Unify lint tool and lint name checking

This shares a little more code between checking command line and
attribute lint specifications.

compiler/rustc_lint/src/context.rs

@@ -16,7 +16,7 @@
 
 use self::TargetLint::*;
 
-use crate::levels::LintLevelsBuilder;
+use crate::levels::{is_known_lint_tool, LintLevelsBuilder};
 use crate::passes::{EarlyLintPassObject, LateLintPassObject};
 use rustc_ast as ast;
 use rustc_data_structures::fx::FxHashMap;
@@ -129,6 +129,8 @@ pub enum CheckLintNameResult<'a> {
     Ok(&'a [LintId]),
     /// Lint doesn't exist. Potentially contains a suggestion for a correct lint name.
     NoLint(Option<Symbol>),
+    /// The lint refers to a tool that has not been registered.
+    NoTool,
     /// The lint is either renamed or removed. This is the warning
     /// message, and an optional new name (`None` if removed).
     Warning(String, Option<String>),
@@ -334,16 +336,17 @@ impl LintStore {
         }
     }
 
-    /// Checks the validity of lint names derived from the command line. Returns
-    /// true if the lint is valid, false otherwise.
+    /// Checks the validity of lint names derived from the command line.
     pub fn check_lint_name_cmdline(
         &self,
         sess: &Session,
         lint_name: &str,
-        level: Option<Level>,
-    ) -> bool {
+        level: Level,
+        crate_attrs: &[ast::Attribute],
+    ) {
         let (tool_name, lint_name) = parse_lint_and_tool_name(lint_name);
-        let db = match self.check_lint_name(lint_name, tool_name) {
+
+        let db = match self.check_lint_and_tool_name(sess, tool_name, lint_name, crate_attrs) {
             CheckLintNameResult::Ok(_) => None,
             CheckLintNameResult::Warning(ref msg, _) => Some(sess.struct_warn(msg)),
             CheckLintNameResult::NoLint(suggestion) => {
@@ -365,6 +368,13 @@ impl LintStore {
                 ))),
                 _ => None,
             },
+            CheckLintNameResult::NoTool => Some(struct_span_err!(
+                sess,
+                DUMMY_SP,
+                E0602,
+                "unknown lint tool: `{}`",
+                tool_name.unwrap()
+            )),
         };
 
         if let Some(mut db) = db {
@@ -398,6 +408,22 @@ impl LintStore {
         }
     }
 
+    pub fn check_lint_and_tool_name(
+        &self,
+        sess: &Session,
+        tool_name: Option<Symbol>,
+        lint_name: &str,
+        crate_attrs: &[ast::Attribute],
+    ) -> CheckLintNameResult<'_> {
+        if let Some(tool_name) = tool_name {
+            if !is_known_lint_tool(tool_name, sess, crate_attrs) {
+                return CheckLintNameResult::NoTool;
+            }
+        }
+
+        self.check_lint_name(lint_name, tool_name)
+    }
+
     /// Checks the name of a lint for its existence, and whether it was
     /// renamed or removed. Generates a DiagnosticBuilder containing a
     /// warning for renamed and removed lints. This is over both lint
@@ -1028,7 +1054,11 @@ impl<'tcx> LayoutOf for LateContext<'tcx> {
 
 pub fn parse_lint_and_tool_name(lint_name: &str) -> (Option<Symbol>, &str) {
     match lint_name.split_once("::") {
-        Some((tool_name, lint_name)) => (Some(Symbol::intern(tool_name)), lint_name),
+        Some((tool_name, lint_name)) => {
+            let tool_name = Symbol::intern(tool_name);
+
+            (Some(tool_name), lint_name)
+        }
         None => (None, lint_name),
     }
 }

compiler/rustc_lint/src/levels.rs

@@ -88,7 +88,7 @@ impl<'s> LintLevelsBuilder<'s> {
         self.sets.lint_cap = sess.opts.lint_cap.unwrap_or(Level::Forbid);
 
         for &(ref lint_name, level) in &sess.opts.lint_opts {
-            store.check_lint_name_cmdline(sess, &lint_name, level);
+            store.check_lint_name_cmdline(sess, &lint_name, level, self.crate_attrs);
             let orig_level = level;
 
             // If the cap is less than this specified level, e.g., if we've got
@@ -110,7 +110,7 @@ impl<'s> LintLevelsBuilder<'s> {
         }
 
         for lint_name in &sess.opts.force_warns {
-            store.check_lint_name_cmdline(sess, lint_name, Level::ForceWarn);
+            store.check_lint_name_cmdline(sess, lint_name, Level::ForceWarn, self.crate_attrs);
             let lints = store
                 .find_lints(lint_name)
                 .unwrap_or_else(|_| bug!("A valid lint failed to produce a lint ids"));
@@ -321,33 +321,15 @@ impl<'s> LintLevelsBuilder<'s> {
                         continue;
                     }
                 };
-                let tool_name = if meta_item.path.segments.len() > 1 {
-                    let tool_ident = meta_item.path.segments[0].ident;
-                    if !is_known_lint_tool(tool_ident.name, sess, &self.crate_attrs) {
-                        let mut err = struct_span_err!(
-                            sess,
-                            tool_ident.span,
-                            E0710,
-                            "unknown tool name `{}` found in scoped lint: `{}`",
-                            tool_ident.name,
-                            pprust::path_to_string(&meta_item.path),
-                        );
-                        if sess.is_nightly_build() {
-                            err.help(&format!(
-                                "add `#![register_tool({})]` to the crate root",
-                                tool_ident.name
-                            ));
-                        }
-                        err.emit();
-                        continue;
-                    }
-
-                    Some(meta_item.path.segments.remove(0).ident.name)
+                let tool_ident = if meta_item.path.segments.len() > 1 {
+                    Some(meta_item.path.segments.remove(0).ident)
                 } else {
                     None
                 };
+                let tool_name = tool_ident.map(|ident| ident.name);
                 let name = pprust::path_to_string(&meta_item.path);
-                let lint_result = store.check_lint_name(&name, tool_name);
+                let lint_result =
+                    store.check_lint_and_tool_name(sess, tool_name, &name, self.crate_attrs);
                 match &lint_result {
                     CheckLintNameResult::Ok(ids) => {
                         let src = LintLevelSource::Node(
@@ -364,7 +346,8 @@ impl<'s> LintLevelsBuilder<'s> {
                     CheckLintNameResult::Tool(result) => {
                         match *result {
                             Ok(ids) => {
-                                let complete_name = &format!("{}::{}", tool_name.unwrap(), name);
+                                let complete_name =
+                                    &format!("{}::{}", tool_ident.unwrap().name, name);
                                 let src = LintLevelSource::Node(
                                     Symbol::intern(complete_name),
                                     sp,
@@ -419,6 +402,26 @@ impl<'s> LintLevelsBuilder<'s> {
                         }
                     }
 
+                    &CheckLintNameResult::NoTool => {
+                        let mut err = struct_span_err!(
+                            sess,
+                            tool_ident.map_or(DUMMY_SP, |ident| ident.span),
+                            E0710,
+                            "unknown tool name `{}` found in scoped lint: `{}::{}`",
+                            tool_name.unwrap(),
+                            tool_name.unwrap(),
+                            pprust::path_to_string(&meta_item.path),
+                        );
+                        if sess.is_nightly_build() {
+                            err.help(&format!(
+                                "add `#![register_tool({})]` to the crate root",
+                                tool_name.unwrap()
+                            ));
+                        }
+                        err.emit();
+                        continue;
+                    }
+
                     _ if !self.warn_about_weird_lints => {}
 
                     CheckLintNameResult::Warning(msg, renamed) => {
@@ -450,8 +453,8 @@ impl<'s> LintLevelsBuilder<'s> {
                         let (level, src) =
                             self.sets.get_lint_level(lint, self.cur, Some(&specs), self.sess);
                         struct_lint_level(self.sess, lint, level, src, Some(sp.into()), |lint| {
-                            let name = if let Some(tool_name) = tool_name {
-                                format!("{}::{}", tool_name, name)
+                            let name = if let Some(tool_ident) = tool_ident {
+                                format!("{}::{}", tool_ident.name, name)
                             } else {
                                 name.to_string()
                             };
@@ -578,7 +581,7 @@ impl<'s> LintLevelsBuilder<'s> {
     }
 }
 
-fn is_known_lint_tool(m_item: Symbol, sess: &Session, attrs: &[ast::Attribute]) -> bool {
+pub fn is_known_lint_tool(m_item: Symbol, sess: &Session, attrs: &[ast::Attribute]) -> bool {
     if [sym::clippy, sym::rustc, sym::rustdoc].contains(&m_item) {
         return true;
     }

src/test/ui/lint/command-line-register-unknown-lint-tool.stderr

@@ -1,10 +1,10 @@
-error[E0602]: unknown lint: `unknown_tool::foo`
+error[E0602]: unknown lint tool: `unknown_tool`
    |
-   = note: requested on the command line with `-A unknown_tool::foo`
+   = note: requested on the command line with `-A foo`
 
-error[E0602]: unknown lint: `unknown_tool::foo`
+error[E0602]: unknown lint tool: `unknown_tool`
    |
-   = note: requested on the command line with `-A unknown_tool::foo`
+   = note: requested on the command line with `-A foo`
 
 error: aborting due to 2 previous errors