Auto merge of #80563 - petrochenkov:expattronmac, r=Aaron1011

resolve/expand: Improve attribute expansion on macro definitions and calls

- Do not forget to visit attributes on macro definitions and calls in couple of places.
- Remove some weird special treatment of macro definition items, which is probably left from old times when macro definitions were treated more like macro calls.

Fixes #80540

Author: bors

compiler/rustc_expand/src/expand.rs

@@ -1543,13 +1543,8 @@ impl<'a, 'b> MutVisitor for InvocationCollector<'a, 'b> {
     }
 
     fn visit_item_kind(&mut self, item: &mut ast::ItemKind) {
-        match item {
-            ast::ItemKind::MacroDef(..) => {}
-            _ => {
-                self.cfg.configure_item_kind(item);
-                noop_visit_item_kind(item, self);
-            }
-        }
+        self.cfg.configure_item_kind(item);
+        noop_visit_item_kind(item, self);
     }
 
     fn flat_map_generic_param(

compiler/rustc_expand/src/placeholders.rs

@@ -258,12 +258,9 @@ impl<'a, 'b> MutVisitor for PlaceholderExpander<'a, 'b> {
 
     fn flat_map_item(&mut self, item: P<ast::Item>) -> SmallVec<[P<ast::Item>; 1]> {
         match item.kind {
-            ast::ItemKind::MacCall(_) => return self.remove(item.id).make_items(),
-            ast::ItemKind::MacroDef(_) => return smallvec![item],
-            _ => {}
+            ast::ItemKind::MacCall(_) => self.remove(item.id).make_items(),
+            _ => noop_flat_map_item(item, self),
         }
-
-        noop_flat_map_item(item, self)
     }
 
     fn flat_map_trait_item(&mut self, item: P<ast::AssocItem>) -> SmallVec<[P<ast::AssocItem>; 1]> {

compiler/rustc_resolve/src/build_reduced_graph.rs

@@ -1298,26 +1298,31 @@ impl<'a, 'b> Visitor<'b> for BuildReducedGraphVisitor<'a, 'b> {
     method!(visit_ty: ast::Ty, ast::TyKind::MacCall, walk_ty);
 
     fn visit_item(&mut self, item: &'b Item) {
-        let macro_use = match item.kind {
+        let orig_module_scope = self.parent_scope.module;
+        self.parent_scope.macro_rules = match item.kind {
             ItemKind::MacroDef(..) => {
-                self.parent_scope.macro_rules = self.define_macro(item);
-                return;
+                let macro_rules_scope = self.define_macro(item);
+                visit::walk_item(self, item);
+                macro_rules_scope
             }
             ItemKind::MacCall(..) => {
-                self.parent_scope.macro_rules = self.visit_invoc_in_module(item.id);
-                return;
+                let macro_rules_scope = self.visit_invoc_in_module(item.id);
+                visit::walk_item(self, item);
+                macro_rules_scope
+            }
+            _ => {
+                let orig_macro_rules_scope = self.parent_scope.macro_rules;
+                self.build_reduced_graph_for_item(item);
+                visit::walk_item(self, item);
+                match item.kind {
+                    ItemKind::Mod(..) if self.contains_macro_use(&item.attrs) => {
+                        self.parent_scope.macro_rules
+                    }
+                    _ => orig_macro_rules_scope,
+                }
             }
-            ItemKind::Mod(..) => self.contains_macro_use(&item.attrs),
-            _ => false,
         };
-        let orig_current_module = self.parent_scope.module;
-        let orig_current_macro_rules_scope = self.parent_scope.macro_rules;
-        self.build_reduced_graph_for_item(item);
-        visit::walk_item(self, item);
-        self.parent_scope.module = orig_current_module;
-        if !macro_use {
-            self.parent_scope.macro_rules = orig_current_macro_rules_scope;
-        }
+        self.parent_scope.module = orig_module_scope;
     }
 
     fn visit_stmt(&mut self, stmt: &'b ast::Stmt) {

compiler/rustc_resolve/src/def_collector.rs

@@ -91,7 +91,10 @@ impl<'a, 'b> visit::Visitor<'a> for DefCollector<'a, 'b> {
                 DefPathData::ValueNs(i.ident.name)
             }
             ItemKind::MacroDef(..) => DefPathData::MacroNs(i.ident.name),
-            ItemKind::MacCall(..) => return self.visit_macro_invoc(i.id),
+            ItemKind::MacCall(..) => {
+                visit::walk_item(self, i);
+                return self.visit_macro_invoc(i.id);
+            }
             ItemKind::GlobalAsm(..) => DefPathData::Misc,
             ItemKind::Use(..) => {
                 return visit::walk_item(self, i);

src/test/ui/attributes/key-value-expansion-on-mac.rs

@@ -0,0 +1,15 @@
+#![feature(extended_key_value_attributes)]
+#![feature(rustc_attrs)]
+
+#[rustc_dummy = stringify!(a)] // OK
+macro_rules! bar {
+    () => {};
+}
+
+// FIXME?: `bar` here expands before `stringify` has a chance to expand.
+// `#[rustc_dummy = ...]` is validated and dropped during expansion of `bar`,
+// the "unexpected token" errors comes from the validation.
+#[rustc_dummy = stringify!(b)] //~ ERROR unexpected token: `stringify!(b)`
+bar!();
+
+fn main() {}

src/test/ui/attributes/key-value-expansion-on-mac.stderr

@@ -0,0 +1,8 @@
+error: unexpected token: `stringify!(b)`
+  --> $DIR/key-value-expansion-on-mac.rs:12:17
+   |
+LL | #[rustc_dummy = stringify!(b)]
+   |                 ^^^^^^^^^^^^^
+
+error: aborting due to previous error
+

src/test/ui/feature-gates/issue-43106-gating-of-builtin-attrs.stderr

@@ -172,12 +172,6 @@ warning: unknown lint: `x5100`
 LL |     #[deny(x5100)] impl S { }
    |            ^^^^^
 
-warning: `#[macro_escape]` is a deprecated synonym for `#[macro_use]`
-  --> $DIR/issue-43106-gating-of-builtin-attrs.rs:438:1
-   |
-LL | #[macro_escape]
-   | ^^^^^^^^^^^^^^^
-
 warning: `#[macro_escape]` is a deprecated synonym for `#[macro_use]`
   --> $DIR/issue-43106-gating-of-builtin-attrs.rs:441:17
    |
@@ -186,6 +180,12 @@ LL |     mod inner { #![macro_escape] }
    |
    = help: try an outer attribute: `#[macro_use]`
 
+warning: `#[macro_escape]` is a deprecated synonym for `#[macro_use]`
+  --> $DIR/issue-43106-gating-of-builtin-attrs.rs:438:1
+   |
+LL | #[macro_escape]
+   | ^^^^^^^^^^^^^^^
+
 warning: use of deprecated attribute `plugin_registrar`: compiler plugins are deprecated. See https://github.com/rust-lang/rust/pull/64675
   --> $DIR/issue-43106-gating-of-builtin-attrs.rs:228:17
    |

src/test/ui/feature-gates/issue-43106-gating-of-macro_use.stderr

@@ -1,8 +1,8 @@
 error: arguments to `macro_use` are not allowed here
-  --> $DIR/issue-43106-gating-of-macro_use.rs:6:1
+  --> $DIR/issue-43106-gating-of-macro_use.rs:12:17
    |
-LL | #![macro_use(my_macro)]
-   | ^^^^^^^^^^^^^^^^^^^^^^^
+LL |     mod inner { #![macro_use(my_macro)] }
+   |                 ^^^^^^^^^^^^^^^^^^^^^^^
 
 error: arguments to `macro_use` are not allowed here
   --> $DIR/issue-43106-gating-of-macro_use.rs:9:1
@@ -11,10 +11,10 @@ LL | #[macro_use(my_macro)]
    | ^^^^^^^^^^^^^^^^^^^^^^
 
 error: arguments to `macro_use` are not allowed here
-  --> $DIR/issue-43106-gating-of-macro_use.rs:12:17
+  --> $DIR/issue-43106-gating-of-macro_use.rs:6:1
    |
-LL |     mod inner { #![macro_use(my_macro)] }
-   |                 ^^^^^^^^^^^^^^^^^^^^^^^
+LL | #![macro_use(my_macro)]
+   | ^^^^^^^^^^^^^^^^^^^^^^^
 
 error: malformed `macro_use` attribute input
   --> $DIR/issue-43106-gating-of-macro_use.rs:15:5