[WIP] Preliminary work splitting const qualification into separate passes

src/librustc_data_structures/indexed_set.rs

@@ -210,6 +210,16 @@ impl<T: Idx> IdxSet<T> {
         self.bits.set_bit(elem.index())
     }
 
+    /// Adds `elem` to the set `self` if `member` is `true`, otherwise removes `elem` from the set;
+    /// returns true iff this changed `self`.
+    pub fn set_member(&mut self, elem: &T, member: bool) -> bool {
+        if member {
+            self.add(elem)
+        } else {
+            self.remove(elem)
+        }
+    }
+
     pub fn range(&self, elems: &Range<T>) -> &Self {
         let elems = elems.start.index()..elems.end.index();
         unsafe { Self::from_slice(&self.bits[elems]) }

src/librustc_mir/lib.rs

@@ -42,14 +42,14 @@ Rust MIR: a lowered representation of Rust. Also: an experiment!
 extern crate arena;
 
 #[macro_use]
-extern crate bitflags;
-#[macro_use] extern crate log;
+extern crate log;
 extern crate either;
 extern crate graphviz as dot;
 extern crate polonius_engine;
 #[macro_use]
 extern crate rustc;
-#[macro_use] extern crate rustc_data_structures;
+#[macro_use]
+extern crate rustc_data_structures;
 extern crate serialize as rustc_serialize;
 extern crate rustc_errors;
 #[macro_use]

src/librustc_mir/transform/promote_consts.rs

@@ -384,9 +384,8 @@ impl<'a, 'tcx> MutVisitor<'tcx> for Promoter<'a, 'tcx> {
                    local: &mut Local,
                    _: PlaceContext<'tcx>,
                    _: Location) {
-        if self.source.local_kind(*local) == LocalKind::Temp {
-            *local = self.promote_temp(*local);
-        }
+        assert_eq!(self.source.local_kind(*local), LocalKind::Temp);
+        *local = self.promote_temp(*local);
     }
 }