Port #[should_panic] to the new attribute parsing infrastructure

Signed-off-by: Jonathan Brouwer <[email protected]>

Author: JonathanBrouwer

compiler/rustc_attr_data_structures/src/attributes.rs

@@ -355,6 +355,9 @@ pub enum AttributeKind {
     /// Represents `#[rustc_object_lifetime_default]`.
     RustcObjectLifetimeDefault,
 
+    /// Represents `#[should_panic]`
+    ShouldPanic { reason: Option<Symbol>, span: Span },
+
     /// Represents `#[rustc_skip_during_method_dispatch]`.
     SkipDuringMethodDispatch { array: bool, boxed_slice: bool, span: Span },
 

compiler/rustc_attr_data_structures/src/encode_cross_crate.rs

@@ -59,6 +59,7 @@ impl AttributeKind {
             RustcLayoutScalarValidRangeEnd(..) => Yes,
             RustcLayoutScalarValidRangeStart(..) => Yes,
             RustcObjectLifetimeDefault => No,
+            ShouldPanic { .. } => No,
             SkipDuringMethodDispatch { .. } => No,
             SpecializationTrait(..) => No,
             Stability { .. } => Yes,

compiler/rustc_attr_parsing/src/attributes/test_attrs.rs

@@ -44,3 +44,55 @@ impl<S: Stage> SingleAttributeParser<S> for IgnoreParser {
         })
     }
 }
+
+pub(crate) struct ShouldPanicParser;
+
+impl<S: Stage> SingleAttributeParser<S> for ShouldPanicParser {
+    const PATH: &[Symbol] = &[sym::should_panic];
+    const ATTRIBUTE_ORDER: AttributeOrder = AttributeOrder::KeepOutermost;
+    const ON_DUPLICATE: OnDuplicate<S> = OnDuplicate::WarnButFutureError;
+    const TEMPLATE: AttributeTemplate =
+        template!(Word, List: r#"expected = "reason""#, NameValueStr: "reason");
+
+    fn convert(cx: &mut AcceptContext<'_, '_, S>, args: &ArgParser<'_>) -> Option<AttributeKind> {
+        Some(AttributeKind::ShouldPanic {
+            span: cx.attr_span,
+            reason: match args {
+                ArgParser::NoArgs => None,
+                ArgParser::NameValue(name_value) => {
+                    let Some(str_value) = name_value.value_as_str() else {
+                        cx.expected_string_literal(
+                            name_value.value_span,
+                            Some(name_value.value_as_lit()),
+                        );
+                        return None;
+                    };
+                    Some(str_value)
+                }
+                ArgParser::List(list) => {
+                    let Some(single) = list.single() else {
+                        cx.expected_single_argument(list.span);
+                        return None;
+                    };
+                    let Some(single) = single.meta_item() else {
+                        cx.expected_name_value(single.span(), Some(sym::expected));
+                        return None;
+                    };
+                    if !single.path().word_is(sym::expected) {
+                        cx.expected_specific_argument_strings(list.span, vec!["expected"]);
+                        return None;
+                    }
+                    let Some(nv) = single.args().name_value() else {
+                        cx.expected_name_value(single.span(), Some(sym::expected));
+                        return None;
+                    };
+                    let Some(expected) = nv.value_as_str() else {
+                        cx.expected_string_literal(nv.value_span, Some(nv.value_as_lit()));
+                        return None;
+                    };
+                    Some(expected)
+                }
+            },
+        })
+    }
+}

compiler/rustc_attr_parsing/src/context.rs

@@ -42,7 +42,7 @@ use crate::attributes::semantics::MayDangleParser;
 use crate::attributes::stability::{
     BodyStabilityParser, ConstStabilityIndirectParser, ConstStabilityParser, StabilityParser,
 };
-use crate::attributes::test_attrs::IgnoreParser;
+use crate::attributes::test_attrs::{IgnoreParser, ShouldPanicParser};
 use crate::attributes::traits::{
     AllowIncoherentImplParser, CoherenceIsCoreParser, CoinductiveParser, ConstTraitParser,
     DenyExplicitImplParser, DoNotImplementViaObjectParser, FundamentalParser, MarkerParser,
@@ -149,6 +149,7 @@ attribute_parsers!(
         Single<RustcLayoutScalarValidRangeEnd>,
         Single<RustcLayoutScalarValidRangeStart>,
         Single<RustcObjectLifetimeDefaultParser>,
+        Single<ShouldPanicParser>,
         Single<SkipDuringMethodDispatchParser>,
         Single<TransparencyParser>,
         Single<WithoutArgs<AllowIncoherentImplParser>>,

compiler/rustc_builtin_macros/src/test.rs

@@ -5,10 +5,13 @@ use std::assert_matches::assert_matches;
 use std::iter;
 
 use rustc_ast::ptr::P;
-use rustc_ast::{self as ast, GenericParamKind, attr};
+use rustc_ast::{self as ast, GenericParamKind, HasNodeId, attr};
 use rustc_ast_pretty::pprust;
+use rustc_attr_data_structures::AttributeKind;
+use rustc_attr_parsing::AttributeParser;
 use rustc_errors::{Applicability, Diag, Level};
 use rustc_expand::base::*;
+use rustc_hir::Attribute;
 use rustc_span::{ErrorGuaranteed, FileNameDisplayPreference, Ident, Span, Symbol, sym};
 use thin_vec::{ThinVec, thin_vec};
 use tracing::debug;
@@ -478,39 +481,12 @@ fn should_ignore_message(i: &ast::Item) -> Option<Symbol> {
 }
 
 fn should_panic(cx: &ExtCtxt<'_>, i: &ast::Item) -> ShouldPanic {
-    match attr::find_by_name(&i.attrs, sym::should_panic) {
-        Some(attr) => {
-            match attr.meta_item_list() {
-                // Handle #[should_panic(expected = "foo")]
-                Some(list) => {
-                    let msg = list
-                        .iter()
-                        .find(|mi| mi.has_name(sym::expected))
-                        .and_then(|mi| mi.meta_item())
-                        .and_then(|mi| mi.value_str());
-                    if list.len() != 1 || msg.is_none() {
-                        cx.dcx()
-                            .struct_span_warn(
-                                attr.span,
-                                "argument must be of the form: \
-                             `expected = \"error message\"`",
-                            )
-                            .with_note(
-                                "errors in this attribute were erroneously \
-                                allowed and will become a hard error in a \
-                                future release",
-                            )
-                            .emit();
-                        ShouldPanic::Yes(None)
-                    } else {
-                        ShouldPanic::Yes(msg)
-                    }
-                }
-                // Handle #[should_panic] and #[should_panic = "expected"]
-                None => ShouldPanic::Yes(attr.value_str()),
-            }
-        }
-        None => ShouldPanic::No,
+    if let Some(Attribute::Parsed(AttributeKind::ShouldPanic { reason, .. })) =
+        AttributeParser::parse_limited(cx.sess, &i.attrs, sym::should_panic, i.span, i.node_id())
+    {
+        ShouldPanic::Yes(reason)
+    } else {
+        ShouldPanic::No
     }
 }
 

compiler/rustc_hir/src/hir.rs

@@ -1304,6 +1304,7 @@ impl AttributeExt for Attribute {
             Attribute::Parsed(AttributeKind::DocComment { span, .. }) => *span,
             Attribute::Parsed(AttributeKind::MayDangle(span)) => *span,
             Attribute::Parsed(AttributeKind::Ignore { span, .. }) => *span,
+            Attribute::Parsed(AttributeKind::ShouldPanic { span, .. }) => *span,
             a => panic!("can't get the span of an arbitrary parsed attribute: {a:?}"),
         }
     }

compiler/rustc_parse/src/validate_attr.rs

@@ -316,6 +316,7 @@ pub fn check_builtin_meta_item(
                 | sym::rustc_layout_scalar_valid_range_start
                 | sym::rustc_layout_scalar_valid_range_end
                 | sym::no_implicit_prelude
+                | sym::should_panic
         ) {
             return;
         }

compiler/rustc_passes/src/check_attr.rs

@@ -265,6 +265,8 @@ impl<'tcx> CheckAttrVisitor<'tcx> {
                 Attribute::Parsed(AttributeKind::Used { span: attr_span, .. }) => {
                     self.check_used(*attr_span, target, span);
                 }
+                Attribute::Parsed(AttributeKind::ShouldPanic { span: attr_span, .. }) => self
+                    .check_generic_attr(hir_id, sym::should_panic, *attr_span, target, Target::Fn),
                 &Attribute::Parsed(AttributeKind::PassByValue(attr_span)) => {
                     self.check_pass_by_value(attr_span, span, target)
                 }
@@ -334,9 +336,6 @@ impl<'tcx> CheckAttrVisitor<'tcx> {
                         }
                         [sym::path, ..] => self.check_generic_attr_unparsed(hir_id, attr, target, Target::Mod),
                         [sym::macro_export, ..] => self.check_macro_export(hir_id, attr, target),
-                        [sym::should_panic, ..] => {
-                            self.check_generic_attr_unparsed(hir_id, attr, target, Target::Fn)
-                        }
                         [sym::automatically_derived, ..] => {
                             self.check_generic_attr_unparsed(hir_id, attr, target, Target::Impl)
                         }