Adding upstream version 1.64.0+dfsg1.upstream/1.64.0+dfsg1

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 456 insertions, 0 deletions

diff --git a/compiler/rustc_lint/src/early.rs b/compiler/rustc_lint/src/early.rs
new file mode 100644
index 000000000..d13711c3a
--- /dev/null
+++ b/compiler/rustc_lint/src/early.rs
@@ -0,0 +1,456 @@
+//! Implementation of lint checking.
+//!
+//! The lint checking is mostly consolidated into one pass which runs
+//! after all other analyses. Throughout compilation, lint warnings
+//! can be added via the `add_lint` method on the Session structure. This
+//! requires a span and an ID of the node that the lint is being added to. The
+//! lint isn't actually emitted at that time because it is unknown what the
+//! actual lint level at that location is.
+//!
+//! To actually emit lint warnings/errors, a separate pass is used.
+//! A context keeps track of the current state of all lint levels.
+//! Upon entering a node of the ast which can modify the lint settings, the
+//! previous lint state is pushed onto a stack and the ast is then recursed
+//! upon. As the ast is traversed, this keeps track of the current lint level
+//! for all lint attributes.
+
+use crate::context::{EarlyContext, LintContext, LintStore};
+use crate::passes::{EarlyLintPass, EarlyLintPassObject};
+use rustc_ast::ptr::P;
+use rustc_ast::visit::{self as ast_visit, Visitor};
+use rustc_ast::{self as ast, walk_list, HasAttrs};
+use rustc_middle::ty::RegisteredTools;
+use rustc_session::lint::{BufferedEarlyLint, LintBuffer, LintPass};
+use rustc_session::Session;
+use rustc_span::symbol::Ident;
+use rustc_span::Span;
+
+use std::slice;
+use tracing::debug;
+
+macro_rules! run_early_pass { ($cx:expr, $f:ident, $($args:expr),*) => ({
+    $cx.pass.$f(&$cx.context, $($args),*);
+}) }
+
+pub struct EarlyContextAndPass<'a, T: EarlyLintPass> {
+    context: EarlyContext<'a>,
+    pass: T,
+}
+
+impl<'a, T: EarlyLintPass> EarlyContextAndPass<'a, T> {
+    fn check_id(&mut self, id: ast::NodeId) {
+        for early_lint in self.context.buffered.take(id) {
+            let BufferedEarlyLint { span, msg, node_id: _, lint_id, diagnostic } = early_lint;
+            self.context.lookup_with_diagnostics(
+                lint_id.lint,
+                Some(span),
+                |lint| {
+                    lint.build(&msg).emit();
+                },
+                diagnostic,
+            );
+        }
+    }
+
+    /// Merge the lints specified by any lint attributes into the
+    /// current lint context, call the provided function, then reset the
+    /// lints in effect to their previous state.
+    fn with_lint_attrs<F>(&mut self, id: ast::NodeId, attrs: &'a [ast::Attribute], f: F)
+    where
+        F: FnOnce(&mut Self),
+    {
+        let is_crate_node = id == ast::CRATE_NODE_ID;
+        let push = self.context.builder.push(attrs, is_crate_node, None);
+
+        self.check_id(id);
+        debug!("early context: enter_attrs({:?})", attrs);
+        run_early_pass!(self, enter_lint_attrs, attrs);
+        f(self);
+        debug!("early context: exit_attrs({:?})", attrs);
+        run_early_pass!(self, exit_lint_attrs, attrs);
+        self.context.builder.pop(push);
+    }
+}
+
+impl<'a, T: EarlyLintPass> ast_visit::Visitor<'a> for EarlyContextAndPass<'a, T> {
+    fn visit_param(&mut self, param: &'a ast::Param) {
+        self.with_lint_attrs(param.id, &param.attrs, |cx| {
+            run_early_pass!(cx, check_param, param);
+            ast_visit::walk_param(cx, param);
+        });
+    }
+
+    fn visit_item(&mut self, it: &'a ast::Item) {
+        self.with_lint_attrs(it.id, &it.attrs, |cx| {
+            run_early_pass!(cx, check_item, it);
+            ast_visit::walk_item(cx, it);
+            run_early_pass!(cx, check_item_post, it);
+        })
+    }
+
+    fn visit_foreign_item(&mut self, it: &'a ast::ForeignItem) {
+        self.with_lint_attrs(it.id, &it.attrs, |cx| {
+            ast_visit::walk_foreign_item(cx, it);
+        })
+    }
+
+    fn visit_pat(&mut self, p: &'a ast::Pat) {
+        run_early_pass!(self, check_pat, p);
+        self.check_id(p.id);
+        ast_visit::walk_pat(self, p);
+        run_early_pass!(self, check_pat_post, p);
+    }
+
+    fn visit_anon_const(&mut self, c: &'a ast::AnonConst) {
+        self.check_id(c.id);
+        ast_visit::walk_anon_const(self, c);
+    }
+
+    fn visit_expr(&mut self, e: &'a ast::Expr) {
+        self.with_lint_attrs(e.id, &e.attrs, |cx| {
+            run_early_pass!(cx, check_expr, e);
+            ast_visit::walk_expr(cx, e);
+        })
+    }
+
+    fn visit_expr_field(&mut self, f: &'a ast::ExprField) {
+        self.with_lint_attrs(f.id, &f.attrs, |cx| {
+            ast_visit::walk_expr_field(cx, f);
+        })
+    }
+
+    fn visit_stmt(&mut self, s: &'a ast::Stmt) {
+        // Add the statement's lint attributes to our
+        // current state when checking the statement itself.
+        // This allows us to handle attributes like
+        // `#[allow(unused_doc_comments)]`, which apply to
+        // sibling attributes on the same target
+        //
+        // Note that statements get their attributes from
+        // the AST struct that they wrap (e.g. an item)
+        self.with_lint_attrs(s.id, s.attrs(), |cx| {
+            run_early_pass!(cx, check_stmt, s);
+            cx.check_id(s.id);
+        });
+        // The visitor for the AST struct wrapped
+        // by the statement (e.g. `Item`) will call
+        // `with_lint_attrs`, so do this walk
+        // outside of the above `with_lint_attrs` call
+        ast_visit::walk_stmt(self, s);
+    }
+
+    fn visit_fn(&mut self, fk: ast_visit::FnKind<'a>, span: Span, id: ast::NodeId) {
+        run_early_pass!(self, check_fn, fk, span, id);
+        self.check_id(id);
+        ast_visit::walk_fn(self, fk, span);
+
+        // Explicitly check for lints associated with 'closure_id', since
+        // it does not have a corresponding AST node
+        if let ast_visit::FnKind::Fn(_, _, sig, _, _, _) = fk {
+            if let ast::Async::Yes { closure_id, .. } = sig.header.asyncness {
+                self.check_id(closure_id);
+            }
+        }
+    }
+
+    fn visit_variant_data(&mut self, s: &'a ast::VariantData) {
+        if let Some(ctor_hir_id) = s.ctor_id() {
+            self.check_id(ctor_hir_id);
+        }
+        ast_visit::walk_struct_def(self, s);
+    }
+
+    fn visit_field_def(&mut self, s: &'a ast::FieldDef) {
+        self.with_lint_attrs(s.id, &s.attrs, |cx| {
+            ast_visit::walk_field_def(cx, s);
+        })
+    }
+
+    fn visit_variant(&mut self, v: &'a ast::Variant) {
+        self.with_lint_attrs(v.id, &v.attrs, |cx| {
+            run_early_pass!(cx, check_variant, v);
+            ast_visit::walk_variant(cx, v);
+        })
+    }
+
+    fn visit_ty(&mut self, t: &'a ast::Ty) {
+        run_early_pass!(self, check_ty, t);
+        self.check_id(t.id);
+        ast_visit::walk_ty(self, t);
+    }
+
+    fn visit_ident(&mut self, ident: Ident) {
+        run_early_pass!(self, check_ident, ident);
+    }
+
+    fn visit_local(&mut self, l: &'a ast::Local) {
+        self.with_lint_attrs(l.id, &l.attrs, |cx| {
+            run_early_pass!(cx, check_local, l);
+            ast_visit::walk_local(cx, l);
+        })
+    }
+
+    fn visit_block(&mut self, b: &'a ast::Block) {
+        run_early_pass!(self, check_block, b);
+        self.check_id(b.id);
+        ast_visit::walk_block(self, b);
+    }
+
+    fn visit_arm(&mut self, a: &'a ast::Arm) {
+        self.with_lint_attrs(a.id, &a.attrs, |cx| {
+            run_early_pass!(cx, check_arm, a);
+            ast_visit::walk_arm(cx, a);
+        })
+    }
+
+    fn visit_expr_post(&mut self, e: &'a ast::Expr) {
+        // Explicitly check for lints associated with 'closure_id', since
+        // it does not have a corresponding AST node
+        match e.kind {
+            ast::ExprKind::Closure(_, _, ast::Async::Yes { closure_id, .. }, ..)
+            | ast::ExprKind::Async(_, closure_id, ..) => self.check_id(closure_id),
+            _ => {}
+        }
+    }
+
+    fn visit_generic_arg(&mut self, arg: &'a ast::GenericArg) {
+        run_early_pass!(self, check_generic_arg, arg);
+        ast_visit::walk_generic_arg(self, arg);
+    }
+
+    fn visit_generic_param(&mut self, param: &'a ast::GenericParam) {
+        run_early_pass!(self, check_generic_param, param);
+        self.check_id(param.id);
+        ast_visit::walk_generic_param(self, param);
+    }
+
+    fn visit_generics(&mut self, g: &'a ast::Generics) {
+        run_early_pass!(self, check_generics, g);
+        ast_visit::walk_generics(self, g);
+    }
+
+    fn visit_where_predicate(&mut self, p: &'a ast::WherePredicate) {
+        ast_visit::walk_where_predicate(self, p);
+    }
+
+    fn visit_poly_trait_ref(&mut self, t: &'a ast::PolyTraitRef, m: &'a ast::TraitBoundModifier) {
+        run_early_pass!(self, check_poly_trait_ref, t, m);
+        ast_visit::walk_poly_trait_ref(self, t, m);
+    }
+
+    fn visit_assoc_item(&mut self, item: &'a ast::AssocItem, ctxt: ast_visit::AssocCtxt) {
+        self.with_lint_attrs(item.id, &item.attrs, |cx| match ctxt {
+            ast_visit::AssocCtxt::Trait => {
+                run_early_pass!(cx, check_trait_item, item);
+                ast_visit::walk_assoc_item(cx, item, ctxt);
+            }
+            ast_visit::AssocCtxt::Impl => {
+                run_early_pass!(cx, check_impl_item, item);
+                ast_visit::walk_assoc_item(cx, item, ctxt);
+            }
+        });
+    }
+
+    fn visit_lifetime(&mut self, lt: &'a ast::Lifetime, _: ast_visit::LifetimeCtxt) {
+        self.check_id(lt.id);
+    }
+
+    fn visit_path(&mut self, p: &'a ast::Path, id: ast::NodeId) {
+        self.check_id(id);
+        ast_visit::walk_path(self, p);
+    }
+
+    fn visit_path_segment(&mut self, path_span: Span, s: &'a ast::PathSegment) {
+        self.check_id(s.id);
+        ast_visit::walk_path_segment(self, path_span, s);
+    }
+
+    fn visit_attribute(&mut self, attr: &'a ast::Attribute) {
+        run_early_pass!(self, check_attribute, attr);
+    }
+
+    fn visit_mac_def(&mut self, mac: &'a ast::MacroDef, id: ast::NodeId) {
+        run_early_pass!(self, check_mac_def, mac, id);
+        self.check_id(id);
+    }
+
+    fn visit_mac_call(&mut self, mac: &'a ast::MacCall) {
+        run_early_pass!(self, check_mac, mac);
+        ast_visit::walk_mac(self, mac);
+    }
+}
+
+struct EarlyLintPassObjects<'a> {
+    lints: &'a mut [EarlyLintPassObject],
+}
+
+#[allow(rustc::lint_pass_impl_without_macro)]
+impl LintPass for EarlyLintPassObjects<'_> {
+    fn name(&self) -> &'static str {
+        panic!()
+    }
+}
+
+macro_rules! expand_early_lint_pass_impl_methods {
+    ([$($(#[$attr:meta])* fn $name:ident($($param:ident: $arg:ty),*);)*]) => (
+        $(fn $name(&mut self, context: &EarlyContext<'_>, $($param: $arg),*) {
+            for obj in self.lints.iter_mut() {
+                obj.$name(context, $($param),*);
+            }
+        })*
+    )
+}
+
+macro_rules! early_lint_pass_impl {
+    ([], [$($methods:tt)*]) => (
+        impl EarlyLintPass for EarlyLintPassObjects<'_> {
+            expand_early_lint_pass_impl_methods!([$($methods)*]);
+        }
+    )
+}
+
+crate::early_lint_methods!(early_lint_pass_impl, []);
+
+/// Early lints work on different nodes - either on the crate root, or on freshly loaded modules.
+/// This trait generalizes over those nodes.
+pub trait EarlyCheckNode<'a>: Copy {
+    fn id(self) -> ast::NodeId;
+    fn attrs<'b>(self) -> &'b [ast::Attribute]
+    where
+        'a: 'b;
+    fn check<'b>(self, cx: &mut EarlyContextAndPass<'b, impl EarlyLintPass>)
+    where
+        'a: 'b;
+}
+
+impl<'a> EarlyCheckNode<'a> for &'a ast::Crate {
+    fn id(self) -> ast::NodeId {
+        ast::CRATE_NODE_ID
+    }
+    fn attrs<'b>(self) -> &'b [ast::Attribute]
+    where
+        'a: 'b,
+    {
+        &self.attrs
+    }
+    fn check<'b>(self, cx: &mut EarlyContextAndPass<'b, impl EarlyLintPass>)
+    where
+        'a: 'b,
+    {
+        run_early_pass!(cx, check_crate, self);
+        ast_visit::walk_crate(cx, self);
+        run_early_pass!(cx, check_crate_post, self);
+    }
+}
+
+impl<'a> EarlyCheckNode<'a> for (ast::NodeId, &'a [ast::Attribute], &'a [P<ast::Item>]) {
+    fn id(self) -> ast::NodeId {
+        self.0
+    }
+    fn attrs<'b>(self) -> &'b [ast::Attribute]
+    where
+        'a: 'b,
+    {
+        self.1
+    }
+    fn check<'b>(self, cx: &mut EarlyContextAndPass<'b, impl EarlyLintPass>)
+    where
+        'a: 'b,
+    {
+        walk_list!(cx, visit_attribute, self.1);
+        walk_list!(cx, visit_item, self.2);
+    }
+}
+
+fn early_lint_node<'a>(
+    sess: &Session,
+    warn_about_weird_lints: bool,
+    lint_store: &LintStore,
+    registered_tools: &RegisteredTools,
+    buffered: LintBuffer,
+    pass: impl EarlyLintPass,
+    check_node: impl EarlyCheckNode<'a>,
+) -> LintBuffer {
+    let mut cx = EarlyContextAndPass {
+        context: EarlyContext::new(
+            sess,
+            warn_about_weird_lints,
+            lint_store,
+            registered_tools,
+            buffered,
+        ),
+        pass,
+    };
+
+    cx.with_lint_attrs(check_node.id(), check_node.attrs(), |cx| check_node.check(cx));
+    cx.context.buffered
+}
+
+pub fn check_ast_node<'a>(
+    sess: &Session,
+    pre_expansion: bool,
+    lint_store: &LintStore,
+    registered_tools: &RegisteredTools,
+    lint_buffer: Option<LintBuffer>,
+    builtin_lints: impl EarlyLintPass,
+    check_node: impl EarlyCheckNode<'a>,
+) {
+    let passes =
+        if pre_expansion { &lint_store.pre_expansion_passes } else { &lint_store.early_passes };
+    let mut passes: Vec<_> = passes.iter().map(|p| (p)()).collect();
+    let mut buffered = lint_buffer.unwrap_or_default();
+
+    if sess.opts.unstable_opts.no_interleave_lints {
+        for (i, pass) in passes.iter_mut().enumerate() {
+            buffered =
+                sess.prof.extra_verbose_generic_activity("run_lint", pass.name()).run(|| {
+                    early_lint_node(
+                        sess,
+                        !pre_expansion && i == 0,
+                        lint_store,
+                        registered_tools,
+                        buffered,
+                        EarlyLintPassObjects { lints: slice::from_mut(pass) },
+                        check_node,
+                    )
+                });
+        }
+    } else {
+        buffered = early_lint_node(
+            sess,
+            !pre_expansion,
+            lint_store,
+            registered_tools,
+            buffered,
+            builtin_lints,
+            check_node,
+        );
+
+        if !passes.is_empty() {
+            buffered = early_lint_node(
+                sess,
+                false,
+                lint_store,
+                registered_tools,
+                buffered,
+                EarlyLintPassObjects { lints: &mut passes[..] },
+                check_node,
+            );
+        }
+    }
+
+    // All of the buffered lints should have been emitted at this point.
+    // If not, that means that we somehow buffered a lint for a node id
+    // that was not lint-checked (perhaps it doesn't exist?). This is a bug.
+    for (id, lints) in buffered.map {
+        for early_lint in lints {
+            sess.delay_span_bug(
+                early_lint.span,
+                &format!(
+                    "failed to process buffered lint here (dummy = {})",
+                    id == ast::DUMMY_NODE_ID
+                ),
+            );
+        }
+    }
+}