,
             span: c.span,
             exported_macros: hir::HirVec::from(self.exported_macros),
+            non_exported_macro_attrs: hir::HirVec::from(self.non_exported_macro_attrs),
             items: self.items,
             trait_items: self.trait_items,
             impl_items: self.impl_items,
@@ -4022,6 +4025,8 @@ impl<'a> LoweringContext<'a> {
                     body,
                     legacy: def.legacy,
                 });
+            } else {
+                self.non_exported_macro_attrs.extend(attrs.into_iter());
             }
             return None;
         }

src/librustc/hir/map/collector.rs

@@ -119,6 +119,7 @@ impl<'a, 'hir> NodeCollector<'a, 'hir> {
                 span,
                 // These fields are handled separately:
                 exported_macros: _,
+                non_exported_macro_attrs: _,
                 items: _,
                 trait_items: _,
                 impl_items: _,

src/librustc/hir/mod.rs

@@ -727,6 +727,8 @@ pub struct Crate {
     pub attrs: HirVec<Attribute>,
     pub span: Span,
     pub exported_macros: HirVec<MacroDef>,
+    // Attributes from non-exported macros, kept only for collecting the library feature list.
+    pub non_exported_macro_attrs: HirVec<Attribute>,
 
     // N.B., we use a BTreeMap here so that `visit_all_items` iterates
     // over the ids in increasing order. In principle it should not

src/librustc/middle/lib_features.rs

@@ -144,6 +144,10 @@ impl Visitor<'tcx> for LibFeatureCollector<'tcx> {
 
 pub fn collect(tcx: TyCtxt<'_>) -> LibFeatures {
     let mut collector = LibFeatureCollector::new(tcx);
-    intravisit::walk_crate(&mut collector, tcx.hir().krate());
+    let krate = tcx.hir().krate();
+    for attr in &krate.non_exported_macro_attrs {
+        collector.visit_attribute(attr);
+    }
+    intravisit::walk_crate(&mut collector, krate);
     collector.lib_features
 }

src/test/run-pass/macros/macro-stability.rs

@@ -1,7 +1,7 @@
 // run-pass
 // aux-build:unstable-macros.rs
 
-#![feature(unstable_macros)]
+#![feature(unstable_macros, local_unstable)]
 
 #[macro_use] extern crate unstable_macros;