Prefer hir::SelfParam and fix signature help of methods from macros

Author: oxalica

crates/hir/src/lib.rs

@@ -4406,14 +4406,13 @@ impl Callable {
             Other => CallableKind::Other,
         }
     }
-    pub fn receiver_param(&self, db: &dyn HirDatabase) -> Option<(ast::SelfParam, Type)> {
+    pub fn receiver_param(&self, db: &dyn HirDatabase) -> Option<(SelfParam, Type)> {
         let func = match self.callee {
             Callee::Def(CallableDefId::FunctionId(it)) if self.is_bound_method => it,
             _ => return None,
         };
-        let src = func.lookup(db.upcast()).source(db.upcast());
-        let param_list = src.value.param_list()?;
-        Some((param_list.self_param()?, self.ty.derived(self.sig.params()[0].clone())))
+        let func = Function { id: func };
+        Some((func.self_param(db)?, self.ty.derived(self.sig.params()[0].clone())))
     }
     pub fn n_params(&self) -> usize {
         self.sig.params().len() - if self.is_bound_method { 1 } else { 0 }

crates/ide-ssr/src/matching.rs

@@ -560,8 +560,10 @@ impl<'db, 'sema> Matcher<'db, 'sema> {
                         placeholder_value.autoref_kind = self
                             .sema
                             .resolve_method_call_as_callable(code)
-                            .and_then(|callable| callable.receiver_param(self.sema.db))
-                            .map(|(self_param, _)| self_param.kind())
+                            .and_then(|callable| {
+                                let (self_param, _) = callable.receiver_param(self.sema.db)?;
+                                Some(self_param.source(self.sema.db)?.value.kind())
+                            })
                             .unwrap_or(ast::SelfParamKind::Owned);
                     }
                 }

crates/ide/src/signature_help.rs

@@ -202,7 +202,7 @@ fn signature_help_for_call(
     res.signature.push('(');
     {
         if let Some((self_param, _)) = callable.receiver_param(db) {
-            format_to!(res.signature, "{}", self_param)
+            format_to!(res.signature, "{}", self_param.display(db))
         }
         let mut buf = String::new();
         for (idx, (pat, ty)) in callable.params(db).into_iter().enumerate() {
@@ -1314,6 +1314,25 @@ id! {
         );
     }
 
+    #[test]
+    fn fn_signature_for_method_call_defined_in_macro() {
+        check(
+            r#"
+macro_rules! id { ($($tt:tt)*) => { $($tt)* } }
+struct S;
+id! {
+    impl S {
+        fn foo<'a>(&'a mut self) {}
+    }
+}
+fn test() { S.foo($0); }
+"#,
+            expect![[r#"
+                fn foo(&'a mut self)
+            "#]],
+        );
+    }
+
     #[test]
     fn call_info_for_lambdas() {
         check(