Make useless_attribute suggestion MaybeIncorrect

Author: phansch

clippy_lints/src/attrs.rs

@@ -277,7 +277,7 @@ impl<'a, 'tcx> LateLintPass<'a, 'tcx> for Attributes {
                                                         line_span,
                                                         "if you just forgot a `!`, use",
                                                         sugg,
-                                                        Applicability::MachineApplicable,
+                                                        Applicability::MaybeIncorrect,
                                                     );
                                                 },
                                             );

tests/ui/useless_attribute.fixed

@@ -1,4 +1,3 @@
-// run-rustfix
 // aux-build:proc_macro_derive.rs
 
 #![warn(clippy::useless_attribute)]

tests/ui/useless_attribute.rs

@@ -1,13 +1,13 @@
 error: useless lint attribute
-  --> $DIR/useless_attribute.rs:7:1
+  --> $DIR/useless_attribute.rs:6:1
    |
 LL | #[allow(dead_code)]
    | ^^^^^^^^^^^^^^^^^^^ help: if you just forgot a `!`, use: `#![allow(dead_code)]`
    |
    = note: `-D clippy::useless-attribute` implied by `-D warnings`
 
 error: useless lint attribute
-  --> $DIR/useless_attribute.rs:8:1
+  --> $DIR/useless_attribute.rs:7:1
    |
 LL | #[cfg_attr(feature = "cargo-clippy", allow(dead_code))]
    | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: if you just forgot a `!`, use: `#![cfg_attr(feature = "cargo-clippy", allow(dead_code)`