Don't suggest turning crate-level attributes into outer style

compiler/rustc_ast/src/ast.rs

@@ -2898,6 +2898,17 @@ pub struct AttrItem {
     pub tokens: Option<LazyAttrTokenStream>,
 }
 
+impl AttrItem {
+    pub fn is_valid_for_outer_style(&self) -> bool {
+        self.path == sym::cfg_attr
+            || self.path == sym::cfg
+            || self.path == sym::forbid
+            || self.path == sym::warn
+            || self.path == sym::allow
+            || self.path == sym::deny
+    }
+}
+
 /// `TraitRef`s appear in impls.
 ///
 /// Resolution maps each `TraitRef`'s `ref_id` to its defining trait; that's all

compiler/rustc_parse/src/parser/attr.rs

@@ -67,6 +67,7 @@ impl<'a> Parser<'a> {
                             token::CommentKind::Line => OuterAttributeType::DocComment,
                             token::CommentKind::Block => OuterAttributeType::DocBlockComment,
                         },
+                        true,
                     ) {
                         err.note(fluent::parse_note);
                         err.span_suggestion_verbose(
@@ -130,7 +131,11 @@ impl<'a> Parser<'a> {
 
             // Emit error if inner attribute is encountered and forbidden.
             if style == ast::AttrStyle::Inner {
-                this.error_on_forbidden_inner_attr(attr_sp, inner_parse_policy);
+                this.error_on_forbidden_inner_attr(
+                    attr_sp,
+                    inner_parse_policy,
+                    item.is_valid_for_outer_style(),
+                );
             }
 
             Ok(attr::mk_attr_from_item(&self.psess.attr_id_generator, item, None, style, attr_sp))
@@ -142,6 +147,7 @@ impl<'a> Parser<'a> {
         err: &mut Diag<'_>,
         span: Span,
         attr_type: OuterAttributeType,
+        suggest_to_outer: bool,
     ) -> Option<Span> {
         let mut snapshot = self.create_snapshot_for_diagnostic();
         let lo = span.lo()
@@ -176,16 +182,18 @@ impl<'a> Parser<'a> {
                 // FIXME(#100717)
                 err.arg("item", item.kind.descr());
                 err.span_label(item.span, fluent::parse_label_does_not_annotate_this);
-                err.span_suggestion_verbose(
-                    replacement_span,
-                    fluent::parse_sugg_change_inner_to_outer,
-                    match attr_type {
-                        OuterAttributeType::Attribute => "",
-                        OuterAttributeType::DocBlockComment => "*",
-                        OuterAttributeType::DocComment => "/",
-                    },
-                    rustc_errors::Applicability::MachineApplicable,
-                );
+                if suggest_to_outer {
+                    err.span_suggestion_verbose(
+                        replacement_span,
+                        fluent::parse_sugg_change_inner_to_outer,
+                        match attr_type {
+                            OuterAttributeType::Attribute => "",
+                            OuterAttributeType::DocBlockComment => "*",
+                            OuterAttributeType::DocComment => "/",
+                        },
+                        rustc_errors::Applicability::MachineApplicable,
+                    );
+                }
                 return None;
             }
             Err(item_err) => {
@@ -196,7 +204,12 @@ impl<'a> Parser<'a> {
         Some(replacement_span)
     }
 
-    pub(super) fn error_on_forbidden_inner_attr(&self, attr_sp: Span, policy: InnerAttrPolicy) {
+    pub(super) fn error_on_forbidden_inner_attr(
+        &self,
+        attr_sp: Span,
+        policy: InnerAttrPolicy,
+        suggest_to_outer: bool,
+    ) {
         if let InnerAttrPolicy::Forbidden(reason) = policy {
             let mut diag = match reason.as_ref().copied() {
                 Some(InnerAttrForbiddenReason::AfterOuterDocComment { prev_doc_comment_span }) => {
@@ -230,6 +243,7 @@ impl<'a> Parser<'a> {
                     &mut diag,
                     attr_sp,
                     OuterAttributeType::Attribute,
+                    suggest_to_outer,
                 )
                 .is_some()
             {

compiler/rustc_parse/src/parser/stmt.rs

@@ -439,11 +439,16 @@ impl<'a> Parser<'a> {
     pub fn parse_block(&mut self) -> PResult<'a, P<Block>> {
         let (attrs, block) = self.parse_inner_attrs_and_block()?;
         if let [.., last] = &*attrs {
+            let suggest_to_outer = match &last.kind {
+                ast::AttrKind::Normal(attr) => attr.item.is_valid_for_outer_style(),
+                _ => false,
+            };
             self.error_on_forbidden_inner_attr(
                 last.span,
                 super::attr::InnerAttrPolicy::Forbidden(Some(
                     InnerAttrForbiddenReason::InCodeBlock,
                 )),
+                suggest_to_outer,
             );
         }
         Ok(block)

tests/ui/delegation/inner-attr.stderr

@@ -8,11 +8,6 @@ LL | fn main() {}
    | ------------ the inner attribute doesn't annotate this function
    |
    = note: inner attributes, like `#![no_std]`, annotate the item enclosing them, and are usually found at the beginning of source files
-help: to annotate the function, change the attribute from inner to outer style
-   |
-LL - reuse a as b { #![rustc_dummy] self }
-LL + reuse a as b { #[rustc_dummy] self }
-   |
 
 error: aborting due to 1 previous error
 

tests/ui/parser/attribute/attr-stmt-expr-attr-bad.stderr

@@ -359,11 +359,6 @@ LL | #[cfg(FALSE)] fn s() { #[attr] #![attr] foo!(); }
    |                        previous outer attribute
    |
    = note: inner attributes, like `#![no_std]`, annotate the item enclosing them, and are usually found at the beginning of source files
-help: to annotate the item macro invocation, change the attribute from inner to outer style
-   |
-LL - #[cfg(FALSE)] fn s() { #[attr] #![attr] foo!(); }
-LL + #[cfg(FALSE)] fn s() { #[attr] #[attr] foo!(); }
-   |
 
 error: an inner attribute is not permitted following an outer attribute
   --> $DIR/attr-stmt-expr-attr-bad.rs:77:32
@@ -375,11 +370,6 @@ LL | #[cfg(FALSE)] fn s() { #[attr] #![attr] foo![]; }
    |                        previous outer attribute
    |
    = note: inner attributes, like `#![no_std]`, annotate the item enclosing them, and are usually found at the beginning of source files
-help: to annotate the item macro invocation, change the attribute from inner to outer style
-   |
-LL - #[cfg(FALSE)] fn s() { #[attr] #![attr] foo![]; }
-LL + #[cfg(FALSE)] fn s() { #[attr] #[attr] foo![]; }
-   |
 
 error: an inner attribute is not permitted following an outer attribute
   --> $DIR/attr-stmt-expr-attr-bad.rs:79:32
@@ -391,11 +381,6 @@ LL | #[cfg(FALSE)] fn s() { #[attr] #![attr] foo!{}; }
    |                        previous outer attribute
    |
    = note: inner attributes, like `#![no_std]`, annotate the item enclosing them, and are usually found at the beginning of source files
-help: to annotate the item macro invocation, change the attribute from inner to outer style
-   |
-LL - #[cfg(FALSE)] fn s() { #[attr] #![attr] foo!{}; }
-LL + #[cfg(FALSE)] fn s() { #[attr] #[attr] foo!{}; }
-   |
 
 error[E0586]: inclusive range with no end
   --> $DIR/attr-stmt-expr-attr-bad.rs:85:35

tests/ui/parser/attribute/attr.stderr

@@ -7,11 +7,6 @@ LL | fn foo() {}
    | ----------- the inner attribute doesn't annotate this function
    |
    = note: inner attributes, like `#![no_std]`, annotate the item enclosing them, and are usually found at the beginning of source files
-help: to annotate the function, change the attribute from inner to outer style
-   |
-LL - #![lang = "foo"]
-LL + #[lang = "foo"]
-   |
 
 error: aborting due to 1 previous error
 

tests/ui/parser/inner-attr-after-doc-comment.stderr

@@ -13,11 +13,6 @@ LL |   fn main() {}
    |   ------------ the inner attribute doesn't annotate this function
    |
    = note: inner attributes, like `#![no_std]`, annotate the item enclosing them, and are usually found at the beginning of source files
-help: to annotate the function, change the attribute from inner to outer style
-   |
-LL - #![recursion_limit="100"]
-LL + #[recursion_limit="100"]
-   |
 
 error: aborting due to 1 previous error
 

tests/ui/parser/inner-attr.stderr

@@ -10,11 +10,6 @@ LL | fn main() {}
    | ------------ the inner attribute doesn't annotate this function
    |
    = note: inner attributes, like `#![no_std]`, annotate the item enclosing them, and are usually found at the beginning of source files
-help: to annotate the function, change the attribute from inner to outer style
-   |
-LL - #![recursion_limit="100"]
-LL + #[recursion_limit="100"]
-   |
 
 error: aborting due to 1 previous error
 

tests/ui/parser/issues/isgg-invalid-outer-attttr-issue-127930.rs

@@ -0,0 +1,10 @@
+#![allow(dead_code)]
+fn foo() {}
+
+#![feature(iter_array_chunks)] //~ ERROR an inner attribute is not permitted in this context
+fn bar() {}
+
+fn main() {
+    foo();
+    bar();
+}

tests/ui/parser/issues/isgg-invalid-outer-attttr-issue-127930.stderr

@@ -0,0 +1,12 @@
+error: an inner attribute is not permitted in this context
+  --> $DIR/isgg-invalid-outer-attttr-issue-127930.rs:4:1
+   |
+LL | #![feature(iter_array_chunks)]
+   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+LL | fn bar() {}
+   | ----------- the inner attribute doesn't annotate this function
+   |
+   = note: inner attributes, like `#![no_std]`, annotate the item enclosing them, and are usually found at the beginning of source files
+
+error: aborting due to 1 previous error
+

tests/ui/parser/issues/issue-30318.fixed

@@ -6,7 +6,7 @@ fn foo() { }
 //~^ ERROR expected outer doc comment
 fn bar() { } //~ NOTE the inner doc comment doesn't annotate this function
 
-#[test] //~ ERROR an inner attribute is not permitted in this context
+#[cfg(test)] //~ ERROR an inner attribute is not permitted in this context
 fn baz() { } //~ NOTE the inner attribute doesn't annotate this function
 //~^^ NOTE inner attributes, like `#![no_std]`, annotate the item enclosing them, and are usually
 

tests/ui/parser/issues/issue-30318.rs

@@ -6,7 +6,7 @@ fn foo() { }
 //~^ ERROR expected outer doc comment
 fn bar() { } //~ NOTE the inner doc comment doesn't annotate this function
 
-#![test] //~ ERROR an inner attribute is not permitted in this context
+#![cfg(test)] //~ ERROR an inner attribute is not permitted in this context
 fn baz() { } //~ NOTE the inner attribute doesn't annotate this function
 //~^^ NOTE inner attributes, like `#![no_std]`, annotate the item enclosing them, and are usually
 

tests/ui/parser/issues/issue-30318.stderr

@@ -15,16 +15,16 @@ LL | /// Misplaced comment...
 error: an inner attribute is not permitted in this context
   --> $DIR/issue-30318.rs:9:1
    |
-LL | #![test]
-   | ^^^^^^^^
+LL | #![cfg(test)]
+   | ^^^^^^^^^^^^^
 LL | fn baz() { }
    | ------------ the inner attribute doesn't annotate this function
    |
    = note: inner attributes, like `#![no_std]`, annotate the item enclosing them, and are usually found at the beginning of source files
 help: to annotate the function, change the attribute from inner to outer style
    |
-LL - #![test]
-LL + #[test]
+LL - #![cfg(test)]
+LL + #[cfg(test)]
    |
 
 error[E0753]: expected outer doc comment