From 2aebde6c0b47a1f2ce3d49af457683258d813cdc Mon Sep 17 00:00:00 2001
From: Jonas Schievink <jonasschievink@gmail.com>
Date: Thu, 28 Jan 2021 18:00:10 +0100
Subject: ItemTree: Treat items in `MacroStmts` as top-level

---
 crates/hir_def/src/item_tree.rs       | 10 ++++++----
 crates/hir_def/src/item_tree/lower.rs | 26 ++++++++++++++++++++++++++
 2 files changed, 32 insertions(+), 4 deletions(-)

diff --git a/crates/hir_def/src/item_tree.rs b/crates/hir_def/src/item_tree.rs
index 1e5c94660..42d9f0947 100644
--- a/crates/hir_def/src/item_tree.rs
+++ b/crates/hir_def/src/item_tree.rs
@@ -98,15 +98,17 @@ impl ItemTree {
                     ctx.lower_module_items(&items)
                 },
                 ast::MacroStmts(stmts) => {
-                    ctx.lower_inner_items(stmts.syntax())
+                    // The produced statements can include items, which should be added as top-level
+                    // items.
+                    ctx.lower_macro_stmts(stmts)
                 },
-                // Macros can expand to expressions. We return an empty item tree in this case, but
-                // still need to collect inner items.
                 ast::Expr(e) => {
+                    // Macros can expand to expressions. We return an empty item tree in this case, but
+                    // still need to collect inner items.
                     ctx.lower_inner_items(e.syntax())
                 },
                 _ => {
-                    panic!("cannot create item tree from {:?}", syntax);
+                    panic!("cannot create item tree from {:?} {}", syntax, syntax);
                 },
             }
         };
diff --git a/crates/hir_def/src/item_tree/lower.rs b/crates/hir_def/src/item_tree/lower.rs
index 8a71376b9..acc001add 100644
--- a/crates/hir_def/src/item_tree/lower.rs
+++ b/crates/hir_def/src/item_tree/lower.rs
@@ -61,6 +61,32 @@ impl Ctx {
         self.tree
     }
 
+    pub(super) fn lower_macro_stmts(mut self, stmts: ast::MacroStmts) -> ItemTree {
+        self.tree.top_level = stmts
+            .statements()
+            .filter_map(|stmt| match stmt {
+                ast::Stmt::Item(item) => Some(item),
+                _ => None,
+            })
+            .flat_map(|item| self.lower_mod_item(&item, false))
+            .flat_map(|items| items.0)
+            .collect();
+
+        // Non-items need to have their inner items collected.
+        for stmt in stmts.statements() {
+            match stmt {
+                ast::Stmt::ExprStmt(_) | ast::Stmt::LetStmt(_) => {
+                    self.collect_inner_items(stmt.syntax())
+                }
+                _ => {}
+            }
+        }
+        if let Some(expr) = stmts.expr() {
+            self.collect_inner_items(expr.syntax());
+        }
+        self.tree
+    }
+
     pub(super) fn lower_inner_items(mut self, within: &SyntaxNode) -> ItemTree {
         self.collect_inner_items(within);
         self.tree
-- 
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