Port rustc_no_implicit_bounds attribute to parser.

compiler/rustc_attr_parsing/src/attributes/crate_level.rs

@@ -283,3 +283,12 @@ impl<S: Stage> NoArgsAttributeParser<S> for RustcPreserveUbChecksParser {
     const ALLOWED_TARGETS: AllowedTargets = AllowedTargets::AllowList(&[Allow(Target::Crate)]);
     const CREATE: fn(Span) -> AttributeKind = |_| AttributeKind::RustcPreserveUbChecks;
 }
+
+pub(crate) struct RustcNoImplicitBoundsParser;
+
+impl<S: Stage> NoArgsAttributeParser<S> for RustcNoImplicitBoundsParser {
+    const PATH: &[Symbol] = &[sym::rustc_no_implicit_bounds];
+    const ON_DUPLICATE: OnDuplicate<S> = OnDuplicate::Warn;
+    const ALLOWED_TARGETS: AllowedTargets = AllowedTargets::AllowList(&[Allow(Target::Crate)]);
+    const CREATE: fn(Span) -> AttributeKind = |_| AttributeKind::RustcNoImplicitBounds;
+}

compiler/rustc_attr_parsing/src/context.rs

@@ -281,6 +281,7 @@ attribute_parsers!(
         Single<WithoutArgs<RustcMainParser>>,
         Single<WithoutArgs<RustcNeverReturnsNullPointerParser>>,
         Single<WithoutArgs<RustcNoImplicitAutorefsParser>>,
+        Single<WithoutArgs<RustcNoImplicitBoundsParser>>,
         Single<WithoutArgs<RustcNonConstTraitMethodParser>>,
         Single<WithoutArgs<RustcNounwindParser>>,
         Single<WithoutArgs<RustcOffloadKernelParser>>,

compiler/rustc_hir/src/attrs/data_structures.rs

@@ -1177,6 +1177,9 @@ pub enum AttributeKind {
     /// Represents `#[rustc_no_implicit_autorefs]`
     RustcNoImplicitAutorefs,
 
+    /// Represents `#[rustc_no_implicit_bounds]`
+    RustcNoImplicitBounds,
+
     /// Represents `#[rustc_non_const_trait_method]`.
     RustcNonConstTraitMethod,
 

compiler/rustc_hir/src/attrs/encode_cross_crate.rs

@@ -137,6 +137,7 @@ impl AttributeKind {
             RustcMustImplementOneOf { .. } => No,
             RustcNeverReturnsNullPointer => Yes,
             RustcNoImplicitAutorefs => Yes,
+            RustcNoImplicitBounds => No,
             RustcNonConstTraitMethod => No, // should be reported via other queries like `constness`
             RustcNounwind => No,
             RustcObjcClass { .. } => No,

compiler/rustc_hir_analysis/src/hir_ty_lowering/bounds.rs

@@ -4,15 +4,16 @@ use rustc_data_structures::fx::{FxIndexMap, FxIndexSet};
 use rustc_errors::codes::*;
 use rustc_errors::struct_span_code_err;
 use rustc_hir as hir;
-use rustc_hir::PolyTraitRef;
+use rustc_hir::attrs::AttributeKind;
 use rustc_hir::def::{DefKind, Res};
 use rustc_hir::def_id::{CRATE_DEF_ID, DefId};
+use rustc_hir::{PolyTraitRef, find_attr};
 use rustc_middle::bug;
 use rustc_middle::ty::{
     self as ty, IsSuggestable, Ty, TyCtxt, TypeSuperVisitable, TypeVisitable, TypeVisitableExt,
     TypeVisitor, Upcast,
 };
-use rustc_span::{ErrorGuaranteed, Ident, Span, kw, sym};
+use rustc_span::{ErrorGuaranteed, Ident, Span, kw};
 use rustc_trait_selection::traits;
 use smallvec::SmallVec;
 use tracing::{debug, instrument};
@@ -170,7 +171,7 @@ impl<'tcx> dyn HirTyLowerer<'tcx> + '_ {
         let tcx = self.tcx();
 
         // Skip adding any default bounds if `#![rustc_no_implicit_bounds]`
-        if tcx.has_attr(CRATE_DEF_ID, sym::rustc_no_implicit_bounds) {
+        if find_attr!(tcx.get_all_attrs(CRATE_DEF_ID), AttributeKind::RustcNoImplicitBounds) {
             return;
         }
 
@@ -284,7 +285,8 @@ impl<'tcx> dyn HirTyLowerer<'tcx> + '_ {
         context: ImpliedBoundsContext<'tcx>,
     ) -> bool {
         let collected = collect_bounds(hir_bounds, context, trait_def_id);
-        !self.tcx().has_attr(CRATE_DEF_ID, sym::rustc_no_implicit_bounds) && !collected.any()
+        !find_attr!(self.tcx().get_all_attrs(CRATE_DEF_ID), AttributeKind::RustcNoImplicitBounds)
+            && !collected.any()
     }
 
     fn reject_duplicate_relaxed_bounds(&self, relaxed_bounds: SmallVec<[&PolyTraitRef<'_>; 1]>) {

compiler/rustc_passes/src/check_attr.rs

@@ -330,6 +330,7 @@ impl<'tcx> CheckAttrVisitor<'tcx> {
                     | AttributeKind::RustcMir(_)
                     | AttributeKind::RustcNeverReturnsNullPointer
                     | AttributeKind::RustcNoImplicitAutorefs
+                    | AttributeKind::RustcNoImplicitBounds
                     | AttributeKind::RustcNonConstTraitMethod
                     | AttributeKind::RustcNounwind
                     | AttributeKind::RustcObjcClass { .. }
@@ -413,7 +414,6 @@ impl<'tcx> CheckAttrVisitor<'tcx> {
                             // crate-level attrs, are checked below
                             | sym::feature
                             | sym::register_tool
-                            | sym::rustc_no_implicit_bounds
                             | sym::test_runner,
                             ..
                         ] => {}