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

@@ -3034,6 +3034,7 @@ impl NormalAttr {
                 path: Path::from_ident(ident),
                 args: AttrArgs::Empty,
                 tokens: None,
+                span: ident.span,
             },
             tokens: None,
         }
@@ -3047,6 +3048,7 @@ 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

@@ -219,7 +219,7 @@ 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,
         }
     }
@@ -285,12 +285,12 @@ 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(),
         })
     }
 
@@ -406,7 +406,7 @@ impl MetaItem {
                 Path { span, segments, tokens: None }
             }
             Some(TokenTree::Token(Token { kind: token::Interpolated(nt), .. }, _)) => match &**nt {
-                token::Nonterminal::NtMeta(item) => return item.meta(item.path.span),
+                token::Nonterminal::NtMeta(item) => return item.meta(),
                 token::Nonterminal::NtPath(path) => (**path).clone(),
                 _ => return None,
             },
@@ -620,8 +620,15 @@ pub 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(
@@ -645,10 +652,11 @@ 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(
@@ -658,6 +666,7 @@ 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)),
@@ -670,7 +679,7 @@ 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(
@@ -680,6 +689,7 @@ 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 {
@@ -691,7 +701,7 @@ 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/mut_visit.rs

@@ -723,13 +723,14 @@ fn walk_attribute<T: MutVisitor>(vis: &mut T, attr: &mut Attribute) {
     match kind {
         AttrKind::Normal(normal) => {
             let NormalAttr {
-                item: AttrItem { unsafety: _, path, args, tokens },
+                item: AttrItem { unsafety: _, path, args, tokens, span },
                 tokens: attr_tokens,
             } = &mut **normal;
             vis.visit_path(path);
             visit_attr_args(vis, args);
             visit_lazy_tts(vis, tokens);
             visit_lazy_tts(vis, attr_tokens);
+            vis.visit_span(span);
         }
         AttrKind::DocComment(_kind, _sym) => {}
     }
@@ -909,10 +910,11 @@ fn visit_nonterminal<T: MutVisitor>(vis: &mut T, nt: &mut token::Nonterminal) {
         token::NtExpr(expr) => vis.visit_expr(expr),
         token::NtLiteral(expr) => vis.visit_expr(expr),
         token::NtMeta(item) => {
-            let AttrItem { unsafety: _, path, args, tokens } = item.deref_mut();
+            let AttrItem { unsafety: _, path, args, tokens, span } = item.deref_mut();
             vis.visit_path(path);
             visit_attr_args(vis, args);
             visit_lazy_tts(vis, tokens);
+            vis.visit_span(span);
         }
         token::NtPath(path) => vis.visit_path(path),
     }

compiler/rustc_ast/src/visit.rs

@@ -1308,7 +1308,7 @@ pub fn walk_attribute<'a, V: Visitor<'a>>(visitor: &mut V, attr: &'a Attribute)
     match kind {
         AttrKind::Normal(normal) => {
             let NormalAttr { item, tokens: _ } = &**normal;
-            let AttrItem { unsafety: _, path, args, tokens: _ } = item;
+            let AttrItem { unsafety: _, path, args, tokens: _, span: _ } = item;
             try_visit!(visitor.visit_path(path, DUMMY_NODE_ID));
             try_visit!(walk_attr_args(visitor, args));
         }

compiler/rustc_ast_lowering/src/expr.rs

@@ -1985,6 +1985,7 @@ 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

@@ -257,6 +257,7 @@ pub fn print_crate<'a>(
             sym::feature,
             sym::prelude_import,
             DUMMY_SP,
+            DUMMY_SP,
         );
         s.print_attribute(&fake_attr);
 
@@ -270,6 +271,7 @@ pub fn print_crate<'a>(
                 Safety::Default,
                 sym::no_std,
                 DUMMY_SP,
+                DUMMY_SP,
             );
             s.print_attribute(&fake_attr);
         }

compiler/rustc_builtin_macros/src/alloc_error_handler.rs

@@ -90,7 +90,7 @@ fn generate_handler(cx: &ExtCtxt<'_>, handler: Ident, span: Span, sig_span: Span
         body,
     }));
 
-    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, Ident::from_str_and_span("__rg_oom", span), attrs, kind);
     cx.stmt_item(sig_span, item)

compiler/rustc_builtin_macros/src/assert/context.rs

@@ -113,7 +113,12 @@ impl<'cx, 'a> Context<'cx, 'a> {
             self.cx.item(
                 self.span,
                 Ident::empty(),
-                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/cmdline_attrs.rs

@@ -17,18 +17,16 @@ pub fn inject(krate: &mut ast::Crate, psess: &ParseSess, attrs: &[String]) {
             raw_attr.clone(),
         ));
 
-        let start_span = parser.token.span;
-        let AttrItem { unsafety, path, args, tokens: _ } =
+        let AttrItem { unsafety, path, args, tokens: _, span } =
             match parser.parse_attr_item(ForceCollect::No) {
                 Ok(ai) => ai,
                 Err(err) => {
                     err.emit();
                     continue;
                 }
             };
-        let end_span = parser.token.span;
         if parser.token != token::Eof {
-            psess.dcx().emit_err(errors::InvalidCrateAttr { span: start_span.to(end_span) });
+            psess.dcx().emit_err(errors::InvalidCrateAttr { span });
             continue;
         }
 
@@ -38,7 +36,8 @@ pub fn inject(krate: &mut ast::Crate, psess: &ParseSess, attrs: &[String]) {
             unsafety,
             path,
             args,
-            start_span.to(end_span),
+            span,
+            span,
         ));
     }
 }

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,
         }],