15 files changed, 671 insertions, 134 deletions

diff --git a/crates/hir/src/code_model.rs b/crates/hir/src/code_model.rs
index 7656db974..9ee4b3059 100644
--- a/crates/hir/src/code_model.rs
+++ b/crates/hir/src/code_model.rs
@@ -365,14 +365,14 @@ impl Module {
         let _p = profile::span("Module::diagnostics").detail(|| {
             format!("{:?}", self.name(db).map_or("<unknown>".into(), |name| name.to_string()))
         });
-        let crate_def_map = self.id.def_map(db.upcast());
-        crate_def_map.add_diagnostics(db.upcast(), self.id.local_id, sink);
+        let def_map = self.id.def_map(db.upcast());
+        def_map.add_diagnostics(db.upcast(), self.id.local_id, sink);
         for decl in self.declarations(db) {
             match decl {
                 crate::ModuleDef::Function(f) => f.diagnostics(db, sink),
                 crate::ModuleDef::Module(m) => {
                     // Only add diagnostics from inline modules
-                    if crate_def_map[m.id.local_id].origin.is_inline() {
+                    if def_map[m.id.local_id].origin.is_inline() {
                         m.diagnostics(db, sink)
                     }
                 }
diff --git a/crates/hir_def/src/body.rs b/crates/hir_def/src/body.rs
index ff4b4a0cf..16e1bac40 100644
--- a/crates/hir_def/src/body.rs
+++ b/crates/hir_def/src/body.rs
@@ -87,11 +87,11 @@ impl Expander {
         module: ModuleId,
     ) -> Expander {
         let cfg_expander = CfgExpander::new(db, current_file_id, module.krate);
-        let crate_def_map = module.def_map(db);
+        let def_map = module.def_map(db);
         let ast_id_map = db.ast_id_map(current_file_id);
         Expander {
             cfg_expander,
-            def_map: crate_def_map,
+            def_map,
             current_file_id,
             ast_id_map,
             module: module.local_id,
diff --git a/crates/hir_def/src/child_by_source.rs b/crates/hir_def/src/child_by_source.rs
index 65d85c86a..75c2d756b 100644
--- a/crates/hir_def/src/child_by_source.rs
+++ b/crates/hir_def/src/child_by_source.rs
@@ -74,8 +74,8 @@ impl ChildBySource for ImplId {
 
 impl ChildBySource for ModuleId {
     fn child_by_source(&self, db: &dyn DefDatabase) -> DynMap {
-        let crate_def_map = self.def_map(db);
-        let module_data = &crate_def_map[self.local_id];
+        let def_map = self.def_map(db);
+        let module_data = &def_map[self.local_id];
         module_data.scope.child_by_source(db)
     }
 }
diff --git a/crates/hir_def/src/resolver.rs b/crates/hir_def/src/resolver.rs
index e85f85e49..77ff21739 100644
--- a/crates/hir_def/src/resolver.rs
+++ b/crates/hir_def/src/resolver.rs
@@ -34,7 +34,7 @@ pub struct Resolver {
 // FIXME how to store these best
 #[derive(Debug, Clone)]
 struct ModuleItemMap {
-    crate_def_map: Arc<DefMap>,
+    def_map: Arc<DefMap>,
     module_id: LocalModuleId,
 }
 
@@ -337,11 +337,11 @@ impl Resolver {
         let mut traits = FxHashSet::default();
         for scope in &self.scopes {
             if let Scope::ModuleScope(m) = scope {
-                if let Some(prelude) = m.crate_def_map.prelude() {
+                if let Some(prelude) = m.def_map.prelude() {
                     let prelude_def_map = prelude.def_map(db);
                     traits.extend(prelude_def_map[prelude.local_id].scope.traits());
                 }
-                traits.extend(m.crate_def_map[m.module_id].scope.traits());
+                traits.extend(m.def_map[m.module_id].scope.traits());
             }
         }
         traits
@@ -349,7 +349,7 @@ impl Resolver {
 
     fn module_scope(&self) -> Option<(&DefMap, LocalModuleId)> {
         self.scopes.iter().rev().find_map(|scope| match scope {
-            Scope::ModuleScope(m) => Some((&*m.crate_def_map, m.module_id)),
+            Scope::ModuleScope(m) => Some((&*m.def_map, m.module_id)),
 
             _ => None,
         })
@@ -413,21 +413,21 @@ impl Scope {
                 //         def: m.module.into(),
                 //     }),
                 // );
-                m.crate_def_map[m.module_id].scope.entries().for_each(|(name, def)| {
+                m.def_map[m.module_id].scope.entries().for_each(|(name, def)| {
                     f(name.clone(), ScopeDef::PerNs(def));
                 });
-                m.crate_def_map[m.module_id].scope.legacy_macros().for_each(|(name, macro_)| {
+                m.def_map[m.module_id].scope.legacy_macros().for_each(|(name, macro_)| {
                     let scope = PerNs::macros(macro_, Visibility::Public);
                     seen.insert((name.clone(), scope));
                     f(name.clone(), ScopeDef::PerNs(scope));
                 });
-                m.crate_def_map.extern_prelude().for_each(|(name, &def)| {
+                m.def_map.extern_prelude().for_each(|(name, &def)| {
                     f(name.clone(), ScopeDef::PerNs(PerNs::types(def, Visibility::Public)));
                 });
                 BUILTIN_SCOPE.iter().for_each(|(name, &def)| {
                     f(name.clone(), ScopeDef::PerNs(def));
                 });
-                if let Some(prelude) = m.crate_def_map.prelude() {
+                if let Some(prelude) = m.def_map.prelude() {
                     let prelude_def_map = prelude.def_map(db);
                     prelude_def_map[prelude.local_id].scope.entries().for_each(|(name, def)| {
                         let seen_tuple = (name.clone(), def);
@@ -513,8 +513,8 @@ impl Resolver {
         self.push_scope(Scope::ImplDefScope(impl_def))
     }
 
-    fn push_module_scope(self, crate_def_map: Arc<DefMap>, module_id: LocalModuleId) -> Resolver {
-        self.push_scope(Scope::ModuleScope(ModuleItemMap { crate_def_map, module_id }))
+    fn push_module_scope(self, def_map: Arc<DefMap>, module_id: LocalModuleId) -> Resolver {
+        self.push_scope(Scope::ModuleScope(ModuleItemMap { def_map, module_id }))
     }
 
     fn push_expr_scope(
@@ -534,7 +534,7 @@ impl ModuleItemMap {
         path: &ModPath,
     ) -> Option<ResolveValueResult> {
         let (module_def, idx) =
-            self.crate_def_map.resolve_path(db, self.module_id, &path, BuiltinShadowMode::Other);
+            self.def_map.resolve_path(db, self.module_id, &path, BuiltinShadowMode::Other);
         match idx {
             None => {
                 let value = to_value_ns(module_def)?;
@@ -564,7 +564,7 @@ impl ModuleItemMap {
         path: &ModPath,
     ) -> Option<(TypeNs, Option<usize>)> {
         let (module_def, idx) =
-            self.crate_def_map.resolve_path(db, self.module_id, &path, BuiltinShadowMode::Other);
+            self.def_map.resolve_path(db, self.module_id, &path, BuiltinShadowMode::Other);
         let res = to_type_ns(module_def)?;
         Some((res, idx))
     }
diff --git a/crates/ide_assists/src/handlers/generate_default_from_new.rs b/crates/ide_assists/src/handlers/generate_default_from_new.rs
new file mode 100644
index 000000000..fa1254579
--- /dev/null
+++ b/crates/ide_assists/src/handlers/generate_default_from_new.rs
@@ -0,0 +1,374 @@
+use crate::{
+    assist_context::{AssistContext, Assists},
+    AssistId,
+};
+use ide_db::helpers::FamousDefs;
+use syntax::{
+    ast::{self, Impl, NameOwner},
+    AstNode,
+};
+use test_utils::mark;
+
+// Assist: generate_default_from_new
+//
+// Generates default implementation from new method.
+//
+// ```
+// struct Example { _inner: () }
+//
+// impl Example {
+//     pub fn n$0ew() -> Self {
+//         Self { _inner: () }
+//     }
+// }
+// ```
+// ->
+// ```
+// struct Example { _inner: () }
+//
+// impl Example {
+//     pub fn new() -> Self {
+//         Self { _inner: () }
+//     }
+// }
+//
+// impl Default for Example {
+//     fn default() -> Self {
+//         Self::new()
+//     }
+// }
+// ```
+pub(crate) fn generate_default_from_new(acc: &mut Assists, ctx: &AssistContext) -> Option<()> {
+    let fn_node = ctx.find_node_at_offset::<ast::Fn>()?;
+    let fn_name = fn_node.name()?;
+
+    if fn_name.text() != "new" {
+        mark::hit!(other_function_than_new);
+        return None;
+    }
+
+    if fn_node.param_list()?.params().next().is_some() {
+        mark::hit!(new_function_with_parameters);
+        return None;
+    }
+
+    let impl_ = fn_node.syntax().ancestors().into_iter().find_map(ast::Impl::cast)?;
+    if is_default_implemented(ctx, &impl_) {
+        mark::hit!(default_block_is_already_present);
+        mark::hit!(struct_in_module_with_default);
+        return None;
+    }
+
+    let insert_location = impl_.syntax().text_range();
+
+    acc.add(
+        AssistId("generate_default_from_new", crate::AssistKind::Generate),
+        "Generate a Default impl from a new fn",
+        insert_location,
+        move |builder| {
+            let code = default_fn_node_for_new(impl_);
+            builder.insert(insert_location.end(), code);
+        },
+    )
+}
+
+fn default_fn_node_for_new(impl_: Impl) -> String {
+    format!(
+        "
+
+impl Default for {} {{
+    fn default() -> Self {{
+        Self::new()
+    }}
+}}",
+        impl_.self_ty().unwrap().syntax().text()
+    )
+}
+
+fn is_default_implemented(ctx: &AssistContext, impl_: &Impl) -> bool {
+    let db = ctx.sema.db;
+    let impl_ = ctx.sema.to_def(impl_);
+    let impl_def = match impl_ {
+        Some(value) => value,
+        None => return false,
+    };
+
+    let ty = impl_def.target_ty(db);
+    let krate = impl_def.module(db).krate();
+    let default = FamousDefs(&ctx.sema, Some(krate)).core_default_Default();
+    let default_trait = match default {
+        Some(value) => value,
+        None => return false,
+    };
+
+    ty.impls_trait(db, default_trait, &[])
+}
+
+#[cfg(test)]
+mod tests {
+    use ide_db::helpers::FamousDefs;
+
+    use crate::tests::{check_assist, check_assist_not_applicable};
+
+    use super::*;
+
+    #[test]
+    fn generate_default() {
+        check_pass(
+            r#"
+struct Example { _inner: () }
+
+impl Example {
+    pub fn ne$0w() -> Self {
+        Self { _inner: () }
+    }
+}
+
+fn main() {}
+"#,
+            r#"
+struct Example { _inner: () }
+
+impl Example {
+    pub fn new() -> Self {
+        Self { _inner: () }
+    }
+}
+
+impl Default for Example {
+    fn default() -> Self {
+        Self::new()
+    }
+}
+
+fn main() {}
+"#,
+        );
+    }
+
+    #[test]
+    fn generate_default2() {
+        check_pass(
+            r#"
+struct Test { value: u32 }
+
+impl Test {
+    pub fn ne$0w() -> Self {
+        Self { value: 0 }
+    }
+}
+"#,
+            r#"
+struct Test { value: u32 }
+
+impl Test {
+    pub fn new() -> Self {
+        Self { value: 0 }
+    }
+}
+
+impl Default for Test {
+    fn default() -> Self {
+        Self::new()
+    }
+}
+"#,
+        );
+    }
+
+    #[test]
+    fn new_function_with_parameters() {
+        mark::check!(new_function_with_parameters);
+        check_not_applicable(
+            r#"
+struct Example { _inner: () }
+
+impl Example {
+    pub fn $0new(value: ()) -> Self {
+        Self { _inner: value }
+    }
+}
+"#,
+        );
+    }
+
+    #[test]
+    fn other_function_than_new() {
+        mark::check!(other_function_than_new);
+        check_not_applicable(
+            r#"
+struct Example { _inner: () }
+
+impl Example {
+    pub fn a$0dd() -> Self {
+        Self { _inner: () }
+    }
+}
+
+"#,
+        );
+    }
+
+    #[test]
+    fn default_block_is_already_present() {
+        mark::check!(default_block_is_already_present);
+        check_not_applicable(
+            r#"
+struct Example { _inner: () }
+
+impl Example {
+    pub fn n$0ew() -> Self {
+        Self { _inner: () }
+    }
+}
+
+impl Default for Example {
+    fn default() -> Self {
+        Self::new()
+    }
+}
+"#,
+        );
+    }
+
+    #[test]
+    fn standalone_new_function() {
+        check_not_applicable(
+            r#"
+fn n$0ew() -> u32 {
+    0
+}
+"#,
+        );
+    }
+
+    #[test]
+    fn multiple_struct_blocks() {
+        check_pass(
+            r#"
+struct Example { _inner: () }
+struct Test { value: u32 }
+
+impl Example {
+    pub fn new$0() -> Self {
+        Self { _inner: () }
+    }
+}
+"#,
+            r#"
+struct Example { _inner: () }
+struct Test { value: u32 }
+
+impl Example {
+    pub fn new() -> Self {
+        Self { _inner: () }
+    }
+}
+
+impl Default for Example {
+    fn default() -> Self {
+        Self::new()
+    }
+}
+"#,
+        );
+    }
+
+    #[test]
+    fn when_struct_is_after_impl() {
+        check_pass(
+            r#"
+impl Example {
+    pub fn $0new() -> Self {
+        Self { _inner: () }
+    }
+}
+
+struct Example { _inner: () }
+"#,
+            r#"
+impl Example {
+    pub fn new() -> Self {
+        Self { _inner: () }
+    }
+}
+
+impl Default for Example {
+    fn default() -> Self {
+        Self::new()
+    }
+}
+
+struct Example { _inner: () }
+"#,
+        );
+    }
+
+    #[test]
+    fn struct_in_module() {
+        check_pass(
+            r#"
+mod test {
+    struct Example { _inner: () }
+
+    impl Example {
+        pub fn n$0ew() -> Self {
+            Self { _inner: () }
+        }
+    }
+}
+"#,
+            r#"
+mod test {
+    struct Example { _inner: () }
+
+    impl Example {
+        pub fn new() -> Self {
+            Self { _inner: () }
+        }
+    }
+
+impl Default for Example {
+    fn default() -> Self {
+        Self::new()
+    }
+}
+}
+"#,
+        );
+    }
+
+    #[test]
+    fn struct_in_module_with_default() {
+        mark::check!(struct_in_module_with_default);
+        check_not_applicable(
+            r#"
+mod test {
+    struct Example { _inner: () }
+
+    impl Example {
+        pub fn n$0ew() -> Self {
+            Self { _inner: () }
+        }
+    }
+
+    impl Default for Example {
+        fn default() -> Self {
+            Self::new()
+        }
+    }
+}
+"#,
+        );
+    }
+
+    fn check_pass(before: &str, after: &str) {
+        let before = &format!("//- /main.rs crate:main deps:core{}{}", before, FamousDefs::FIXTURE);
+        check_assist(generate_default_from_new, before, after);
+    }
+
+    fn check_not_applicable(before: &str) {
+        let before = &format!("//- /main.rs crate:main deps:core{}{}", before, FamousDefs::FIXTURE);
+        check_assist_not_applicable(generate_default_from_new, before);
+    }
+}
diff --git a/crates/ide_assists/src/handlers/generate_function.rs b/crates/ide_assists/src/handlers/generate_function.rs
index 959824981..3870b7e75 100644
--- a/crates/ide_assists/src/handlers/generate_function.rs
+++ b/crates/ide_assists/src/handlers/generate_function.rs
@@ -1,6 +1,7 @@
 use hir::HirDisplay;
 use ide_db::{base_db::FileId, helpers::SnippetCap};
 use rustc_hash::{FxHashMap, FxHashSet};
+use stdx::to_lower_snake_case;
 use syntax::{
     ast::{
         self,
@@ -257,14 +258,15 @@ fn deduplicate_arg_names(arg_names: &mut Vec<String>) {
 fn fn_arg_name(fn_arg: &ast::Expr) -> Option<String> {
     match fn_arg {
         ast::Expr::CastExpr(cast_expr) => fn_arg_name(&cast_expr.expr()?),
-        _ => Some(
-            fn_arg
+        _ => {
+            let s = fn_arg
                 .syntax()
                 .descendants()
                 .filter(|d| ast::NameRef::can_cast(d.kind()))
                 .last()?
-                .to_string(),
-        ),
+                .to_string();
+            Some(to_lower_snake_case(&s))
+        }
     }
 }
 
@@ -448,6 +450,52 @@ mod baz {
     }
 
     #[test]
+    fn add_function_with_upper_camel_case_arg() {
+        check_assist(
+            generate_function,
+            r"
+struct BazBaz;
+fn foo() {
+    bar$0(BazBaz);
+}
+",
+            r"
+struct BazBaz;
+fn foo() {
+    bar(BazBaz);
+}
+
+fn bar(baz_baz: BazBaz) ${0:-> ()} {
+    todo!()
+}
+",
+        );
+    }
+
+    #[test]
+    fn add_function_with_upper_camel_case_arg_as_cast() {
+        check_assist(
+            generate_function,
+            r"
+struct BazBaz;
+fn foo() {
+    bar$0(&BazBaz as *const BazBaz);
+}
+",
+            r"
+struct BazBaz;
+fn foo() {
+    bar(&BazBaz as *const BazBaz);
+}
+
+fn bar(baz_baz: *const BazBaz) ${0:-> ()} {
+    todo!()
+}
+",
+        );
+    }
+
+    #[test]
     fn add_function_with_function_call_arg() {
         check_assist(
             generate_function,
diff --git a/crates/ide_assists/src/handlers/replace_string_with_char.rs b/crates/ide_assists/src/handlers/replace_string_with_char.rs
index 317318c24..634b9c0b7 100644
--- a/crates/ide_assists/src/handlers/replace_string_with_char.rs
+++ b/crates/ide_assists/src/handlers/replace_string_with_char.rs
@@ -25,13 +25,16 @@ pub(crate) fn replace_string_with_char(acc: &mut Assists, ctx: &AssistContext) -
     if value.chars().take(2).count() != 1 {
         return None;
     }
+    let quote_offets = token.quote_offsets()?;
 
     acc.add(
         AssistId("replace_string_with_char", AssistKind::RefactorRewrite),
         "Replace string with char",
         target,
         |edit| {
-            edit.replace(token.syntax().text_range(), format!("'{}'", value));
+            let (left, right) = quote_offets.quotes;
+            edit.replace(left, String::from('\''));
+            edit.replace(right, String::from('\''));
         },
     )
 }
@@ -47,10 +50,10 @@ mod tests {
         check_assist_target(
             replace_string_with_char,
             r#"
-            fn f() {
-                let s = "$0c";
-            }
-            "#,
+fn f() {
+    let s = "$0c";
+}
+"#,
             r#""c""#,
         );
     }
@@ -60,15 +63,15 @@ mod tests {
         check_assist(
             replace_string_with_char,
             r#"
-    fn f() {
-        let s = "$0c";
-    }
-    "#,
+fn f() {
+    let s = "$0c";
+}
+"#,
             r##"
-    fn f() {
-        let s = 'c';
-    }
-    "##,
+fn f() {
+    let s = 'c';
+}
+"##,
         )
     }
 
@@ -77,15 +80,15 @@ mod tests {
         check_assist(
             replace_string_with_char,
             r#"
-    fn f() {
-        let s = "$0😀";
-    }
-    "#,
+fn f() {
+    let s = "$0😀";
+}
+"#,
             r##"
-    fn f() {
-        let s = '😀';
-    }
-    "##,
+fn f() {
+    let s = '😀';
+}
+"##,
         )
     }
 
@@ -94,10 +97,10 @@ mod tests {
         check_assist_not_applicable(
             replace_string_with_char,
             r#"
-    fn f() {
-        let s = "$0test";
-    }
-    "#,
+fn f() {
+    let s = "$0test";
+}
+"#,
         )
     }
 
@@ -106,15 +109,15 @@ mod tests {
         check_assist(
             replace_string_with_char,
             r#"
-                fn f() {
-                    format!($0"x", 92)
-                }
-                "#,
+fn f() {
+    format!($0"x", 92)
+}
+"#,
             r##"
-                fn f() {
-                    format!('x', 92)
-                }
-                "##,
+fn f() {
+    format!('x', 92)
+}
+"##,
         )
     }
 
@@ -123,15 +126,66 @@ mod tests {
         check_assist(
             replace_string_with_char,
             r#"
-                fn f() {
-                    find($0"x");
-                }
-                "#,
+fn f() {
+    find($0"x");
+}
+"#,
             r##"
-                fn f() {
-                    find('x');
-                }
-                "##,
+fn f() {
+    find('x');
+}
+"##,
+        )
+    }
+
+    #[test]
+    fn replace_string_with_char_newline() {
+        check_assist(
+            replace_string_with_char,
+            r#"
+fn f() {
+    find($0"\n");
+}
+"#,
+            r##"
+fn f() {
+    find('\n');
+}
+"##,
+        )
+    }
+
+    #[test]
+    fn replace_string_with_char_unicode_escape() {
+        check_assist(
+            replace_string_with_char,
+            r#"
+fn f() {
+    find($0"\u{7FFF}");
+}
+"#,
+            r##"
+fn f() {
+    find('\u{7FFF}');
+}
+"##,
+        )
+    }
+
+    #[test]
+    fn replace_raw_string_with_char() {
+        check_assist(
+            replace_string_with_char,
+            r##"
+fn f() {
+    $0r#"X"#
+}
+"##,
+            r##"
+fn f() {
+    'X'
+}
+"##,
         )
     }
 }
diff --git a/crates/ide_assists/src/lib.rs b/crates/ide_assists/src/lib.rs
index 9c8148462..ea62d5f5d 100644
--- a/crates/ide_assists/src/lib.rs
+++ b/crates/ide_assists/src/lib.rs
@@ -127,6 +127,7 @@ mod handlers {
     mod flip_comma;
     mod flip_trait_bound;
     mod generate_default_from_enum_variant;
+    mod generate_default_from_new;
     mod generate_derive;
     mod generate_enum_is_method;
     mod generate_enum_projection_method;
@@ -189,6 +190,7 @@ mod handlers {
             flip_comma::flip_comma,
             flip_trait_bound::flip_trait_bound,
             generate_default_from_enum_variant::generate_default_from_enum_variant,
+            generate_default_from_new::generate_default_from_new,
             generate_derive::generate_derive,
             generate_enum_is_method::generate_enum_is_method,
             generate_enum_projection_method::generate_enum_as_method,
diff --git a/crates/ide_assists/src/tests/generated.rs b/crates/ide_assists/src/tests/generated.rs
index 4f007aa48..304b5798f 100644
--- a/crates/ide_assists/src/tests/generated.rs
+++ b/crates/ide_assists/src/tests/generated.rs
@@ -440,6 +440,37 @@ impl Default for Version {
 }
 
 #[test]
+fn doctest_generate_default_from_new() {
+    check_doc_test(
+        "generate_default_from_new",
+        r#####"
+struct Example { _inner: () }
+
+impl Example {
+    pub fn n$0ew() -> Self {
+        Self { _inner: () }
+    }
+}
+"#####,
+        r#####"
+struct Example { _inner: () }
+
+impl Example {
+    pub fn new() -> Self {
+        Self { _inner: () }
+    }
+}
+
+impl Default for Example {
+    fn default() -> Self {
+        Self::new()
+    }
+}
+"#####,
+    )
+}
+
+#[test]
 fn doctest_generate_derive() {
     check_doc_test(
         "generate_derive",
diff --git a/crates/proc_macro_srv/src/dylib.rs b/crates/proc_macro_srv/src/dylib.rs
index 28a6ee547..baf10fea9 100644
--- a/crates/proc_macro_srv/src/dylib.rs
+++ b/crates/proc_macro_srv/src/dylib.rs
@@ -138,7 +138,7 @@ impl Expander {
                         parsed_body,
                         false,
                     );
-                    return res.map(|it| it.subtree);
+                    return res.map(|it| it.into_subtree());
                 }
                 bridge::client::ProcMacro::Bang { name, client } if *name == macro_name => {
                     let res = client.run(
@@ -147,7 +147,7 @@ impl Expander {
                         parsed_body,
                         false,
                     );
-                    return res.map(|it| it.subtree);
+                    return res.map(|it| it.into_subtree());
                 }
                 bridge::client::ProcMacro::Attr { name, client } if *name == macro_name => {
                     let res = client.run(
@@ -157,7 +157,7 @@ impl Expander {
                         parsed_body,
                         false,
                     );
-                    return res.map(|it| it.subtree);
+                    return res.map(|it| it.into_subtree());
                 }
                 _ => continue,
             }
diff --git a/crates/proc_macro_srv/src/proc_macro/bridge/client.rs b/crates/proc_macro_srv/src/proc_macro/bridge/client.rs
index ca6749b9b..b036d4e20 100644
--- a/crates/proc_macro_srv/src/proc_macro/bridge/client.rs
+++ b/crates/proc_macro_srv/src/proc_macro/bridge/client.rs
@@ -238,7 +238,7 @@ macro_rules! define_client_side {
         $(impl $name {
             #[allow(unused)]
             $(pub(crate) fn $method($($arg: $arg_ty),*) $(-> $ret_ty)* {
-                panic!("hello");
+                panic!("crates should be linked against the sysroot version of proc_macro, not this one from rust-analyzer");
                 // Bridge::with(|bridge| {
                 //     let mut b = bridge.cached_buffer.take();
 
diff --git a/crates/proc_macro_srv/src/rustc_server.rs b/crates/proc_macro_srv/src/rustc_server.rs
index 14c853c77..ceefd187d 100644
--- a/crates/proc_macro_srv/src/rustc_server.rs
+++ b/crates/proc_macro_srv/src/rustc_server.rs
@@ -25,27 +25,35 @@ type Span = tt::TokenId;
 
 #[derive(Debug, Clone)]
 pub struct TokenStream {
-    pub subtree: tt::Subtree,
+    pub token_trees: Vec<TokenTree>,
 }
 
 impl TokenStream {
     pub fn new() -> Self {
-        TokenStream { subtree: Default::default() }
+        TokenStream { token_trees: Default::default() }
     }
 
     pub fn with_subtree(subtree: tt::Subtree) -> Self {
-        TokenStream { subtree }
+        if subtree.delimiter.is_some() {
+            TokenStream { token_trees: vec![TokenTree::Subtree(subtree)] }
+        } else {
+            TokenStream { token_trees: subtree.token_trees }
+        }
+    }
+
+    pub fn into_subtree(self) -> tt::Subtree {
+        tt::Subtree { delimiter: None, token_trees: self.token_trees }
     }
 
     pub fn is_empty(&self) -> bool {
-        self.subtree.token_trees.is_empty()
+        self.token_trees.is_empty()
     }
 }
 
 /// Creates a token stream containing a single token tree.
 impl From<TokenTree> for TokenStream {
     fn from(tree: TokenTree) -> TokenStream {
-        TokenStream { subtree: tt::Subtree { delimiter: None, token_trees: vec![tree] } }
+        TokenStream { token_trees: vec![tree] }
     }
 }
 
@@ -78,10 +86,10 @@ impl Extend<TokenStream> for TokenStream {
             for tkn in item {
                 match tkn {
                     tt::TokenTree::Subtree(subtree) if subtree.delimiter.is_none() => {
-                        self.subtree.token_trees.extend(subtree.token_trees);
+                        self.token_trees.extend(subtree.token_trees);
                     }
                     _ => {
-                        self.subtree.token_trees.push(tkn);
+                        self.token_trees.push(tkn);
                     }
                 }
             }
@@ -164,7 +172,7 @@ pub mod token_stream {
         type IntoIter = super::IntoIter<TokenTree>;
 
         fn into_iter(self) -> Self::IntoIter {
-            self.subtree.token_trees.into_iter()
+            self.token_trees.into_iter()
         }
     }
 
@@ -185,28 +193,22 @@ pub mod token_stream {
                 mbe::parse_to_token_tree(src).ok_or("Failed to parse from mbe")?;
 
             let subtree = subtree_replace_token_ids_with_unspecified(subtree);
-            Ok(TokenStream { subtree })
+            Ok(TokenStream::with_subtree(subtree))
         }
     }
 
     impl ToString for TokenStream {
         fn to_string(&self) -> String {
-            let tt = self.subtree.clone().into();
-            to_text(&tt)
-        }
-    }
+            return tokentrees_to_text(&self.token_trees[..]);
 
-    fn to_text(tkn: &tt::TokenTree) -> String {
-        match tkn {
-            tt::TokenTree::Leaf(tt::Leaf::Ident(ident)) => ident.text.clone().into(),
-            tt::TokenTree::Leaf(tt::Leaf::Literal(literal)) => literal.text.clone().into(),
-            tt::TokenTree::Leaf(tt::Leaf::Punct(punct)) => format!("{}", punct.char),
-            tt::TokenTree::Subtree(subtree) => {
-                let content = subtree
-                    .token_trees
-                    .iter()
+            fn tokentrees_to_text(tkns: &[tt::TokenTree]) -> String {
+                tkns.iter()
                     .fold((String::new(), true), |(last, last_to_joint), tkn| {
-                        let s = [last, to_text(tkn)].join(if last_to_joint { "" } else { " " });
+                        let s = [last, tokentree_to_text(tkn)].join(if last_to_joint {
+                            ""
+                        } else {
+                            " "
+                        });
                         let mut is_joint = false;
                         if let tt::TokenTree::Leaf(tt::Leaf::Punct(punct)) = tkn {
                             if punct.spacing == tt::Spacing::Joint {
@@ -215,15 +217,25 @@ pub mod token_stream {
                         }
                         (s, is_joint)
                     })
-                    .0;
-
-                let (open, close) = match subtree.delimiter.map(|it| it.kind) {
-                    None => ("", ""),
-                    Some(tt::DelimiterKind::Brace) => ("{", "}"),
-                    Some(tt::DelimiterKind::Parenthesis) => ("(", ")"),
-                    Some(tt::DelimiterKind::Bracket) => ("[", "]"),
-                };
-                format!("{}{}{}", open, content, close)
+                    .0
+            }
+
+            fn tokentree_to_text(tkn: &tt::TokenTree) -> String {
+                match tkn {
+                    tt::TokenTree::Leaf(tt::Leaf::Ident(ident)) => ident.text.clone().into(),
+                    tt::TokenTree::Leaf(tt::Leaf::Literal(literal)) => literal.text.clone().into(),
+                    tt::TokenTree::Leaf(tt::Leaf::Punct(punct)) => format!("{}", punct.char),
+                    tt::TokenTree::Subtree(subtree) => {
+                        let content = tokentrees_to_text(&subtree.token_trees);
+                        let (open, close) = match subtree.delimiter.map(|it| it.kind) {
+                            None => ("", ""),
+                            Some(tt::DelimiterKind::Brace) => ("{", "}"),
+                            Some(tt::DelimiterKind::Parenthesis) => ("(", ")"),
+                            Some(tt::DelimiterKind::Bracket) => ("[", "]"),
+                        };
+                        format!("{}{}{}", open, content, close)
+                    }
+                }
             }
         }
     }
@@ -433,10 +445,7 @@ fn spacing_to_external(spacing: Spacing) -> bridge::Spacing {
 
 impl server::Group for Rustc {
     fn new(&mut self, delimiter: bridge::Delimiter, stream: Self::TokenStream) -> Self::Group {
-        Self::Group {
-            delimiter: delim_to_internal(delimiter),
-            token_trees: stream.subtree.token_trees,
-        }
+        Self::Group { delimiter: delim_to_internal(delimiter), token_trees: stream.token_trees }
     }
     fn delimiter(&mut self, group: &Self::Group) -> bridge::Delimiter {
         delim_to_external(group.delimiter)
@@ -444,9 +453,7 @@ impl server::Group for Rustc {
 
     // NOTE: Return value of do not include delimiter
     fn stream(&mut self, group: &Self::Group) -> Self::TokenStream {
-        TokenStream {
-            subtree: tt::Subtree { delimiter: None, token_trees: group.token_trees.clone() },
-        }
+        TokenStream { token_trees: group.token_trees.clone() }
     }
 
     fn span(&mut self, group: &Self::Group) -> Self::Span {
@@ -755,28 +762,48 @@ mod tests {
     #[test]
     fn test_rustc_server_to_string() {
         let s = TokenStream {
-            subtree: tt::Subtree {
-                delimiter: None,
-                token_trees: vec![
-                    tt::TokenTree::Leaf(tt::Leaf::Ident(tt::Ident {
-                        text: "struct".into(),
-                        id: tt::TokenId::unspecified(),
-                    })),
-                    tt::TokenTree::Leaf(tt::Leaf::Ident(tt::Ident {
-                        text: "T".into(),
+            token_trees: vec![
+                tt::TokenTree::Leaf(tt::Leaf::Ident(tt::Ident {
+                    text: "struct".into(),
+                    id: tt::TokenId::unspecified(),
+                })),
+                tt::TokenTree::Leaf(tt::Leaf::Ident(tt::Ident {
+                    text: "T".into(),
+                    id: tt::TokenId::unspecified(),
+                })),
+                tt::TokenTree::Subtree(tt::Subtree {
+                    delimiter: Some(tt::Delimiter {
                         id: tt::TokenId::unspecified(),
-                    })),
-                    tt::TokenTree::Subtree(tt::Subtree {
-                        delimiter: Some(tt::Delimiter {
-                            id: tt::TokenId::unspecified(),
-                            kind: tt::DelimiterKind::Brace,
-                        }),
-                        token_trees: vec![],
+                        kind: tt::DelimiterKind::Brace,
                     }),
-                ],
-            },
+                    token_trees: vec![],
+                }),
+            ],
         };
 
         assert_eq!(s.to_string(), "struct T {}");
     }
+
+    #[test]
+    fn test_rustc_server_from_str() {
+        use std::str::FromStr;
+        let subtree_paren_a = tt::TokenTree::Subtree(tt::Subtree {
+            delimiter: Some(tt::Delimiter {
+                id: tt::TokenId::unspecified(),
+                kind: tt::DelimiterKind::Parenthesis,
+            }),
+            token_trees: vec![tt::TokenTree::Leaf(tt::Leaf::Ident(tt::Ident {
+                text: "a".into(),
+                id: tt::TokenId::unspecified(),
+            }))],
+        });
+
+        let t1 = TokenStream::from_str("(a)").unwrap();
+        assert_eq!(t1.token_trees.len(), 1);
+        assert_eq!(t1.token_trees[0], subtree_paren_a);
+
+        let t2 = TokenStream::from_str("(a);").unwrap();
+        assert_eq!(t2.token_trees.len(), 2);
+        assert_eq!(t2.token_trees[0], subtree_paren_a);
+    }
 }
diff --git a/crates/proc_macro_srv/src/tests/utils.rs b/crates/proc_macro_srv/src/tests/utils.rs
index 22813052d..0484c3af4 100644
--- a/crates/proc_macro_srv/src/tests/utils.rs
+++ b/crates/proc_macro_srv/src/tests/utils.rs
@@ -52,7 +52,7 @@ pub fn assert_expand(
     let expander = dylib::Expander::new(&path).unwrap();
     let fixture = parse_string(ra_fixture).unwrap();
 
-    let res = expander.expand(macro_name, &fixture.subtree, None).unwrap();
+    let res = expander.expand(macro_name, &fixture.into_subtree(), None).unwrap();
     assert_eq_text!(&expect.trim(), &format!("{:?}", res));
 }
 
diff --git a/crates/rust-analyzer/Cargo.toml b/crates/rust-analyzer/Cargo.toml
index 8789f0852..3130785cc 100644
--- a/crates/rust-analyzer/Cargo.toml
+++ b/crates/rust-analyzer/Cargo.toml
@@ -24,7 +24,7 @@ jod-thread = "0.1.0"
 log = "0.4.8"
 lsp-types = { version = "0.88.0", features = ["proposed"] }
 parking_lot = "0.11.0"
-xflags = "0.1.2"
+xflags = "0.2.1"
 oorandom = "11.1.2"
 rustc-hash = "1.1.0"
 serde = { version = "1.0.106", features = ["derive"] }
diff --git a/crates/rust-analyzer/src/bin/flags.rs b/crates/rust-analyzer/src/bin/flags.rs
index 244912d26..3a7caaf3f 100644
--- a/crates/rust-analyzer/src/bin/flags.rs
+++ b/crates/rust-analyzer/src/bin/flags.rs
@@ -6,7 +6,9 @@ use ide_ssr::{SsrPattern, SsrRule};
 use rust_analyzer::cli::{BenchWhat, Position, Verbosity};
 use vfs::AbsPathBuf;
 
-xflags::args_parser! {
+xflags::xflags! {
+    src "./src/bin/flags.rs"
+
     /// LSP server for the Rust programming language.
     cmd rust-analyzer {
         /// Verbosity level, can be repeated multiple times.
@@ -120,7 +122,7 @@ xflags::args_parser! {
 
 // generated start
 // The following code is generated by `xflags` macro.
-// Run `env XFLAGS_DUMP= cargo build` to regenerate.
+// Run `env UPDATE_XFLAGS=1 cargo build` to regenerate.
 #[derive(Debug)]
 pub struct RustAnalyzer {
     pub verbose: u32,
@@ -158,7 +160,7 @@ pub struct Parse {
 }
 
 #[derive(Debug)]
-pub struct Symbols {}
+pub struct Symbols;
 
 #[derive(Debug)]
 pub struct Highlight {
@@ -211,14 +213,13 @@ pub struct Search {
 }
 
 #[derive(Debug)]
-pub struct ProcMacro {}
+pub struct ProcMacro;
 
 impl RustAnalyzer {
-    pub const HELP: &'static str = Self::_HELP;
+    pub const HELP: &'static str = Self::HELP_;
 
     pub fn from_env() -> xflags::Result<Self> {
-        let mut p = xflags::rt::Parser::new_from_env();
-        Self::_parse(&mut p)
+        Self::from_env_()
     }
 }
 // generated end