Make OP_REF lint suggestion MaybeIncorrect

cc #2597

Author: flip1995

clippy_lints/src/eq_op.rs

@@ -155,7 +155,7 @@ impl<'a, 'tcx> LateLintPass<'a, 'tcx> for EqOp {
                                     left.span,
                                     "use the left value directly",
                                     lsnip,
-                                    Applicability::MachineApplicable, // snippet
+                                    Applicability::MaybeIncorrect, // FIXME #2597
                                 );
                             })
                         }
@@ -173,7 +173,7 @@ impl<'a, 'tcx> LateLintPass<'a, 'tcx> for EqOp {
                                     right.span,
                                     "use the right value directly",
                                     rsnip,
-                                    Applicability::MachineApplicable, // snippet
+                                    Applicability::MaybeIncorrect, // FIXME #2597
                                 );
                             })
                         }