Rewrite inline attr parsing

.mailmap

@@ -276,7 +276,7 @@ Jacob Greenfield <[email protected]>
 Jacob Pratt <[email protected]> <[email protected]>
 Jacob Pratt <[email protected]> <[email protected]>
 Jake Goulding <[email protected]>
-Jake Goulding <[email protected]> <[email protected]> 
+Jake Goulding <[email protected]> <[email protected]>
 Jake Goulding <[email protected]> <[email protected]>
 Jake Vossen <[email protected]>
 Jakob Degen <[email protected]> <[email protected]>
@@ -292,6 +292,9 @@ James Hinshelwood <[email protected]> <[email protected]>
 James Miller <[email protected]> <[email protected]>
 James Perry <[email protected]>
 James Sanderson <[email protected]>
+Jana Dönszelmann <[email protected]>
+Jana Dönszelmann <[email protected]> <[email protected]>
+Jana Dönszelmann <[email protected]> <[email protected]>
 Jan-Erik Rediger <[email protected]> <[email protected]>
 Jaro Fietz <[email protected]>
 Jason Fager <[email protected]>

Cargo.lock

@@ -3286,6 +3286,7 @@ dependencies = [
  "rustc_hir",
  "rustc_lexer",
  "rustc_macros",
+ "rustc_middle",
  "rustc_serialize",
  "rustc_session",
  "rustc_span",
@@ -3741,7 +3742,7 @@ dependencies = [
  "rustc_abi",
  "rustc_ast",
  "rustc_ast_pretty",
- "rustc_attr_parsing",
+ "rustc_attr_data_structures",
  "rustc_hir",
  "rustc_span",
 ]
@@ -4008,7 +4009,8 @@ dependencies = [
  "rustc_apfloat",
  "rustc_arena",
  "rustc_ast",
- "rustc_attr_parsing",
+ "rustc_ast_ir",
+ "rustc_attr_data_structures",
  "rustc_data_structures",
  "rustc_error_messages",
  "rustc_errors",

compiler/rustc_ast_lowering/src/expr.rs

@@ -74,14 +74,12 @@ impl<'hir> LoweringContext<'_, 'hir> {
                     // Merge attributes into the inner expression.
                     if !e.attrs.is_empty() {
                         let old_attrs = self.attrs.get(&ex.hir_id.local_id).copied().unwrap_or(&[]);
-                        self.attrs.insert(
-                            ex.hir_id.local_id,
-                            &*self.arena.alloc_from_iter(
-                                self.lower_attrs_vec(&e.attrs, e.span)
-                                    .into_iter()
-                                    .chain(old_attrs.iter().cloned()),
-                            ),
-                        );
+                        let new_attrs = self
+                            .lower_attrs_vec(&e.attrs, e.span, ex.hir_id)
+                            .into_iter()
+                            .chain(old_attrs.iter().cloned());
+                        self.attrs
+                            .insert(ex.hir_id.local_id, &*self.arena.alloc_from_iter(new_attrs));
                     }
                     return ex;
                 }
@@ -2024,7 +2022,7 @@ impl<'hir> LoweringContext<'_, 'hir> {
                 let ret_expr = self.checked_return(Some(from_residual_expr));
                 self.arena.alloc(self.expr(try_span, ret_expr))
             };
-            self.lower_attrs(ret_expr.hir_id, &attrs, ret_expr.span);
+            self.lower_attrs(ret_expr.hir_id, &attrs, span);
 
             let break_pat = self.pat_cf_break(try_span, residual_local);
             self.arm(break_pat, ret_expr)

compiler/rustc_ast_lowering/src/lib.rs

@@ -187,7 +187,7 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> {
             // interact with `gen`/`async gen` blocks
             allow_async_iterator: [sym::gen_future, sym::async_iterator].into(),
 
-            attribute_parser: AttributeParser::new(tcx.sess, tcx.features(), registered_tools),
+            attribute_parser: AttributeParser::new(tcx, tcx.features(), registered_tools),
         }
     }
 
@@ -196,6 +196,22 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> {
     }
 }
 
+struct SpanLowerer {
+    is_incremental: bool,
+    defid: LocalDefId,
+}
+
+impl SpanLowerer {
+    fn lower(&self, span: Span) -> Span {
+        if self.is_incremental {
+            span.with_parent(Some(self.defid))
+        } else {
+            // Do not make spans relative when not using incremental compilation.
+            span
+        }
+    }
+}
+
 #[extension(trait ResolverAstLoweringExt)]
 impl ResolverAstLowering {
     fn legacy_const_generic_args(&self, expr: &Expr) -> Option<Vec<usize>> {
@@ -739,15 +755,17 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> {
         })
     }
 
+    fn span_lowerer(&self) -> SpanLowerer {
+        SpanLowerer {
+            is_incremental: self.tcx.sess.opts.incremental.is_some(),
+            defid: self.current_hir_id_owner.def_id,
+        }
+    }
+
     /// Intercept all spans entering HIR.
     /// Mark a span as relative to the current owning item.
     fn lower_span(&self, span: Span) -> Span {
-        if self.tcx.sess.opts.incremental.is_some() {
-            span.with_parent(Some(self.current_hir_id_owner.def_id))
-        } else {
-            // Do not make spans relative when not using incremental compilation.
-            span
-        }
+        self.span_lowerer().lower(span)
     }
 
     fn lower_ident(&self, ident: Ident) -> Ident {
@@ -870,7 +888,7 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> {
         if attrs.is_empty() {
             &[]
         } else {
-            let lowered_attrs = self.lower_attrs_vec(attrs, self.lower_span(target_span));
+            let lowered_attrs = self.lower_attrs_vec(attrs, self.lower_span(target_span), id);
 
             debug_assert_eq!(id.owner, self.current_hir_id_owner);
             let ret = self.arena.alloc_from_iter(lowered_attrs);
@@ -890,9 +908,20 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> {
         }
     }
 
-    fn lower_attrs_vec(&self, attrs: &[Attribute], target_span: Span) -> Vec<hir::Attribute> {
-        self.attribute_parser
-            .parse_attribute_list(attrs, target_span, OmitDoc::Lower, |s| self.lower_span(s))
+    fn lower_attrs_vec(
+        &mut self,
+        attrs: &[Attribute],
+        target_span: Span,
+        target_hir_id: HirId,
+    ) -> Vec<hir::Attribute> {
+        let l = self.span_lowerer();
+        self.attribute_parser.parse_attribute_list(
+            attrs,
+            target_span,
+            target_hir_id,
+            OmitDoc::Lower,
+            |s| l.lower(s),
+        )
     }
 
     fn alias_attrs(&mut self, id: HirId, target_id: HirId) {

compiler/rustc_attr_data_structures/src/attributes.rs

@@ -8,7 +8,7 @@ use thin_vec::ThinVec;
 
 use crate::{DefaultBodyStability, PartialConstStability, PrintAttribute, RustcVersion, Stability};
 
-#[derive(Copy, Clone, PartialEq, Encodable, Decodable, Debug, HashStable_Generic)]
+#[derive(Copy, Clone, PartialEq, Encodable, Decodable, Debug, HashStable_Generic, PrintAttribute)]
 pub enum InlineAttr {
     None,
     Hint,
@@ -186,8 +186,10 @@ pub enum AttributeKind {
         span: Span,
         comment: Symbol,
     },
+    Inline(InlineAttr, Span),
     MacroTransparency(Transparency),
     Repr(ThinVec<(ReprAttr, Span)>),
+    RustcForceInline(Span, Option<Symbol>),
     Stability {
         stability: Stability,
         /// Span of the `#[stable(...)]` or `#[unstable(...)]` attribute

compiler/rustc_attr_data_structures/src/lib.rs

@@ -149,3 +149,47 @@ print_tup!(A B C D E F G H);
 print_skip!(Span, ());
 print_disp!(Symbol, u16, bool, NonZero<u32>);
 print_debug!(UintTy, IntTy, Align, AttrStyle, CommentKind, Transparency);
+
+/// Finds attributes in sequences of attributes by pattern matching.
+///
+/// A little like `matches` but for attributes.
+///
+/// ```rust,ignore (illustrative)
+/// // finds the repr attribute
+/// if let Some(r) = find_attr!(attrs, AttributeKind::Repr(r) => r) {
+///
+/// }
+///
+/// // checks if one has matched
+/// if find_attr!(attrs, AttributeKind::Repr(_)) {
+///
+/// }
+/// ```
+///
+/// Often this requires you to first end up with a list of attributes.
+/// A common way to get those is through `tcx.get_all_attrs(did)`
+#[macro_export]
+macro_rules! find_attr {
+    ($attributes_list: expr, $pattern: pat $(if $guard: expr)?) => {{
+        $crate::find_attr!($attributes_list, $pattern $(if $guard)? => ()).is_some()
+    }};
+
+    ($attributes_list: expr, $pattern: pat $(if $guard: expr)? => $e: expr) => {{
+        fn check_attribute_iterator<'a>(_: &'_ impl IntoIterator<Item = &'a rustc_hir::Attribute>) {}
+        check_attribute_iterator(&$attributes_list);
+
+        let find_attribute = |iter| {
+            for i in $attributes_list {
+                match i {
+                    rustc_hir::Attribute::Parsed($pattern) $(if $guard)? => {
+                        return Some($e);
+                    }
+                    _ => {}
+                }
+            }
+
+            None
+        };
+        find_attribute($attributes_list)
+    }};
+}

compiler/rustc_attr_parsing/Cargo.toml

@@ -16,6 +16,7 @@ rustc_fluent_macro = { path = "../rustc_fluent_macro" }
 rustc_hir = { path = "../rustc_hir" }
 rustc_lexer = { path = "../rustc_lexer" }
 rustc_macros = { path = "../rustc_macros" }
+rustc_middle = { path = "../rustc_middle" }
 rustc_serialize = { path = "../rustc_serialize" }
 rustc_session = { path = "../rustc_session" }
 rustc_span = { path = "../rustc_span" }

compiler/rustc_attr_parsing/messages.ftl

@@ -23,8 +23,10 @@ attr_parsing_expects_feature_list =
 attr_parsing_expects_features =
     `{$name}` expects feature names
 
-attr_parsing_incorrect_meta_item = expected a quoted string literal
-attr_parsing_incorrect_meta_item_suggestion = consider surrounding this with quotes
+attr_parsing_ill_formed_attribute_input = {$num_suggestions ->
+        [1] attribute must be of the form {$suggestions}
+        *[other] valid forms for the attribute are {$suggestions}
+    }
 
 attr_parsing_incorrect_repr_format_align_one_arg =
     incorrect `repr(align)` attribute format: `align` takes exactly one argument in parentheses
@@ -81,9 +83,6 @@ attr_parsing_missing_note =
 attr_parsing_missing_since =
     missing 'since'
 
-attr_parsing_multiple_item =
-    multiple '{$item}' items
-
 attr_parsing_multiple_stability_levels =
     multiple stability levels
 
@@ -131,7 +130,16 @@ attr_parsing_unsupported_literal_generic =
 attr_parsing_unsupported_literal_suggestion =
     consider removing the prefix
 
+attr_parsing_unused_duplicate =
+    unused attribute
+    .suggestion = remove this attribute
+    .note = attribute also specified here
+    .warn = {-passes_previously_accepted}
+
 attr_parsing_unused_multiple =
     multiple `{$name}` attributes
     .suggestion = remove this attribute
     .note = attribute also specified here
+
+-attr_parsing_perviously_accepted =
+    this was previously accepted by the compiler but is being phased out; it will become a hard error in a future release!

compiler/rustc_attr_parsing/src/attributes/allow_unstable.rs

@@ -1,44 +1,49 @@
 use std::iter;
 
 use rustc_attr_data_structures::AttributeKind;
+use rustc_feature::{AttributeTemplate, template};
 use rustc_span::{Span, Symbol, sym};
 
 use super::{CombineAttributeParser, ConvertFn};
-use crate::context::AcceptContext;
+use crate::context::{AcceptContext, Stage};
 use crate::parser::ArgParser;
 use crate::session_diagnostics;
 
 pub(crate) struct AllowInternalUnstableParser;
-impl CombineAttributeParser for AllowInternalUnstableParser {
+impl<S: Stage> CombineAttributeParser<S> for AllowInternalUnstableParser {
     const PATH: &'static [rustc_span::Symbol] = &[sym::allow_internal_unstable];
     type Item = (Symbol, Span);
     const CONVERT: ConvertFn<Self::Item> = AttributeKind::AllowInternalUnstable;
+    const TEMPLATE: AttributeTemplate = template!(Word, List: "feat1, feat2, ...");
 
-    fn extend<'a>(
-        cx: &'a AcceptContext<'a>,
-        args: &'a ArgParser<'a>,
-    ) -> impl IntoIterator<Item = Self::Item> + 'a {
-        parse_unstable(cx, args, Self::PATH[0]).into_iter().zip(iter::repeat(cx.attr_span))
+    fn extend<'c>(
+        cx: &'c mut AcceptContext<'_, '_, S>,
+        args: &'c ArgParser<'_>,
+    ) -> impl IntoIterator<Item = Self::Item> {
+        parse_unstable(cx, args, <Self as CombineAttributeParser<S>>::PATH[0])
+            .into_iter()
+            .zip(iter::repeat(cx.attr_span))
     }
 }
 
 pub(crate) struct AllowConstFnUnstableParser;
-impl CombineAttributeParser for AllowConstFnUnstableParser {
+impl<S: Stage> CombineAttributeParser<S> for AllowConstFnUnstableParser {
     const PATH: &'static [rustc_span::Symbol] = &[sym::rustc_allow_const_fn_unstable];
     type Item = Symbol;
     const CONVERT: ConvertFn<Self::Item> = AttributeKind::AllowConstFnUnstable;
+    const TEMPLATE: AttributeTemplate = template!(Word, List: "feat1, feat2, ...");
 
-    fn extend<'a>(
-        cx: &'a AcceptContext<'a>,
-        args: &'a ArgParser<'a>,
-    ) -> impl IntoIterator<Item = Self::Item> + 'a {
-        parse_unstable(cx, args, Self::PATH[0])
+    fn extend<'c>(
+        cx: &'c mut AcceptContext<'_, '_, S>,
+        args: &'c ArgParser<'_>,
+    ) -> impl IntoIterator<Item = Self::Item> + 'c {
+        parse_unstable(cx, args, <Self as CombineAttributeParser<S>>::PATH[0])
     }
 }
 
-fn parse_unstable<'a>(
-    cx: &AcceptContext<'_>,
-    args: &'a ArgParser<'a>,
+fn parse_unstable<S: Stage>(
+    cx: &AcceptContext<'_, '_, S>,
+    args: &ArgParser<'_>,
     symbol: Symbol,
 ) -> impl IntoIterator<Item = Symbol> {
     let mut res = Vec::new();