Update clippy for latest rustc changes

Specifically, this revises the clippy integration to utilize a new
callback to register its lints, as the prior editing of lint store in
Session is no longer possible.

clippy_lints/src/trivially_copy_pass_by_ref.rs

@@ -54,6 +54,7 @@ declare_clippy_lint! {
     "functions taking small copyable arguments by reference"
 }
 
+#[derive(Copy, Clone)]
 pub struct TriviallyCopyPassByRef {
     limit: u64,
 }
@@ -159,7 +160,7 @@ impl<'a, 'tcx> LateLintPass<'a, 'tcx> for TriviallyCopyPassByRef {
                         return;
                     }
                 }
-            },
+            }
             FnKind::Method(..) => (),
             _ => return,
         }

src/driver.rs

@@ -61,51 +61,20 @@ fn test_arg_value() {
 struct ClippyCallbacks;
 
 impl rustc_driver::Callbacks for ClippyCallbacks {
-    fn after_parsing(&mut self, compiler: &interface::Compiler) -> rustc_driver::Compilation {
-        let sess = compiler.session();
-        let mut registry = rustc_driver::plugin::registry::Registry::new(
-            sess,
-            compiler
-                .parse()
-                .expect(
-                    "at this compilation stage \
-                     the crate must be parsed",
-                )
-                .peek()
-                .span,
-        );
-        registry.args_hidden = Some(Vec::new());
+    fn config(&mut self, config: &mut interface::Config) {
+        let previous = config.register_lints.take();
+        config.register_lints = Some(Box::new(move |sess, mut lint_store| {
+            // technically we're ~guaranteed that this is none but might as well call anything that
+            // is there already. Certainly it can't hurt.
+            if let Some(previous) = &previous {
+                (previous)(sess, lint_store);
+            }
 
-        let conf = clippy_lints::read_conf(&registry);
-        clippy_lints::register_plugins(&mut registry, &conf);
-
-        let rustc_driver::plugin::registry::Registry {
-            early_lint_passes,
-            late_lint_passes,
-            lint_groups,
-            llvm_passes,
-            attributes,
-            ..
-        } = registry;
-        let mut ls = sess.lint_store.borrow_mut();
-        for pass in early_lint_passes {
-            ls.register_early_pass(Some(sess), true, false, pass);
-        }
-        for pass in late_lint_passes {
-            ls.register_late_pass(Some(sess), true, false, false, pass);
-        }
-
-        for (name, (to, deprecated_name)) in lint_groups {
-            ls.register_group(Some(sess), true, name, deprecated_name, to);
-        }
-        clippy_lints::register_pre_expansion_lints(sess, &mut ls, &conf);
-        clippy_lints::register_renamed(&mut ls);
-
-        sess.plugin_llvm_passes.borrow_mut().extend(llvm_passes);
-        sess.plugin_attributes.borrow_mut().extend(attributes);
-
-        // Continue execution
-        rustc_driver::Compilation::Continue
+            let conf = clippy_lints::read_conf(&[], &sess);
+            clippy_lints::register_plugins(&mut lint_store, &sess, &conf);
+            clippy_lints::register_pre_expansion_lints(&mut lint_store, &conf);
+            clippy_lints::register_renamed(&mut lint_store);
+        }));
     }
 }
 

src/lib.rs

@@ -11,22 +11,20 @@ use self::rustc_driver::plugin::Registry;
 
 #[plugin_registrar]
 pub fn plugin_registrar(reg: &mut Registry<'_>) {
-    reg.sess.lint_store.with_read_lock(|lint_store| {
-        for (lint, _, _) in lint_store.get_lint_groups() {
-            reg.sess
-                .struct_warn(
-                    "the clippy plugin is being deprecated, please use cargo clippy or rls with the clippy feature",
-                )
-                .emit();
-            if lint == "clippy" {
-                // cargo clippy run on a crate that also uses the plugin
-                return;
-            }
+    for (lint, _, _) in reg.lint_store.get_lint_groups() {
+        reg.sess
+            .struct_warn(
+                "the clippy plugin is being deprecated, please use cargo clippy or rls with the clippy feature",
+            )
+            .emit();
+        if lint == "clippy" {
+            // cargo clippy run on a crate that also uses the plugin
+            return;
         }
-    });
+    }
 
-    let conf = clippy_lints::read_conf(reg);
-    clippy_lints::register_plugins(reg, &conf);
+    let conf = clippy_lints::read_conf(reg.args(), &reg.sess);
+    clippy_lints::register_plugins(&mut reg.lint_store, &reg.sess, &conf);
 }
 
 // only exists to let the dogfood integration test works.