librustc: Add a new nop statement to the MIR.

This is useful when passes want to remove statements without affecting
`Location`s.

2 files changed, 3 insertions, 1 deletions

diff --git a/src/librustc_mir/transform/qualify_consts.rs b/src/librustc_mir/transform/qualify_consts.rs
index a3f8f7a63ee..9f162aabe0c 100644
--- a/src/librustc_mir/transform/qualify_consts.rs
+++ b/src/librustc_mir/transform/qualify_consts.rs
@@ -910,7 +910,8 @@ impl<'a, 'tcx> Visitor<'tcx> for Qualifier<'a, 'tcx, 'tcx> {
                 }
                 StatementKind::SetDiscriminant { .. } |
                 StatementKind::StorageLive(_) |
-                StatementKind::StorageDead(_) => {}
+                StatementKind::StorageDead(_) |
+                StatementKind::Nop => {}
             }
         });
     }
diff --git a/src/librustc_mir/transform/type_check.rs b/src/librustc_mir/transform/type_check.rs
index 7fda658185e..412759cd5b2 100644
--- a/src/librustc_mir/transform/type_check.rs
+++ b/src/librustc_mir/transform/type_check.rs
@@ -385,6 +385,7 @@ impl<'a, 'gcx, 'tcx> TypeChecker<'a, 'gcx, 'tcx> {
                     }
                 }
             }
+            StatementKind::Nop => {}
         }
     }