Move validate_attr to `rustc_attr_parsing`

21 files changed, 99 insertions, 85 deletions

diff --git a/Cargo.lock b/Cargo.lock
index 91528a4135e..8eb77165cf2 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -3459,7 +3459,6 @@ dependencies = [
  "rustc_feature",
  "rustc_fluent_macro",
  "rustc_macros",
- "rustc_parse",
  "rustc_session",
  "rustc_span",
  "rustc_target",
@@ -3490,6 +3489,7 @@ dependencies = [
  "rustc_hir",
  "rustc_lexer",
  "rustc_macros",
+ "rustc_parse",
  "rustc_session",
  "rustc_span",
  "thin-vec",
@@ -4355,7 +4355,6 @@ dependencies = [
  "rustc-literal-escaper",
  "rustc_ast",
  "rustc_ast_pretty",
- "rustc_attr_parsing",
  "rustc_data_structures",
  "rustc_errors",
  "rustc_feature",
diff --git a/compiler/rustc_ast_passes/Cargo.toml b/compiler/rustc_ast_passes/Cargo.toml
index 1940628b44a..3e04f8b11ec 100644
--- a/compiler/rustc_ast_passes/Cargo.toml
+++ b/compiler/rustc_ast_passes/Cargo.toml
@@ -15,7 +15,6 @@ rustc_errors = { path = "../rustc_errors" }
 rustc_feature = { path = "../rustc_feature" }
 rustc_fluent_macro = { path = "../rustc_fluent_macro" }
 rustc_macros = { path = "../rustc_macros" }
-rustc_parse = { path = "../rustc_parse" }
 rustc_session = { path = "../rustc_session" }
 rustc_span = { path = "../rustc_span" }
 rustc_target = { path = "../rustc_target" }
diff --git a/compiler/rustc_ast_passes/src/ast_validation.rs b/compiler/rustc_ast_passes/src/ast_validation.rs
index ef4410566c5..508eb083672 100644
--- a/compiler/rustc_ast_passes/src/ast_validation.rs
+++ b/compiler/rustc_ast_passes/src/ast_validation.rs
@@ -25,10 +25,10 @@ use rustc_abi::{CanonAbi, ExternAbi, InterruptKind};
 use rustc_ast::visit::{AssocCtxt, BoundKind, FnCtxt, FnKind, Visitor, walk_list};
 use rustc_ast::*;
 use rustc_ast_pretty::pprust::{self, State};
+use rustc_attr_parsing::validate_attr;
 use rustc_data_structures::fx::FxIndexMap;
 use rustc_errors::DiagCtxtHandle;
 use rustc_feature::Features;
-use rustc_parse::validate_attr;
 use rustc_session::Session;
 use rustc_session::lint::builtin::{
     DEPRECATED_WHERE_CLAUSE_LOCATION, MISSING_ABI, MISSING_UNSAFE_ON_EXTERN,
diff --git a/compiler/rustc_attr_parsing/Cargo.toml b/compiler/rustc_attr_parsing/Cargo.toml
index cec9d62e656..fd8f7ffb2ed 100644
--- a/compiler/rustc_attr_parsing/Cargo.toml
+++ b/compiler/rustc_attr_parsing/Cargo.toml
@@ -14,6 +14,7 @@ rustc_fluent_macro = { path = "../rustc_fluent_macro" }
 rustc_hir = { path = "../rustc_hir" }
 rustc_lexer = { path = "../rustc_lexer" }
 rustc_macros = { path = "../rustc_macros" }
+rustc_parse = { path = "../rustc_parse" }
 rustc_session = { path = "../rustc_session" }
 rustc_span = { path = "../rustc_span" }
 thin-vec = "0.2.12"
diff --git a/compiler/rustc_attr_parsing/messages.ftl b/compiler/rustc_attr_parsing/messages.ftl
index 067d95a0f48..1a2815c54ec 100644
--- a/compiler/rustc_attr_parsing/messages.ftl
+++ b/compiler/rustc_attr_parsing/messages.ftl
@@ -170,3 +170,15 @@ attr_parsing_unused_multiple =
 
 -attr_parsing_previously_accepted =
     this was previously accepted by the compiler but is being phased out; it will become a hard error in a future release!
+
+attr_parsing_meta_bad_delim = wrong meta list delimiters
+attr_parsing_meta_bad_delim_suggestion = the delimiters should be `(` and `)`
+
+attr_parsing_unsafe_attr_outside_unsafe = unsafe attribute used without unsafe
+    .label = usage of unsafe attribute
+attr_parsing_unsafe_attr_outside_unsafe_suggestion = wrap the attribute in `unsafe(...)`
+
+attr_parsing_invalid_attr_unsafe = `{$name}` is not an unsafe attribute
+    .label = this is not an unsafe attribute
+    .suggestion = remove the `unsafe(...)`
+    .note = extraneous unsafe is not allowed in attributes
diff --git a/compiler/rustc_attr_parsing/src/lib.rs b/compiler/rustc_attr_parsing/src/lib.rs
index 99842cd9687..969c24a4f89 100644
--- a/compiler/rustc_attr_parsing/src/lib.rs
+++ b/compiler/rustc_attr_parsing/src/lib.rs
@@ -102,6 +102,7 @@ pub mod parser;
 mod lints;
 mod session_diagnostics;
 mod target_checking;
+pub mod validate_attr;
 
 pub use attributes::cfg::{CFG_TEMPLATE, EvalConfigResult, eval_config_entry, parse_cfg_attr};
 pub use attributes::cfg_old::*;
diff --git a/compiler/rustc_attr_parsing/src/session_diagnostics.rs b/compiler/rustc_attr_parsing/src/session_diagnostics.rs
index 2993881f717..b877caa143a 100644
--- a/compiler/rustc_attr_parsing/src/session_diagnostics.rs
+++ b/compiler/rustc_attr_parsing/src/session_diagnostics.rs
@@ -1,6 +1,6 @@
 use std::num::IntErrorKind;
 
-use rustc_ast::{self as ast, AttrStyle};
+use rustc_ast::{self as ast, AttrStyle, Path};
 use rustc_errors::codes::*;
 use rustc_errors::{
     Applicability, Diag, DiagArgValue, DiagCtxtHandle, Diagnostic, EmissionGuarantee, Level,
@@ -737,3 +737,56 @@ impl<'a, G: EmissionGuarantee> Diagnostic<'a, G> for AttributeParseError {
         diag
     }
 }
+
+#[derive(Diagnostic)]
+#[diag(attr_parsing_invalid_attr_unsafe)]
+#[note]
+pub(crate) struct InvalidAttrUnsafe {
+    #[primary_span]
+    #[label]
+    pub span: Span,
+    pub name: Path,
+}
+
+#[derive(Diagnostic)]
+#[diag(attr_parsing_unsafe_attr_outside_unsafe)]
+pub(crate) struct UnsafeAttrOutsideUnsafe {
+    #[primary_span]
+    #[label]
+    pub span: Span,
+    #[subdiagnostic]
+    pub suggestion: UnsafeAttrOutsideUnsafeSuggestion,
+}
+
+#[derive(Subdiagnostic)]
+#[multipart_suggestion(
+    attr_parsing_unsafe_attr_outside_unsafe_suggestion,
+    applicability = "machine-applicable"
+)]
+pub(crate) struct UnsafeAttrOutsideUnsafeSuggestion {
+    #[suggestion_part(code = "unsafe(")]
+    pub left: Span,
+    #[suggestion_part(code = ")")]
+    pub right: Span,
+}
+
+#[derive(Diagnostic)]
+#[diag(attr_parsing_meta_bad_delim)]
+pub(crate) struct MetaBadDelim {
+    #[primary_span]
+    pub span: Span,
+    #[subdiagnostic]
+    pub sugg: MetaBadDelimSugg,
+}
+
+#[derive(Subdiagnostic)]
+#[multipart_suggestion(
+    attr_parsing_meta_bad_delim_suggestion,
+    applicability = "machine-applicable"
+)]
+pub(crate) struct MetaBadDelimSugg {
+    #[suggestion_part(code = "(")]
+    pub open: Span,
+    #[suggestion_part(code = ")")]
+    pub close: Span,
+}
diff --git a/compiler/rustc_parse/src/validate_attr.rs b/compiler/rustc_attr_parsing/src/validate_attr.rs
index 68ef6d6f32c..da3a1cbe016 100644
--- a/compiler/rustc_parse/src/validate_attr.rs
+++ b/compiler/rustc_attr_parsing/src/validate_attr.rs
@@ -8,16 +8,16 @@ use rustc_ast::{
     self as ast, AttrArgs, Attribute, DelimArgs, MetaItem, MetaItemInner, MetaItemKind, NodeId,
     Path, Safety,
 };
-use rustc_attr_parsing::{AttributeParser, Late};
 use rustc_errors::{Applicability, DiagCtxtHandle, FatalError, PResult};
 use rustc_feature::{AttributeSafety, AttributeTemplate, BUILTIN_ATTRIBUTE_MAP, BuiltinAttribute};
+use rustc_parse::parse_in;
 use rustc_session::errors::report_lit_error;
 use rustc_session::lint::BuiltinLintDiag;
 use rustc_session::lint::builtin::{ILL_FORMED_ATTRIBUTE_INPUT, UNSAFE_ATTR_OUTSIDE_UNSAFE};
 use rustc_session::parse::ParseSess;
 use rustc_span::{Span, Symbol, sym};
 
-use crate::{errors, parse_in};
+use crate::{AttributeParser, Late, session_diagnostics as errors};
 
 pub fn check_attr(psess: &ParseSess, attr: &Attribute, id: NodeId) {
     if attr.is_doc_comment() || attr.has_name(sym::cfg_trace) || attr.has_name(sym::cfg_attr_trace)
@@ -133,16 +133,6 @@ fn check_meta_bad_delim(psess: &ParseSess, span: DelimSpan, delim: Delimiter) {
     });
 }
 
-pub(super) fn check_cfg_attr_bad_delim(psess: &ParseSess, span: DelimSpan, delim: Delimiter) {
-    if let Delimiter::Parenthesis = delim {
-        return;
-    }
-    psess.dcx().emit_err(errors::CfgAttrBadDelim {
-        span: span.entire(),
-        sugg: errors::MetaBadDelimSugg { open: span.open, close: span.close },
-    });
-}
-
 /// Checks that the given meta-item is compatible with this `AttributeTemplate`.
 fn is_attr_template_compatible(template: &AttributeTemplate, meta: &ast::MetaItemKind) -> bool {
     let is_one_allowed_subword = |items: &[MetaItemInner]| match items {
diff --git a/compiler/rustc_builtin_macros/src/cfg_accessible.rs b/compiler/rustc_builtin_macros/src/cfg_accessible.rs
index f7d8f4aa783..48d80004cdd 100644
--- a/compiler/rustc_builtin_macros/src/cfg_accessible.rs
+++ b/compiler/rustc_builtin_macros/src/cfg_accessible.rs
@@ -1,9 +1,9 @@
 //! Implementation of the `#[cfg_accessible(path)]` attribute macro.
 
 use rustc_ast as ast;
+use rustc_attr_parsing::validate_attr;
 use rustc_expand::base::{Annotatable, ExpandResult, ExtCtxt, Indeterminate, MultiItemModifier};
 use rustc_feature::AttributeTemplate;
-use rustc_parse::validate_attr;
 use rustc_span::{Span, sym};
 
 use crate::errors;
diff --git a/compiler/rustc_builtin_macros/src/derive.rs b/compiler/rustc_builtin_macros/src/derive.rs
index a33eca43de5..09d827b0635 100644
--- a/compiler/rustc_builtin_macros/src/derive.rs
+++ b/compiler/rustc_builtin_macros/src/derive.rs
@@ -1,10 +1,10 @@
 use rustc_ast as ast;
 use rustc_ast::{GenericParamKind, ItemKind, MetaItemInner, MetaItemKind, StmtKind};
+use rustc_attr_parsing::validate_attr;
 use rustc_expand::base::{
     Annotatable, DeriveResolution, ExpandResult, ExtCtxt, Indeterminate, MultiItemModifier,
 };
 use rustc_feature::AttributeTemplate;
-use rustc_parse::validate_attr;
 use rustc_session::Session;
 use rustc_span::{ErrorGuaranteed, Ident, Span, sym};
 
diff --git a/compiler/rustc_builtin_macros/src/util.rs b/compiler/rustc_builtin_macros/src/util.rs
index f00c170e485..3a4585d5be9 100644
--- a/compiler/rustc_builtin_macros/src/util.rs
+++ b/compiler/rustc_builtin_macros/src/util.rs
@@ -1,12 +1,13 @@
 use rustc_ast::tokenstream::TokenStream;
 use rustc_ast::{self as ast, AttrStyle, Attribute, MetaItem, attr, token};
+use rustc_attr_parsing::validate_attr;
 use rustc_errors::{Applicability, Diag, ErrorGuaranteed};
 use rustc_expand::base::{Annotatable, ExpandResult, ExtCtxt};
 use rustc_expand::expand::AstFragment;
 use rustc_feature::AttributeTemplate;
 use rustc_lint_defs::BuiltinLintDiag;
 use rustc_lint_defs::builtin::DUPLICATE_MACRO_ATTRIBUTES;
-use rustc_parse::{exp, parser, validate_attr};
+use rustc_parse::{exp, parser};
 use rustc_session::errors::report_lit_error;
 use rustc_span::{BytePos, Span, Symbol};
 
diff --git a/compiler/rustc_expand/src/config.rs b/compiler/rustc_expand/src/config.rs
index 83a8d601afe..db5b45ff3d5 100644
--- a/compiler/rustc_expand/src/config.rs
+++ b/compiler/rustc_expand/src/config.rs
@@ -11,8 +11,10 @@ use rustc_ast::{
     NodeId, NormalAttr,
 };
 use rustc_attr_parsing as attr;
+use rustc_attr_parsing::validate_attr::deny_builtin_meta_unsafety;
 use rustc_attr_parsing::{
     AttributeParser, CFG_TEMPLATE, EvalConfigResult, ShouldEmit, eval_config_entry, parse_cfg_attr,
+    validate_attr,
 };
 use rustc_data_structures::flat_map_in_place::FlatMapInPlace;
 use rustc_feature::{
@@ -20,8 +22,6 @@ use rustc_feature::{
     REMOVED_LANG_FEATURES, UNSTABLE_LANG_FEATURES,
 };
 use rustc_lint_defs::BuiltinLintDiag;
-use rustc_parse::validate_attr;
-use rustc_parse::validate_attr::deny_builtin_meta_unsafety;
 use rustc_session::Session;
 use rustc_session::parse::feature_err;
 use rustc_span::{STDLIB_STABLE_CRATES, Span, Symbol, sym};
diff --git a/compiler/rustc_expand/src/expand.rs b/compiler/rustc_expand/src/expand.rs
index 755275d3cda..7bc380f0939 100644
--- a/compiler/rustc_expand/src/expand.rs
+++ b/compiler/rustc_expand/src/expand.rs
@@ -12,7 +12,7 @@ use rustc_ast::{
     MetaItemKind, ModKind, NodeId, PatKind, StmtKind, TyKind, token,
 };
 use rustc_ast_pretty::pprust;
-use rustc_attr_parsing::{EvalConfigResult, ShouldEmit};
+use rustc_attr_parsing::{EvalConfigResult, ShouldEmit, validate_attr};
 use rustc_data_structures::flat_map_in_place::FlatMapInPlace;
 use rustc_errors::PResult;
 use rustc_feature::Features;
@@ -21,7 +21,6 @@ use rustc_parse::parser::{
     AttemptLocalParseRecovery, CommaRecoveryMode, ForceCollect, Parser, RecoverColon, RecoverComma,
     token_descr,
 };
-use rustc_parse::validate_attr;
 use rustc_session::lint::BuiltinLintDiag;
 use rustc_session::lint::builtin::{UNUSED_ATTRIBUTES, UNUSED_DOC_COMMENTS};
 use rustc_session::parse::feature_err;
diff --git a/compiler/rustc_expand/src/module.rs b/compiler/rustc_expand/src/module.rs
index 6666ea33cd3..19f3cdbc549 100644
--- a/compiler/rustc_expand/src/module.rs
+++ b/compiler/rustc_expand/src/module.rs
@@ -2,8 +2,9 @@ use std::iter::once;
 use std::path::{self, Path, PathBuf};
 
 use rustc_ast::{AttrVec, Attribute, Inline, Item, ModSpans};
+use rustc_attr_parsing::validate_attr;
 use rustc_errors::{Diag, ErrorGuaranteed};
-use rustc_parse::{exp, new_parser_from_file, unwrap_or_emit_fatal, validate_attr};
+use rustc_parse::{exp, new_parser_from_file, unwrap_or_emit_fatal};
 use rustc_session::Session;
 use rustc_session::parse::ParseSess;
 use rustc_span::{Ident, Span, sym};
diff --git a/compiler/rustc_interface/src/passes.rs b/compiler/rustc_interface/src/passes.rs
index 3ba224723e3..424cba2dae8 100644
--- a/compiler/rustc_interface/src/passes.rs
+++ b/compiler/rustc_interface/src/passes.rs
@@ -6,6 +6,7 @@ use std::sync::{Arc, LazyLock, OnceLock};
 use std::{env, fs, iter};
 
 use rustc_ast as ast;
+use rustc_attr_parsing::validate_attr;
 use rustc_codegen_ssa::traits::CodegenBackend;
 use rustc_data_structures::jobserver::Proxy;
 use rustc_data_structures::steal::Steal;
@@ -25,9 +26,7 @@ use rustc_middle::arena::Arena;
 use rustc_middle::dep_graph::DepsType;
 use rustc_middle::ty::{self, CurrentGcx, GlobalCtxt, RegisteredTools, TyCtxt};
 use rustc_middle::util::Providers;
-use rustc_parse::{
-    new_parser_from_file, new_parser_from_source_str, unwrap_or_emit_fatal, validate_attr,
-};
+use rustc_parse::{new_parser_from_file, new_parser_from_source_str, unwrap_or_emit_fatal};
 use rustc_passes::{abi_test, input_stats, layout_test};
 use rustc_resolve::{Resolver, ResolverOutputs};
 use rustc_session::config::{CrateType, Input, OutFileName, OutputFilenames, OutputType};
diff --git a/compiler/rustc_interface/src/util.rs b/compiler/rustc_interface/src/util.rs
index 0ca4fcc66ca..49ac3b7a10d 100644
--- a/compiler/rustc_interface/src/util.rs
+++ b/compiler/rustc_interface/src/util.rs
@@ -5,12 +5,12 @@ use std::sync::{Arc, OnceLock};
 use std::{env, thread};
 
 use rustc_ast as ast;
+use rustc_attr_parsing::validate_attr;
 use rustc_codegen_ssa::traits::CodegenBackend;
 use rustc_data_structures::jobserver::Proxy;
 use rustc_data_structures::sync;
 use rustc_metadata::{DylibError, load_symbol_from_dylib};
 use rustc_middle::ty::CurrentGcx;
-use rustc_parse::validate_attr;
 use rustc_session::config::{Cfg, OutFileName, OutputFilenames, OutputTypes, Sysroot, host_tuple};
 use rustc_session::lint::{self, BuiltinLintDiag, LintBuffer};
 use rustc_session::output::{CRATE_TYPES, categorize_crate_type};
diff --git a/compiler/rustc_parse/Cargo.toml b/compiler/rustc_parse/Cargo.toml
index 0ae0b613fa2..6d738a10371 100644
--- a/compiler/rustc_parse/Cargo.toml
+++ b/compiler/rustc_parse/Cargo.toml
@@ -9,7 +9,6 @@ bitflags = "2.4.1"
 rustc-literal-escaper = "0.0.5"
 rustc_ast = { path = "../rustc_ast" }
 rustc_ast_pretty = { path = "../rustc_ast_pretty" }
-rustc_attr_parsing = { path = "../rustc_attr_parsing" }
 rustc_data_structures = { path = "../rustc_data_structures" }
 rustc_errors = { path = "../rustc_errors" }
 rustc_feature = { path = "../rustc_feature" }
diff --git a/compiler/rustc_parse/messages.ftl b/compiler/rustc_parse/messages.ftl
index a107a682184..1c09cab53b8 100644
--- a/compiler/rustc_parse/messages.ftl
+++ b/compiler/rustc_parse/messages.ftl
@@ -436,11 +436,6 @@ parse_inner_doc_comment_not_permitted = expected outer doc comment
     .label_does_not_annotate_this = the inner doc comment doesn't annotate this {$item}
     .sugg_change_inner_to_outer = to annotate the {$item}, change the doc comment from inner to outer style
 
-parse_invalid_attr_unsafe = `{$name}` is not an unsafe attribute
-    .label = this is not an unsafe attribute
-    .suggestion = remove the `unsafe(...)`
-    .note = extraneous unsafe is not allowed in attributes
-
 parse_invalid_block_macro_segment = cannot use a `block` macro fragment here
     .label = the `block` fragment is within this context
     .suggestion = wrap this in another block
@@ -601,7 +596,6 @@ parse_maybe_report_ambiguous_plus =
     ambiguous `+` in a type
     .suggestion = use parentheses to disambiguate
 
-parse_meta_bad_delim = wrong meta list delimiters
 parse_meta_bad_delim_suggestion = the delimiters should be `(` and `)`
 
 parse_mismatched_closing_delimiter = mismatched closing delimiter: `{$delimiter}`
@@ -990,10 +984,6 @@ parse_unmatched_angle_brackets = {$num_extra_brackets ->
            *[other] remove extra angle brackets
         }
 
-parse_unsafe_attr_outside_unsafe = unsafe attribute used without unsafe
-    .label = usage of unsafe attribute
-parse_unsafe_attr_outside_unsafe_suggestion = wrap the attribute in `unsafe(...)`
-
 
 parse_unskipped_whitespace = whitespace symbol '{$ch}' is not skipped
     .label = {parse_unskipped_whitespace}
diff --git a/compiler/rustc_parse/src/errors.rs b/compiler/rustc_parse/src/errors.rs
index 2c046329e33..dfd4f38cf03 100644
--- a/compiler/rustc_parse/src/errors.rs
+++ b/compiler/rustc_parse/src/errors.rs
@@ -3346,15 +3346,6 @@ pub(crate) struct KwBadCase<'a> {
 }
 
 #[derive(Diagnostic)]
-#[diag(parse_meta_bad_delim)]
-pub(crate) struct MetaBadDelim {
-    #[primary_span]
-    pub span: Span,
-    #[subdiagnostic]
-    pub sugg: MetaBadDelimSugg,
-}
-
-#[derive(Diagnostic)]
 #[diag(parse_cfg_attr_bad_delim)]
 pub(crate) struct CfgAttrBadDelim {
     #[primary_span]
@@ -3494,38 +3485,6 @@ pub(crate) struct DotDotRangeAttribute {
 }
 
 #[derive(Diagnostic)]
-#[diag(parse_invalid_attr_unsafe)]
-#[note]
-pub(crate) struct InvalidAttrUnsafe {
-    #[primary_span]
-    #[label]
-    pub span: Span,
-    pub name: Path,
-}
-
-#[derive(Diagnostic)]
-#[diag(parse_unsafe_attr_outside_unsafe)]
-pub(crate) struct UnsafeAttrOutsideUnsafe {
-    #[primary_span]
-    #[label]
-    pub span: Span,
-    #[subdiagnostic]
-    pub suggestion: UnsafeAttrOutsideUnsafeSuggestion,
-}
-
-#[derive(Subdiagnostic)]
-#[multipart_suggestion(
-    parse_unsafe_attr_outside_unsafe_suggestion,
-    applicability = "machine-applicable"
-)]
-pub(crate) struct UnsafeAttrOutsideUnsafeSuggestion {
-    #[suggestion_part(code = "unsafe(")]
-    pub left: Span,
-    #[suggestion_part(code = ")")]
-    pub right: Span,
-}
-
-#[derive(Diagnostic)]
 #[diag(parse_binder_before_modifiers)]
 pub(crate) struct BinderBeforeModifiers {
     #[primary_span]
diff --git a/compiler/rustc_parse/src/lib.rs b/compiler/rustc_parse/src/lib.rs
index adad5751871..48289b2e8ab 100644
--- a/compiler/rustc_parse/src/lib.rs
+++ b/compiler/rustc_parse/src/lib.rs
@@ -16,7 +16,7 @@ use std::str::Utf8Error;
 use std::sync::Arc;
 
 use rustc_ast as ast;
-use rustc_ast::tokenstream::TokenStream;
+use rustc_ast::tokenstream::{DelimSpan, TokenStream};
 use rustc_ast::{AttrItem, Attribute, MetaItemInner, token};
 use rustc_ast_pretty::pprust;
 use rustc_errors::{Diag, EmissionGuarantee, FatalError, PResult, pluralize};
@@ -31,8 +31,9 @@ pub const MACRO_ARGUMENTS: Option<&str> = Some("macro arguments");
 #[macro_use]
 pub mod parser;
 use parser::Parser;
+use rustc_ast::token::Delimiter;
+
 pub mod lexer;
-pub mod validate_attr;
 
 mod errors;
 
@@ -235,7 +236,7 @@ pub fn parse_cfg_attr(
         ast::AttrArgs::Delimited(ast::DelimArgs { dspan, delim, ref tokens })
             if !tokens.is_empty() =>
         {
-            crate::validate_attr::check_cfg_attr_bad_delim(psess, dspan, delim);
+            check_cfg_attr_bad_delim(psess, dspan, delim);
             match parse_in(psess, tokens.clone(), "`cfg_attr` input", |p| p.parse_cfg_attr()) {
                 Ok(r) => return Some(r),
                 Err(e) => {
@@ -254,3 +255,13 @@ pub fn parse_cfg_attr(
     }
     None
 }
+
+fn check_cfg_attr_bad_delim(psess: &ParseSess, span: DelimSpan, delim: Delimiter) {
+    if let Delimiter::Parenthesis = delim {
+        return;
+    }
+    psess.dcx().emit_err(errors::CfgAttrBadDelim {
+        span: span.entire(),
+        sugg: errors::MetaBadDelimSugg { open: span.open, close: span.close },
+    });
+}
diff --git a/compiler/rustc_parse/src/parser/attr.rs b/compiler/rustc_parse/src/parser/attr.rs
index 7f6afeba28c..acd338156ce 100644
--- a/compiler/rustc_parse/src/parser/attr.rs
+++ b/compiler/rustc_parse/src/parser/attr.rs
@@ -399,7 +399,7 @@ impl<'a> Parser<'a> {
     }
 
     /// Matches `COMMASEP(meta_item_inner)`.
-    pub(crate) fn parse_meta_seq_top(&mut self) -> PResult<'a, ThinVec<ast::MetaItemInner>> {
+    pub fn parse_meta_seq_top(&mut self) -> PResult<'a, ThinVec<ast::MetaItemInner>> {
         // Presumably, the majority of the time there will only be one attr.
         let mut nmis = ThinVec::with_capacity(1);
         while self.token != token::Eof {