Fix incorrect cfg structured suggestion

Keep a span for the attribute *within* the square brackets as part of
the `AttrKind`.

```
error: `cfg` is not followed by parentheses
  --> $DIR/cfg-attr-syntax-validation.rs:4:1
   |
LL | #[cfg = 10]
   | ^^^^^^^^^^^
   |
help: expected syntax is
   |
LL - #[cfg = 10]
LL + #[cfg(/* predicate */)]
   |
```

Noticed in #137343 (comment).

Author: estebank

compiler/rustc_ast/src/ast.rs

@@ -3326,6 +3326,7 @@ impl NormalAttr {
                 path: Path::from_ident(ident),
                 args: AttrArgs::Empty,
                 tokens: None,
+                span: ident.span,
             },
             tokens: None,
         }
@@ -3339,6 +3340,7 @@ pub struct AttrItem {
     pub args: AttrArgs,
     // Tokens for the meta item, e.g. just the `foo` within `#[foo]` or `#![foo]`.
     pub tokens: Option<LazyAttrTokenStream>,
+    pub span: Span,
 }
 
 impl AttrItem {

compiler/rustc_ast/src/attr/mod.rs

@@ -231,7 +231,7 @@ impl Attribute {
     /// Extracts the MetaItem from inside this Attribute.
     pub fn meta(&self) -> Option<MetaItem> {
         match &self.kind {
-            AttrKind::Normal(normal) => normal.item.meta(self.span),
+            AttrKind::Normal(normal) => normal.item.meta(),
             AttrKind::DocComment(..) => None,
         }
     }
@@ -297,12 +297,12 @@ impl AttrItem {
         }
     }
 
-    pub fn meta(&self, span: Span) -> Option<MetaItem> {
+    pub fn meta(&self) -> Option<MetaItem> {
         Some(MetaItem {
             unsafety: Safety::Default,
             path: self.path.clone(),
             kind: self.meta_kind()?,
-            span,
+            span: self.span(),
         })
     }
 
@@ -644,8 +644,15 @@ fn mk_attr(
     path: Path,
     args: AttrArgs,
     span: Span,
+    inner_span: Span,
 ) -> Attribute {
-    mk_attr_from_item(g, AttrItem { unsafety, path, args, tokens: None }, None, style, span)
+    mk_attr_from_item(
+        g,
+        AttrItem { unsafety, path, args, tokens: None, span: inner_span },
+        None,
+        style,
+        span,
+    )
 }
 
 pub fn mk_attr_from_item(
@@ -669,10 +676,11 @@ pub fn mk_attr_word(
     unsafety: Safety,
     name: Symbol,
     span: Span,
+    inner_span: Span,
 ) -> Attribute {
     let path = Path::from_ident(Ident::new(name, span));
     let args = AttrArgs::Empty;
-    mk_attr(g, style, unsafety, path, args, span)
+    mk_attr(g, style, unsafety, path, args, span, inner_span)
 }
 
 pub fn mk_attr_nested_word(
@@ -682,6 +690,7 @@ pub fn mk_attr_nested_word(
     outer: Symbol,
     inner: Symbol,
     span: Span,
+    inner_span: Span,
 ) -> Attribute {
     let inner_tokens = TokenStream::new(vec![TokenTree::Token(
         Token::from_ast_ident(Ident::new(inner, span)),
@@ -694,7 +703,7 @@ pub fn mk_attr_nested_word(
         delim: Delimiter::Parenthesis,
         tokens: inner_tokens,
     });
-    mk_attr(g, style, unsafety, path, attr_args, span)
+    mk_attr(g, style, unsafety, path, attr_args, span, inner_span)
 }
 
 pub fn mk_attr_name_value_str(
@@ -704,6 +713,7 @@ pub fn mk_attr_name_value_str(
     name: Symbol,
     val: Symbol,
     span: Span,
+    inner_span: Span,
 ) -> Attribute {
     let lit = token::Lit::new(token::Str, escape_string_symbol(val), None);
     let expr = P(Expr {
@@ -715,7 +725,7 @@ pub fn mk_attr_name_value_str(
     });
     let path = Path::from_ident(Ident::new(name, span));
     let args = AttrArgs::Eq { eq_span: span, expr };
-    mk_attr(g, style, unsafety, path, args, span)
+    mk_attr(g, style, unsafety, path, args, span, inner_span)
 }
 
 pub fn filter_by_name<A: AttributeExt>(attrs: &[A], name: Symbol) -> impl Iterator<Item = &A> {

compiler/rustc_ast/src/visit.rs

@@ -1878,7 +1878,7 @@ macro_rules! common_visitor_and_walkers {
             match kind {
                 AttrKind::Normal(normal) => {
                     let NormalAttr { item, tokens: _ } = &$($mut)?**normal;
-                    let AttrItem { unsafety: _, path, args, tokens: _ } = item;
+                    let AttrItem { unsafety: _, path, args, tokens: _, span: _ } = item;
                     try_visit!(vis.visit_path(path));
                     try_visit!(walk_attr_args(vis, args));
                 }

compiler/rustc_ast_lowering/src/expr.rs

@@ -1992,6 +1992,7 @@ impl<'hir> LoweringContext<'_, 'hir> {
             sym::allow,
             sym::unreachable_code,
             try_span,
+            try_span,
         );
         let attrs: AttrVec = thin_vec![attr];
 

compiler/rustc_ast_pretty/src/pprust/state.rs

@@ -287,6 +287,7 @@ fn print_crate_inner<'a>(
             sym::feature,
             sym::prelude_import,
             DUMMY_SP,
+            DUMMY_SP,
         );
         s.print_attribute(&fake_attr);
 
@@ -300,6 +301,7 @@ fn print_crate_inner<'a>(
                 Safety::Default,
                 sym::no_std,
                 DUMMY_SP,
+                DUMMY_SP,
             );
             s.print_attribute(&fake_attr);
         }

compiler/rustc_builtin_macros/src/alloc_error_handler.rs

@@ -92,7 +92,7 @@ fn generate_handler(cx: &ExtCtxt<'_>, handler: Ident, span: Span, sig_span: Span
         define_opaque: None,
     }));
 
-    let attrs = thin_vec![cx.attr_word(sym::rustc_std_internal_symbol, span)];
+    let attrs = thin_vec![cx.attr_word(sym::rustc_std_internal_symbol, span, span)];
 
     let item = cx.item(span, attrs, kind);
     cx.stmt_item(sig_span, item)

compiler/rustc_builtin_macros/src/assert/context.rs

@@ -112,7 +112,12 @@ impl<'cx, 'a> Context<'cx, 'a> {
             self.span,
             self.cx.item(
                 self.span,
-                thin_vec![self.cx.attr_nested_word(sym::allow, sym::unused_imports, self.span)],
+                thin_vec![self.cx.attr_nested_word(
+                    sym::allow,
+                    sym::unused_imports,
+                    self.span,
+                    self.span
+                )],
                 ItemKind::Use(UseTree {
                     prefix: self.cx.path(self.span, self.cx.std_path(&[sym::asserting])),
                     kind: UseTreeKind::Nested {

compiler/rustc_builtin_macros/src/autodiff.rs

@@ -362,6 +362,7 @@ mod llvm_enzyme {
             path: ast::Path::from_ident(Ident::with_dummy_span(sym::inline)),
             args: ast::AttrArgs::Delimited(never_arg),
             tokens: None,
+            span,
         };
         let inline_never_attr = P(ast::NormalAttr { item: inline_item, tokens: None });
         let new_id = ecx.sess.psess.attr_id_generator.mk_attr_id();

compiler/rustc_builtin_macros/src/deriving/clone.rs

@@ -81,7 +81,7 @@ pub(crate) fn expand_deriving_clone(
             explicit_self: true,
             nonself_args: Vec::new(),
             ret_ty: Self_,
-            attributes: thin_vec![cx.attr_word(sym::inline, span)],
+            attributes: thin_vec![cx.attr_word(sym::inline, span, span)],
             fieldless_variants_strategy: FieldlessVariantsStrategy::Default,
             combine_substructure: substructure,
         }],

compiler/rustc_builtin_macros/src/deriving/cmp/eq.rs

@@ -32,9 +32,9 @@ pub(crate) fn expand_deriving_eq(
             nonself_args: vec![],
             ret_ty: Unit,
             attributes: thin_vec![
-                cx.attr_word(sym::inline, span),
-                cx.attr_nested_word(sym::doc, sym::hidden, span),
-                cx.attr_nested_word(sym::coverage, sym::off, span)
+                cx.attr_word(sym::inline, span, span),
+                cx.attr_nested_word(sym::doc, sym::hidden, span, span),
+                cx.attr_nested_word(sym::coverage, sym::off, span, span)
             ],
             fieldless_variants_strategy: FieldlessVariantsStrategy::Unify,
             combine_substructure: combine_substructure(Box::new(|a, b, c| {