Rollup merge of #145155 - scrabsha:push-tkvwkolzooyq, r=jdonszelmann

Port `#[allow_internal_unsafe]` to the new attribute system (attempt 2)

This is a slightly modified version of ae1487aa9922de7642c448cc0908584026699e1c, which caused a performance regression (reverted in https://github.com/rust-lang/rust/pull/145086#issue-3303428759). The diff between this PR and the previous one can be seen in 027a1def.

r? ```````@jdonszelmann``````` :sparkling_heart:

11 files changed, 85 insertions, 28 deletions

diff --git a/compiler/rustc_attr_parsing/src/attributes/macro_attrs.rs b/compiler/rustc_attr_parsing/src/attributes/macro_attrs.rs
index 886f7a889d3..0779248e1a9 100644
--- a/compiler/rustc_attr_parsing/src/attributes/macro_attrs.rs
+++ b/compiler/rustc_attr_parsing/src/attributes/macro_attrs.rs
@@ -113,3 +113,11 @@ impl<S: Stage> AttributeParser<S> for MacroUseParser {
         Some(AttributeKind::MacroUse { span: self.first_span?, arguments: self.state })
     }
 }
+
+pub(crate) struct AllowInternalUnsafeParser;
+
+impl<S: Stage> NoArgsAttributeParser<S> for AllowInternalUnsafeParser {
+    const PATH: &[Symbol] = &[sym::allow_internal_unsafe];
+    const ON_DUPLICATE: OnDuplicate<S> = OnDuplicate::Ignore;
+    const CREATE: fn(Span) -> AttributeKind = |span| AttributeKind::AllowInternalUnsafe(span);
+}
diff --git a/compiler/rustc_attr_parsing/src/context.rs b/compiler/rustc_attr_parsing/src/context.rs
index 80dfdffdb55..1420753a44e 100644
--- a/compiler/rustc_attr_parsing/src/context.rs
+++ b/compiler/rustc_attr_parsing/src/context.rs
@@ -33,7 +33,9 @@ use crate::attributes::lint_helpers::{
     AsPtrParser, AutomaticallyDerivedParser, PassByValueParser, PubTransparentParser,
 };
 use crate::attributes::loop_match::{ConstContinueParser, LoopMatchParser};
-use crate::attributes::macro_attrs::{MacroEscapeParser, MacroUseParser};
+use crate::attributes::macro_attrs::{
+    AllowInternalUnsafeParser, MacroEscapeParser, MacroUseParser,
+};
 use crate::attributes::must_use::MustUseParser;
 use crate::attributes::no_implicit_prelude::NoImplicitPreludeParser;
 use crate::attributes::non_exhaustive::NonExhaustiveParser;
@@ -178,6 +180,7 @@ attribute_parsers!(
         Single<SkipDuringMethodDispatchParser>,
         Single<TransparencyParser>,
         Single<WithoutArgs<AllowIncoherentImplParser>>,
+        Single<WithoutArgs<AllowInternalUnsafeParser>>,
         Single<WithoutArgs<AsPtrParser>>,
         Single<WithoutArgs<AutomaticallyDerivedParser>>,
         Single<WithoutArgs<CoherenceIsCoreParser>>,
diff --git a/compiler/rustc_expand/src/base.rs b/compiler/rustc_expand/src/base.rs
index c234aa43c09..7da3bf27eb5 100644
--- a/compiler/rustc_expand/src/base.rs
+++ b/compiler/rustc_expand/src/base.rs
@@ -904,10 +904,7 @@ impl SyntaxExtension {
             find_attr!(attrs, AttributeKind::AllowInternalUnstable(i, _) => i)
                 .map(|i| i.as_slice())
                 .unwrap_or_default();
-        // FIXME(jdonszelman): allow_internal_unsafe isn't yet new-style
-        // let allow_internal_unsafe = find_attr!(attrs, AttributeKind::AllowInternalUnsafe);
-        let allow_internal_unsafe =
-            ast::attr::find_by_name(attrs, sym::allow_internal_unsafe).is_some();
+        let allow_internal_unsafe = find_attr!(attrs, AttributeKind::AllowInternalUnsafe(_));
 
         let local_inner_macros = ast::attr::find_by_name(attrs, sym::macro_export)
             .and_then(|macro_export| macro_export.meta_item_list())
diff --git a/compiler/rustc_hir/src/attrs/data_structures.rs b/compiler/rustc_hir/src/attrs/data_structures.rs
index 5f419315467..e02edf5fe24 100644
--- a/compiler/rustc_hir/src/attrs/data_structures.rs
+++ b/compiler/rustc_hir/src/attrs/data_structures.rs
@@ -249,6 +249,9 @@ pub enum AttributeKind {
     /// Represents `#[rustc_allow_incoherent_impl]`.
     AllowIncoherentImpl(Span),
 
+    /// Represents `#[allow_internal_unsafe]`.
+    AllowInternalUnsafe(Span),
+
     /// Represents `#[allow_internal_unstable]`.
     AllowInternalUnstable(ThinVec<(Symbol, Span)>, Span),
 
diff --git a/compiler/rustc_hir/src/attrs/encode_cross_crate.rs b/compiler/rustc_hir/src/attrs/encode_cross_crate.rs
index e3a7f0b97a8..7ce624dcc55 100644
--- a/compiler/rustc_hir/src/attrs/encode_cross_crate.rs
+++ b/compiler/rustc_hir/src/attrs/encode_cross_crate.rs
@@ -16,6 +16,7 @@ impl AttributeKind {
             Align { .. } => No,
             AllowConstFnUnstable(..) => No,
             AllowIncoherentImpl(..) => No,
+            AllowInternalUnsafe(..) => Yes,
             AllowInternalUnstable(..) => Yes,
             AsPtr(..) => Yes,
             AutomaticallyDerived(..) => Yes,
diff --git a/compiler/rustc_hir/src/hir.rs b/compiler/rustc_hir/src/hir.rs
index d11ffce87cb..b27c223527e 100644
--- a/compiler/rustc_hir/src/hir.rs
+++ b/compiler/rustc_hir/src/hir.rs
@@ -1310,6 +1310,7 @@ impl AttributeExt for Attribute {
             Attribute::Parsed(AttributeKind::Ignore { span, .. }) => *span,
             Attribute::Parsed(AttributeKind::ShouldPanic { span, .. }) => *span,
             Attribute::Parsed(AttributeKind::AutomaticallyDerived(span)) => *span,
+            Attribute::Parsed(AttributeKind::AllowInternalUnsafe(span)) => *span,
             a => panic!("can't get the span of an arbitrary parsed attribute: {a:?}"),
         }
     }
diff --git a/compiler/rustc_lint/src/builtin.rs b/compiler/rustc_lint/src/builtin.rs
index 54769f9e097..8006cfcf30f 100644
--- a/compiler/rustc_lint/src/builtin.rs
+++ b/compiler/rustc_lint/src/builtin.rs
@@ -21,6 +21,7 @@ use rustc_ast::tokenstream::{TokenStream, TokenTree};
 use rustc_ast::visit::{FnCtxt, FnKind};
 use rustc_ast::{self as ast, *};
 use rustc_ast_pretty::pprust::expr_to_string;
+use rustc_attr_parsing::AttributeParser;
 use rustc_errors::{Applicability, LintDiagnostic};
 use rustc_feature::GateIssue;
 use rustc_hir as hir;
@@ -248,12 +249,6 @@ impl UnsafeCode {
 }
 
 impl EarlyLintPass for UnsafeCode {
-    fn check_attribute(&mut self, cx: &EarlyContext<'_>, attr: &ast::Attribute) {
-        if attr.has_name(sym::allow_internal_unsafe) {
-            self.report_unsafe(cx, attr.span, BuiltinUnsafe::AllowInternalUnsafe);
-        }
-    }
-
     #[inline]
     fn check_expr(&mut self, cx: &EarlyContext<'_>, e: &ast::Expr) {
         if let ast::ExprKind::Block(ref blk, _) = e.kind {
@@ -315,6 +310,19 @@ impl EarlyLintPass for UnsafeCode {
                 }
             }
 
+            ast::ItemKind::MacroDef(..) => {
+                if let Some(attr) = AttributeParser::parse_limited(
+                    cx.builder.sess(),
+                    &it.attrs,
+                    sym::allow_internal_unsafe,
+                    it.span,
+                    DUMMY_NODE_ID,
+                    Some(cx.builder.features()),
+                ) {
+                    self.report_unsafe(cx, attr.span(), BuiltinUnsafe::AllowInternalUnsafe);
+                }
+            }
+
             _ => {}
         }
     }
diff --git a/compiler/rustc_passes/messages.ftl b/compiler/rustc_passes/messages.ftl
index 6a28fe2617e..4a1f01cc5c8 100644
--- a/compiler/rustc_passes/messages.ftl
+++ b/compiler/rustc_passes/messages.ftl
@@ -29,7 +29,7 @@ passes_allow_incoherent_impl =
     `rustc_allow_incoherent_impl` attribute should be applied to impl items
     .label = the only currently supported targets are inherent methods
 
-passes_allow_internal_unstable =
+passes_macro_only_attribute =
     attribute should be applied to a macro
     .label = not a macro
 
diff --git a/compiler/rustc_passes/src/check_attr.rs b/compiler/rustc_passes/src/check_attr.rs
index dbdc8a3dbf5..d1e58e60dbe 100644
--- a/compiler/rustc_passes/src/check_attr.rs
+++ b/compiler/rustc_passes/src/check_attr.rs
@@ -207,6 +207,9 @@ impl<'tcx> CheckAttrVisitor<'tcx> {
                 Attribute::Parsed(AttributeKind::ConstContinue(attr_span)) => {
                     self.check_const_continue(hir_id, *attr_span, target)
                 }
+                Attribute::Parsed(AttributeKind::AllowInternalUnsafe(attr_span)) => {
+                    self.check_allow_internal_unsafe(hir_id, *attr_span, span, target, attrs)
+                }
                 Attribute::Parsed(AttributeKind::AllowInternalUnstable(_, first_span)) => {
                     self.check_allow_internal_unstable(hir_id, *first_span, span, target, attrs)
                 }
@@ -413,7 +416,6 @@ impl<'tcx> CheckAttrVisitor<'tcx> {
                             // internal
                             | sym::prelude_import
                             | sym::panic_handler
-                            | sym::allow_internal_unsafe
                             | sym::lang
                             | sym::needs_allocator
                             | sym::default_lib_allocator
@@ -2211,7 +2213,6 @@ impl<'tcx> CheckAttrVisitor<'tcx> {
 
     /// Outputs an error for `#[allow_internal_unstable]` which can only be applied to macros.
     /// (Allows proc_macro functions)
-    // FIXME(jdonszelmann): if possible, move to attr parsing
     fn check_allow_internal_unstable(
         &self,
         hir_id: HirId,
@@ -2220,6 +2221,42 @@ impl<'tcx> CheckAttrVisitor<'tcx> {
         target: Target,
         attrs: &[Attribute],
     ) {
+        self.check_macro_only_attr(
+            hir_id,
+            attr_span,
+            span,
+            target,
+            attrs,
+            "allow_internal_unstable",
+        )
+    }
+
+    /// Outputs an error for `#[allow_internal_unsafe]` which can only be applied to macros.
+    /// (Allows proc_macro functions)
+    fn check_allow_internal_unsafe(
+        &self,
+        hir_id: HirId,
+        attr_span: Span,
+        span: Span,
+        target: Target,
+        attrs: &[Attribute],
+    ) {
+        self.check_macro_only_attr(hir_id, attr_span, span, target, attrs, "allow_internal_unsafe")
+    }
+
+    /// Outputs an error for attributes that can only be applied to macros, such as
+    /// `#[allow_internal_unsafe]` and `#[allow_internal_unstable]`.
+    /// (Allows proc_macro functions)
+    // FIXME(jdonszelmann): if possible, move to attr parsing
+    fn check_macro_only_attr(
+        &self,
+        hir_id: HirId,
+        attr_span: Span,
+        span: Span,
+        target: Target,
+        attrs: &[Attribute],
+        attr_name: &str,
+    ) {
         match target {
             Target::Fn => {
                 for attr in attrs {
@@ -2237,18 +2274,14 @@ impl<'tcx> CheckAttrVisitor<'tcx> {
             // erroneously allowed it and some crates used it accidentally, to be compatible
             // with crates depending on them, we can't throw an error here.
             Target::Field | Target::Arm => {
-                self.inline_attr_str_error_without_macro_def(
-                    hir_id,
-                    attr_span,
-                    "allow_internal_unstable",
-                );
+                self.inline_attr_str_error_without_macro_def(hir_id, attr_span, attr_name);
                 return;
             }
             // otherwise continue out of the match
             _ => {}
         }
 
-        self.tcx.dcx().emit_err(errors::AllowInternalUnstable { attr_span, span });
+        self.tcx.dcx().emit_err(errors::MacroOnlyAttribute { attr_span, span });
     }
 
     /// Checks if the items on the `#[debugger_visualizer]` attribute are valid.
diff --git a/compiler/rustc_passes/src/errors.rs b/compiler/rustc_passes/src/errors.rs
index c6ab6b0d601..10b30fbe8c9 100644
--- a/compiler/rustc_passes/src/errors.rs
+++ b/compiler/rustc_passes/src/errors.rs
@@ -643,8 +643,8 @@ pub(crate) struct UsedStatic {
 }
 
 #[derive(Diagnostic)]
-#[diag(passes_allow_internal_unstable)]
-pub(crate) struct AllowInternalUnstable {
+#[diag(passes_macro_only_attribute)]
+pub(crate) struct MacroOnlyAttribute {
     #[primary_span]
     pub attr_span: Span,
     #[label]
diff --git a/tests/ui/attributes/malformed-attrs.stderr b/tests/ui/attributes/malformed-attrs.stderr
index dd9dd3a6ce7..74110183450 100644
--- a/tests/ui/attributes/malformed-attrs.stderr
+++ b/tests/ui/attributes/malformed-attrs.stderr
@@ -145,12 +145,6 @@ LL - #[macro_export = 18]
 LL + #[macro_export]
    |
 
-error: malformed `allow_internal_unsafe` attribute input
-  --> $DIR/malformed-attrs.rs:213:1
-   |
-LL | #[allow_internal_unsafe = 1]
-   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: must be of the form: `#[allow_internal_unsafe]`
-
 error: the `#[proc_macro]` attribute is only usable with crates of the `proc-macro` crate type
   --> $DIR/malformed-attrs.rs:96:1
    |
@@ -561,6 +555,15 @@ error: valid forms for the attribute are `#[macro_use(name1, name2, ...)]` and `
 LL | #[macro_use = 1]
    | ^^^^^^^^^^^^^^^^
 
+error[E0565]: malformed `allow_internal_unsafe` attribute input
+  --> $DIR/malformed-attrs.rs:213:1
+   |
+LL | #[allow_internal_unsafe = 1]
+   | ^^^^^^^^^^^^^^^^^^^^^^^^---^
+   | |                       |
+   | |                       didn't expect any arguments here
+   | help: must be of the form: `#[allow_internal_unsafe]`
+
 error[E0565]: malformed `type_const` attribute input
   --> $DIR/malformed-attrs.rs:140:5
    |