Rollup merge of #91526 - petrochenkov:earlint, r=cjgillot

rustc_lint: Some early linting refactorings

The first one removes and renames some fields and methods from `EarlyContext`.

The second one uses the set of registered tools (for tool attributes and tool lints) in a more centralized way.

The third one removes creation of a fake `ast::Crate` from `fn pre_expansion_lint`.
Pre-expansion linting is done with per-module granularity on freshly loaded modules, and it previously synthesized an `ast::Crate` to visit non-root modules, now they are visited as modules.
The node ID used for pre-expansion linting is also made more precise (the loaded module ID is used).

Author: matthiaskrgr

compiler/rustc_expand/src/base.rs

@@ -8,7 +8,7 @@ use rustc_ast::tokenstream::{CanSynthesizeMissingTokens, TokenStream};
 use rustc_ast::visit::{AssocCtxt, Visitor};
 use rustc_ast::{self as ast, AstLike, Attribute, Item, NodeId, PatKind};
 use rustc_attr::{self as attr, Deprecation, Stability};
-use rustc_data_structures::fx::FxHashMap;
+use rustc_data_structures::fx::{FxHashMap, FxHashSet};
 use rustc_data_structures::sync::{self, Lrc};
 use rustc_errors::{Applicability, DiagnosticBuilder, ErrorReported};
 use rustc_lint_defs::builtin::PROC_MACRO_BACK_COMPAT;
@@ -920,8 +920,25 @@ pub trait ResolverExpand {
     /// we generated proc macros harnesses, so that we can map
     /// HIR proc macros items back to their harness items.
     fn declare_proc_macro(&mut self, id: NodeId);
+
+    /// Tools registered with `#![register_tool]` and used by tool attributes and lints.
+    fn registered_tools(&self) -> &FxHashSet<Ident>;
 }
 
+pub trait LintStoreExpand {
+    fn pre_expansion_lint(
+        &self,
+        sess: &Session,
+        registered_tools: &FxHashSet<Ident>,
+        node_id: NodeId,
+        attrs: &[Attribute],
+        items: &[P<Item>],
+        name: &str,
+    );
+}
+
+type LintStoreExpandDyn<'a> = Option<&'a (dyn LintStoreExpand + 'a)>;
+
 #[derive(Clone, Default)]
 pub struct ModuleData {
     /// Path to the module starting from the crate name, like `my_crate::foo::bar`.
@@ -956,9 +973,6 @@ pub struct ExpansionData {
     pub is_trailing_mac: bool,
 }
 
-type OnExternModLoaded<'a> =
-    Option<&'a dyn Fn(Ident, Vec<Attribute>, Vec<P<Item>>, Span) -> (Vec<Attribute>, Vec<P<Item>>)>;
-
 /// One of these is made during expansion and incrementally updated as we go;
 /// when a macro expansion occurs, the resulting nodes have the `backtrace()
 /// -> expn_data` of their expansion context stored into their span.
@@ -973,10 +987,8 @@ pub struct ExtCtxt<'a> {
     /// (or during eager expansion, but that's a hack).
     pub force_mode: bool,
     pub expansions: FxHashMap<Span, Vec<String>>,
-    /// Called directly after having parsed an external `mod foo;` in expansion.
-    ///
-    /// `Ident` is the module name.
-    pub(super) extern_mod_loaded: OnExternModLoaded<'a>,
+    /// Used for running pre-expansion lints on freshly loaded modules.
+    pub(super) lint_store: LintStoreExpandDyn<'a>,
     /// When we 'expand' an inert attribute, we leave it
     /// in the AST, but insert it here so that we know
     /// not to expand it again.
@@ -988,14 +1000,14 @@ impl<'a> ExtCtxt<'a> {
         sess: &'a Session,
         ecfg: expand::ExpansionConfig<'a>,
         resolver: &'a mut dyn ResolverExpand,
-        extern_mod_loaded: OnExternModLoaded<'a>,
+        lint_store: LintStoreExpandDyn<'a>,
     ) -> ExtCtxt<'a> {
         ExtCtxt {
             sess,
             ecfg,
             reduced_recursion_limit: None,
             resolver,
-            extern_mod_loaded,
+            lint_store,
             root_path: PathBuf::new(),
             current_expansion: ExpansionData {
                 id: LocalExpnId::ROOT,

compiler/rustc_expand/src/expand.rs

@@ -1097,7 +1097,7 @@ impl InvocationCollectorNode for P<ast::Item> {
             ModKind::Unloaded => {
                 // We have an outline `mod foo;` so we need to parse the file.
                 let old_attrs_len = attrs.len();
-                let ParsedExternalMod { mut items, inner_span, file_path, dir_path, dir_ownership } =
+                let ParsedExternalMod { items, inner_span, file_path, dir_path, dir_ownership } =
                     parse_external_mod(
                         &ecx.sess,
                         ident,
@@ -1107,8 +1107,15 @@ impl InvocationCollectorNode for P<ast::Item> {
                         &mut attrs,
                     );
 
-                if let Some(extern_mod_loaded) = ecx.extern_mod_loaded {
-                    (attrs, items) = extern_mod_loaded(ident, attrs, items, inner_span);
+                if let Some(lint_store) = ecx.lint_store {
+                    lint_store.pre_expansion_lint(
+                        ecx.sess,
+                        ecx.resolver.registered_tools(),
+                        ecx.current_expansion.lint_node_id,
+                        &attrs,
+                        &items,
+                        ident.name.as_str(),
+                    );
                 }
 
                 *mod_kind = ModKind::Loaded(items, Inline::No, inner_span);

compiler/rustc_interface/src/passes.rs

@@ -3,24 +3,24 @@ use crate::proc_macro_decls;
 use crate::util;
 
 use rustc_ast::mut_visit::MutVisitor;
-use rustc_ast::{self as ast, visit, DUMMY_NODE_ID};
+use rustc_ast::{self as ast, visit};
 use rustc_borrowck as mir_borrowck;
 use rustc_codegen_ssa::back::link::emit_metadata;
 use rustc_codegen_ssa::traits::CodegenBackend;
 use rustc_data_structures::parallel;
 use rustc_data_structures::sync::{Lrc, OnceCell, WorkerLocal};
 use rustc_data_structures::temp_dir::MaybeTempDir;
 use rustc_errors::{Applicability, ErrorReported, PResult};
-use rustc_expand::base::ExtCtxt;
+use rustc_expand::base::{ExtCtxt, LintStoreExpand, ResolverExpand};
 use rustc_hir::def_id::{StableCrateId, LOCAL_CRATE};
 use rustc_hir::Crate;
-use rustc_lint::LintStore;
+use rustc_lint::{EarlyCheckNode, LintStore};
 use rustc_metadata::creader::CStore;
 use rustc_metadata::{encode_metadata, EncodedMetadata};
 use rustc_middle::arena::Arena;
 use rustc_middle::dep_graph::DepGraph;
 use rustc_middle::ty::query::{ExternProviders, Providers};
-use rustc_middle::ty::{self, GlobalCtxt, ResolverOutputs, TyCtxt};
+use rustc_middle::ty::{self, GlobalCtxt, RegisteredTools, ResolverOutputs, TyCtxt};
 use rustc_mir_build as mir_build;
 use rustc_parse::{parse_crate_from_file, parse_crate_from_source_str, validate_attr};
 use rustc_passes::{self, hir_stats, layout_test};
@@ -34,7 +34,7 @@ use rustc_session::lint;
 use rustc_session::output::{filename_for_input, filename_for_metadata};
 use rustc_session::search_paths::PathKind;
 use rustc_session::{Limit, Session};
-use rustc_span::symbol::{sym, Ident, Symbol};
+use rustc_span::symbol::{sym, Symbol};
 use rustc_span::{FileName, MultiSpan};
 use rustc_trait_selection::traits;
 use rustc_typeck as typeck;
@@ -233,26 +233,43 @@ pub fn register_plugins<'a>(
     Ok((krate, lint_store))
 }
 
-fn pre_expansion_lint(
+fn pre_expansion_lint<'a>(
     sess: &Session,
     lint_store: &LintStore,
-    krate: &ast::Crate,
-    crate_attrs: &[ast::Attribute],
-    crate_name: &str,
+    registered_tools: &RegisteredTools,
+    check_node: impl EarlyCheckNode<'a>,
+    node_name: &str,
 ) {
-    sess.prof.generic_activity_with_arg("pre_AST_expansion_lint_checks", crate_name).run(|| {
-        rustc_lint::check_ast_crate(
+    sess.prof.generic_activity_with_arg("pre_AST_expansion_lint_checks", node_name).run(|| {
+        rustc_lint::check_ast_node(
             sess,
-            lint_store,
-            krate,
-            crate_attrs,
             true,
+            lint_store,
+            registered_tools,
             None,
             rustc_lint::BuiltinCombinedPreExpansionLintPass::new(),
+            check_node,
         );
     });
 }
 
+// Cannot implement directly for `LintStore` due to trait coherence.
+struct LintStoreExpandImpl<'a>(&'a LintStore);
+
+impl LintStoreExpand for LintStoreExpandImpl<'_> {
+    fn pre_expansion_lint(
+        &self,
+        sess: &Session,
+        registered_tools: &RegisteredTools,
+        node_id: ast::NodeId,
+        attrs: &[ast::Attribute],
+        items: &[rustc_ast::ptr::P<ast::Item>],
+        name: &str,
+    ) {
+        pre_expansion_lint(sess, self.0, registered_tools, (node_id, attrs, items), name);
+    }
+}
+
 /// Runs the "early phases" of the compiler: initial `cfg` processing, loading compiler plugins,
 /// syntax expansion, secondary `cfg` expansion, synthesis of a test
 /// harness if one is to be provided, injection of a dependency on the
@@ -265,7 +282,7 @@ pub fn configure_and_expand(
     resolver: &mut Resolver<'_>,
 ) -> Result<ast::Crate> {
     tracing::trace!("configure_and_expand");
-    pre_expansion_lint(sess, lint_store, &krate, &krate.attrs, crate_name);
+    pre_expansion_lint(sess, lint_store, resolver.registered_tools(), &krate, crate_name);
     rustc_builtin_macros::register_builtin_macros(resolver);
 
     krate = sess.time("crate_injection", || {
@@ -321,13 +338,8 @@ pub fn configure_and_expand(
             ..rustc_expand::expand::ExpansionConfig::default(crate_name.to_string())
         };
 
-        let crate_attrs = krate.attrs.clone();
-        let extern_mod_loaded = |ident: Ident, attrs, items, span| {
-            let krate = ast::Crate { attrs, items, span, id: DUMMY_NODE_ID, is_placeholder: false };
-            pre_expansion_lint(sess, lint_store, &krate, &crate_attrs, ident.name.as_str());
-            (krate.attrs, krate.items)
-        };
-        let mut ecx = ExtCtxt::new(sess, cfg, resolver, Some(&extern_mod_loaded));
+        let lint_store = LintStoreExpandImpl(lint_store);
+        let mut ecx = ExtCtxt::new(sess, cfg, resolver, Some(&lint_store));
 
         // Expand macros now!
         let krate = sess.time("expand_crate", || ecx.monotonic_expander().expand_crate(krate));
@@ -499,14 +511,15 @@ pub fn lower_to_hir<'res, 'tcx>(
     );
 
     sess.time("early_lint_checks", || {
-        rustc_lint::check_ast_crate(
+        let lint_buffer = Some(std::mem::take(resolver.lint_buffer()));
+        rustc_lint::check_ast_node(
             sess,
-            lint_store,
-            &krate,
-            &krate.attrs,
             false,
-            Some(std::mem::take(resolver.lint_buffer())),
+            lint_store,
+            resolver.registered_tools(),
+            lint_buffer,
             rustc_lint::BuiltinCombinedEarlyLintPass::new(),
+            &*krate,
         )
     });
 

compiler/rustc_lint/src/builtin.rs

@@ -912,7 +912,7 @@ declare_lint_pass!(
 
 impl EarlyLintPass for AnonymousParameters {
     fn check_trait_item(&mut self, cx: &EarlyContext<'_>, it: &ast::AssocItem) {
-        if cx.sess.edition() != Edition::Edition2015 {
+        if cx.sess().edition() != Edition::Edition2015 {
             // This is a hard error in future editions; avoid linting and erroring
             return;
         }
@@ -921,7 +921,7 @@ impl EarlyLintPass for AnonymousParameters {
                 if let ast::PatKind::Ident(_, ident, None) = arg.pat.kind {
                     if ident.name == kw::Empty {
                         cx.struct_span_lint(ANONYMOUS_PARAMETERS, arg.pat.span, |lint| {
-                            let ty_snip = cx.sess.source_map().span_to_snippet(arg.ty.span);
+                            let ty_snip = cx.sess().source_map().span_to_snippet(arg.ty.span);
 
                             let (ty_snip, appl) = if let Ok(ref snip) = ty_snip {
                                 (snip.as_str(), Applicability::MachineApplicable)
@@ -1775,7 +1775,7 @@ impl EarlyLintPass for EllipsisInclusiveRangePatterns {
                 };
                 if join.edition() >= Edition::Edition2021 {
                     let mut err =
-                        rustc_errors::struct_span_err!(cx.sess, pat.span, E0783, "{}", msg,);
+                        rustc_errors::struct_span_err!(cx.sess(), pat.span, E0783, "{}", msg,);
                     err.span_suggestion(
                         pat.span,
                         suggestion,
@@ -1799,7 +1799,7 @@ impl EarlyLintPass for EllipsisInclusiveRangePatterns {
                 let replace = "..=".to_owned();
                 if join.edition() >= Edition::Edition2021 {
                     let mut err =
-                        rustc_errors::struct_span_err!(cx.sess, pat.span, E0783, "{}", msg,);
+                        rustc_errors::struct_span_err!(cx.sess(), pat.span, E0783, "{}", msg,);
                     err.span_suggestion_short(
                         join,
                         suggestion,
@@ -1983,7 +1983,7 @@ impl KeywordIdents {
         UnderMacro(under_macro): UnderMacro,
         ident: Ident,
     ) {
-        let next_edition = match cx.sess.edition() {
+        let next_edition = match cx.sess().edition() {
             Edition::Edition2015 => {
                 match ident.name {
                     kw::Async | kw::Await | kw::Try => Edition::Edition2018,
@@ -2011,7 +2011,7 @@ impl KeywordIdents {
         };
 
         // Don't lint `r#foo`.
-        if cx.sess.parse_sess.raw_identifier_spans.borrow().contains(&ident.span) {
+        if cx.sess().parse_sess.raw_identifier_spans.borrow().contains(&ident.span) {
             return;
         }
 
@@ -2379,7 +2379,7 @@ declare_lint_pass!(
 
 impl EarlyLintPass for IncompleteFeatures {
     fn check_crate(&mut self, cx: &EarlyContext<'_>, _: &ast::Crate) {
-        let features = cx.sess.features_untracked();
+        let features = cx.sess().features_untracked();
         features
             .declared_lang_features
             .iter()