Rollup of 5 pull requests

compiler/rustc_attr_parsing/src/attributes/cfg_select.rs

@@ -28,6 +28,33 @@ pub struct CfgSelectBranches {
     pub unreachable: Vec<(CfgSelectPredicate, TokenStream, Span)>,
 }
 
+impl CfgSelectBranches {
+    /// Removes the top-most branch for which `predicate` returns `true`,
+    /// or the wildcard if none of the reachable branches satisfied the predicate.
+    pub fn pop_first_match<F>(&mut self, predicate: F) -> Option<(TokenStream, Span)>
+    where
+        F: Fn(&CfgEntry) -> bool,
+    {
+        for (index, (cfg, _, _)) in self.reachable.iter().enumerate() {
+            if predicate(cfg) {
+                let matched = self.reachable.remove(index);
+                return Some((matched.1, matched.2));
+            }
+        }
+
+        self.wildcard.take().map(|(_, tts, span)| (tts, span))
+    }
+
+    /// Consume this value and iterate over all the `TokenStream`s that it stores.
+    pub fn into_iter_tts(self) -> impl Iterator<Item = (TokenStream, Span)> {
+        let it1 = self.reachable.into_iter().map(|(_, tts, span)| (tts, span));
+        let it2 = self.wildcard.into_iter().map(|(_, tts, span)| (tts, span));
+        let it3 = self.unreachable.into_iter().map(|(_, tts, span)| (tts, span));
+
+        it1.chain(it2).chain(it3)
+    }
+}
+
 pub fn parse_cfg_select(
     p: &mut Parser<'_>,
     sess: &Session,

compiler/rustc_builtin_macros/src/cfg_select.rs

@@ -1,22 +1,62 @@
 use rustc_ast::tokenstream::TokenStream;
+use rustc_ast::{Expr, ast};
 use rustc_attr_parsing as attr;
 use rustc_attr_parsing::{
     CfgSelectBranches, CfgSelectPredicate, EvalConfigResult, parse_cfg_select,
 };
-use rustc_expand::base::{DummyResult, ExpandResult, ExtCtxt, MacroExpanderResult};
+use rustc_expand::base::{DummyResult, ExpandResult, ExtCtxt, MacResult, MacroExpanderResult};
 use rustc_span::{Ident, Span, sym};
+use smallvec::SmallVec;
 
 use crate::errors::{CfgSelectNoMatches, CfgSelectUnreachable};
 
-/// Selects the first arm whose predicate evaluates to true.
-fn select_arm(ecx: &ExtCtxt<'_>, branches: CfgSelectBranches) -> Option<(TokenStream, Span)> {
-    for (cfg, tt, arm_span) in branches.reachable {
-        if let EvalConfigResult::True = attr::eval_config_entry(&ecx.sess, &cfg) {
-            return Some((tt, arm_span));
-        }
+/// This intermediate structure is used to emit parse errors for the branches that are not chosen.
+/// The `MacResult` instance below parses all branches, emitting any errors it encounters, but only
+/// keeps the parse result for the selected branch.
+struct CfgSelectResult<'cx, 'sess> {
+    ecx: &'cx mut ExtCtxt<'sess>,
+    site_span: Span,
+    selected_tts: TokenStream,
+    selected_span: Span,
+    other_branches: CfgSelectBranches,
+}
+
+fn tts_to_mac_result<'cx, 'sess>(
+    ecx: &'cx mut ExtCtxt<'sess>,
+    site_span: Span,
+    tts: TokenStream,
+    span: Span,
+) -> Box<dyn MacResult + 'cx> {
+    match ExpandResult::from_tts(ecx, tts, site_span, span, Ident::with_dummy_span(sym::cfg_select))
+    {
+        ExpandResult::Ready(x) => x,
+        _ => unreachable!("from_tts always returns Ready"),
     }
+}
+
+macro_rules! forward_to_parser_any_macro {
+    ($method_name:ident, $ret_ty:ty) => {
+        fn $method_name(self: Box<Self>) -> Option<$ret_ty> {
+            let CfgSelectResult { ecx, site_span, selected_tts, selected_span, .. } = *self;
+
+            for (tts, span) in self.other_branches.into_iter_tts() {
+                let _ = tts_to_mac_result(ecx, site_span, tts, span).$method_name();
+            }
+
+            tts_to_mac_result(ecx, site_span, selected_tts, selected_span).$method_name()
+        }
+    };
+}
+
+impl<'cx, 'sess> MacResult for CfgSelectResult<'cx, 'sess> {
+    forward_to_parser_any_macro!(make_expr, Box<Expr>);
+    forward_to_parser_any_macro!(make_stmts, SmallVec<[ast::Stmt; 1]>);
+    forward_to_parser_any_macro!(make_items, SmallVec<[Box<ast::Item>; 1]>);
 
-    branches.wildcard.map(|(_, tt, span)| (tt, span))
+    forward_to_parser_any_macro!(make_impl_items, SmallVec<[Box<ast::AssocItem>; 1]>);
+    forward_to_parser_any_macro!(make_trait_impl_items, SmallVec<[Box<ast::AssocItem>; 1]>);
+    forward_to_parser_any_macro!(make_trait_items, SmallVec<[Box<ast::AssocItem>; 1]>);
+    forward_to_parser_any_macro!(make_foreign_items, SmallVec<[Box<ast::ForeignItem>; 1]>);
 }
 
 pub(super) fn expand_cfg_select<'cx>(
@@ -31,7 +71,7 @@ pub(super) fn expand_cfg_select<'cx>(
             Some(ecx.ecfg.features),
             ecx.current_expansion.lint_node_id,
         ) {
-            Ok(branches) => {
+            Ok(mut branches) => {
                 if let Some((underscore, _, _)) = branches.wildcard {
                     // Warn for every unreachable predicate. We store the fully parsed branch for rustfmt.
                     for (predicate, _, _) in &branches.unreachable {
@@ -44,14 +84,17 @@ pub(super) fn expand_cfg_select<'cx>(
                     }
                 }
 
-                if let Some((tts, arm_span)) = select_arm(ecx, branches) {
-                    return ExpandResult::from_tts(
+                if let Some((selected_tts, selected_span)) = branches.pop_first_match(|cfg| {
+                    matches!(attr::eval_config_entry(&ecx.sess, cfg), EvalConfigResult::True)
+                }) {
+                    let mac = CfgSelectResult {
                         ecx,
-                        tts,
-                        sp,
-                        arm_span,
-                        Ident::with_dummy_span(sym::cfg_select),
-                    );
+                        selected_tts,
+                        selected_span,
+                        other_branches: branches,
+                        site_span: sp,
+                    };
+                    return ExpandResult::Ready(Box::new(mac));
                 } else {
                     // Emit a compiler error when none of the predicates matched.
                     let guar = ecx.dcx().emit_err(CfgSelectNoMatches { span: sp });

compiler/rustc_hir/src/attrs/data_structures.rs

@@ -530,7 +530,7 @@ pub struct CfgHideShow {
     pub values: ThinVec<CfgInfo>,
 }
 
-#[derive(Clone, Debug, Default, HashStable_Generic, Encodable, Decodable, PrintAttribute)]
+#[derive(Clone, Debug, Default, HashStable_Generic, Decodable, PrintAttribute)]
 pub struct DocAttribute {
     pub aliases: FxIndexMap<Symbol, Span>,
     pub hidden: Option<Span>,
@@ -566,6 +566,62 @@ pub struct DocAttribute {
     pub no_crate_inject: Option<Span>,
 }
 
+impl<E: rustc_span::SpanEncoder> rustc_serialize::Encodable<E> for DocAttribute {
+    fn encode(&self, encoder: &mut E) {
+        let DocAttribute {
+            aliases,
+            hidden,
+            inline,
+            cfg,
+            auto_cfg,
+            auto_cfg_change,
+            fake_variadic,
+            keyword,
+            attribute,
+            masked,
+            notable_trait,
+            search_unbox,
+            html_favicon_url,
+            html_logo_url,
+            html_playground_url,
+            html_root_url,
+            html_no_source,
+            issue_tracker_base_url,
+            rust_logo,
+            test_attrs,
+            no_crate_inject,
+        } = self;
+        rustc_serialize::Encodable::<E>::encode(aliases, encoder);
+        rustc_serialize::Encodable::<E>::encode(hidden, encoder);
+
+        // FIXME: The `doc(inline)` attribute is never encoded, but is it actually the right thing
+        // to do? I suspect the condition was broken, should maybe instead not encode anything if we
+        // have `doc(no_inline)`.
+        let inline: ThinVec<_> =
+            inline.iter().filter(|(i, _)| *i != DocInline::Inline).cloned().collect();
+        rustc_serialize::Encodable::<E>::encode(&inline, encoder);
+
+        rustc_serialize::Encodable::<E>::encode(cfg, encoder);
+        rustc_serialize::Encodable::<E>::encode(auto_cfg, encoder);
+        rustc_serialize::Encodable::<E>::encode(auto_cfg_change, encoder);
+        rustc_serialize::Encodable::<E>::encode(fake_variadic, encoder);
+        rustc_serialize::Encodable::<E>::encode(keyword, encoder);
+        rustc_serialize::Encodable::<E>::encode(attribute, encoder);
+        rustc_serialize::Encodable::<E>::encode(masked, encoder);
+        rustc_serialize::Encodable::<E>::encode(notable_trait, encoder);
+        rustc_serialize::Encodable::<E>::encode(search_unbox, encoder);
+        rustc_serialize::Encodable::<E>::encode(html_favicon_url, encoder);
+        rustc_serialize::Encodable::<E>::encode(html_logo_url, encoder);
+        rustc_serialize::Encodable::<E>::encode(html_playground_url, encoder);
+        rustc_serialize::Encodable::<E>::encode(html_root_url, encoder);
+        rustc_serialize::Encodable::<E>::encode(html_no_source, encoder);
+        rustc_serialize::Encodable::<E>::encode(issue_tracker_base_url, encoder);
+        rustc_serialize::Encodable::<E>::encode(rust_logo, encoder);
+        rustc_serialize::Encodable::<E>::encode(test_attrs, encoder);
+        rustc_serialize::Encodable::<E>::encode(no_crate_inject, encoder);
+    }
+}
+
 /// Represents parsed *built-in* inert attributes.
 ///
 /// ## Overview

compiler/rustc_metadata/src/rmeta/encoder.rs

@@ -879,13 +879,9 @@ fn analyze_attr(attr: &hir::Attribute, state: &mut AnalyzeAttrState<'_>) -> bool
             should_encode = true;
         }
     } else if let hir::Attribute::Parsed(AttributeKind::Doc(d)) = attr {
-        // If this is a `doc` attribute that doesn't have anything except maybe `inline` (as in
-        // `#[doc(inline)]`), then we can remove it. It won't be inlinable in downstream crates.
-        if d.inline.is_empty() {
-            should_encode = true;
-            if d.hidden.is_some() {
-                state.is_doc_hidden = true;
-            }
+        should_encode = true;
+        if d.hidden.is_some() {
+            state.is_doc_hidden = true;
         }
     } else if let &[sym::diagnostic, seg] = &*attr.path() {
         should_encode = rustc_feature::is_stable_diagnostic_attribute(seg, state.features);

compiler/rustc_mir_build/src/builder/matches/buckets.rs

@@ -7,7 +7,7 @@ use tracing::debug;
 
 use crate::builder::Builder;
 use crate::builder::matches::test::is_switch_ty;
-use crate::builder::matches::{Candidate, Test, TestBranch, TestCase, TestKind};
+use crate::builder::matches::{Candidate, Test, TestBranch, TestKind, TestableCase};
 
 /// Output of [`Builder::partition_candidates_into_buckets`].
 pub(crate) struct PartitionedCandidates<'tcx, 'b, 'c> {
@@ -140,12 +140,12 @@ impl<'a, 'tcx> Builder<'a, 'tcx> {
         // branch, so it can be removed. If false, the match pair is _compatible_
         // with its test branch, but still needs a more specific test.
         let fully_matched;
-        let ret = match (&test.kind, &match_pair.test_case) {
+        let ret = match (&test.kind, &match_pair.testable_case) {
             // If we are performing a variant switch, then this
             // informs variant patterns, but nothing else.
             (
                 &TestKind::Switch { adt_def: tested_adt_def },
-                &TestCase::Variant { adt_def, variant_index },
+                &TestableCase::Variant { adt_def, variant_index },
             ) => {
                 assert_eq!(adt_def, tested_adt_def);
                 fully_matched = true;
@@ -159,24 +159,23 @@ impl<'a, 'tcx> Builder<'a, 'tcx> {
             // things out here, in some cases.
             //
             // FIXME(Zalathar): Is the `is_switch_ty` test unnecessary?
-            (TestKind::SwitchInt, &TestCase::Constant { value })
+            (TestKind::SwitchInt, &TestableCase::Constant { value })
                 if is_switch_ty(match_pair.pattern_ty) =>
             {
                 // An important invariant of candidate bucketing is that a candidate
                 // must not match in multiple branches. For `SwitchInt` tests, adding
                 // a new value might invalidate that property for range patterns that
                 // have already been partitioned into the failure arm, so we must take care
                 // not to add such values here.
-                let is_covering_range = |test_case: &TestCase<'tcx>| {
-                    test_case.as_range().is_some_and(|range| {
+                let is_covering_range = |testable_case: &TestableCase<'tcx>| {
+                    testable_case.as_range().is_some_and(|range| {
                         matches!(range.contains(value, self.tcx), None | Some(true))
                     })
                 };
                 let is_conflicting_candidate = |candidate: &&mut Candidate<'tcx>| {
-                    candidate
-                        .match_pairs
-                        .iter()
-                        .any(|mp| mp.place == Some(test_place) && is_covering_range(&mp.test_case))
+                    candidate.match_pairs.iter().any(|mp| {
+                        mp.place == Some(test_place) && is_covering_range(&mp.testable_case)
+                    })
                 };
                 if prior_candidates
                     .get(&TestBranch::Failure)
@@ -189,7 +188,7 @@ impl<'a, 'tcx> Builder<'a, 'tcx> {
                     Some(TestBranch::Constant(value))
                 }
             }
-            (TestKind::SwitchInt, TestCase::Range(range)) => {
+            (TestKind::SwitchInt, TestableCase::Range(range)) => {
                 // When performing a `SwitchInt` test, a range pattern can be
                 // sorted into the failure arm if it doesn't contain _any_ of
                 // the values being tested. (This restricts what values can be
@@ -207,7 +206,7 @@ impl<'a, 'tcx> Builder<'a, 'tcx> {
                 })
             }
 
-            (TestKind::If, TestCase::Constant { value }) => {
+            (TestKind::If, TestableCase::Constant { value }) => {
                 fully_matched = true;
                 let value = value.try_to_bool().unwrap_or_else(|| {
                     span_bug!(test.span, "expected boolean value but got {value:?}")
@@ -217,7 +216,7 @@ impl<'a, 'tcx> Builder<'a, 'tcx> {
 
             (
                 &TestKind::Len { len: test_len, op: BinOp::Eq },
-                &TestCase::Slice { len, variable_length },
+                &TestableCase::Slice { len, variable_length },
             ) => {
                 match (test_len.cmp(&(len as u64)), variable_length) {
                     (Ordering::Equal, false) => {
@@ -249,7 +248,7 @@ impl<'a, 'tcx> Builder<'a, 'tcx> {
             }
             (
                 &TestKind::Len { len: test_len, op: BinOp::Ge },
-                &TestCase::Slice { len, variable_length },
+                &TestableCase::Slice { len, variable_length },
             ) => {
                 // the test is `$actual_len >= test_len`
                 match (test_len.cmp(&(len as u64)), variable_length) {
@@ -281,7 +280,7 @@ impl<'a, 'tcx> Builder<'a, 'tcx> {
                 }
             }
 
-            (TestKind::Range(test), TestCase::Range(pat)) => {
+            (TestKind::Range(test), TestableCase::Range(pat)) => {
                 if test == pat {
                     fully_matched = true;
                     Some(TestBranch::Success)
@@ -292,7 +291,7 @@ impl<'a, 'tcx> Builder<'a, 'tcx> {
                     if !test.overlaps(pat, self.tcx)? { Some(TestBranch::Failure) } else { None }
                 }
             }
-            (TestKind::Range(range), &TestCase::Constant { value }) => {
+            (TestKind::Range(range), &TestableCase::Constant { value }) => {
                 fully_matched = false;
                 if !range.contains(value, self.tcx)? {
                     // `value` is not contained in the testing range,
@@ -303,7 +302,7 @@ impl<'a, 'tcx> Builder<'a, 'tcx> {
                 }
             }
 
-            (TestKind::Eq { value: test_val, .. }, TestCase::Constant { value: case_val }) => {
+            (TestKind::Eq { value: test_val, .. }, TestableCase::Constant { value: case_val }) => {
                 if test_val == case_val {
                     fully_matched = true;
                     Some(TestBranch::Success)
@@ -313,7 +312,7 @@ impl<'a, 'tcx> Builder<'a, 'tcx> {
                 }
             }
 
-            (TestKind::Deref { temp: test_temp, .. }, TestCase::Deref { temp, .. })
+            (TestKind::Deref { temp: test_temp, .. }, TestableCase::Deref { temp, .. })
                 if test_temp == temp =>
             {
                 fully_matched = true;