6 files changed, 95 insertions, 120 deletions

diff --git a/crates/ra_proc_macro_srv/src/cli.rs b/crates/ra_proc_macro_srv/src/cli.rs
index c771f2b38..5f1f3ba3c 100644
--- a/crates/ra_proc_macro_srv/src/cli.rs
+++ b/crates/ra_proc_macro_srv/src/cli.rs
@@ -2,55 +2,43 @@
 
 use crate::{expand_task, list_macros};
 use ra_proc_macro::msg::{self, Message};
-
 use std::io;
 
-fn read_request() -> Result<Option<msg::Request>, io::Error> {
-    let stdin = io::stdin();
-    let mut stdin = stdin.lock();
-    msg::Request::read(&mut stdin)
-}
-
-fn write_response(res: Result<msg::Response, String>) -> Result<(), io::Error> {
-    let msg: msg::Response = match res {
-        Ok(res) => res,
-        Err(err) => msg::Response::Error(msg::ResponseError {
-            code: msg::ErrorCode::ExpansionError,
-            message: err,
-        }),
-    };
-
-    let stdout = io::stdout();
-    let mut stdout = stdout.lock();
-    msg.write(&mut stdout)
-}
-
 pub fn run() {
     loop {
         let req = match read_request() {
             Err(err) => {
-                eprintln!("Read message error on ra_proc_macro_srv: {}", err.to_string());
+                eprintln!("Read message error on ra_proc_macro_srv: {}", err);
                 continue;
             }
             Ok(None) => continue,
             Ok(Some(req)) => req,
         };
 
-        match req {
-            msg::Request::ListMacro(task) => {
-                if let Err(err) =
-                    write_response(list_macros(&task).map(|it| msg::Response::ListMacro(it)))
-                {
-                    eprintln!("Write message error on list macro: {}", err);
-                }
-            }
+        let res = match req {
+            msg::Request::ListMacro(task) => Ok(msg::Response::ListMacro(list_macros(&task))),
             msg::Request::ExpansionMacro(task) => {
-                if let Err(err) =
-                    write_response(expand_task(&task).map(|it| msg::Response::ExpansionMacro(it)))
-                {
-                    eprintln!("Write message error on expansion macro: {}", err);
-                }
+                expand_task(&task).map(msg::Response::ExpansionMacro)
             }
+        };
+
+        let msg = res.unwrap_or_else(|err| {
+            msg::Response::Error(msg::ResponseError {
+                code: msg::ErrorCode::ExpansionError,
+                message: err,
+            })
+        });
+
+        if let Err(err) = write_response(msg) {
+            eprintln!("Write message error: {}", err);
         }
     }
 }
+
+fn read_request() -> io::Result<Option<msg::Request>> {
+    msg::Request::read(&mut io::stdin().lock())
+}
+
+fn write_response(msg: msg::Response) -> io::Result<()> {
+    msg.write(&mut io::stdout().lock())
+}
diff --git a/crates/ra_proc_macro_srv/src/dylib.rs b/crates/ra_proc_macro_srv/src/dylib.rs
index 16bd7466e..d202eb0fd 100644
--- a/crates/ra_proc_macro_srv/src/dylib.rs
+++ b/crates/ra_proc_macro_srv/src/dylib.rs
@@ -9,43 +9,37 @@ use libloading::Library;
 use memmap::Mmap;
 use ra_proc_macro::ProcMacroKind;
 
-use std::io::Error as IoError;
-use std::io::ErrorKind as IoErrorKind;
+use std::io;
 
 const NEW_REGISTRAR_SYMBOL: &str = "_rustc_proc_macro_decls_";
 
-fn invalid_data_err(e: impl Into<Box<dyn std::error::Error + Send + Sync>>) -> IoError {
-    IoError::new(IoErrorKind::InvalidData, e)
+fn invalid_data_err(e: impl Into<Box<dyn std::error::Error + Send + Sync>>) -> io::Error {
+    io::Error::new(io::ErrorKind::InvalidData, e)
 }
 
 fn is_derive_registrar_symbol(symbol: &str) -> bool {
     symbol.contains(NEW_REGISTRAR_SYMBOL)
 }
 
-fn find_registrar_symbol(file: &Path) -> Result<Option<String>, IoError> {
+fn find_registrar_symbol(file: &Path) -> io::Result<Option<String>> {
     let file = File::open(file)?;
     let buffer = unsafe { Mmap::map(&file)? };
     let object = Object::parse(&buffer).map_err(invalid_data_err)?;
 
-    match object {
+    let name = match object {
         Object::Elf(elf) => {
             let symbols = elf.dynstrtab.to_vec().map_err(invalid_data_err)?;
-            let name =
-                symbols.iter().find(|s| is_derive_registrar_symbol(s)).map(|s| s.to_string());
-            Ok(name)
-        }
-        Object::PE(pe) => {
-            let name = pe
-                .exports
-                .iter()
-                .flat_map(|s| s.name)
-                .find(|s| is_derive_registrar_symbol(s))
-                .map(|s| s.to_string());
-            Ok(name)
+            symbols.into_iter().find(|s| is_derive_registrar_symbol(s)).map(&str::to_owned)
         }
+        Object::PE(pe) => pe
+            .exports
+            .iter()
+            .flat_map(|s| s.name)
+            .find(|s| is_derive_registrar_symbol(s))
+            .map(&str::to_owned),
         Object::Mach(Mach::Binary(binary)) => {
             let exports = binary.exports().map_err(invalid_data_err)?;
-            let name = exports
+            exports
                 .iter()
                 .map(|s| {
                     // In macos doc:
@@ -59,11 +53,11 @@ fn find_registrar_symbol(file: &Path) -> Result<Option<String>, IoError> {
                     }
                 })
                 .find(|s| is_derive_registrar_symbol(s))
-                .map(|s| s.to_string());
-            Ok(name)
+                .map(&str::to_owned)
         }
-        _ => Ok(None),
-    }
+        _ => return Ok(None),
+    };
+    return Ok(name);
 }
 
 /// Loads dynamic library in platform dependent manner.
@@ -93,15 +87,16 @@ fn load_library(file: &Path) -> Result<Library, libloading::Error> {
 }
 
 struct ProcMacroLibraryLibloading {
-    // Hold the dylib to prevent it for unloadeding
+    // Hold the dylib to prevent it from unloading
     _lib: Library,
     exported_macros: Vec<bridge::client::ProcMacro>,
 }
 
 impl ProcMacroLibraryLibloading {
-    fn open(file: &Path) -> Result<Self, IoError> {
-        let symbol_name = find_registrar_symbol(file)?
-            .ok_or(invalid_data_err(format!("Cannot find registrar symbol in file {:?}", file)))?;
+    fn open(file: &Path) -> io::Result<Self> {
+        let symbol_name = find_registrar_symbol(file)?.ok_or_else(|| {
+            invalid_data_err(format!("Cannot find registrar symbol in file {}", file.display()))
+        })?;
 
         let lib = load_library(file).map_err(invalid_data_err)?;
         let exported_macros = {
@@ -121,18 +116,16 @@ pub struct Expander {
 }
 
 impl Expander {
-    pub fn new<P: AsRef<Path>>(lib: &P) -> Result<Expander, String> {
-        let mut libs = vec![];
-        /* Some libraries for dynamic loading require canonicalized path (even when it is
-        already absolute
-        */
-        let lib =
-            lib.as_ref().canonicalize().expect(&format!("Cannot canonicalize {:?}", lib.as_ref()));
+    pub fn new(lib: &Path) -> Result<Expander, String> {
+        // Some libraries for dynamic loading require canonicalized path even when it is
+        // already absolute
+        let lib = lib
+            .canonicalize()
+            .unwrap_or_else(|err| panic!("Cannot canonicalize {}: {:?}", lib.display(), err));
 
         let library = ProcMacroLibraryImpl::open(&lib).map_err(|e| e.to_string())?;
-        libs.push(library);
 
-        Ok(Expander { libs })
+        Ok(Expander { libs: vec![library] })
     }
 
     pub fn expand(
@@ -176,7 +169,6 @@ impl Expander {
                             parsed_attributes,
                             parsed_body,
                         );
-
                         return res.map(|it| it.subtree);
                     }
                     _ => continue,
@@ -187,26 +179,21 @@ impl Expander {
         Err(bridge::PanicMessage::String("Nothing to expand".to_string()))
     }
 
-    pub fn list_macros(&self) -> Result<Vec<(String, ProcMacroKind)>, bridge::PanicMessage> {
-        let mut result = vec![];
-
-        for lib in &self.libs {
-            for proc_macro in &lib.exported_macros {
-                let res = match proc_macro {
-                    bridge::client::ProcMacro::CustomDerive { trait_name, .. } => {
-                        (trait_name.to_string(), ProcMacroKind::CustomDerive)
-                    }
-                    bridge::client::ProcMacro::Bang { name, .. } => {
-                        (name.to_string(), ProcMacroKind::FuncLike)
-                    }
-                    bridge::client::ProcMacro::Attr { name, .. } => {
-                        (name.to_string(), ProcMacroKind::Attr)
-                    }
-                };
-                result.push(res);
-            }
-        }
-
-        Ok(result)
+    pub fn list_macros(&self) -> Vec<(String, ProcMacroKind)> {
+        self.libs
+            .iter()
+            .flat_map(|it| &it.exported_macros)
+            .map(|proc_macro| match proc_macro {
+                bridge::client::ProcMacro::CustomDerive { trait_name, .. } => {
+                    (trait_name.to_string(), ProcMacroKind::CustomDerive)
+                }
+                bridge::client::ProcMacro::Bang { name, .. } => {
+                    (name.to_string(), ProcMacroKind::FuncLike)
+                }
+                bridge::client::ProcMacro::Attr { name, .. } => {
+                    (name.to_string(), ProcMacroKind::Attr)
+                }
+            })
+            .collect()
     }
 }
diff --git a/crates/ra_proc_macro_srv/src/lib.rs b/crates/ra_proc_macro_srv/src/lib.rs
index c62b0ed89..3aca859db 100644
--- a/crates/ra_proc_macro_srv/src/lib.rs
+++ b/crates/ra_proc_macro_srv/src/lib.rs
@@ -3,10 +3,10 @@
 //! This library is able to call compiled Rust custom derive dynamic libraries on arbitrary code.
 //! The general idea here is based on https://github.com/fedochet/rust-proc-macro-expander.
 //!
-//! But we change some several design for fitting RA needs:
+//! But we adapt it to better fit RA needs:
 //!
-//! * We use `ra_tt` for proc-macro `TokenStream` server, it is easy to manipute and interact with
-//!   RA then proc-macro2 token stream.
+//! * We use `ra_tt` for proc-macro `TokenStream` server, it is easier to manipulate and interact with
+//!   RA than `proc-macro2` token stream.
 //! * By **copying** the whole rustc `lib_proc_macro` code, we are able to build this with `stable`
 //!   rustc rather than `unstable`. (Although in gerenal ABI compatibility is still an issue)
 
@@ -21,36 +21,28 @@ mod dylib;
 
 use proc_macro::bridge::client::TokenStream;
 use ra_proc_macro::{ExpansionResult, ExpansionTask, ListMacrosResult, ListMacrosTask};
+use std::path::Path;
 
 pub(crate) fn expand_task(task: &ExpansionTask) -> Result<ExpansionResult, String> {
-    let expander = dylib::Expander::new(&task.lib)
-        .expect(&format!("Cannot expand with provided libraries: ${:?}", &task.lib));
+    let expander = create_expander(&task.lib);
 
     match expander.expand(&task.macro_name, &task.macro_body, task.attributes.as_ref()) {
         Ok(expansion) => Ok(ExpansionResult { expansion }),
         Err(msg) => {
-            let reason = format!(
-                "Cannot perform expansion for {}: error {:?}!",
-                &task.macro_name,
-                msg.as_str()
-            );
-            Err(reason)
+            Err(format!("Cannot perform expansion for {}: error {:?}", &task.macro_name, msg))
         }
     }
 }
 
-pub(crate) fn list_macros(task: &ListMacrosTask) -> Result<ListMacrosResult, String> {
-    let expander = dylib::Expander::new(&task.lib)
-        .expect(&format!("Cannot expand with provided libraries: ${:?}", &task.lib));
+pub(crate) fn list_macros(task: &ListMacrosTask) -> ListMacrosResult {
+    let expander = create_expander(&task.lib);
 
-    match expander.list_macros() {
-        Ok(macros) => Ok(ListMacrosResult { macros }),
-        Err(msg) => {
-            let reason =
-                format!("Cannot perform expansion for {:?}: error {:?}!", &task.lib, msg.as_str());
-            Err(reason)
-        }
-    }
+    ListMacrosResult { macros: expander.list_macros() }
+}
+
+fn create_expander(lib: &Path) -> dylib::Expander {
+    dylib::Expander::new(lib)
+        .unwrap_or_else(|err| panic!("Cannot create expander for {}: {:?}", lib.display(), err))
 }
 
 pub mod cli;
diff --git a/crates/ra_proc_macro_srv/src/rustc_server.rs b/crates/ra_proc_macro_srv/src/rustc_server.rs
index ec0d35692..f481d70b2 100644
--- a/crates/ra_proc_macro_srv/src/rustc_server.rs
+++ b/crates/ra_proc_macro_srv/src/rustc_server.rs
@@ -6,7 +6,7 @@
 //! The original idea from fedochet is using proc-macro2 as backend,
 //! we use ra_tt instead for better intergation with RA.
 //!
-//! FIXME: No span and source file informatin is implemented yet
+//! FIXME: No span and source file information is implemented yet
 
 use crate::proc_macro::bridge::{self, server};
 use ra_tt as tt;
@@ -76,7 +76,16 @@ impl Extend<TokenTree> for TokenStream {
 impl Extend<TokenStream> for TokenStream {
     fn extend<I: IntoIterator<Item = TokenStream>>(&mut self, streams: I) {
         for item in streams {
-            self.subtree.token_trees.extend(&mut item.into_iter())
+            for tkn in item {
+                match tkn {
+                    tt::TokenTree::Subtree(subtree) if subtree.delimiter.is_none() => {
+                        self.subtree.token_trees.extend(subtree.token_trees);
+                    }
+                    _ => {
+                        self.subtree.token_trees.push(tkn);
+                    }
+                }
+            }
         }
     }
 }
diff --git a/crates/ra_proc_macro_srv/src/tests/fixtures/test_serialize_proc_macro.txt b/crates/ra_proc_macro_srv/src/tests/fixtures/test_serialize_proc_macro.txt
index 24507d98d..1f5d940fa 100644
--- a/crates/ra_proc_macro_srv/src/tests/fixtures/test_serialize_proc_macro.txt
+++ b/crates/ra_proc_macro_srv/src/tests/fixtures/test_serialize_proc_macro.txt
@@ -25,8 +25,7 @@ SUBTREE $
       SUBTREE () 4294967295
         IDENT   feature 4294967295
         PUNCH   = [alone] 4294967295
-        SUBTREE $
-          LITERAL "cargo-clippy" 0
+        LITERAL "cargo-clippy" 0
         PUNCH   , [alone] 4294967295
         IDENT   allow 4294967295
         SUBTREE () 4294967295
diff --git a/crates/ra_proc_macro_srv/src/tests/utils.rs b/crates/ra_proc_macro_srv/src/tests/utils.rs
index 1ee409449..2139ec7a4 100644
--- a/crates/ra_proc_macro_srv/src/tests/utils.rs
+++ b/crates/ra_proc_macro_srv/src/tests/utils.rs
@@ -60,6 +60,6 @@ pub fn list(crate_name: &str, version: &str) -> Vec<String> {
     let path = fixtures::dylib_path(crate_name, version);
     let task = ListMacrosTask { lib: path };
 
-    let res = list_macros(&task).unwrap();
+    let res = list_macros(&task);
     res.macros.into_iter().map(|(name, kind)| format!("{} [{:?}]", name, kind)).collect()
 }