From 13f30e9ef5f3d78fdaef450e935782a2edd9f88e Mon Sep 17 00:00:00 2001
From: Edwin Cheng <edwin0cheng@gmail.com>
Date: Thu, 18 Mar 2021 19:39:40 +0800
Subject: Handle inner recursive macro rules cases

---
 crates/hir_def/src/item_tree.rs       |  4 ++++
 crates/hir_def/src/item_tree/lower.rs |  8 ++++++++
 crates/hir_ty/src/tests/macros.rs     | 22 ++++++++++++++++++++++
 3 files changed, 34 insertions(+)

diff --git a/crates/hir_def/src/item_tree.rs b/crates/hir_def/src/item_tree.rs
index 7bb22c4c4..4477bdd36 100644
--- a/crates/hir_def/src/item_tree.rs
+++ b/crates/hir_def/src/item_tree.rs
@@ -115,6 +115,10 @@ impl ItemTree {
                     // still need to collect inner items.
                     ctx.lower_inner_items(stmt.syntax())
                 },
+                ast::Item(item) => {
+                    // Macros can expand to stmt and other item, and we add it as top level item
+                    ctx.lower_single_item(item)
+                },
                 _ => {
                     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 7e91b991d..d684b89d0 100644
--- a/crates/hir_def/src/item_tree/lower.rs
+++ b/crates/hir_def/src/item_tree/lower.rs
@@ -87,6 +87,14 @@ impl Ctx {
         self.tree
     }
 
+    pub(super) fn lower_single_item(mut self, item: ast::Item) -> ItemTree {
+        self.tree.top_level = self
+            .lower_mod_item(&item, false)
+            .map(|item| item.0)
+            .unwrap_or_else(|| Default::default());
+        self.tree
+    }
+
     pub(super) fn lower_inner_items(mut self, within: &SyntaxNode) -> ItemTree {
         self.collect_inner_items(within);
         self.tree
diff --git a/crates/hir_ty/src/tests/macros.rs b/crates/hir_ty/src/tests/macros.rs
index af4f8bb11..c1e605740 100644
--- a/crates/hir_ty/src/tests/macros.rs
+++ b/crates/hir_ty/src/tests/macros.rs
@@ -231,6 +231,28 @@ fn expr_macro_expanded_in_stmts() {
     );
 }
 
+#[test]
+fn recursive_inner_item_macro_rules() {
+    check_infer(
+        r#"
+        macro_rules! mac {
+            () => { mac!($)};
+            ($x:tt) => { macro_rules! blub { () => { 1 }; } };
+        }
+        fn foo() {
+            mac!();
+            let a = blub!();
+        }
+        "#,
+        expect![[r#"
+            !0..1 '1': i32
+            !0..7 'mac!($)': {unknown}
+            107..143 '{     ...!(); }': ()
+            129..130 'a': i32
+        "#]],
+    );
+}
+
 #[test]
 fn infer_type_value_macro_having_same_name() {
     check_infer(
-- 
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