Tweak CheckLintNameResult::Tool.

The `String` only makes sense alongside the `&'a [LintId]`, so this
commit moves it inside the `Option`, avoiding the need for a
`String::new` in one place.

Author: nnethercote

compiler/rustc_lint/src/context.rs

@@ -131,7 +131,7 @@ pub enum CheckLintNameResult<'a> {
     /// compiled with the tool and therefore the lint was never
     /// added to the `LintStore`. Otherwise the `LintId` will be
     /// returned as if it where a rustc lint.
-    Tool(Result<&'a [LintId], (Option<&'a [LintId]>, String)>),
+    Tool(Result<&'a [LintId], Option<(&'a [LintId], String)>>),
 }
 
 impl LintStore {
@@ -384,7 +384,7 @@ impl LintStore {
                         } else {
                             // 2. The tool isn't currently running, so no lints will be registered.
                             // To avoid giving a false positive, ignore all unknown lints.
-                            CheckLintNameResult::Tool(Err((None, String::new())))
+                            CheckLintNameResult::Tool(Err(None))
                         };
                     }
                     Some(LintGroup { lint_ids, .. }) => {
@@ -411,7 +411,7 @@ impl LintStore {
                         return if *silent {
                             CheckLintNameResult::Ok(lint_ids)
                         } else {
-                            CheckLintNameResult::Tool(Err((Some(lint_ids), (*name).to_string())))
+                            CheckLintNameResult::Tool(Err(Some((lint_ids, (*name).to_string()))))
                         };
                     }
                     CheckLintNameResult::Ok(lint_ids)
@@ -473,16 +473,17 @@ impl LintStore {
                     if let Some(LintAlias { name, silent }) = depr {
                         let LintGroup { lint_ids, .. } = self.lint_groups.get(name).unwrap();
                         return if *silent {
-                            CheckLintNameResult::Tool(Err((Some(lint_ids), complete_name)))
+                            // njn: factor
+                            CheckLintNameResult::Tool(Err(Some((lint_ids, complete_name))))
                         } else {
-                            CheckLintNameResult::Tool(Err((Some(lint_ids), (*name).to_string())))
+                            CheckLintNameResult::Tool(Err(Some((lint_ids, (*name).to_string()))))
                         };
                     }
-                    CheckLintNameResult::Tool(Err((Some(lint_ids), complete_name)))
+                    CheckLintNameResult::Tool(Err(Some((lint_ids, complete_name))))
                 }
             },
             Some(Id(id)) => {
-                CheckLintNameResult::Tool(Err((Some(slice::from_ref(id)), complete_name)))
+                CheckLintNameResult::Tool(Err(Some((slice::from_ref(id), complete_name))))
             }
             Some(other) => {
                 debug!("got renamed lint {:?}", other);

compiler/rustc_lint/src/levels.rs

@@ -591,7 +591,7 @@ impl<'s, P: LintLevelsProvider> LintLevelsBuilder<'s, P> {
                     let lint = UnknownLintFromCommandLine { name, suggestion, requested_level };
                     self.emit_lint(UNKNOWN_LINTS, lint);
                 }
-                CheckLintNameResult::Tool(Err((Some(_), ref replace))) => {
+                CheckLintNameResult::Tool(Err(Some((_, ref replace)))) => {
                     let name = lint_name.clone();
                     let requested_level = RequestedLevel { level, lint_name };
                     let lint = DeprecatedLintNameFromCommandLine { name, replace, requested_level };
@@ -919,7 +919,7 @@ impl<'s, P: LintLevelsProvider> LintLevelsBuilder<'s, P> {
                                     );
                                 }
                             }
-                            Err((Some(ids), ref new_lint_name)) => {
+                            Err(Some((ids, ref new_lint_name))) => {
                                 let lint = builtin::RENAMED_AND_REMOVED_LINTS;
                                 self.emit_span_lint(
                                     lint,
@@ -946,8 +946,8 @@ impl<'s, P: LintLevelsProvider> LintLevelsBuilder<'s, P> {
                                     );
                                 }
                             }
-                            Err((None, _)) => {
-                                // If Tool(Err(None, _)) is returned, then either the lint does not
+                            Err(None) => {
+                                // If Tool(Err(None)) is returned, then either the lint does not
                                 // exist in the tool or the code was not compiled with the tool and
                                 // therefore the lint was never added to the `LintStore`. To detect
                                 // this is the responsibility of the lint tool.