Parse tool name for command line lint options

compiler/rustc_lint/src/context.rs

@@ -334,9 +334,16 @@ pub fn find_lints(&self, mut lint_name: &str) -> Result<Vec<LintId>, FindLintErr
         }
     }
 
-    /// Checks the validity of lint names derived from the command line
-    pub fn check_lint_name_cmdline(&self, sess: &Session, lint_name: &str, level: Level) {
-        let db = match self.check_lint_name(lint_name, None) {
+    /// Checks the validity of lint names derived from the command line. Returns
+    /// true if the lint is valid, false otherwise.
+    pub fn check_lint_name_cmdline(
+        &self,
+        sess: &Session,
+        lint_name: &str,
+        level: Option<Level>,
+    ) -> bool {
+        let (tool_name, lint_name) = parse_lint_and_tool_name(lint_name);
+        let db = match self.check_lint_name(lint_name, tool_name) {
             CheckLintNameResult::Ok(_) => None,
             CheckLintNameResult::Warning(ref msg, _) => Some(sess.struct_warn(msg)),
             CheckLintNameResult::NoLint(suggestion) => {
@@ -1018,3 +1025,10 @@ fn layout_of(&self, ty: Ty<'tcx>) -> Self::TyAndLayout {
         self.tcx.layout_of(self.param_env.and(ty))
     }
 }
+
+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),
+        None => (None, lint_name),
+    }
+}

compiler/rustc_lint/src/lib.rs

@@ -494,3 +494,6 @@ fn register_internals(store: &mut LintStore) {
         ],
     );
 }
+
+#[cfg(test)]
+mod tests;

compiler/rustc_lint/src/tests.rs

@@ -0,0 +1,24 @@
+use crate::context::parse_lint_and_tool_name;
+use rustc_span::{with_default_session_globals, Symbol};
+
+#[test]
+fn parse_lint_no_tool() {
+    with_default_session_globals(|| assert_eq!(parse_lint_and_tool_name("foo"), (None, "foo")));
+}
+
+#[test]
+fn parse_lint_with_tool() {
+    with_default_session_globals(|| {
+        assert_eq!(parse_lint_and_tool_name("clippy::foo"), (Some(Symbol::intern("clippy")), "foo"))
+    });
+}
+
+#[test]
+fn parse_lint_multiple_path() {
+    with_default_session_globals(|| {
+        assert_eq!(
+            parse_lint_and_tool_name("clippy::foo::bar"),
+            (Some(Symbol::intern("clippy")), "foo::bar")
+        )
+    });
+}