Moved map_err_ignore to restriction and updated help message

clippy_lints/src/lib.rs

@@ -1214,6 +1214,7 @@ pub fn register_plugins(store: &mut rustc_lint::LintStore, sess: &Session, conf:
         LintId::of(&integer_division::INTEGER_DIVISION),
         LintId::of(&let_underscore::LET_UNDERSCORE_MUST_USE),
         LintId::of(&literal_representation::DECIMAL_LITERAL_REPRESENTATION),
+        LintId::of(&map_err_ignore::MAP_ERR_IGNORE),
         LintId::of(&matches::REST_PAT_IN_FULLY_BOUND_STRUCTS),
         LintId::of(&matches::WILDCARD_ENUM_MATCH_ARM),
         LintId::of(&mem_forget::MEM_FORGET),
@@ -1280,7 +1281,6 @@ pub fn register_plugins(store: &mut rustc_lint::LintStore, sess: &Session, conf:
         LintId::of(&loops::EXPLICIT_ITER_LOOP),
         LintId::of(&macro_use::MACRO_USE_IMPORTS),
         LintId::of(&manual_ok_or::MANUAL_OK_OR),
-        LintId::of(&map_err_ignore::MAP_ERR_IGNORE),
         LintId::of(&match_on_vec_items::MATCH_ON_VEC_ITEMS),
         LintId::of(&matches::MATCH_BOOL),
         LintId::of(&matches::MATCH_SAME_ARMS),

clippy_lints/src/map_err_ignore.rs

@@ -99,7 +99,7 @@ declare_clippy_lint! {
     /// }
     /// ```
     pub MAP_ERR_IGNORE,
-    pedantic,
+    restriction,
     "`map_err` should not ignore the original error"
 }
 
@@ -135,7 +135,7 @@ impl<'tcx> LateLintPass<'tcx> for MapErrIgnore {
                                     body_span,
                                     "`map_err(|_|...` ignores the original error",
                                     None,
-                                    "Consider wrapping the error in an enum variant",
+                                    "Consider wrapping the error in an enum variant for more error context, or using a named wildcard (`.map_err(|_ignored| ...`) to intentionally ignore the error",
                                 );
                             }
                         }

tests/ui/map_err.stderr

@@ -5,7 +5,7 @@ LL |     println!("{:?}", x.map_err(|_| Errors::Ignored));
    |                                ^^^
    |
    = note: `-D clippy::map-err-ignore` implied by `-D warnings`
-   = help: Consider wrapping the error in an enum variant
+   = help: Consider wrapping the error in an enum variant for more error context, or using a named wildcard (`.map_err(|_ignored| ...`) to intentionally ignore the error
 
 error: aborting due to previous error