fix --emit=mir: StructCtors are functions

Author: RalfJung

src/librustc/hir/map/mod.rs

@@ -375,6 +375,10 @@ impl<'hir> Map<'hir> {
                 let def_id = self.local_def_id(item.id);
                 Some(Def::Const(def_id))
             }
+            Node::StructCtor(variant) => {
+                let def_id = self.local_def_id(variant.id());
+                Some(Def::Fn(def_id))
+            }
             Node::Field(_) |
             Node::Expr(_) |
             Node::Stmt(_) |
@@ -383,7 +387,6 @@ impl<'hir> Map<'hir> {
             Node::TraitRef(_) |
             Node::Pat(_) |
             Node::Binding(_) |
-            Node::StructCtor(_) |
             Node::Lifetime(_) |
             Node::Visibility(_) |
             Node::Block(_) |

src/librustc_mir/util/pretty.rs

@@ -594,7 +594,7 @@ fn write_mir_sig(
 ) -> io::Result<()> {
     use rustc::hir::def::Def;
 
-    trace!("write_mir_sig: {:?} {:?}", src, tcx.hir().get_if_local(src.def_id()));
+    trace!("write_mir_sig: {:?}", src.instance);
     let descr = tcx.describe_def(src.def_id()).unwrap();
     match (descr, src.promoted) {
         (_, Some(i)) => write!(w, "{:?} in", i)?,