Merge #2626

2626: Recursive collect macros in impl items r=matklad a=edwin0cheng



Co-authored-by: Edwin Cheng <edwin0cheng@gmail.com>

crates/ra_hir_def/src/data.rs

@@ -225,22 +225,48 @@ fn collect_impl_items_in_macros(
     let mut expander = Expander::new(db, impl_block.file_id, module_id);
     let mut res = Vec::new();
 
+    // We set a limit to protect against infinite recursion
+    let limit = 100;
+
     for m in impl_block.value.syntax().children().filter_map(ast::MacroCall::cast) {
-        if let Some((mark, items)) = expander.enter_expand(db, m) {
-            let items: InFile<ast::MacroItems> = expander.to_source(items);
-            expander.exit(db, mark);
-            res.extend(collect_impl_items(
-                db,
-                items.value.items().filter_map(|it| ImplItem::cast(it.syntax().clone())),
-                items.file_id,
-                id,
-            ));
-        }
+        res.extend(collect_impl_items_in_macro(db, &mut expander, m, id, limit))
     }
 
     res
 }
 
+fn collect_impl_items_in_macro(
+    db: &impl DefDatabase,
+    expander: &mut Expander,
+    m: ast::MacroCall,
+    id: ImplId,
+    limit: usize,
+) -> Vec<AssocItemId> {
+    if limit == 0 {
+        return Vec::new();
+    }
+
+    if let Some((mark, items)) = expander.enter_expand(db, m) {
+        let items: InFile<ast::MacroItems> = expander.to_source(items);
+        let mut res = collect_impl_items(
+            db,
+            items.value.items().filter_map(|it| ImplItem::cast(it.syntax().clone())),
+            items.file_id,
+            id,
+        );
+        // Recursive collect macros
+        // Note that ast::ModuleItem do not include ast::MacroCall
+        // We cannot use ModuleItemOwner::items here
+        for it in items.value.syntax().children().filter_map(ast::MacroCall::cast) {
+            res.extend(collect_impl_items_in_macro(db, expander, it, id, limit - 1))
+        }
+        expander.exit(db, mark);
+        res
+    } else {
+        Vec::new()
+    }
+}
+
 fn collect_impl_items(
     db: &impl DefDatabase,
     impl_items: impl Iterator<Item = ImplItem>,

crates/ra_hir_ty/src/tests/macros.rs

@@ -201,6 +201,29 @@ impl S {
     assert_eq!(t, "u128");
 }
 
+#[test]
+fn infer_impl_items_generated_by_macros_chain() {
+    let t = type_at(
+        r#"
+//- /main.rs
+macro_rules! m_inner {
+    () => {fn foo(&self) -> u128 {0}}
+}
+macro_rules! m {
+    () => {m_inner!();}
+}
+
+struct S;
+impl S {
+    m!();
+}
+
+fn test() { S.foo()<|>; }
+"#,
+    );
+    assert_eq!(t, "u128");
+}
+
 #[test]
 fn infer_macro_with_dollar_crate_is_correct_in_expr() {
     let (db, pos) = TestDB::with_position(