mark applicability

src/librustc/middle/liveness.rs

@@ -106,6 +106,7 @@ use self::LoopKind::*;
 use self::LiveNodeKind::*;
 use self::VarKind::*;
 
+use errors::Applicability;
 use hir::def::*;
 use ty::{self, TyCtxt};
 use lint;
@@ -1558,8 +1559,9 @@ impl<'a, 'tcx> Liveness<'a, 'tcx> {
                         err.span_suggestion(sp, "try ignoring the field",
                                             format!("{}: _", name));
                     } else {
-                        err.span_suggestion_short(sp, &suggest_underscore_msg,
-                                                  format!("_{}", name));
+                        err.span_suggestion_with_applicability(
+                            sp, &suggest_underscore_msg,
+                            format!("_{}", name), Applicability::MachineApplicable);
                     }
                     err.emit()
                 }

src/test/ui/lint/issue-47390-unused-variable-in-struct-pattern.rs

@@ -9,6 +9,7 @@
 // except according to those terms.
 
 // compile-pass
+// run-rustfix
 
 #![feature(box_syntax)]
 #![feature(box_patterns)]