Add feature flags to lint checks

compiler/rustc_ast_passes/src/ast_validation.rs

@@ -870,7 +870,7 @@ fn validate_generic_param_order(
 
 impl<'a> Visitor<'a> for AstValidator<'a> {
     fn visit_attribute(&mut self, attr: &Attribute) {
-        validate_attr::check_attr(&self.session.psess, attr);
+        validate_attr::check_attr(&self.features, &self.session.psess, attr);
     }
 
     fn visit_ty(&mut self, ty: &'a Ty) {

compiler/rustc_expand/src/expand.rs

@@ -1796,7 +1796,7 @@ impl<'a, 'b> InvocationCollector<'a, 'b> {
         let mut span: Option<Span> = None;
         while let Some(attr) = attrs.next() {
             rustc_ast_passes::feature_gate::check_attribute(attr, self.cx.sess, features);
-            validate_attr::check_attr(&self.cx.sess.psess, attr);
+            validate_attr::check_attr(features, &self.cx.sess.psess, attr);
 
             let current_span = if let Some(sp) = span { sp.to(attr.span) } else { attr.span };
             span = Some(current_span);

compiler/rustc_parse/src/validate_attr.rs

@@ -7,65 +7,70 @@ use rustc_ast::tokenstream::DelimSpan;
 use rustc_ast::MetaItemKind;
 use rustc_ast::{self as ast, AttrArgs, AttrArgsEq, Attribute, DelimArgs, MetaItem, Safety};
 use rustc_errors::{Applicability, FatalError, PResult};
-use rustc_feature::{AttributeSafety, AttributeTemplate, BuiltinAttribute, BUILTIN_ATTRIBUTE_MAP};
+use rustc_feature::{
+    AttributeSafety, AttributeTemplate, BuiltinAttribute, Features, BUILTIN_ATTRIBUTE_MAP,
+};
 use rustc_session::errors::report_lit_error;
 use rustc_session::lint::builtin::{ILL_FORMED_ATTRIBUTE_INPUT, UNSAFE_ATTR_OUTSIDE_UNSAFE};
 use rustc_session::lint::BuiltinLintDiag;
 use rustc_session::parse::ParseSess;
 use rustc_span::{sym, BytePos, Span, Symbol};
 
-pub fn check_attr(psess: &ParseSess, attr: &Attribute) {
+pub fn check_attr(features: &Features, psess: &ParseSess, attr: &Attribute) {
     if attr.is_doc_comment() {
         return;
     }
 
     let attr_info = attr.ident().and_then(|ident| BUILTIN_ATTRIBUTE_MAP.get(&ident.name));
     let attr_item = attr.get_normal_item();
 
-    let is_unsafe_attr =
-        attr_info.map(|attr| attr.safety == AttributeSafety::Unsafe).unwrap_or(false);
+    let is_unsafe_attr = attr_info.is_some_and(|attr| attr.safety == AttributeSafety::Unsafe);
 
-    if is_unsafe_attr {
-        if let ast::Safety::Default = attr_item.unsafety {
-            let path_span = attr_item.path.span;
+    if features.unsafe_attributes {
+        if is_unsafe_attr {
+            if let ast::Safety::Default = attr_item.unsafety {
+                let path_span = attr_item.path.span;
 
-            // If the `attr_item`'s span is not from a macro, then just suggest
-            // wrapping it in `unsafe(...)`. Otherwise, we suggest putting the
-            // `unsafe(`, `)` right after and right before the opening and closing
-            // square bracket respectively.
-            let diag_span = if attr_item.span().can_be_used_for_suggestions() {
-                attr_item.span()
-            } else {
-                attr.span.with_lo(attr.span.lo() + BytePos(2)).with_hi(attr.span.hi() - BytePos(1))
-            };
+                // If the `attr_item`'s span is not from a macro, then just suggest
+                // wrapping it in `unsafe(...)`. Otherwise, we suggest putting the
+                // `unsafe(`, `)` right after and right before the opening and closing
+                // square bracket respectively.
+                let diag_span = if attr_item.span().can_be_used_for_suggestions() {
+                    attr_item.span()
+                } else {
+                    attr.span
+                        .with_lo(attr.span.lo() + BytePos(2))
+                        .with_hi(attr.span.hi() - BytePos(1))
+                };
 
-            if attr.span.at_least_rust_2024() {
-                psess.dcx.emit_err(errors::UnsafeAttrOutsideUnsafe {
-                    span: path_span,
-                    suggestion: errors::UnsafeAttrOutsideUnsafeSuggestion {
-                        left: diag_span.shrink_to_lo(),
-                        right: diag_span.shrink_to_hi(),
-                    },
+                if attr.span.at_least_rust_2024() {
+                    psess.dcx.emit_err(errors::UnsafeAttrOutsideUnsafe {
+                        span: path_span,
+                        suggestion: errors::UnsafeAttrOutsideUnsafeSuggestion {
+                            left: diag_span.shrink_to_lo(),
+                            right: diag_span.shrink_to_hi(),
+                        },
+                    });
+                } else {
+                    psess.buffer_lint(
+                        UNSAFE_ATTR_OUTSIDE_UNSAFE,
+                        path_span,
+                        ast::CRATE_NODE_ID,
+                        BuiltinLintDiag::UnsafeAttrOutsideUnsafe {
+                            attribute_name_span: path_span,
+                            sugg_spans: (diag_span.shrink_to_lo(), diag_span.shrink_to_hi()),
+                        },
+                    );
+                }
+            }
+        } else {
+            if let Safety::Unsafe(unsafe_span) = attr_item.unsafety {
+                psess.dcx.emit_err(errors::InvalidAttrUnsafe {
+                    span: unsafe_span,
+                    name: attr_item.path.clone(),
                 });
-            } else {
-                psess.buffer_lint(
-                    UNSAFE_ATTR_OUTSIDE_UNSAFE,
-                    path_span,
-                    ast::CRATE_NODE_ID,
-                    BuiltinLintDiag::UnsafeAttrOutsideUnsafe {
-                        attribute_name_span: path_span,
-                        sugg_spans: (diag_span.shrink_to_lo(), diag_span.shrink_to_hi()),
-                    },
-                );
             }
         }
-    } else {
-        if let Safety::Unsafe(unsafe_span) = attr_item.unsafety {
-            psess.dcx.emit_err(errors::InvalidAttrUnsafe {
-                span: unsafe_span,
-                name: attr_item.path.clone(),
-            });
-        }
     }
 
     // Check input tokens for built-in and key-value attributes.

tests/ui/rust-2024/unsafe-attributes/in_2024_compatibility.rs

@@ -1,4 +1,5 @@
 #![deny(rust_2024_compatibility)]
+#![feature(unsafe_attributes)]
 
 #[no_mangle]
 //~^ ERROR: unsafe attribute used without unsafe

tests/ui/rust-2024/unsafe-attributes/in_2024_compatibility.stderr

@@ -1,5 +1,5 @@
 error: unsafe attribute used without unsafe
-  --> $DIR/in_2024_compatibility.rs:3:3
+  --> $DIR/in_2024_compatibility.rs:4:3
    |
 LL | #[no_mangle]
    |   ^^^^^^^^^ usage of unsafe attribute