consider glob imports in cfg suggestion

Author: bvanjoi

compiler/rustc_expand/src/expand.rs

@@ -1319,10 +1319,12 @@ impl InvocationCollectorNode for P<ast::Item> {
 
             let mut idents = Vec::new();
             collect_use_tree_leaves(ut, &mut idents);
-            return idents;
+            idents
+        } else if let Some(ident) = self.kind.ident() {
+            vec![ident]
+        } else {
+            vec![]
         }
-
-        if let Some(ident) = self.kind.ident() { vec![ident] } else { vec![] }
     }
 }
 

compiler/rustc_resolve/src/diagnostics.rs

@@ -2623,7 +2623,13 @@ impl<'ra, 'tcx> Resolver<'ra, 'tcx> {
         };
 
         for &StrippedCfgItem { parent_module, ident, ref cfg } in symbols {
-            if parent_module != module || ident.name != *segment {
+            let comes_from_same_module = parent_module == module
+                || self.module_map.get(&parent_module).is_some_and(|m| {
+                    m.glob_importers.borrow().iter().any(|import| {
+                        import.parent_scope.module.opt_def_id().is_some_and(|m| m == module)
+                    })
+                });
+            if !comes_from_same_module || ident.name != *segment {
                 continue;
             }
 

tests/ui/cfg/diagnostics-reexport-2.rs

@@ -0,0 +1,18 @@
+// issue#141256
+
+mod original {
+    #[cfg(false)]   //~ NOTE the item is gated here
+    pub mod gated { //~ NOTE found an item that was configured out
+        pub fn foo() {}
+    }
+}
+
+mod reexport {
+    pub use super::original::*;
+}
+
+fn main() {
+    reexport::gated::foo();
+    //~^ ERROR failed to resolve: could not find `gated` in `reexport`
+    //~| NOTE  could not find `gated` in `reexport`
+}

tests/ui/cfg/diagnostics-reexport-2.stderr

@@ -0,0 +1,20 @@
+error[E0433]: failed to resolve: could not find `gated` in `reexport`
+  --> $DIR/diagnostics-reexport-2.rs:15:15
+   |
+LL |     reexport::gated::foo();
+   |               ^^^^^ could not find `gated` in `reexport`
+   |
+note: found an item that was configured out
+  --> $DIR/diagnostics-reexport-2.rs:5:13
+   |
+LL |     pub mod gated {
+   |             ^^^^^
+note: the item is gated here
+  --> $DIR/diagnostics-reexport-2.rs:4:5
+   |
+LL |     #[cfg(false)]
+   |     ^^^^^^^^^^^^^
+
+error: aborting due to 1 previous error
+
+For more information about this error, try `rustc --explain E0433`.