Auto merge of #54251 - varkor:silence-bad_style, r=Manishearth

Make `bad_style` a silent alias for `nonstandard_style`

Now only `nonstandard_style` is suggested in `rustc -W help`, but `bad_style` will not produce a warning. Closes #41646.

r? @Manishearth

2 files changed, 94 insertions, 45 deletions

diff --git a/src/librustc/lint/context.rs b/src/librustc/lint/context.rs
index 0633286e398..852af2cdaa2 100644
--- a/src/librustc/lint/context.rs
+++ b/src/librustc/lint/context.rs
@@ -67,10 +67,8 @@ pub struct LintStore {
     /// Lints indexed by name.
     by_name: FxHashMap<String, TargetLint>,
 
-    /// Map of registered lint groups to what lints they expand to. The first
-    /// bool is true if the lint group was added by a plugin. The optional string
-    /// is used to store the new names of deprecated lint group names.
-    lint_groups: FxHashMap<&'static str, (Vec<LintId>, bool, Option<&'static str>)>,
+    /// Map of registered lint groups to what lints they expand to.
+    lint_groups: FxHashMap<&'static str, LintGroup>,
 
     /// Extra info for future incompatibility lints, describing the
     /// issue or RFC that caused the incompatibility.
@@ -127,6 +125,18 @@ pub enum FindLintError {
     Removed,
 }
 
+struct LintAlias {
+    name: &'static str,
+    /// Whether deprecation warnings should be suppressed for this alias.
+    silent: bool,
+}
+
+struct LintGroup {
+    lint_ids: Vec<LintId>,
+    from_plugin: bool,
+    depr: Option<LintAlias>,
+}
+
 pub enum CheckLintNameResult<'a> {
     Ok(&'a [LintId]),
     /// Lint doesn't exist
@@ -160,9 +170,15 @@ impl LintStore {
     }
 
     pub fn get_lint_groups<'t>(&'t self) -> Vec<(&'static str, Vec<LintId>, bool)> {
-        self.lint_groups.iter().map(|(k, v)| (*k,
-                                              v.0.clone(),
-                                              v.1)).collect()
+        self.lint_groups.iter()
+            .filter(|(_, LintGroup { depr, .. })| {
+                // Don't display deprecated lint groups.
+                depr.is_none()
+            })
+            .map(|(k, LintGroup { lint_ids, from_plugin, .. })| {
+                (*k, lint_ids.clone(), *from_plugin)
+            })
+            .collect()
     }
 
     pub fn register_early_pass(&mut self,
@@ -245,6 +261,18 @@ impl LintStore {
         self.future_incompatible.get(&id)
     }
 
+    pub fn register_group_alias(
+        &mut self,
+        lint_name: &'static str,
+        alias: &'static str,
+    ) {
+        self.lint_groups.insert(alias, LintGroup {
+            lint_ids: vec![],
+            from_plugin: false,
+            depr: Some(LintAlias { name: lint_name, silent: true }),
+        });
+    }
+
     pub fn register_group(
         &mut self,
         sess: Option<&Session>,
@@ -255,11 +283,18 @@ impl LintStore {
     ) {
         let new = self
             .lint_groups
-            .insert(name, (to, from_plugin, None))
+            .insert(name, LintGroup {
+                lint_ids: to,
+                from_plugin,
+                depr: None,
+            })
             .is_none();
         if let Some(deprecated) = deprecated_name {
-            self.lint_groups
-                .insert(deprecated, (vec![], from_plugin, Some(name)));
+            self.lint_groups.insert(deprecated, LintGroup {
+                lint_ids: vec![],
+                from_plugin,
+                depr: Some(LintAlias { name, silent: false }),
+            });
         }
 
         if !new {
@@ -288,7 +323,7 @@ impl LintStore {
         self.by_name.insert(name.into(), Removed(reason.into()));
     }
 
-    pub fn find_lints(&self, lint_name: &str) -> Result<Vec<LintId>, FindLintError> {
+    pub fn find_lints(&self, mut lint_name: &str) -> Result<Vec<LintId>, FindLintError> {
         match self.by_name.get(lint_name) {
             Some(&Id(lint_id)) => Ok(vec![lint_id]),
             Some(&Renamed(_, lint_id)) => {
@@ -298,9 +333,17 @@ impl LintStore {
                 Err(FindLintError::Removed)
             },
             None => {
-                match self.lint_groups.get(lint_name) {
-                    Some(v) => Ok(v.0.clone()),
-                    None => Err(FindLintError::Removed)
+                loop {
+                    return match self.lint_groups.get(lint_name) {
+                        Some(LintGroup {lint_ids, depr, .. }) => {
+                            if let Some(LintAlias { name, .. }) = depr {
+                                lint_name = name;
+                                continue;
+                            }
+                            Ok(lint_ids.clone())
+                        }
+                        None => Err(FindLintError::Removed)
+                    };
                 }
             }
         }
@@ -366,7 +409,9 @@ impl LintStore {
             match self.by_name.get(&complete_name) {
                 None => match self.lint_groups.get(&*complete_name) {
                     None => return CheckLintNameResult::Tool(Err((None, String::new()))),
-                    Some(ids) => return CheckLintNameResult::Tool(Ok(&ids.0)),
+                    Some(LintGroup { lint_ids, .. }) => {
+                        return CheckLintNameResult::Tool(Ok(&lint_ids));
+                    }
                 },
                 Some(&Id(ref id)) => return CheckLintNameResult::Tool(Ok(slice::from_ref(id))),
                 // If the lint was registered as removed or renamed by the lint tool, we don't need
@@ -390,16 +435,20 @@ impl LintStore {
                 // If neither the lint, nor the lint group exists check if there is a `clippy::`
                 // variant of this lint
                 None => self.check_tool_name_for_backwards_compat(&complete_name, "clippy"),
-                Some(ids) => {
+                Some(LintGroup { lint_ids, depr, .. }) => {
                     // Check if the lint group name is deprecated
-                    if let Some(new_name) = ids.2 {
-                        let lint_ids = self.lint_groups.get(new_name).unwrap();
-                        return CheckLintNameResult::Tool(Err((
-                            Some(&lint_ids.0),
-                            new_name.to_string(),
-                        )));
+                    if let Some(LintAlias { name, silent }) = depr {
+                        let LintGroup { lint_ids, .. } = self.lint_groups.get(name).unwrap();
+                        return if *silent {
+                            CheckLintNameResult::Ok(&lint_ids)
+                        } else {
+                            CheckLintNameResult::Tool(Err((
+                                Some(&lint_ids),
+                                name.to_string(),
+                            )))
+                        };
                     }
-                    CheckLintNameResult::Ok(&ids.0)
+                    CheckLintNameResult::Ok(&lint_ids)
                 }
             },
             Some(&Id(ref id)) => CheckLintNameResult::Ok(slice::from_ref(id)),
@@ -416,16 +465,20 @@ impl LintStore {
             None => match self.lint_groups.get(&*complete_name) {
                 // Now we are sure, that this lint exists nowhere
                 None => CheckLintNameResult::NoLint,
-                Some(ids) => {
-                    // Reaching this would be weird, but lets cover this case anyway
-                    if let Some(new_name) = ids.2 {
-                        let lint_ids = self.lint_groups.get(new_name).unwrap();
-                        return CheckLintNameResult::Tool(Err((
-                            Some(&lint_ids.0),
-                            new_name.to_string(),
-                        )));
+                Some(LintGroup { lint_ids, depr, .. }) => {
+                    // Reaching this would be weird, but let's cover this case anyway
+                    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)))
+                        } else {
+                            CheckLintNameResult::Tool(Err((
+                                Some(&lint_ids),
+                                name.to_string(),
+                            )))
+                        };
                     }
-                    CheckLintNameResult::Tool(Err((Some(&ids.0), complete_name)))
+                    CheckLintNameResult::Tool(Err((Some(&lint_ids), complete_name)))
                 }
             },
             Some(&Id(ref id)) => {
diff --git a/src/librustc_lint/lib.rs b/src/librustc_lint/lib.rs
index bdf09007fdd..7aae22d5739 100644
--- a/src/librustc_lint/lib.rs
+++ b/src/librustc_lint/lib.rs
@@ -84,30 +84,30 @@ pub fn register_builtins(store: &mut lint::LintStore, sess: Option<&Session>) {
         ($sess:ident, $($name:ident),*,) => (
             {$(
                 store.register_early_pass($sess, false, box $name);
-                )*}
-            )
+            )*}
+        )
     }
 
     macro_rules! add_pre_expansion_builtin {
         ($sess:ident, $($name:ident),*,) => (
             {$(
                 store.register_pre_expansion_pass($sess, box $name);
-                )*}
-            )
+            )*}
+        )
     }
 
     macro_rules! add_early_builtin_with_new {
         ($sess:ident, $($name:ident),*,) => (
             {$(
                 store.register_early_pass($sess, false, box $name::new());
-                )*}
-            )
+            )*}
+        )
     }
 
     macro_rules! add_lint_group {
         ($sess:ident, $name:expr, $($lint:ident),*) => (
             store.register_group($sess, false, $name, None, vec![$(LintId::of($lint)),*]);
-            )
+        )
     }
 
     add_pre_expansion_builtin!(sess,
@@ -163,12 +163,6 @@ pub fn register_builtins(store: &mut lint::LintStore, sess: Option<&Session>) {
     store.register_late_pass(sess, false, box BuiltinCombinedLateLintPass::new());
 
     add_lint_group!(sess,
-                    "bad_style",
-                    NON_CAMEL_CASE_TYPES,
-                    NON_SNAKE_CASE,
-                    NON_UPPER_CASE_GLOBALS);
-
-    add_lint_group!(sess,
                     "nonstandard_style",
                     NON_CAMEL_CASE_TYPES,
                     NON_SNAKE_CASE,
@@ -357,6 +351,8 @@ pub fn register_builtins(store: &mut lint::LintStore, sess: Option<&Session>) {
     store.register_removed("unsigned_negation", "replaced by negate_unsigned feature gate");
     store.register_removed("negate_unsigned", "cast a signed value instead");
     store.register_removed("raw_pointer_derive", "using derive with raw pointers is ok");
+    // Register lint group aliases
+    store.register_group_alias("nonstandard_style", "bad_style");
     // This was renamed to raw_pointer_derive, which was then removed,
     // so it is also considered removed
     store.register_removed("raw_pointer_deriving", "using derive with raw pointers is ok");