groundwork refactoring of gather_moves

src/librustc/mir/repr.rs

@@ -1243,7 +1243,7 @@ impl<'a, 'b>  GraphSuccessors<'b> for Mir<'a> {
     type Iter = IntoIter<BasicBlock>;
 }
 
-#[derive(Copy, Clone, PartialEq, Eq, Debug, Hash, Ord, PartialOrd)]
+#[derive(Copy, Clone, PartialEq, Eq, Hash, Ord, PartialOrd)]
 pub struct Location {
     /// the location is within this block
     pub block: BasicBlock,
@@ -1253,3 +1253,8 @@ pub struct Location {
     pub statement_index: usize,
 }
 
+impl fmt::Debug for Location {
+    fn fmt(&self, fmt: &mut fmt::Formatter) -> fmt::Result {
+        write!(fmt, "{:?}[{}]", self.block, self.statement_index)
+    }
+}

src/librustc/mir/visit.rs

@@ -774,9 +774,6 @@ pub enum LvalueContext<'tcx> {
     // Being borrowed
     Borrow { region: &'tcx Region, kind: BorrowKind },
 
-    // Being sliced -- this should be same as being borrowed, probably
-    Slice { from_start: usize, from_end: usize },
-
     // Used as base for another lvalue, e.g. `x` in `x.y`
     Projection,