adjust applicability

Signed-off-by: tabokie <[email protected]>

Author: tabokie

clippy_lints/src/assertions_on_result_states.rs

@@ -26,7 +26,7 @@ declare_clippy_lint! {
     #[clippy::version = "1.64.0"]
     pub ASSERTIONS_ON_RESULT_STATES,
     style,
-    "`assert!(r.is_ok())` gives worse error message than directly calling `r.unwrap()`"
+    "`assert!(r.is_ok())`/`assert!(r.is_err())` gives worse error message than directly calling `r.unwrap()`/`r.unwrap_err()`"
 }
 
 declare_lint_pass!(AssertionsOnResultStates => [ASSERTIONS_ON_RESULT_STATES]);
@@ -54,7 +54,7 @@ impl<'tcx> LateLintPass<'tcx> for AssertionsOnResultStates {
                         "{}.unwrap()",
                         method_receiver_snippet
                     ),
-                    Applicability::MachineApplicable,
+                    Applicability::MaybeIncorrect,
                 );
             } else if method_segment.ident.name == sym!(is_err)
               && let Some(value_type) = get_result_child_type(cx, result_type, false /*err*/)
@@ -70,7 +70,7 @@ impl<'tcx> LateLintPass<'tcx> for AssertionsOnResultStates {
                         "{}.unwrap_err()",
                         method_receiver_snippet
                     ),
-                    Applicability::MachineApplicable,
+                    Applicability::MaybeIncorrect,
                 );
             }
         }
@@ -84,7 +84,7 @@ fn get_result_child_type<'a>(cx: &LateContext<'_>, ty: Ty<'a>, err: bool) -> Opt
             if err {
                 substs.types().nth(1)
             } else {
-                substs.types().nth(0)
+                substs.types().next()
             }
         },
         _ => None,