Add some documentation

src/librustc/lint/context.rs

@@ -155,23 +155,31 @@ impl LintStore {
  .collect()
  }
 
- pub fn register_early_pass(&mut self,
- pass: impl Fn() -> EarlyLintPassObject + 'static + sync::Send + sync::Sync) {
+ pub fn register_early_pass(
+ &mut self,
+ pass: impl Fn() -> EarlyLintPassObject + 'static + sync::Send + sync::Sync
+ ) {
  self.early_passes.push(Box::new(pass));
  }
 
- pub fn register_pre_expansion_pass(&mut self,
- pass: impl Fn() -> EarlyLintPassObject + 'static + sync::Send + sync::Sync) {
+ pub fn register_pre_expansion_pass(
+ &mut self,
+ pass: impl Fn() -> EarlyLintPassObject + 'static + sync::Send + sync::Sync,
+ ) {
  self.pre_expansion_passes.push(Box::new(pass));
  }
 
- pub fn register_late_pass(&mut self,
- pass: impl Fn() -> LateLintPassObject + 'static + sync::Send + sync::Sync) {
+ pub fn register_late_pass(
+ &mut self,
+ pass: impl Fn() -> LateLintPassObject + 'static + sync::Send + sync::Sync,
+ ) {
  self.late_passes.push(Box::new(pass));
  }
 
- pub fn register_late_mod_pass(&mut self,
- pass: impl Fn() -> LateLintPassObject + 'static + sync::Send + sync::Sync) {
+ pub fn register_late_mod_pass(
+ &mut self,
+ pass: impl Fn() -> LateLintPassObject + 'static + sync::Send + sync::Sync,
+ ) {
  self.late_module_passes.push(Box::new(pass));
  }
 

src/librustc_driver/lib.rs

@@ -106,6 +106,7 @@ pub fn abort_on_err<T>(result: Result<T, ErrorReported>, sess: &Session) -> T {
 pub trait Callbacks {
  /// Called before creating the compiler instance
  fn config(&mut self, _config: &mut interface::Config) {}
+ /// Called early during compilation to allow other drivers to easily register lints.
  fn extra_lints(&mut self, _ls: &mut lint::LintStore) {}
  /// Called after parsing. Return value instructs the compiler whether to
  /// continue the compilation afterwards (defaults to `Compilation::Continue`)

src/librustc_interface/interface.rs

@@ -82,6 +82,11 @@ pub struct Config {
  pub crate_name: Option<String>,
  pub lint_caps: FxHashMap<lint::LintId, lint::Level>,
 
+ /// This is a callback from the driver that is called when we're registering lints;
+ /// it is called during plugin registration when we have the LintStore in a non-shared state.
+ ///
+ /// Note that if you find a Some here you probably want to call that function in the new
+ /// function being registered.
  pub register_lints: Option<Box<dyn Fn(&Session, &mut lint::LintStore) + Send + Sync>>,
 }
 

src/librustc_plugin/registry.rs

@@ -25,6 +25,7 @@ pub struct Registry<'a> {
  /// from the plugin registrar.
  pub sess: &'a Session,
 
+ /// The `LintStore` allows plugins to register new lints.
  pub lint_store: &'a mut LintStore,
 
  #[doc(hidden)]