Auto merge of rust-lang#83713 - spastorino:revert-pub-macro-rules, r=nikomatsakis

Revert "Rollup merge of rust-lang#82296 - spastorino:pubrules, r=nikomatsakis"

This reverts commit e2561c5, reversing
changes made to 2982ba5.

As discussed in rust-lang#83641 this feature is not complete and in particular doesn't work cross macros and given that this is not going to be included in edition 2021 nobody seems to be trying to fix the underlying problem. When can add this again I guess, whenever somebody has the time to make it work cross crates.

r? `@nikomatsakis`

Author: bors

compiler/rustc_ast_passes/src/feature_gate.rs

@@ -686,7 +686,6 @@ pub fn check_crate(krate: &ast::Crate, sess: &Session) {
         // involved, so we only emit errors where there are no other parsing errors.
         gate_all!(destructuring_assignment, "destructuring assignments are unstable");
     }
-    gate_all!(pub_macro_rules, "`pub` on `macro_rules` items is unstable");
 
     // All uses of `gate_all!` below this point were added in #65742,
     // and subsequently disabled (with the non-early gating readded).

compiler/rustc_feature/src/active.rs

@@ -628,9 +628,6 @@ declare_features! (
     /// Allows macro attributes to observe output of `#[derive]`.
     (active, macro_attributes_in_derive_output, "1.51.0", Some(81119), None),
 
-    /// Allows `pub` on `macro_rules` items.
-    (active, pub_macro_rules, "1.52.0", Some(78855), None),
-
     /// Allows the use of type alias impl trait in function return positions
     (active, min_type_alias_impl_trait, "1.52.0", Some(63063), None),
 

compiler/rustc_feature/src/removed.rs

@@ -134,6 +134,8 @@ declare_features! (
            which is available from cargo build scripts with `cargo:rustc-link-arg` now")),
     /// Allows using `#[main]` to replace the entrypoint `#[lang = "start"]` calls.
     (removed, main, "1.53.0", Some(29634), None, None),
+    (removed, pub_macro_rules, "1.53.0", Some(78855), None,
+     Some("removed due to being incomplete, in particular it does not work across crates")),
 
     // -------------------------------------------------------------------------
     // feature-group-end: removed features

compiler/rustc_parse/src/parser/item.rs

@@ -1478,7 +1478,15 @@ impl<'a> Parser<'a> {
         let vstr = pprust::vis_to_string(vis);
         let vstr = vstr.trim_end();
         if macro_rules {
-            self.sess.gated_spans.gate(sym::pub_macro_rules, vis.span);
+            let msg = format!("can't qualify macro_rules invocation with `{}`", vstr);
+            self.struct_span_err(vis.span, &msg)
+                .span_suggestion(
+                    vis.span,
+                    "try exporting the macro",
+                    "#[macro_export]".to_owned(),
+                    Applicability::MaybeIncorrect, // speculative
+                )
+                .emit();
         } else {
             self.struct_span_err(vis.span, "can't qualify macro invocation with `pub`")
                 .span_suggestion(

compiler/rustc_resolve/src/build_reduced_graph.rs

@@ -1230,13 +1230,13 @@ impl<'a, 'b> BuildReducedGraphVisitor<'a, 'b> {
         };
 
         let res = Res::Def(DefKind::Macro(ext.macro_kind()), def_id.to_def_id());
-        let is_macro_export = self.r.session.contains_name(&item.attrs, sym::macro_export);
         self.r.macro_map.insert(def_id.to_def_id(), ext);
         self.r.local_macro_def_scopes.insert(def_id, parent_scope.module);
 
-        if macro_rules && matches!(item.vis.kind, ast::VisibilityKind::Inherited) {
+        if macro_rules {
             let ident = ident.normalize_to_macros_2_0();
             self.r.macro_names.insert(ident);
+            let is_macro_export = self.r.session.contains_name(&item.attrs, sym::macro_export);
             let vis = if is_macro_export {
                 ty::Visibility::Public
             } else {
@@ -1261,11 +1261,6 @@ impl<'a, 'b> BuildReducedGraphVisitor<'a, 'b> {
                 }),
             ))
         } else {
-            if is_macro_export {
-                let what = if macro_rules { "`macro_rules` with `pub`" } else { "`macro` items" };
-                let msg = format!("`#[macro_export]` cannot be used on {what}");
-                self.r.session.span_err(item.span, &msg);
-            }
             let module = parent_scope.module;
             let vis = match item.kind {
                 // Visibilities must not be resolved non-speculatively twice

src/test/ui/did_you_mean/pub-macro-rules.rs

@@ -0,0 +1,16 @@
+#[macro_use] mod bleh {
+    pub macro_rules! foo { //~ ERROR can't qualify macro_rules invocation
+        ($n:ident) => (
+            fn $n () -> i32 {
+                1
+            }
+        )
+    }
+
+}
+
+foo!(meh);
+
+fn main() {
+    println!("{}", meh());
+}

src/test/ui/did_you_mean/pub-macro-rules.stderr

@@ -0,0 +1,8 @@
+error: can't qualify macro_rules invocation with `pub`
+  --> $DIR/pub-macro-rules.rs:2:5
+   |
+LL |     pub macro_rules! foo {
+   |     ^^^ help: try exporting the macro: `#[macro_export]`
+
+error: aborting due to previous error
+