92 files changed, 3162 insertions, 3095 deletions

diff --git a/crates/expect/Cargo.toml b/crates/expect/Cargo.toml
new file mode 100644
index 000000000..caee43106
--- /dev/null
+++ b/crates/expect/Cargo.toml
@@ -0,0 +1,10 @@
+[package]
+name = "expect"
+version = "0.1.0"
+authors = ["rust-analyzer developers"]
+edition = "2018"
+
+[dependencies]
+once_cell = "1"
+difference = "2"
+stdx = { path = "../stdx" }
diff --git a/crates/expect/src/lib.rs b/crates/expect/src/lib.rs
new file mode 100644
index 000000000..dd7b96aab
--- /dev/null
+++ b/crates/expect/src/lib.rs
@@ -0,0 +1,293 @@
+//! Snapshot testing library, see
+//! https://github.com/rust-analyzer/rust-analyzer/pull/5101
+use std::{
+    collections::HashMap,
+    env, fmt, fs,
+    ops::Range,
+    panic,
+    path::{Path, PathBuf},
+    sync::Mutex,
+};
+
+use difference::Changeset;
+use once_cell::sync::Lazy;
+use stdx::{lines_with_ends, trim_indent};
+
+const HELP: &str = "
+You can update all `expect![[]]` tests by:
+
+    env UPDATE_EXPECT=1 cargo test
+
+To update a single test, place the cursor on `expect` token and use `run` feature of rust-analyzer.
+";
+
+fn update_expect() -> bool {
+    env::var("UPDATE_EXPECT").is_ok()
+}
+
+/// expect![[""]]
+#[macro_export]
+macro_rules! expect {
+    [[$lit:literal]] => {$crate::Expect {
+        file: file!(),
+        line: line!(),
+        column: column!(),
+        data: $lit,
+    }};
+    [[]] => { $crate::expect![[""]] };
+}
+
+#[derive(Debug)]
+pub struct Expect {
+    pub file: &'static str,
+    pub line: u32,
+    pub column: u32,
+    pub data: &'static str,
+}
+
+impl Expect {
+    pub fn assert_eq(&self, actual: &str) {
+        let trimmed = self.trimmed();
+        if &trimmed == actual {
+            return;
+        }
+        Runtime::fail(self, &trimmed, actual);
+    }
+    pub fn assert_debug_eq(&self, actual: &impl fmt::Debug) {
+        let actual = format!("{:#?}\n", actual);
+        self.assert_eq(&actual)
+    }
+
+    fn trimmed(&self) -> String {
+        if !self.data.contains('\n') {
+            return self.data.to_string();
+        }
+        trim_indent(self.data)
+    }
+
+    fn locate(&self, file: &str) -> Location {
+        let mut target_line = None;
+        let mut line_start = 0;
+        for (i, line) in lines_with_ends(file).enumerate() {
+            if i == self.line as usize - 1 {
+                let pat = "expect![[";
+                let offset = line.find(pat).unwrap();
+                let literal_start = line_start + offset + pat.len();
+                let indent = line.chars().take_while(|&it| it == ' ').count();
+                target_line = Some((literal_start, indent));
+                break;
+            }
+            line_start += line.len();
+        }
+        let (literal_start, line_indent) = target_line.unwrap();
+        let literal_length =
+            file[literal_start..].find("]]").expect("Couldn't find matching `]]` for `expect![[`.");
+        let literal_range = literal_start..literal_start + literal_length;
+        Location { line_indent, literal_range }
+    }
+}
+
+#[derive(Default)]
+struct Runtime {
+    help_printed: bool,
+    per_file: HashMap<&'static str, FileRuntime>,
+}
+static RT: Lazy<Mutex<Runtime>> = Lazy::new(Default::default);
+
+impl Runtime {
+    fn fail(expect: &Expect, expected: &str, actual: &str) {
+        let mut rt = RT.lock().unwrap_or_else(|poisoned| poisoned.into_inner());
+        let mut updated = "";
+        if update_expect() {
+            updated = " (updated)";
+            rt.per_file
+                .entry(expect.file)
+                .or_insert_with(|| FileRuntime::new(expect))
+                .update(expect, actual);
+        }
+        let print_help = !rt.help_printed && !update_expect();
+        rt.help_printed = true;
+
+        let help = if print_help { HELP } else { "" };
+
+        let diff = Changeset::new(actual, expected, "\n");
+
+        println!(
+            "\n
+\x1b[1m\x1b[91merror\x1b[97m: expect test failed\x1b[0m{}
+   \x1b[1m\x1b[34m-->\x1b[0m {}:{}:{}
+{}
+\x1b[1mExpect\x1b[0m:
+----
+{}
+----
+
+\x1b[1mActual\x1b[0m:
+----
+{}
+----
+
+\x1b[1mDiff\x1b[0m:
+----
+{}
+----
+",
+            updated, expect.file, expect.line, expect.column, help, expected, actual, diff
+        );
+        // Use resume_unwind instead of panic!() to prevent a backtrace, which is unnecessary noise.
+        panic::resume_unwind(Box::new(()));
+    }
+}
+
+struct FileRuntime {
+    path: PathBuf,
+    original_text: String,
+    patchwork: Patchwork,
+}
+
+impl FileRuntime {
+    fn new(expect: &Expect) -> FileRuntime {
+        let path = workspace_root().join(expect.file);
+        let original_text = fs::read_to_string(&path).unwrap();
+        let patchwork = Patchwork::new(original_text.clone());
+        FileRuntime { path, original_text, patchwork }
+    }
+    fn update(&mut self, expect: &Expect, actual: &str) {
+        let loc = expect.locate(&self.original_text);
+        let patch = format_patch(loc.line_indent.clone(), actual);
+        self.patchwork.patch(loc.literal_range, &patch);
+        fs::write(&self.path, &self.patchwork.text).unwrap()
+    }
+}
+
+#[derive(Debug)]
+struct Location {
+    line_indent: usize,
+    literal_range: Range<usize>,
+}
+
+#[derive(Debug)]
+struct Patchwork {
+    text: String,
+    indels: Vec<(Range<usize>, usize)>,
+}
+
+impl Patchwork {
+    fn new(text: String) -> Patchwork {
+        Patchwork { text, indels: Vec::new() }
+    }
+    fn patch(&mut self, mut range: Range<usize>, patch: &str) {
+        self.indels.push((range.clone(), patch.len()));
+        self.indels.sort_by_key(|(delete, _insert)| delete.start);
+
+        let (delete, insert) = self
+            .indels
+            .iter()
+            .take_while(|(delete, _)| delete.start < range.start)
+            .map(|(delete, insert)| (delete.end - delete.start, insert))
+            .fold((0usize, 0usize), |(x1, y1), (x2, y2)| (x1 + x2, y1 + y2));
+
+        for pos in &mut [&mut range.start, &mut range.end] {
+            **pos -= delete;
+            **pos += insert;
+        }
+
+        self.text.replace_range(range, &patch);
+    }
+}
+
+fn format_patch(line_indent: usize, patch: &str) -> String {
+    let mut max_hashes = 0;
+    let mut cur_hashes = 0;
+    for byte in patch.bytes() {
+        if byte != b'#' {
+            cur_hashes = 0;
+            continue;
+        }
+        cur_hashes += 1;
+        max_hashes = max_hashes.max(cur_hashes);
+    }
+    let hashes = &"#".repeat(max_hashes + 1);
+    let indent = &" ".repeat(line_indent);
+    let is_multiline = patch.contains('\n');
+
+    let mut buf = String::new();
+    buf.push('r');
+    buf.push_str(hashes);
+    buf.push('"');
+    if is_multiline {
+        buf.push('\n');
+    }
+    let mut final_newline = false;
+    for line in lines_with_ends(patch) {
+        if is_multiline {
+            buf.push_str(indent);
+            buf.push_str("    ");
+        }
+        buf.push_str(line);
+        final_newline = line.ends_with('\n');
+    }
+    if final_newline {
+        buf.push_str(indent);
+    }
+    buf.push('"');
+    buf.push_str(hashes);
+    buf
+}
+
+fn workspace_root() -> PathBuf {
+    Path::new(
+        &env::var("CARGO_MANIFEST_DIR").unwrap_or_else(|_| env!("CARGO_MANIFEST_DIR").to_owned()),
+    )
+    .ancestors()
+    .nth(2)
+    .unwrap()
+    .to_path_buf()
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn test_format_patch() {
+        let patch = format_patch(0, "hello\nworld\n");
+        expect![[r##"
+            r#"
+                hello
+                world
+            "#"##]]
+        .assert_eq(&patch);
+
+        let patch = format_patch(4, "single line");
+        expect![[r##"r#"single line"#"##]].assert_eq(&patch);
+    }
+
+    #[test]
+    fn test_patchwork() {
+        let mut patchwork = Patchwork::new("one two three".to_string());
+        patchwork.patch(4..7, "zwei");
+        patchwork.patch(0..3, "один");
+        patchwork.patch(8..13, "3");
+        expect![[r#"
+            Patchwork {
+                text: "один zwei 3",
+                indels: [
+                    (
+                        0..3,
+                        8,
+                    ),
+                    (
+                        4..7,
+                        4,
+                    ),
+                    (
+                        8..13,
+                        1,
+                    ),
+                ],
+            }
+        "#]]
+        .assert_debug_eq(&patchwork);
+    }
+}
diff --git a/crates/flycheck/src/lib.rs b/crates/flycheck/src/lib.rs
index 92ec4f92e..1023d3040 100644
--- a/crates/flycheck/src/lib.rs
+++ b/crates/flycheck/src/lib.rs
@@ -5,8 +5,9 @@
 use std::{
     fmt,
     io::{self, BufReader},
+    ops,
     path::PathBuf,
-    process::{Command, Stdio},
+    process::{self, Command, Stdio},
     time::Duration,
 };
 
@@ -49,8 +50,8 @@ impl fmt::Display for FlycheckConfig {
 #[derive(Debug)]
 pub struct FlycheckHandle {
     // XXX: drop order is significant
-    cmd_send: Sender<Restart>,
-    handle: jod_thread::JoinHandle,
+    sender: Sender<Restart>,
+    thread: jod_thread::JoinHandle,
 }
 
 impl FlycheckHandle {
@@ -59,16 +60,15 @@ impl FlycheckHandle {
         config: FlycheckConfig,
         workspace_root: PathBuf,
     ) -> FlycheckHandle {
-        let (cmd_send, cmd_recv) = unbounded::<Restart>();
-        let handle = jod_thread::spawn(move || {
-            FlycheckActor::new(sender, config, workspace_root).run(cmd_recv);
-        });
-        FlycheckHandle { cmd_send, handle }
+        let actor = FlycheckActor::new(sender, config, workspace_root);
+        let (sender, receiver) = unbounded::<Restart>();
+        let thread = jod_thread::spawn(move || actor.run(receiver));
+        FlycheckHandle { sender, thread }
     }
 
     /// Schedule a re-start of the cargo check worker.
     pub fn update(&self) {
-        self.cmd_send.send(Restart).unwrap();
+        self.sender.send(Restart).unwrap();
     }
 }
 
@@ -85,7 +85,7 @@ pub enum Message {
 pub enum Progress {
     DidStart,
     DidCheckCrate(String),
-    DidFinish,
+    DidFinish(io::Result<()>),
     DidCancel,
 }
 
@@ -100,8 +100,7 @@ struct FlycheckActor {
     /// doesn't provide a way to read sub-process output without blocking, so we
     /// have to wrap sub-processes output handling in a thread and pass messages
     /// back over a channel.
-    // XXX: drop order is significant
-    check_process: Option<(Receiver<cargo_metadata::Message>, jod_thread::JoinHandle)>,
+    cargo_handle: Option<CargoHandle>,
 }
 
 enum Event {
@@ -115,29 +114,36 @@ impl FlycheckActor {
         config: FlycheckConfig,
         workspace_root: PathBuf,
     ) -> FlycheckActor {
-        FlycheckActor { sender, config, workspace_root, check_process: None }
+        FlycheckActor { sender, config, workspace_root, cargo_handle: None }
     }
     fn next_event(&self, inbox: &Receiver<Restart>) -> Option<Event> {
-        let check_chan = self.check_process.as_ref().map(|(chan, _thread)| chan);
+        let check_chan = self.cargo_handle.as_ref().map(|cargo| &cargo.receiver);
         select! {
             recv(inbox) -> msg => msg.ok().map(Event::Restart),
             recv(check_chan.unwrap_or(&never())) -> msg => Some(Event::CheckEvent(msg.ok())),
         }
     }
-    fn run(&mut self, inbox: Receiver<Restart>) {
+    fn run(mut self, inbox: Receiver<Restart>) {
         while let Some(event) = self.next_event(&inbox) {
             match event {
                 Event::Restart(Restart) => {
                     while let Ok(Restart) = inbox.recv_timeout(Duration::from_millis(50)) {}
+
                     self.cancel_check_process();
-                    self.check_process = Some(self.start_check_process());
-                    self.send(Message::Progress(Progress::DidStart));
+
+                    let mut command = self.check_command();
+                    command.stdout(Stdio::piped()).stderr(Stdio::null()).stdin(Stdio::null());
+                    if let Ok(child) = command.spawn().map(JodChild) {
+                        self.cargo_handle = Some(CargoHandle::spawn(child));
+                        self.send(Message::Progress(Progress::DidStart));
+                    }
                 }
                 Event::CheckEvent(None) => {
                     // Watcher finished, replace it with a never channel to
                     // avoid busy-waiting.
-                    assert!(self.check_process.take().is_some());
-                    self.send(Message::Progress(Progress::DidFinish));
+                    let cargo_handle = self.cargo_handle.take().unwrap();
+                    let res = cargo_handle.join();
+                    self.send(Message::Progress(Progress::DidFinish(res)));
                 }
                 Event::CheckEvent(Some(message)) => match message {
                     cargo_metadata::Message::CompilerArtifact(msg) => {
@@ -162,11 +168,11 @@ impl FlycheckActor {
         self.cancel_check_process();
     }
     fn cancel_check_process(&mut self) {
-        if self.check_process.take().is_some() {
+        if self.cargo_handle.take().is_some() {
             self.send(Message::Progress(Progress::DidCancel));
         }
     }
-    fn start_check_process(&self) -> (Receiver<cargo_metadata::Message>, jod_thread::JoinHandle) {
+    fn check_command(&self) -> Command {
         let mut cmd = match &self.config {
             FlycheckConfig::CargoCommand {
                 command,
@@ -198,33 +204,7 @@ impl FlycheckActor {
             }
         };
         cmd.current_dir(&self.workspace_root);
-
-        let (message_send, message_recv) = unbounded();
-        let thread = jod_thread::spawn(move || {
-            // If we trigger an error here, we will do so in the loop instead,
-            // which will break out of the loop, and continue the shutdown
-            let res = run_cargo(cmd, &mut |message| {
-                // Skip certain kinds of messages to only spend time on what's useful
-                match &message {
-                    cargo_metadata::Message::CompilerArtifact(artifact) if artifact.fresh => {
-                        return true
-                    }
-                    cargo_metadata::Message::BuildScriptExecuted(_)
-                    | cargo_metadata::Message::Unknown => return true,
-                    _ => {}
-                }
-
-                // if the send channel was closed, we want to shutdown
-                message_send.send(message).is_ok()
-            });
-
-            if let Err(err) = res {
-                // FIXME: make the `message_send` to be `Sender<Result<CheckEvent, CargoError>>`
-                // to display user-caused misconfiguration errors instead of just logging them here
-                log::error!("Cargo watcher failed {:?}", err);
-            }
-        });
-        (message_recv, thread)
+        cmd
     }
 
     fn send(&self, check_task: Message) {
@@ -232,54 +212,104 @@ impl FlycheckActor {
     }
 }
 
-fn run_cargo(
-    mut command: Command,
-    on_message: &mut dyn FnMut(cargo_metadata::Message) -> bool,
-) -> io::Result<()> {
-    let mut child =
-        command.stdout(Stdio::piped()).stderr(Stdio::null()).stdin(Stdio::null()).spawn()?;
+struct CargoHandle {
+    child: JodChild,
+    #[allow(unused)]
+    thread: jod_thread::JoinHandle<io::Result<bool>>,
+    receiver: Receiver<cargo_metadata::Message>,
+}
 
-    // We manually read a line at a time, instead of using serde's
-    // stream deserializers, because the deserializer cannot recover
-    // from an error, resulting in it getting stuck, because we try to
-    // be resillient against failures.
-    //
-    // Because cargo only outputs one JSON object per line, we can
-    // simply skip a line if it doesn't parse, which just ignores any
-    // erroneus output.
-    let stdout = BufReader::new(child.stdout.take().unwrap());
-    let mut read_at_least_one_message = false;
-    for message in cargo_metadata::Message::parse_stream(stdout) {
-        let message = match message {
-            Ok(message) => message,
-            Err(err) => {
-                log::error!("Invalid json from cargo check, ignoring ({})", err);
-                continue;
-            }
-        };
+impl CargoHandle {
+    fn spawn(mut child: JodChild) -> CargoHandle {
+        let child_stdout = child.stdout.take().unwrap();
+        let (sender, receiver) = unbounded();
+        let actor = CargoActor::new(child_stdout, sender);
+        let thread = jod_thread::spawn(move || actor.run());
+        CargoHandle { child, thread, receiver }
+    }
+    fn join(mut self) -> io::Result<()> {
+        // It is okay to ignore the result, as it only errors if the process is already dead
+        let _ = self.child.kill();
+        let exit_status = self.child.wait()?;
+        let read_at_least_one_message = self.thread.join()?;
+        if !exit_status.success() && !read_at_least_one_message {
+            // FIXME: Read the stderr to display the reason, see `read2()` reference in PR comment:
+            // https://github.com/rust-analyzer/rust-analyzer/pull/3632#discussion_r395605298
+            return Err(io::Error::new(
+                io::ErrorKind::Other,
+                format!(
+                    "Cargo watcher failed,the command produced no valid metadata (exit code: {:?})",
+                    exit_status
+                ),
+            ));
+        }
+        Ok(())
+    }
+}
+
+struct CargoActor {
+    child_stdout: process::ChildStdout,
+    sender: Sender<cargo_metadata::Message>,
+}
+
+impl CargoActor {
+    fn new(
+        child_stdout: process::ChildStdout,
+        sender: Sender<cargo_metadata::Message>,
+    ) -> CargoActor {
+        CargoActor { child_stdout, sender }
+    }
+    fn run(self) -> io::Result<bool> {
+        // We manually read a line at a time, instead of using serde's
+        // stream deserializers, because the deserializer cannot recover
+        // from an error, resulting in it getting stuck, because we try to
+        // be resilient against failures.
+        //
+        // Because cargo only outputs one JSON object per line, we can
+        // simply skip a line if it doesn't parse, which just ignores any
+        // erroneus output.
+        let stdout = BufReader::new(self.child_stdout);
+        let mut read_at_least_one_message = false;
+        for message in cargo_metadata::Message::parse_stream(stdout) {
+            let message = match message {
+                Ok(message) => message,
+                Err(err) => {
+                    log::error!("Invalid json from cargo check, ignoring ({})", err);
+                    continue;
+                }
+            };
 
-        read_at_least_one_message = true;
+            read_at_least_one_message = true;
 
-        if !on_message(message) {
-            break;
+            // Skip certain kinds of messages to only spend time on what's useful
+            match &message {
+                cargo_metadata::Message::CompilerArtifact(artifact) if artifact.fresh => (),
+                cargo_metadata::Message::BuildScriptExecuted(_)
+                | cargo_metadata::Message::Unknown => (),
+                _ => self.sender.send(message).unwrap(),
+            }
         }
+        Ok(read_at_least_one_message)
     }
+}
 
-    // It is okay to ignore the result, as it only errors if the process is already dead
-    let _ = child.kill();
+struct JodChild(process::Child);
 
-    let exit_status = child.wait()?;
-    if !exit_status.success() && !read_at_least_one_message {
-        // FIXME: Read the stderr to display the reason, see `read2()` reference in PR comment:
-        // https://github.com/rust-analyzer/rust-analyzer/pull/3632#discussion_r395605298
-        return Err(io::Error::new(
-            io::ErrorKind::Other,
-            format!(
-                "the command produced no valid metadata (exit code: {:?}): {:?}",
-                exit_status, command
-            ),
-        ));
+impl ops::Deref for JodChild {
+    type Target = process::Child;
+    fn deref(&self) -> &process::Child {
+        &self.0
     }
+}
 
-    Ok(())
+impl ops::DerefMut for JodChild {
+    fn deref_mut(&mut self) -> &mut process::Child {
+        &mut self.0
+    }
+}
+
+impl Drop for JodChild {
+    fn drop(&mut self) {
+        let _ = self.0.kill();
+    }
 }
diff --git a/crates/ra_assists/src/assist_context.rs b/crates/ra_assists/src/assist_context.rs
index ee614de72..3640bb4d2 100644
--- a/crates/ra_assists/src/assist_context.rs
+++ b/crates/ra_assists/src/assist_context.rs
@@ -55,7 +55,6 @@ use crate::{
 pub(crate) struct AssistContext<'a> {
     pub(crate) config: &'a AssistConfig,
     pub(crate) sema: Semantics<'a, RootDatabase>,
-    pub(crate) db: &'a RootDatabase,
     pub(crate) frange: FileRange,
     source_file: SourceFile,
 }
@@ -67,8 +66,11 @@ impl<'a> AssistContext<'a> {
         frange: FileRange,
     ) -> AssistContext<'a> {
         let source_file = sema.parse(frange.file_id);
-        let db = sema.db;
-        AssistContext { config, sema, db, frange, source_file }
+        AssistContext { config, sema, frange, source_file }
+    }
+
+    pub(crate) fn db(&self) -> &RootDatabase {
+        self.sema.db
     }
 
     // NB, this ignores active selection.
diff --git a/crates/ra_assists/src/ast_transform.rs b/crates/ra_assists/src/ast_transform.rs
index 00fa95b6c..01adb834c 100644
--- a/crates/ra_assists/src/ast_transform.rs
+++ b/crates/ra_assists/src/ast_transform.rs
@@ -2,7 +2,6 @@
 use rustc_hash::FxHashMap;
 
 use hir::{HirDisplay, PathResolution, SemanticsScope};
-use ra_ide_db::RootDatabase;
 use ra_syntax::{
     algo::SyntaxRewriter,
     ast::{self, AstNode},
@@ -32,14 +31,14 @@ impl<'a> AstTransform<'a> for NullTransformer {
 }
 
 pub struct SubstituteTypeParams<'a> {
-    source_scope: &'a SemanticsScope<'a, RootDatabase>,
+    source_scope: &'a SemanticsScope<'a>,
     substs: FxHashMap<hir::TypeParam, ast::TypeRef>,
     previous: Box<dyn AstTransform<'a> + 'a>,
 }
 
 impl<'a> SubstituteTypeParams<'a> {
     pub fn for_trait_impl(
-        source_scope: &'a SemanticsScope<'a, RootDatabase>,
+        source_scope: &'a SemanticsScope<'a>,
         // FIXME: there's implicit invariant that `trait_` and  `source_scope` match...
         trait_: hir::Trait,
         impl_def: ast::ImplDef,
@@ -126,16 +125,13 @@ impl<'a> AstTransform<'a> for SubstituteTypeParams<'a> {
 }
 
 pub struct QualifyPaths<'a> {
-    target_scope: &'a SemanticsScope<'a, RootDatabase>,
-    source_scope: &'a SemanticsScope<'a, RootDatabase>,
+    target_scope: &'a SemanticsScope<'a>,
+    source_scope: &'a SemanticsScope<'a>,
     previous: Box<dyn AstTransform<'a> + 'a>,
 }
 
 impl<'a> QualifyPaths<'a> {
-    pub fn new(
-        target_scope: &'a SemanticsScope<'a, RootDatabase>,
-        source_scope: &'a SemanticsScope<'a, RootDatabase>,
-    ) -> Self {
+    pub fn new(target_scope: &'a SemanticsScope<'a>, source_scope: &'a SemanticsScope<'a>) -> Self {
         Self { target_scope, source_scope, previous: Box::new(NullTransformer) }
     }
 
@@ -156,7 +152,7 @@ impl<'a> QualifyPaths<'a> {
         let resolution = self.source_scope.resolve_hir_path(&hir_path?)?;
         match resolution {
             PathResolution::Def(def) => {
-                let found_path = from.find_use_path(self.source_scope.db, def)?;
+                let found_path = from.find_use_path(self.source_scope.db.upcast(), def)?;
                 let mut path = path_to_ast(found_path);
 
                 let type_args = p
diff --git a/crates/ra_assists/src/handlers/add_explicit_type.rs b/crates/ra_assists/src/handlers/add_explicit_type.rs
index 90b06a625..11df922a2 100644
--- a/crates/ra_assists/src/handlers/add_explicit_type.rs
+++ b/crates/ra_assists/src/handlers/add_explicit_type.rs
@@ -57,7 +57,7 @@ pub(crate) fn add_explicit_type(acc: &mut Assists, ctx: &AssistContext) -> Optio
         return None;
     }
 
-    let inferred_type = ty.display_source_code(ctx.db, module.into()).ok()?;
+    let inferred_type = ty.display_source_code(ctx.db(), module.into()).ok()?;
     acc.add(
         AssistId("add_explicit_type"),
         format!("Insert explicit type `{}`", inferred_type),
diff --git a/crates/ra_assists/src/handlers/add_function.rs b/crates/ra_assists/src/handlers/add_function.rs
index 1cfbd75aa..fc4e82309 100644
--- a/crates/ra_assists/src/handlers/add_function.rs
+++ b/crates/ra_assists/src/handlers/add_function.rs
@@ -117,7 +117,7 @@ impl FunctionBuilder {
         let mut file = ctx.frange.file_id;
         let target = match &target_module {
             Some(target_module) => {
-                let module_source = target_module.definition_source(ctx.db);
+                let module_source = target_module.definition_source(ctx.db());
                 let (in_file, target) = next_space_for_fn_in_module(ctx.sema.db, &module_source)?;
                 file = in_file;
                 target
@@ -269,7 +269,7 @@ fn fn_arg_type(
         return None;
     }
 
-    if let Ok(rendered) = ty.display_source_code(ctx.db, target_module.into()) {
+    if let Ok(rendered) = ty.display_source_code(ctx.db(), target_module.into()) {
         Some(rendered)
     } else {
         None
diff --git a/crates/ra_assists/src/handlers/add_missing_impl_members.rs b/crates/ra_assists/src/handlers/add_missing_impl_members.rs
index abacd4065..77e092f62 100644
--- a/crates/ra_assists/src/handlers/add_missing_impl_members.rs
+++ b/crates/ra_assists/src/handlers/add_missing_impl_members.rs
@@ -128,9 +128,9 @@ fn add_missing_impl_members_inner(
     let missing_items = get_missing_assoc_items(&ctx.sema, &impl_def)
         .iter()
         .map(|i| match i {
-            hir::AssocItem::Function(i) => ast::AssocItem::FnDef(i.source(ctx.db).value),
-            hir::AssocItem::TypeAlias(i) => ast::AssocItem::TypeAliasDef(i.source(ctx.db).value),
-            hir::AssocItem::Const(i) => ast::AssocItem::ConstDef(i.source(ctx.db).value),
+            hir::AssocItem::Function(i) => ast::AssocItem::FnDef(i.source(ctx.db()).value),
+            hir::AssocItem::TypeAlias(i) => ast::AssocItem::TypeAliasDef(i.source(ctx.db()).value),
+            hir::AssocItem::Const(i) => ast::AssocItem::ConstDef(i.source(ctx.db()).value),
         })
         .filter(|t| def_name(&t).is_some())
         .filter(|t| match t {
diff --git a/crates/ra_assists/src/handlers/add_new.rs b/crates/ra_assists/src/handlers/add_new.rs
index 837aa8377..e41b2aa06 100644
--- a/crates/ra_assists/src/handlers/add_new.rs
+++ b/crates/ra_assists/src/handlers/add_new.rs
@@ -122,7 +122,7 @@ fn generate_impl_text(strukt: &ast::StructDef, code: &str) -> String {
 // FIXME: change the new fn checking to a more semantic approach when that's more
 // viable (e.g. we process proc macros, etc)
 fn find_struct_impl(ctx: &AssistContext, strukt: &ast::StructDef) -> Option<Option<ast::ImplDef>> {
-    let db = ctx.db;
+    let db = ctx.db();
     let module = strukt.syntax().ancestors().find(|node| {
         ast::Module::can_cast(node.kind()) || ast::SourceFile::can_cast(node.kind())
     })?;
diff --git a/crates/ra_assists/src/handlers/auto_import.rs b/crates/ra_assists/src/handlers/auto_import.rs
index d1cafa7d9..e8060a491 100644
--- a/crates/ra_assists/src/handlers/auto_import.rs
+++ b/crates/ra_assists/src/handlers/auto_import.rs
@@ -36,7 +36,7 @@ use crate::{utils::insert_use_statement, AssistContext, AssistId, Assists, Group
 // ```
 pub(crate) fn auto_import(acc: &mut Assists, ctx: &AssistContext) -> Option<()> {
     let auto_import_assets = AutoImportAssets::new(&ctx)?;
-    let proposed_imports = auto_import_assets.search_for_imports(ctx.db);
+    let proposed_imports = auto_import_assets.search_for_imports(ctx.db());
     if proposed_imports.is_empty() {
         return None;
     }
diff --git a/crates/ra_assists/src/handlers/change_visibility.rs b/crates/ra_assists/src/handlers/change_visibility.rs
index c21d75be0..157c7b665 100644
--- a/crates/ra_assists/src/handlers/change_visibility.rs
+++ b/crates/ra_assists/src/handlers/change_visibility.rs
@@ -1,15 +1,12 @@
 use ra_syntax::{
     ast::{self, NameOwner, VisibilityOwner},
     AstNode,
-    SyntaxKind::{
-        ATTR, COMMENT, CONST_DEF, ENUM_DEF, FN_DEF, MODULE, STRUCT_DEF, TRAIT_DEF, VISIBILITY,
-        WHITESPACE,
-    },
-    SyntaxNode, TextSize, T,
+    SyntaxKind::{CONST_DEF, ENUM_DEF, FN_DEF, MODULE, STRUCT_DEF, TRAIT_DEF, VISIBILITY},
+    T,
 };
 use test_utils::mark;
 
-use crate::{AssistContext, AssistId, Assists};
+use crate::{utils::vis_offset, AssistContext, AssistId, Assists};
 
 // Assist: change_visibility
 //
@@ -30,9 +27,8 @@ pub(crate) fn change_visibility(acc: &mut Assists, ctx: &AssistContext) -> Optio
 }
 
 fn add_vis(acc: &mut Assists, ctx: &AssistContext) -> Option<()> {
-    let item_keyword = ctx.token_at_offset().find(|leaf| match leaf.kind() {
-        T![const] | T![fn] | T![mod] | T![struct] | T![enum] | T![trait] => true,
-        _ => false,
+    let item_keyword = ctx.token_at_offset().find(|leaf| {
+        matches!(leaf.kind(), T![const] | T![fn] | T![mod] | T![struct] | T![enum] | T![trait])
     });
 
     let (offset, target) = if let Some(keyword) = item_keyword {
@@ -71,17 +67,6 @@ fn add_vis(acc: &mut Assists, ctx: &AssistContext) -> Option<()> {
     })
 }
 
-fn vis_offset(node: &SyntaxNode) -> TextSize {
-    node.children_with_tokens()
-        .skip_while(|it| match it.kind() {
-            WHITESPACE | COMMENT | ATTR => true,
-            _ => false,
-        })
-        .next()
-        .map(|it| it.text_range().start())
-        .unwrap_or_else(|| node.text_range().start())
-}
-
 fn change_vis(acc: &mut Assists, vis: ast::Visibility) -> Option<()> {
     if vis.syntax().text() == "pub" {
         let target = vis.syntax().text_range();
diff --git a/crates/ra_assists/src/handlers/extract_struct_from_enum_variant.rs b/crates/ra_assists/src/handlers/extract_struct_from_enum_variant.rs
index 43b4584b4..bdf9d7ae2 100644
--- a/crates/ra_assists/src/handlers/extract_struct_from_enum_variant.rs
+++ b/crates/ra_assists/src/handlers/extract_struct_from_enum_variant.rs
@@ -37,15 +37,15 @@ pub(crate) fn extract_struct_from_enum_variant(
     };
     let variant_name = variant.name()?.to_string();
     let variant_hir = ctx.sema.to_def(&variant)?;
-    if existing_struct_def(ctx.db, &variant_name, &variant_hir) {
+    if existing_struct_def(ctx.db(), &variant_name, &variant_hir) {
         return None;
     }
     let enum_ast = variant.parent_enum();
     let visibility = enum_ast.visibility();
     let enum_hir = ctx.sema.to_def(&enum_ast)?;
-    let variant_hir_name = variant_hir.name(ctx.db);
+    let variant_hir_name = variant_hir.name(ctx.db());
     let enum_module_def = ModuleDef::from(enum_hir);
-    let current_module = enum_hir.module(ctx.db);
+    let current_module = enum_hir.module(ctx.db());
     let target = variant.syntax().text_range();
     acc.add(
         AssistId("extract_struct_from_enum_variant"),
@@ -53,7 +53,7 @@ pub(crate) fn extract_struct_from_enum_variant(
         target,
         |builder| {
             let definition = Definition::ModuleDef(ModuleDef::EnumVariant(variant_hir));
-            let res = definition.find_usages(&ctx.db, None);
+            let res = definition.find_usages(&ctx.db(), None);
             let start_offset = variant.parent_enum().syntax().text_range().start();
             let mut visited_modules_set = FxHashSet::default();
             visited_modules_set.insert(current_module);
@@ -101,7 +101,7 @@ fn insert_import(
     enum_module_def: &ModuleDef,
     variant_hir_name: &Name,
 ) -> Option<()> {
-    let db = ctx.db;
+    let db = ctx.db();
     let mod_path = module.find_use_path(db, enum_module_def.clone());
     if let Some(mut mod_path) = mod_path {
         mod_path.segments.pop();
diff --git a/crates/ra_assists/src/handlers/fill_match_arms.rs b/crates/ra_assists/src/handlers/fill_match_arms.rs
index 64270c86f..5b1235682 100644
--- a/crates/ra_assists/src/handlers/fill_match_arms.rs
+++ b/crates/ra_assists/src/handlers/fill_match_arms.rs
@@ -51,11 +51,11 @@ pub(crate) fn fill_match_arms(acc: &mut Assists, ctx: &AssistContext) -> Option<
     let module = ctx.sema.scope(expr.syntax()).module()?;
 
     let missing_arms: Vec<MatchArm> = if let Some(enum_def) = resolve_enum_def(&ctx.sema, &expr) {
-        let variants = enum_def.variants(ctx.db);
+        let variants = enum_def.variants(ctx.db());
 
         let mut variants = variants
             .into_iter()
-            .filter_map(|variant| build_pat(ctx.db, module, variant))
+            .filter_map(|variant| build_pat(ctx.db(), module, variant))
             .filter(|variant_pat| is_variant_missing(&mut arms, variant_pat))
             .map(|pat| make::match_arm(iter::once(pat), make::expr_empty_block()))
             .collect::<Vec<_>>();
@@ -84,11 +84,11 @@ pub(crate) fn fill_match_arms(acc: &mut Assists, ctx: &AssistContext) -> Option<
         // where each tuple represents a proposed match arm.
         enum_defs
             .into_iter()
-            .map(|enum_def| enum_def.variants(ctx.db))
+            .map(|enum_def| enum_def.variants(ctx.db()))
             .multi_cartesian_product()
             .map(|variants| {
                 let patterns =
-                    variants.into_iter().filter_map(|variant| build_pat(ctx.db, module, variant));
+                    variants.into_iter().filter_map(|variant| build_pat(ctx.db(), module, variant));
                 ast::Pat::from(make::tuple_pat(patterns))
             })
             .filter(|variant_pat| is_variant_missing(&mut arms, variant_pat))
diff --git a/crates/ra_assists/src/handlers/fix_visibility.rs b/crates/ra_assists/src/handlers/fix_visibility.rs
index 54601d1f3..c0f57c329 100644
--- a/crates/ra_assists/src/handlers/fix_visibility.rs
+++ b/crates/ra_assists/src/handlers/fix_visibility.rs
@@ -1,12 +1,8 @@
 use hir::{db::HirDatabase, HasSource, HasVisibility, PathResolution};
 use ra_db::FileId;
-use ra_syntax::{
-    ast, AstNode,
-    SyntaxKind::{ATTR, COMMENT, WHITESPACE},
-    SyntaxNode, TextRange, TextSize,
-};
+use ra_syntax::{ast, AstNode, TextRange, TextSize};
 
-use crate::{AssistContext, AssistId, Assists};
+use crate::{utils::vis_offset, AssistContext, AssistId, Assists};
 
 // FIXME: this really should be a fix for diagnostic, rather than an assist.
 
@@ -45,14 +41,14 @@ fn add_vis_to_referenced_module_def(acc: &mut Assists, ctx: &AssistContext) -> O
     };
 
     let current_module = ctx.sema.scope(&path.syntax()).module()?;
-    let target_module = def.module(ctx.db)?;
+    let target_module = def.module(ctx.db())?;
 
-    let vis = target_module.visibility_of(ctx.db, &def)?;
-    if vis.is_visible_from(ctx.db, current_module.into()) {
+    let vis = target_module.visibility_of(ctx.db(), &def)?;
+    if vis.is_visible_from(ctx.db(), current_module.into()) {
         return None;
     };
 
-    let (offset, target, target_file, target_name) = target_data_for_def(ctx.db, def)?;
+    let (offset, target, target_file, target_name) = target_data_for_def(ctx.db(), def)?;
 
     let missing_visibility =
         if current_module.krate() == target_module.krate() { "pub(crate)" } else { "pub" };
@@ -76,16 +72,16 @@ fn add_vis_to_referenced_record_field(acc: &mut Assists, ctx: &AssistContext) ->
     let (record_field_def, _) = ctx.sema.resolve_record_field(&record_field)?;
 
     let current_module = ctx.sema.scope(record_field.syntax()).module()?;
-    let visibility = record_field_def.visibility(ctx.db);
-    if visibility.is_visible_from(ctx.db, current_module.into()) {
+    let visibility = record_field_def.visibility(ctx.db());
+    if visibility.is_visible_from(ctx.db(), current_module.into()) {
         return None;
     }
 
-    let parent = record_field_def.parent_def(ctx.db);
-    let parent_name = parent.name(ctx.db);
-    let target_module = parent.module(ctx.db);
+    let parent = record_field_def.parent_def(ctx.db());
+    let parent_name = parent.name(ctx.db());
+    let target_module = parent.module(ctx.db());
 
-    let in_file_source = record_field_def.source(ctx.db);
+    let in_file_source = record_field_def.source(ctx.db());
     let (offset, target) = match in_file_source.value {
         hir::FieldSource::Named(it) => {
             let s = it.syntax();
@@ -99,9 +95,9 @@ fn add_vis_to_referenced_record_field(acc: &mut Assists, ctx: &AssistContext) ->
 
     let missing_visibility =
         if current_module.krate() == target_module.krate() { "pub(crate)" } else { "pub" };
-    let target_file = in_file_source.file_id.original_file(ctx.db);
+    let target_file = in_file_source.file_id.original_file(ctx.db());
 
-    let target_name = record_field_def.name(ctx.db);
+    let target_name = record_field_def.name(ctx.db());
     let assist_label =
         format!("Change visibility of {}.{} to {}", parent_name, target_name, missing_visibility);
 
@@ -177,17 +173,6 @@ fn target_data_for_def(
     Some((offset, target, target_file, target_name))
 }
 
-fn vis_offset(node: &SyntaxNode) -> TextSize {
-    node.children_with_tokens()
-        .skip_while(|it| match it.kind() {
-            WHITESPACE | COMMENT | ATTR => true,
-            _ => false,
-        })
-        .next()
-        .map(|it| it.text_range().start())
-        .unwrap_or_else(|| node.text_range().start())
-}
-
 #[cfg(test)]
 mod tests {
     use crate::tests::{check_assist, check_assist_not_applicable};
diff --git a/crates/ra_assists/src/handlers/inline_local_variable.rs b/crates/ra_assists/src/handlers/inline_local_variable.rs
index d26e68847..f4fb0056b 100644
--- a/crates/ra_assists/src/handlers/inline_local_variable.rs
+++ b/crates/ra_assists/src/handlers/inline_local_variable.rs
@@ -44,7 +44,7 @@ pub(crate) fn inline_local_variable(acc: &mut Assists, ctx: &AssistContext) -> O
 
     let def = ctx.sema.to_def(&bind_pat)?;
     let def = Definition::Local(def);
-    let refs = def.find_usages(ctx.db, None);
+    let refs = def.find_usages(ctx.db(), None);
     if refs.is_empty() {
         mark::hit!(test_not_applicable_if_variable_unused);
         return None;
diff --git a/crates/ra_assists/src/handlers/merge_match_arms.rs b/crates/ra_assists/src/handlers/merge_match_arms.rs
index ca04ec671..90ce66378 100644
--- a/crates/ra_assists/src/handlers/merge_match_arms.rs
+++ b/crates/ra_assists/src/handlers/merge_match_arms.rs
@@ -81,10 +81,7 @@ pub(crate) fn merge_match_arms(acc: &mut Assists, ctx: &AssistContext) -> Option
 }
 
 fn contains_placeholder(a: &ast::MatchArm) -> bool {
-    match a.pat() {
-        Some(ra_syntax::ast::Pat::PlaceholderPat(..)) => true,
-        _ => false,
-    }
+    matches!(a.pat(), Some(ast::Pat::PlaceholderPat(..)))
 }
 
 #[cfg(test)]
diff --git a/crates/ra_assists/src/handlers/reorder_fields.rs b/crates/ra_assists/src/handlers/reorder_fields.rs
index 897da2832..b8cf30e7f 100644
--- a/crates/ra_assists/src/handlers/reorder_fields.rs
+++ b/crates/ra_assists/src/handlers/reorder_fields.rs
@@ -1,7 +1,7 @@
-use std::collections::HashMap;
+use itertools::Itertools;
+use rustc_hash::FxHashMap;
 
 use hir::{Adt, ModuleDef, PathResolution, Semantics, Struct};
-use itertools::Itertools;
 use ra_ide_db::RootDatabase;
 use ra_syntax::{algo, ast, match_ast, AstNode, SyntaxKind, SyntaxKind::*, SyntaxNode};
 
@@ -87,13 +87,13 @@ fn struct_definition(path: &ast::Path, sema: &Semantics<RootDatabase>) -> Option
     }
 }
 
-fn compute_fields_ranks(path: &ast::Path, ctx: &AssistContext) -> Option<HashMap<String, usize>> {
+fn compute_fields_ranks(path: &ast::Path, ctx: &AssistContext) -> Option<FxHashMap<String, usize>> {
     Some(
         struct_definition(path, &ctx.sema)?
-            .fields(ctx.db)
+            .fields(ctx.db())
             .iter()
             .enumerate()
-            .map(|(idx, field)| (field.name(ctx.db).to_string(), idx))
+            .map(|(idx, field)| (field.name(ctx.db()).to_string(), idx))
             .collect(),
     )
 }
diff --git a/crates/ra_assists/src/utils.rs b/crates/ra_assists/src/utils.rs
index b7c45a619..02de902d6 100644
--- a/crates/ra_assists/src/utils.rs
+++ b/crates/ra_assists/src/utils.rs
@@ -7,7 +7,9 @@ use hir::{Adt, Crate, Enum, ScopeDef, Semantics, Trait, Type};
 use ra_ide_db::RootDatabase;
 use ra_syntax::{
     ast::{self, make, NameOwner},
-    AstNode, SyntaxNode, T,
+    AstNode,
+    SyntaxKind::*,
+    SyntaxNode, TextSize, T,
 };
 use rustc_hash::FxHashSet;
 
@@ -120,6 +122,13 @@ pub(crate) fn resolve_target_trait(
     }
 }
 
+pub(crate) fn vis_offset(node: &SyntaxNode) -> TextSize {
+    node.children_with_tokens()
+        .find(|it| !matches!(it.kind(), WHITESPACE | COMMENT | ATTR))
+        .map(|it| it.text_range().start())
+        .unwrap_or_else(|| node.text_range().start())
+}
+
 pub(crate) fn invert_boolean_expression(expr: ast::Expr) -> ast::Expr {
     if let Some(expr) = invert_special_case(&expr) {
         return expr;
diff --git a/crates/ra_db/src/fixture.rs b/crates/ra_db/src/fixture.rs
index 4f4fb4494..209713987 100644
--- a/crates/ra_db/src/fixture.rs
+++ b/crates/ra_db/src/fixture.rs
@@ -149,15 +149,17 @@ fn with_files(
             let crate_id = crate_graph.add_crate_root(
                 file_id,
                 meta.edition,
-                Some(CrateName::new(&krate).unwrap()),
+                Some(krate.clone()),
                 meta.cfg,
                 meta.env,
                 Default::default(),
             );
-            let prev = crates.insert(krate.clone(), crate_id);
+            let crate_name = CrateName::new(&krate).unwrap();
+            let prev = crates.insert(crate_name.clone(), crate_id);
             assert!(prev.is_none());
             for dep in meta.deps {
-                crate_deps.push((krate.clone(), dep))
+                let dep = CrateName::new(&dep).unwrap();
+                crate_deps.push((crate_name.clone(), dep))
             }
         } else if meta.path == "/main.rs" || meta.path == "/lib.rs" {
             assert!(default_crate_root.is_none());
diff --git a/crates/ra_db/src/input.rs b/crates/ra_db/src/input.rs
index 7f3660118..445a1ee48 100644
--- a/crates/ra_db/src/input.rs
+++ b/crates/ra_db/src/input.rs
@@ -67,7 +67,7 @@ pub struct CrateGraph {
 #[derive(Debug, Clone, Copy, PartialEq, Eq, PartialOrd, Ord, Hash)]
 pub struct CrateId(pub u32);
 
-#[derive(Debug, Clone, PartialEq, Eq)]
+#[derive(Debug, Clone, PartialEq, Eq, Hash)]
 pub struct CrateName(SmolStr);
 
 impl CrateName {
@@ -94,6 +94,13 @@ impl fmt::Display for CrateName {
     }
 }
 
+impl ops::Deref for CrateName {
+    type Target = str;
+    fn deref(&self) -> &Self::Target {
+        &*self.0
+    }
+}
+
 #[derive(Debug, Copy, Clone, PartialEq, Eq, Hash)]
 pub struct ProcMacroId(pub u32);
 
@@ -117,7 +124,7 @@ pub struct CrateData {
     /// The name to display to the end user.
     /// This actual crate name can be different in a particular dependent crate
     /// or may even be missing for some cases, such as a dummy crate for the code snippet.
-    pub display_name: Option<CrateName>,
+    pub display_name: Option<String>,
     pub cfg_options: CfgOptions,
     pub env: Env,
     pub dependencies: Vec<Dependency>,
@@ -138,7 +145,7 @@ pub struct Env {
 #[derive(Debug, Clone, PartialEq, Eq)]
 pub struct Dependency {
     pub crate_id: CrateId,
-    pub name: SmolStr,
+    pub name: CrateName,
 }
 
 impl CrateGraph {
@@ -146,7 +153,7 @@ impl CrateGraph {
         &mut self,
         file_id: FileId,
         edition: Edition,
-        display_name: Option<CrateName>,
+        display_name: Option<String>,
         cfg_options: CfgOptions,
         env: Env,
         proc_macro: Vec<(SmolStr, Arc<dyn ra_tt::TokenExpander>)>,
@@ -178,7 +185,7 @@ impl CrateGraph {
         if self.dfs_find(from, to, &mut FxHashSet::default()) {
             return Err(CyclicDependenciesError);
         }
-        self.arena.get_mut(&from).unwrap().add_dep(name.0, to);
+        self.arena.get_mut(&from).unwrap().add_dep(name, to);
         Ok(())
     }
 
@@ -247,7 +254,7 @@ impl CrateId {
 }
 
 impl CrateData {
-    fn add_dep(&mut self, name: SmolStr, crate_id: CrateId) {
+    fn add_dep(&mut self, name: CrateName, crate_id: CrateId) {
         self.dependencies.push(Dependency { name, crate_id })
     }
 }
@@ -429,7 +436,10 @@ mod tests {
             .is_ok());
         assert_eq!(
             graph[crate1].dependencies,
-            vec![Dependency { crate_id: crate2, name: "crate_name_with_dashes".into() }]
+            vec![Dependency {
+                crate_id: crate2,
+                name: CrateName::new("crate_name_with_dashes").unwrap()
+            }]
         );
     }
 }
diff --git a/crates/ra_db/src/lib.rs b/crates/ra_db/src/lib.rs
index 4a3ba57da..1ddacc1f6 100644
--- a/crates/ra_db/src/lib.rs
+++ b/crates/ra_db/src/lib.rs
@@ -80,7 +80,7 @@ pub struct FilePosition {
     pub offset: TextSize,
 }
 
-#[derive(Clone, Copy, Debug)]
+#[derive(Clone, Copy, Debug, Eq, PartialEq)]
 pub struct FileRange {
     pub file_id: FileId,
     pub range: TextRange,
diff --git a/crates/ra_hir/src/code_model.rs b/crates/ra_hir/src/code_model.rs
index 27e94b7fe..e09eb77c2 100644
--- a/crates/ra_hir/src/code_model.rs
+++ b/crates/ra_hir/src/code_model.rs
@@ -31,7 +31,7 @@ use hir_ty::{
     ApplicationTy, Canonical, GenericPredicate, InEnvironment, Substs, TraitEnvironment, Ty,
     TyDefId, TypeCtor,
 };
-use ra_db::{CrateId, CrateName, Edition, FileId};
+use ra_db::{CrateId, Edition, FileId};
 use ra_prof::profile;
 use ra_syntax::ast::{self, AttrsOwner, NameOwner};
 use rustc_hash::FxHashSet;
@@ -94,8 +94,8 @@ impl Crate {
         db.crate_graph()[self.id].edition
     }
 
-    pub fn display_name(self, db: &dyn HirDatabase) -> Option<CrateName> {
-        db.crate_graph()[self.id].display_name.as_ref().cloned()
+    pub fn display_name(self, db: &dyn HirDatabase) -> Option<String> {
+        db.crate_graph()[self.id].display_name.clone()
     }
 
     pub fn query_external_importables(
@@ -543,7 +543,7 @@ impl_froms!(Adt: Struct, Union, Enum);
 impl Adt {
     pub fn has_non_default_type_params(self, db: &dyn HirDatabase) -> bool {
         let subst = db.generic_defaults(self.into());
-        subst.iter().any(|ty| ty == &Ty::Unknown)
+        subst.iter().any(|ty| &ty.value == &Ty::Unknown)
     }
 
     /// Turns this ADT into a type. Any type parameters of the ADT will be
@@ -775,7 +775,7 @@ pub struct TypeAlias {
 impl TypeAlias {
     pub fn has_non_default_type_params(self, db: &dyn HirDatabase) -> bool {
         let subst = db.generic_defaults(self.id.into());
-        subst.iter().any(|ty| ty == &Ty::Unknown)
+        subst.iter().any(|ty| &ty.value == &Ty::Unknown)
     }
 
     pub fn module(self, db: &dyn HirDatabase) -> Module {
@@ -1035,7 +1035,10 @@ impl TypeParam {
         let local_idx = hir_ty::param_idx(db, self.id)?;
         let resolver = self.id.parent.resolver(db.upcast());
         let environment = TraitEnvironment::lower(db, &resolver);
-        params.get(local_idx).cloned().map(|ty| Type {
+        let ty = params.get(local_idx)?.clone();
+        let subst = Substs::type_params(db, self.id.parent);
+        let ty = ty.subst(&subst.prefix(local_idx));
+        Some(Type {
             krate: self.id.parent.module(db.upcast()).krate,
             ty: InEnvironment { value: ty, environment },
         })
diff --git a/crates/ra_hir/src/semantics.rs b/crates/ra_hir/src/semantics.rs
index 6a49c424a..810c49d6f 100644
--- a/crates/ra_hir/src/semantics.rs
+++ b/crates/ra_hir/src/semantics.rs
@@ -297,19 +297,19 @@ impl<'db, DB: HirDatabase> Semantics<'db, DB> {
         self.with_ctx(|ctx| ctx.file_to_def(file)).map(Module::from)
     }
 
-    pub fn scope(&self, node: &SyntaxNode) -> SemanticsScope<'db, DB> {
+    pub fn scope(&self, node: &SyntaxNode) -> SemanticsScope<'db> {
         let node = self.find_file(node.clone());
         let resolver = self.analyze2(node.as_ref(), None).resolver;
         SemanticsScope { db: self.db, resolver }
     }
 
-    pub fn scope_at_offset(&self, node: &SyntaxNode, offset: TextSize) -> SemanticsScope<'db, DB> {
+    pub fn scope_at_offset(&self, node: &SyntaxNode, offset: TextSize) -> SemanticsScope<'db> {
         let node = self.find_file(node.clone());
         let resolver = self.analyze2(node.as_ref(), Some(offset)).resolver;
         SemanticsScope { db: self.db, resolver }
     }
 
-    pub fn scope_for_def(&self, def: Trait) -> SemanticsScope<'db, DB> {
+    pub fn scope_for_def(&self, def: Trait) -> SemanticsScope<'db> {
         let resolver = def.id.resolver(self.db);
         SemanticsScope { db: self.db, resolver }
     }
@@ -419,12 +419,12 @@ fn find_root(node: &SyntaxNode) -> SyntaxNode {
     node.ancestors().last().unwrap()
 }
 
-pub struct SemanticsScope<'a, DB> {
-    pub db: &'a DB,
+pub struct SemanticsScope<'a> {
+    pub db: &'a dyn HirDatabase,
     resolver: Resolver,
 }
 
-impl<'a, DB: HirDatabase> SemanticsScope<'a, DB> {
+impl<'a> SemanticsScope<'a> {
     pub fn module(&self) -> Option<Module> {
         Some(Module { id: self.resolver.module()? })
     }
@@ -433,13 +433,13 @@ impl<'a, DB: HirDatabase> SemanticsScope<'a, DB> {
     // FIXME: rename to visible_traits to not repeat scope?
     pub fn traits_in_scope(&self) -> FxHashSet<TraitId> {
         let resolver = &self.resolver;
-        resolver.traits_in_scope(self.db)
+        resolver.traits_in_scope(self.db.upcast())
     }
 
     pub fn process_all_names(&self, f: &mut dyn FnMut(Name, ScopeDef)) {
         let resolver = &self.resolver;
 
-        resolver.process_all_names(self.db, &mut |name, def| {
+        resolver.process_all_names(self.db.upcast(), &mut |name, def| {
             let def = match def {
                 resolver::ScopeDef::PerNs(it) => {
                     let items = ScopeDef::all_items(it);
diff --git a/crates/ra_hir_def/src/item_scope.rs b/crates/ra_hir_def/src/item_scope.rs
index 4d446c707..beeb98559 100644
--- a/crates/ra_hir_def/src/item_scope.rs
+++ b/crates/ra_hir_def/src/item_scope.rs
@@ -1,6 +1,8 @@
 //! Describes items defined or visible (ie, imported) in a certain scope.
 //! This is shared between modules and blocks.
 
+use std::collections::hash_map::Entry;
+
 use hir_expand::name::Name;
 use once_cell::sync::Lazy;
 use ra_db::CrateId;
@@ -27,7 +29,11 @@ pub struct PerNsGlobImports {
 
 #[derive(Debug, Default, PartialEq, Eq)]
 pub struct ItemScope {
-    visible: FxHashMap<Name, PerNs>,
+    types: FxHashMap<Name, (ModuleDefId, Visibility)>,
+    values: FxHashMap<Name, (ModuleDefId, Visibility)>,
+    macros: FxHashMap<Name, (MacroDefId, Visibility)>,
+    unresolved: FxHashSet<Name>,
+
     defs: Vec<ModuleDefId>,
     impls: Vec<ImplId>,
     /// Macros visible in current module in legacy textual scope
@@ -65,14 +71,16 @@ pub(crate) enum BuiltinShadowMode {
 /// Other methods will only resolve values, types and module scoped macros only.
 impl ItemScope {
     pub fn entries<'a>(&'a self) -> impl Iterator<Item = (&'a Name, PerNs)> + 'a {
-        //FIXME: shadowing
-        self.visible.iter().map(|(n, def)| (n, *def))
-    }
-
-    pub fn entries_without_primitives<'a>(
-        &'a self,
-    ) -> impl Iterator<Item = (&'a Name, PerNs)> + 'a {
-        self.visible.iter().map(|(n, def)| (n, *def))
+        // FIXME: shadowing
+        let keys: FxHashSet<_> = self
+            .types
+            .keys()
+            .chain(self.values.keys())
+            .chain(self.macros.keys())
+            .chain(self.unresolved.iter())
+            .collect();
+
+        keys.into_iter().map(move |name| (name, self.get(name)))
     }
 
     pub fn declarations(&self) -> impl Iterator<Item = ModuleDefId> + '_ {
@@ -91,7 +99,7 @@ impl ItemScope {
 
     /// Iterate over all module scoped macros
     pub(crate) fn macros<'a>(&'a self) -> impl Iterator<Item = (&'a Name, MacroDefId)> + 'a {
-        self.visible.iter().filter_map(|(name, def)| def.take_macros().map(|macro_| (name, macro_)))
+        self.entries().filter_map(|(name, def)| def.take_macros().map(|macro_| (name, macro_)))
     }
 
     /// Iterate over all legacy textual scoped macros visible at the end of the module
@@ -101,12 +109,16 @@ impl ItemScope {
 
     /// Get a name from current module scope, legacy macros are not included
     pub(crate) fn get(&self, name: &Name) -> PerNs {
-        self.visible.get(name).copied().unwrap_or_else(PerNs::none)
+        PerNs {
+            types: self.types.get(name).copied(),
+            values: self.values.get(name).copied(),
+            macros: self.macros.get(name).copied(),
+        }
     }
 
     pub(crate) fn name_of(&self, item: ItemInNs) -> Option<(&Name, Visibility)> {
-        for (name, per_ns) in &self.visible {
-            if let Some(vis) = item.match_with(*per_ns) {
+        for (name, per_ns) in self.entries() {
+            if let Some(vis) = item.match_with(per_ns) {
                 return Some((name, vis));
             }
         }
@@ -114,8 +126,8 @@ impl ItemScope {
     }
 
     pub(crate) fn traits<'a>(&'a self) -> impl Iterator<Item = TraitId> + 'a {
-        self.visible.values().filter_map(|def| match def.take_types() {
-            Some(ModuleDefId::TraitId(t)) => Some(t),
+        self.types.values().filter_map(|(def, _)| match def {
+            ModuleDefId::TraitId(t) => Some(*t),
             _ => None,
         })
     }
@@ -138,21 +150,30 @@ impl ItemScope {
 
     pub(crate) fn push_res(&mut self, name: Name, def: PerNs) -> bool {
         let mut changed = false;
-        let existing = self.visible.entry(name).or_default();
 
-        if existing.types.is_none() && def.types.is_some() {
-            existing.types = def.types;
-            changed = true;
+        if let Some(types) = def.types {
+            self.types.entry(name.clone()).or_insert_with(|| {
+                changed = true;
+                types
+            });
         }
-
-        if existing.values.is_none() && def.values.is_some() {
-            existing.values = def.values;
-            changed = true;
+        if let Some(values) = def.values {
+            self.values.entry(name.clone()).or_insert_with(|| {
+                changed = true;
+                values
+            });
+        }
+        if let Some(macros) = def.macros {
+            self.macros.entry(name.clone()).or_insert_with(|| {
+                changed = true;
+                macros
+            });
         }
 
-        if existing.macros.is_none() && def.macros.is_some() {
-            existing.macros = def.macros;
-            changed = true;
+        if def.is_none() {
+            if self.unresolved.insert(name) {
+                changed = true;
+            }
         }
 
         changed
@@ -166,17 +187,17 @@ impl ItemScope {
         def_import_type: ImportType,
     ) -> bool {
         let mut changed = false;
-        let existing = self.visible.entry(lookup.1.clone()).or_default();
 
         macro_rules! check_changed {
             (
                 $changed:ident,
-                ( $existing:ident / $def:ident ) . $field:ident,
+                ( $this:ident / $def:ident ) . $field:ident,
                 $glob_imports:ident [ $lookup:ident ],
                 $def_import_type:ident
-            ) => {
-                match ($existing.$field, $def.$field) {
-                    (None, Some(_)) => {
+            ) => {{
+                let existing = $this.$field.entry($lookup.1.clone());
+                match (existing, $def.$field) {
+                    (Entry::Vacant(entry), Some(_)) => {
                         match $def_import_type {
                             ImportType::Glob => {
                                 $glob_imports.$field.insert($lookup.clone());
@@ -186,32 +207,42 @@ impl ItemScope {
                             }
                         }
 
-                        $existing.$field = $def.$field;
+                        if let Some(fld) = $def.$field {
+                            entry.insert(fld);
+                        }
                         $changed = true;
                     }
-                    (Some(_), Some(_))
+                    (Entry::Occupied(mut entry), Some(_))
                         if $glob_imports.$field.contains(&$lookup)
                             && matches!($def_import_type, ImportType::Named) =>
                     {
                         mark::hit!(import_shadowed);
                         $glob_imports.$field.remove(&$lookup);
-                        $existing.$field = $def.$field;
+                        if let Some(fld) = $def.$field {
+                            entry.insert(fld);
+                        }
                         $changed = true;
                     }
                     _ => {}
                 }
-            };
+            }};
         }
 
-        check_changed!(changed, (existing / def).types, glob_imports[lookup], def_import_type);
-        check_changed!(changed, (existing / def).values, glob_imports[lookup], def_import_type);
-        check_changed!(changed, (existing / def).macros, glob_imports[lookup], def_import_type);
+        check_changed!(changed, (self / def).types, glob_imports[lookup], def_import_type);
+        check_changed!(changed, (self / def).values, glob_imports[lookup], def_import_type);
+        check_changed!(changed, (self / def).macros, glob_imports[lookup], def_import_type);
+
+        if def.is_none() {
+            if self.unresolved.insert(lookup.1) {
+                changed = true;
+            }
+        }
 
         changed
     }
 
     pub(crate) fn resolutions<'a>(&'a self) -> impl Iterator<Item = (Name, PerNs)> + 'a {
-        self.visible.iter().map(|(name, res)| (name.clone(), *res))
+        self.entries().map(|(name, res)| (name.clone(), res))
     }
 
     pub(crate) fn collect_legacy_macros(&self) -> FxHashMap<Name, MacroDefId> {
diff --git a/crates/ra_hir_def/src/resolver.rs b/crates/ra_hir_def/src/resolver.rs
index 15fdd9019..0bf51eb7b 100644
--- a/crates/ra_hir_def/src/resolver.rs
+++ b/crates/ra_hir_def/src/resolver.rs
@@ -511,11 +511,9 @@ impl Scope {
                     });
                 }
             }
-            Scope::LocalItemsScope(body) => {
-                body.item_scope.entries_without_primitives().for_each(|(name, def)| {
-                    f(name.clone(), ScopeDef::PerNs(def));
-                })
-            }
+            Scope::LocalItemsScope(body) => body.item_scope.entries().for_each(|(name, def)| {
+                f(name.clone(), ScopeDef::PerNs(def));
+            }),
             Scope::GenericParams { params, def } => {
                 for (local_id, param) in params.types.iter() {
                     if let Some(name) = &param.name {
diff --git a/crates/ra_hir_expand/src/builtin_derive.rs b/crates/ra_hir_expand/src/builtin_derive.rs
index 26b667b55..f2d664863 100644
--- a/crates/ra_hir_expand/src/builtin_derive.rs
+++ b/crates/ra_hir_expand/src/builtin_derive.rs
@@ -161,7 +161,7 @@ fn find_builtin_crate(db: &dyn AstDatabase, id: LazyMacroId) -> tt::TokenTree {
     // XXX
     //  All crates except core itself should have a dependency on core,
     //  We detect `core` by seeing whether it doesn't have such a dependency.
-    let tt = if cg[krate].dependencies.iter().any(|dep| dep.name == "core") {
+    let tt = if cg[krate].dependencies.iter().any(|dep| &*dep.name == "core") {
         quote! { core }
     } else {
         quote! { crate }
diff --git a/crates/ra_hir_expand/src/builtin_macro.rs b/crates/ra_hir_expand/src/builtin_macro.rs
index 631358f41..626f9efd0 100644
--- a/crates/ra_hir_expand/src/builtin_macro.rs
+++ b/crates/ra_hir_expand/src/builtin_macro.rs
@@ -99,6 +99,7 @@ register_builtin! {
     EAGER:
     (concat, Concat) => concat_expand,
     (include, Include) => include_expand,
+    (include_bytes, IncludeBytes) => include_bytes_expand,
     (include_str, IncludeStr) => include_str_expand,
     (env, Env) => env_expand,
     (option_env, OptionEnv) => option_env_expand
@@ -337,6 +338,24 @@ fn include_expand(
     Ok((res, FragmentKind::Items))
 }
 
+fn include_bytes_expand(
+    _db: &dyn AstDatabase,
+    _arg_id: EagerMacroId,
+    tt: &tt::Subtree,
+) -> Result<(tt::Subtree, FragmentKind), mbe::ExpandError> {
+    let _path = parse_string(tt)?;
+
+    // FIXME: actually read the file here if the user asked for macro expansion
+    let res = tt::Subtree {
+        delimiter: None,
+        token_trees: vec![tt::TokenTree::Leaf(tt::Leaf::Literal(tt::Literal {
+            text: r#"b"""#.into(),
+            id: tt::TokenId::unspecified(),
+        }))],
+    };
+    Ok((res, FragmentKind::Expr))
+}
+
 fn include_str_expand(
     db: &dyn AstDatabase,
     arg_id: EagerMacroId,
@@ -611,4 +630,20 @@ mod tests {
             r#"std::fmt::Arguments::new_v1(&[], &[std::fmt::ArgumentV1::new(&(arg1(a,b,c)),std::fmt::Display::fmt),std::fmt::ArgumentV1::new(&(arg2),std::fmt::Display::fmt),])"#
         );
     }
+
+    #[test]
+    fn test_include_bytes_expand() {
+        let expanded = expand_builtin_macro(
+            r#"
+            #[rustc_builtin_macro]
+            macro_rules! include_bytes {
+                ($file:expr) => {{ /* compiler built-in */ }};
+                ($file:expr,) => {{ /* compiler built-in */ }};
+            }
+            include_bytes("foo");
+            "#,
+        );
+
+        assert_eq!(expanded, r#"b"""#);
+    }
 }
diff --git a/crates/ra_hir_expand/src/diagnostics.rs b/crates/ra_hir_expand/src/diagnostics.rs
index 99209c6e8..545cff9bd 100644
--- a/crates/ra_hir_expand/src/diagnostics.rs
+++ b/crates/ra_hir_expand/src/diagnostics.rs
@@ -28,7 +28,7 @@ pub trait Diagnostic: Any + Send + Sync + fmt::Debug + 'static {
 
 pub trait AstDiagnostic {
     type AST;
-    fn ast(&self, db: &impl AstDatabase) -> Self::AST;
+    fn ast(&self, db: &dyn AstDatabase) -> Self::AST;
 }
 
 impl dyn Diagnostic {
diff --git a/crates/ra_hir_expand/src/name.rs b/crates/ra_hir_expand/src/name.rs
index b475c8cc7..969a2e5b8 100644
--- a/crates/ra_hir_expand/src/name.rs
+++ b/crates/ra_hir_expand/src/name.rs
@@ -117,7 +117,7 @@ impl AsName for ast::FieldKind {
 
 impl AsName for ra_db::Dependency {
     fn as_name(&self) -> Name {
-        Name::new_text(self.name.clone())
+        Name::new_text(SmolStr::new(&*self.name))
     }
 }
 
@@ -191,6 +191,7 @@ pub mod known {
         stringify,
         concat,
         include,
+        include_bytes,
         include_str,
         format_args,
         format_args_nl,
diff --git a/crates/ra_hir_ty/Cargo.toml b/crates/ra_hir_ty/Cargo.toml
index 407322dc1..d6df48db2 100644
--- a/crates/ra_hir_ty/Cargo.toml
+++ b/crates/ra_hir_ty/Cargo.toml
@@ -27,8 +27,8 @@ test_utils = { path = "../test_utils" }
 
 scoped-tls = "1"
 
-chalk-solve = { version = "0.15.0-dev.0", git = "https://github.com/rust-lang/chalk" }
-chalk-ir = { version = "0.15.0-dev.0", git = "https://github.com/rust-lang/chalk" }
+chalk-solve = { version = "0.15.0" }
+chalk-ir = { version = "0.15.0" }
 
 [dev-dependencies]
 insta = "0.16.0"
diff --git a/crates/ra_hir_ty/src/db.rs b/crates/ra_hir_ty/src/db.rs
index 7889b8d2c..cad553273 100644
--- a/crates/ra_hir_ty/src/db.rs
+++ b/crates/ra_hir_ty/src/db.rs
@@ -14,7 +14,7 @@ use crate::{
     method_resolution::CrateImplDefs,
     traits::{chalk, AssocTyValue, Impl},
     Binders, CallableDef, GenericPredicate, InferenceResult, OpaqueTyId, PolyFnSig,
-    ReturnTypeImplTraits, Substs, TraitRef, Ty, TyDefId, TypeCtor, ValueTyDefId,
+    ReturnTypeImplTraits, TraitRef, Ty, TyDefId, TypeCtor, ValueTyDefId,
 };
 use hir_expand::name::Name;
 
@@ -65,7 +65,7 @@ pub trait HirDatabase: DefDatabase + Upcast<dyn DefDatabase> {
     fn generic_predicates(&self, def: GenericDefId) -> Arc<[Binders<GenericPredicate>]>;
 
     #[salsa::invoke(crate::lower::generic_defaults_query)]
-    fn generic_defaults(&self, def: GenericDefId) -> Substs;
+    fn generic_defaults(&self, def: GenericDefId) -> Arc<[Binders<Ty>]>;
 
     #[salsa::invoke(crate::method_resolution::CrateImplDefs::impls_in_crate_query)]
     fn impls_in_crate(&self, krate: CrateId) -> Arc<CrateImplDefs>;
diff --git a/crates/ra_hir_ty/src/diagnostics.rs b/crates/ra_hir_ty/src/diagnostics.rs
index a59efb347..0289911de 100644
--- a/crates/ra_hir_ty/src/diagnostics.rs
+++ b/crates/ra_hir_ty/src/diagnostics.rs
@@ -32,7 +32,7 @@ impl Diagnostic for NoSuchField {
 impl AstDiagnostic for NoSuchField {
     type AST = ast::RecordField;
 
-    fn ast(&self, db: &impl AstDatabase) -> Self::AST {
+    fn ast(&self, db: &dyn AstDatabase) -> Self::AST {
         let root = db.parse_or_expand(self.source().file_id).unwrap();
         let node = self.source().value.to_node(&root);
         ast::RecordField::cast(node).unwrap()
@@ -65,7 +65,7 @@ impl Diagnostic for MissingFields {
 impl AstDiagnostic for MissingFields {
     type AST = ast::RecordFieldList;
 
-    fn ast(&self, db: &impl AstDatabase) -> Self::AST {
+    fn ast(&self, db: &dyn AstDatabase) -> Self::AST {
         let root = db.parse_or_expand(self.source().file_id).unwrap();
         let node = self.source().value.to_node(&root);
         ast::RecordFieldList::cast(node).unwrap()
@@ -135,7 +135,7 @@ impl Diagnostic for MissingOkInTailExpr {
 impl AstDiagnostic for MissingOkInTailExpr {
     type AST = ast::Expr;
 
-    fn ast(&self, db: &impl AstDatabase) -> Self::AST {
+    fn ast(&self, db: &dyn AstDatabase) -> Self::AST {
         let root = db.parse_or_expand(self.file).unwrap();
         let node = self.source().value.to_node(&root);
         ast::Expr::cast(node).unwrap()
@@ -163,7 +163,7 @@ impl Diagnostic for BreakOutsideOfLoop {
 impl AstDiagnostic for BreakOutsideOfLoop {
     type AST = ast::Expr;
 
-    fn ast(&self, db: &impl AstDatabase) -> Self::AST {
+    fn ast(&self, db: &dyn AstDatabase) -> Self::AST {
         let root = db.parse_or_expand(self.file).unwrap();
         let node = self.source().value.to_node(&root);
         ast::Expr::cast(node).unwrap()
@@ -191,7 +191,7 @@ impl Diagnostic for MissingUnsafe {
 impl AstDiagnostic for MissingUnsafe {
     type AST = ast::Expr;
 
-    fn ast(&self, db: &impl AstDatabase) -> Self::AST {
+    fn ast(&self, db: &dyn AstDatabase) -> Self::AST {
         let root = db.parse_or_expand(self.source().file_id).unwrap();
         let node = self.source().value.to_node(&root);
         ast::Expr::cast(node).unwrap()
diff --git a/crates/ra_hir_ty/src/display.rs b/crates/ra_hir_ty/src/display.rs
index 3c97e1354..23cea1a2a 100644
--- a/crates/ra_hir_ty/src/display.rs
+++ b/crates/ra_hir_ty/src/display.rs
@@ -308,7 +308,6 @@ impl HirDisplay for ApplicationTy {
                 }
 
                 if self.parameters.len() > 0 {
-                    let mut non_default_parameters = Vec::with_capacity(self.parameters.len());
                     let parameters_to_write =
                         if f.display_target.is_source_code() || f.omit_verbose_types() {
                             match self
@@ -319,20 +318,23 @@ impl HirDisplay for ApplicationTy {
                             {
                                 None => self.parameters.0.as_ref(),
                                 Some(default_parameters) => {
+                                    let mut default_from = 0;
                                     for (i, parameter) in self.parameters.iter().enumerate() {
                                         match (parameter, default_parameters.get(i)) {
                                             (&Ty::Unknown, _) | (_, None) => {
-                                                non_default_parameters.push(parameter.clone())
+                                                default_from = i + 1;
                                             }
-                                            (_, Some(default_parameter))
-                                                if parameter != default_parameter =>
-                                            {
-                                                non_default_parameters.push(parameter.clone())
+                                            (_, Some(default_parameter)) => {
+                                                let actual_default = default_parameter
+                                                    .clone()
+                                                    .subst(&self.parameters.prefix(i));
+                                                if parameter != &actual_default {
+                                                    default_from = i + 1;
+                                                }
                                             }
-                                            _ => (),
                                         }
                                     }
-                                    &non_default_parameters
+                                    &self.parameters.0[0..default_from]
                                 }
                             }
                         } else {
diff --git a/crates/ra_hir_ty/src/infer/expr.rs b/crates/ra_hir_ty/src/infer/expr.rs
index 61af5f064..22884522a 100644
--- a/crates/ra_hir_ty/src/infer/expr.rs
+++ b/crates/ra_hir_ty/src/infer/expr.rs
@@ -785,11 +785,7 @@ impl<'a> InferenceContext<'a> {
         for &check_closures in &[false, true] {
             let param_iter = param_tys.iter().cloned().chain(repeat(Ty::Unknown));
             for (&arg, param_ty) in args.iter().zip(param_iter) {
-                let is_closure = match &self.body[arg] {
-                    Expr::Lambda { .. } => true,
-                    _ => false,
-                };
-
+                let is_closure = matches!(&self.body[arg], Expr::Lambda { .. });
                 if is_closure != check_closures {
                     continue;
                 }
diff --git a/crates/ra_hir_ty/src/lib.rs b/crates/ra_hir_ty/src/lib.rs
index 414158139..c9513b752 100644
--- a/crates/ra_hir_ty/src/lib.rs
+++ b/crates/ra_hir_ty/src/lib.rs
@@ -620,17 +620,11 @@ pub enum GenericPredicate {
 
 impl GenericPredicate {
     pub fn is_error(&self) -> bool {
-        match self {
-            GenericPredicate::Error => true,
-            _ => false,
-        }
+        matches!(self, GenericPredicate::Error)
     }
 
     pub fn is_implemented(&self) -> bool {
-        match self {
-            GenericPredicate::Implemented(_) => true,
-            _ => false,
-        }
+        matches!(self, GenericPredicate::Implemented(_))
     }
 
     pub fn trait_ref(&self, db: &dyn HirDatabase) -> Option<TraitRef> {
diff --git a/crates/ra_hir_ty/src/lower.rs b/crates/ra_hir_ty/src/lower.rs
index d5154f436..3dc154e92 100644
--- a/crates/ra_hir_ty/src/lower.rs
+++ b/crates/ra_hir_ty/src/lower.rs
@@ -578,11 +578,13 @@ fn substs_from_path_segment(
     // (i.e. defaults aren't used).
     if !infer_args || had_explicit_args {
         if let Some(def_generic) = def_generic {
-            let default_substs = ctx.db.generic_defaults(def_generic);
-            assert_eq!(total_len, default_substs.len());
+            let defaults = ctx.db.generic_defaults(def_generic);
+            assert_eq!(total_len, defaults.len());
 
-            for default_ty in default_substs.iter().skip(substs.len()) {
-                substs.push(default_ty.clone());
+            for default_ty in defaults.iter().skip(substs.len()) {
+                // each default can depend on the previous parameters
+                let substs_so_far = Substs(substs.clone().into());
+                substs.push(default_ty.clone().subst(&substs_so_far));
             }
         }
     }
@@ -945,17 +947,42 @@ pub(crate) fn generic_predicates_query(
 }
 
 /// Resolve the default type params from generics
-pub(crate) fn generic_defaults_query(db: &dyn HirDatabase, def: GenericDefId) -> Substs {
+pub(crate) fn generic_defaults_query(
+    db: &dyn HirDatabase,
+    def: GenericDefId,
+) -> Arc<[Binders<Ty>]> {
     let resolver = def.resolver(db.upcast());
-    let ctx = TyLoweringContext::new(db, &resolver);
+    let ctx =
+        TyLoweringContext::new(db, &resolver).with_type_param_mode(TypeParamLoweringMode::Variable);
     let generic_params = generics(db.upcast(), def);
 
     let defaults = generic_params
         .iter()
-        .map(|(_idx, p)| p.default.as_ref().map_or(Ty::Unknown, |t| Ty::from_hir(&ctx, t)))
+        .enumerate()
+        .map(|(idx, (_, p))| {
+            let mut ty = p.default.as_ref().map_or(Ty::Unknown, |t| Ty::from_hir(&ctx, t));
+
+            // Each default can only refer to previous parameters.
+            ty.walk_mut_binders(
+                &mut |ty, binders| match ty {
+                    Ty::Bound(BoundVar { debruijn, index }) if *debruijn == binders => {
+                        if *index >= idx {
+                            // type variable default referring to parameter coming
+                            // after it. This is forbidden (FIXME: report
+                            // diagnostic)
+                            *ty = Ty::Unknown;
+                        }
+                    }
+                    _ => {}
+                },
+                DebruijnIndex::INNERMOST,
+            );
+
+            Binders::new(idx, ty)
+        })
         .collect();
 
-    Substs(defaults)
+    defaults
 }
 
 fn fn_sig_for_fn(db: &dyn HirDatabase, def: FunctionId) -> PolyFnSig {
diff --git a/crates/ra_hir_ty/src/test_db.rs b/crates/ra_hir_ty/src/test_db.rs
index 9c2c6959d..fddf0604d 100644
--- a/crates/ra_hir_ty/src/test_db.rs
+++ b/crates/ra_hir_ty/src/test_db.rs
@@ -8,8 +8,10 @@ use std::{
 use hir_def::{db::DefDatabase, AssocItemId, ModuleDefId, ModuleId};
 use hir_expand::{db::AstDatabase, diagnostics::DiagnosticSink};
 use ra_db::{salsa, CrateId, FileId, FileLoader, FileLoaderDelegate, SourceDatabase, Upcast};
-use rustc_hash::FxHashSet;
+use ra_syntax::TextRange;
+use rustc_hash::{FxHashMap, FxHashSet};
 use stdx::format_to;
+use test_utils::extract_annotations;
 
 use crate::{
     db::HirDatabase, diagnostics::Diagnostic, expr::ExprValidator,
@@ -154,6 +156,29 @@ impl TestDB {
         });
         (buf, count)
     }
+
+    pub fn extract_annotations(&self) -> FxHashMap<FileId, Vec<(TextRange, String)>> {
+        let mut files = Vec::new();
+        let crate_graph = self.crate_graph();
+        for krate in crate_graph.iter() {
+            let crate_def_map = self.crate_def_map(krate);
+            for (module_id, _) in crate_def_map.modules.iter() {
+                let file_id = crate_def_map[module_id].origin.file_id();
+                files.extend(file_id)
+            }
+        }
+        files
+            .into_iter()
+            .filter_map(|file_id| {
+                let text = self.file_text(file_id);
+                let annotations = extract_annotations(&text);
+                if annotations.is_empty() {
+                    return None;
+                }
+                Some((file_id, annotations))
+            })
+            .collect()
+    }
 }
 
 impl TestDB {
diff --git a/crates/ra_hir_ty/src/tests.rs b/crates/ra_hir_ty/src/tests.rs
index 2a85ce85d..9084c3bed 100644
--- a/crates/ra_hir_ty/src/tests.rs
+++ b/crates/ra_hir_ty/src/tests.rs
@@ -17,11 +17,11 @@ use hir_def::{
     item_scope::ItemScope,
     keys,
     nameres::CrateDefMap,
-    AssocItemId, DefWithBodyId, LocalModuleId, Lookup, ModuleDefId, ModuleId,
+    AssocItemId, DefWithBodyId, LocalModuleId, Lookup, ModuleDefId,
 };
 use hir_expand::{db::AstDatabase, InFile};
 use insta::assert_snapshot;
-use ra_db::{fixture::WithFixture, salsa::Database, FilePosition, SourceDatabase};
+use ra_db::{fixture::WithFixture, salsa::Database, FileRange, SourceDatabase};
 use ra_syntax::{
     algo,
     ast::{self, AstNode},
@@ -37,21 +37,36 @@ use crate::{
 // against snapshots of the expected results using insta. Use cargo-insta to
 // update the snapshots.
 
-fn type_at_pos(db: &TestDB, pos: FilePosition) -> String {
-    type_at_pos_displayed(db, pos, |ty, _| ty.display(db).to_string())
+fn check_types(ra_fixture: &str) {
+    check_types_impl(ra_fixture, false)
 }
 
-fn displayed_source_at_pos(db: &TestDB, pos: FilePosition) -> String {
-    type_at_pos_displayed(db, pos, |ty, module_id| ty.display_source_code(db, module_id).unwrap())
+fn check_types_source_code(ra_fixture: &str) {
+    check_types_impl(ra_fixture, true)
 }
 
-fn type_at_pos_displayed(
-    db: &TestDB,
-    pos: FilePosition,
-    display_fn: impl FnOnce(&Ty, ModuleId) -> String,
-) -> String {
+fn check_types_impl(ra_fixture: &str, display_source: bool) {
+    let db = TestDB::with_files(ra_fixture);
+    let mut checked_one = false;
+    for (file_id, annotations) in db.extract_annotations() {
+        for (range, expected) in annotations {
+            let ty = type_at_range(&db, FileRange { file_id, range });
+            let actual = if display_source {
+                let module = db.module_for_file(file_id);
+                ty.display_source_code(&db, module).unwrap()
+            } else {
+                ty.display(&db).to_string()
+            };
+            assert_eq!(expected, actual);
+            checked_one = true;
+        }
+    }
+    assert!(checked_one, "no `//^` annotations found");
+}
+
+fn type_at_range(db: &TestDB, pos: FileRange) -> Ty {
     let file = db.parse(pos.file_id).ok().unwrap();
-    let expr = algo::find_node_at_offset::<ast::Expr>(file.syntax(), pos.offset).unwrap();
+    let expr = algo::find_node_at_range::<ast::Expr>(file.syntax(), pos.range).unwrap();
     let fn_def = expr.syntax().ancestors().find_map(ast::FnDef::cast).unwrap();
     let module = db.module_for_file(pos.file_id);
     let func = *module.child_by_source(db)[keys::FUNCTION]
@@ -61,17 +76,11 @@ fn type_at_pos_displayed(
     let (_body, source_map) = db.body_with_source_map(func.into());
     if let Some(expr_id) = source_map.node_expr(InFile::new(pos.file_id.into(), &expr)) {
         let infer = db.infer(func.into());
-        let ty = &infer[expr_id];
-        return display_fn(ty, module);
+        return infer[expr_id].clone();
     }
     panic!("Can't find expression")
 }
 
-fn type_at(ra_fixture: &str) -> String {
-    let (db, file_pos) = TestDB::with_position(ra_fixture);
-    type_at_pos(&db, file_pos)
-}
-
 fn infer(ra_fixture: &str) -> String {
     infer_with_mismatches(ra_fixture, false)
 }
diff --git a/crates/ra_hir_ty/src/tests/coercion.rs b/crates/ra_hir_ty/src/tests/coercion.rs
index 5a1c6ccc3..136d28a91 100644
--- a/crates/ra_hir_ty/src/tests/coercion.rs
+++ b/crates/ra_hir_ty/src/tests/coercion.rs
@@ -1,7 +1,8 @@
-use super::infer_with_mismatches;
 use insta::assert_snapshot;
 use test_utils::mark;
 
+use super::infer_with_mismatches;
+
 // Infer with some common definitions and impls.
 fn infer(source: &str) -> String {
     let defs = r#"
diff --git a/crates/ra_hir_ty/src/tests/display_source_code.rs b/crates/ra_hir_ty/src/tests/display_source_code.rs
index 5dfa0a014..b502135d8 100644
--- a/crates/ra_hir_ty/src/tests/display_source_code.rs
+++ b/crates/ra_hir_ty/src/tests/display_source_code.rs
@@ -1,50 +1,41 @@
-use super::displayed_source_at_pos;
-use crate::test_db::TestDB;
-use ra_db::fixture::WithFixture;
+use super::check_types_source_code;
 
 #[test]
 fn qualify_path_to_submodule() {
-    let (db, pos) = TestDB::with_position(
+    check_types_source_code(
         r#"
-//- /main.rs
-
 mod foo {
     pub struct Foo;
 }
 
 fn bar() {
     let foo: foo::Foo = foo::Foo;
-    foo<|>
-}
+    foo
+}  //^ foo::Foo
 
 "#,
     );
-    assert_eq!("foo::Foo", displayed_source_at_pos(&db, pos));
 }
 
 #[test]
 fn omit_default_type_parameters() {
-    let (db, pos) = TestDB::with_position(
-        r"
-        //- /main.rs
-        struct Foo<T = u8> { t: T }
-        fn main() {
-            let foo = Foo { t: 5u8 };
-            foo<|>;
-        }
-        ",
+    check_types_source_code(
+        r#"
+struct Foo<T = u8> { t: T }
+fn main() {
+    let foo = Foo { t: 5u8 };
+    foo;
+}  //^ Foo
+"#,
     );
-    assert_eq!("Foo", displayed_source_at_pos(&db, pos));
 
-    let (db, pos) = TestDB::with_position(
-        r"
-        //- /main.rs
-        struct Foo<K, T = u8> { k: K, t: T }
-        fn main() {
-            let foo = Foo { k: 400, t: 5u8 };
-            foo<|>;
-        }
-        ",
+    check_types_source_code(
+        r#"
+struct Foo<K, T = u8> { k: K, t: T }
+fn main() {
+    let foo = Foo { k: 400, t: 5u8 };
+    foo;
+}   //^ Foo<i32>
+"#,
     );
-    assert_eq!("Foo<i32>", displayed_source_at_pos(&db, pos));
 }
diff --git a/crates/ra_hir_ty/src/tests/macros.rs b/crates/ra_hir_ty/src/tests/macros.rs
index be2b48dcc..45c4e309e 100644
--- a/crates/ra_hir_ty/src/tests/macros.rs
+++ b/crates/ra_hir_ty/src/tests/macros.rs
@@ -1,16 +1,13 @@
 use std::fs;
 
 use insta::assert_snapshot;
-use ra_db::fixture::WithFixture;
 use test_utils::project_dir;
 
-use crate::test_db::TestDB;
-
-use super::{infer, type_at, type_at_pos};
+use super::{check_types, infer};
 
 #[test]
 fn cfg_impl_def() {
-    let (db, pos) = TestDB::with_position(
+    check_types(
         r#"
 //- /main.rs crate:main deps:foo cfg:test
 use foo::S as T;
@@ -28,8 +25,8 @@ impl S {
 
 fn test() {
     let t = (S.foo1(), S.foo2(), T.foo3(), T.foo4());
-    t<|>;
-}
+    t;
+} //^ (i32, {unknown}, i32, {unknown})
 
 //- /foo.rs crate:foo
 struct S;
@@ -45,7 +42,6 @@ impl S {
 }
 "#,
     );
-    assert_eq!("(i32, {unknown}, i32, {unknown})", type_at_pos(&db, pos));
 }
 
 #[test]
@@ -253,26 +249,24 @@ fn foo() {
 
 #[test]
 fn processes_impls_generated_by_macros() {
-    let t = type_at(
+    check_types(
         r#"
-//- /main.rs
 macro_rules! m {
     ($ident:ident) => (impl Trait for $ident {})
 }
 trait Trait { fn foo(self) -> u128 {} }
 struct S;
 m!(S);
-fn test() { S.foo()<|>; }
+fn test() { S.foo(); }
+                //^ u128
 "#,
     );
-    assert_eq!(t, "u128");
 }
 
 #[test]
 fn infer_assoc_items_generated_by_macros() {
-    let t = type_at(
+    check_types(
         r#"
-//- /main.rs
 macro_rules! m {
     () => (fn foo(&self) -> u128 {0})
 }
@@ -281,17 +275,16 @@ impl S {
     m!();
 }
 
-fn test() { S.foo()<|>; }
+fn test() { S.foo(); }
+                //^ u128
 "#,
     );
-    assert_eq!(t, "u128");
 }
 
 #[test]
 fn infer_assoc_items_generated_by_macros_chain() {
-    let t = type_at(
+    check_types(
         r#"
-//- /main.rs
 macro_rules! m_inner {
     () => {fn foo(&self) -> u128 {0}}
 }
@@ -304,21 +297,21 @@ impl S {
     m!();
 }
 
-fn test() { S.foo()<|>; }
+fn test() { S.foo(); }
+                //^ u128
 "#,
     );
-    assert_eq!(t, "u128");
 }
 
 #[test]
 fn infer_macro_with_dollar_crate_is_correct_in_expr() {
-    let (db, pos) = TestDB::with_position(
+    check_types(
         r#"
 //- /main.rs crate:main deps:foo
 fn test() {
     let x = (foo::foo!(1), foo::foo!(2));
-    x<|>;
-}
+    x;
+} //^ (i32, usize)
 
 //- /lib.rs crate:foo
 #[macro_export]
@@ -335,12 +328,11 @@ macro_rules! bar {
 pub fn baz() -> usize { 31usize }
 "#,
     );
-    assert_eq!("(i32, usize)", type_at_pos(&db, pos));
 }
 
 #[test]
 fn infer_macro_with_dollar_crate_is_correct_in_trait_associate_type() {
-    let (db, pos) = TestDB::with_position(
+    check_types(
         r#"
 //- /main.rs crate:main deps:foo
 use foo::Trait;
@@ -348,7 +340,8 @@ use foo::Trait;
 fn test() {
     let msg = foo::Message(foo::MessageRef);
     let r = msg.deref();
-    r<|>;
+    r;
+  //^ &MessageRef
 }
 
 //- /lib.rs crate:foo
@@ -375,7 +368,6 @@ macro_rules! expand {
 expand!();
 "#,
     );
-    assert_eq!("&MessageRef", type_at_pos(&db, pos));
 }
 
 #[test]
@@ -429,13 +421,13 @@ fn main() {
 
 #[test]
 fn infer_local_inner_macros() {
-    let (db, pos) = TestDB::with_position(
+    check_types(
         r#"
 //- /main.rs crate:main deps:foo
 fn test() {
     let x = foo::foo!(1);
-    x<|>;
-}
+    x;
+} //^ i32
 
 //- /lib.rs crate:foo
 #[macro_export(local_inner_macros)]
@@ -450,7 +442,6 @@ macro_rules! bar {
 
 "#,
     );
-    assert_eq!("i32", type_at_pos(&db, pos));
 }
 
 #[test]
@@ -531,7 +522,7 @@ fn main() {
 
 #[test]
 fn infer_builtin_macros_include() {
-    let (db, pos) = TestDB::with_position(
+    check_types(
         r#"
 //- /main.rs
 #[rustc_builtin_macro]
@@ -540,14 +531,13 @@ macro_rules! include {() => {}}
 include!("foo.rs");
 
 fn main() {
-    bar()<|>;
-}
+    bar();
+}     //^ u32
 
 //- /foo.rs
 fn bar() -> u32 {0}
 "#,
     );
-    assert_eq!("u32", type_at_pos(&db, pos));
 }
 
 #[test]
@@ -565,18 +555,17 @@ macro_rules! include {() => {}}
 include!("foo.rs");
 
 fn main() {
-    RegisterBlock { }<|>;
+    RegisterBlock { };
+                  //^ RegisterBlock
 }
     "#;
     let fixture = format!("{}\n//- /foo.rs\n{}", fixture, big_file);
-
-    let (db, pos) = TestDB::with_position(&fixture);
-    assert_eq!("RegisterBlock", type_at_pos(&db, pos));
+    check_types(&fixture);
 }
 
 #[test]
 fn infer_builtin_macros_include_concat() {
-    let (db, pos) = TestDB::with_position(
+    check_types(
         r#"
 //- /main.rs
 #[rustc_builtin_macro]
@@ -588,19 +577,18 @@ macro_rules! concat {() => {}}
 include!(concat!("f", "oo.rs"));
 
 fn main() {
-    bar()<|>;
-}
+    bar();
+}     //^ u32
 
 //- /foo.rs
 fn bar() -> u32 {0}
 "#,
     );
-    assert_eq!("u32", type_at_pos(&db, pos));
 }
 
 #[test]
 fn infer_builtin_macros_include_concat_with_bad_env_should_failed() {
-    let (db, pos) = TestDB::with_position(
+    check_types(
         r#"
 //- /main.rs
 #[rustc_builtin_macro]
@@ -615,32 +603,29 @@ macro_rules! env {() => {}}
 include!(concat!(env!("OUT_DIR"), "/foo.rs"));
 
 fn main() {
-    bar()<|>;
-}
+    bar();
+}     //^ {unknown}
 
 //- /foo.rs
 fn bar() -> u32 {0}
 "#,
     );
-    assert_eq!("{unknown}", type_at_pos(&db, pos));
 }
 
 #[test]
 fn infer_builtin_macros_include_itself_should_failed() {
-    let (db, pos) = TestDB::with_position(
+    check_types(
         r#"
-//- /main.rs
 #[rustc_builtin_macro]
 macro_rules! include {() => {}}
 
 include!("main.rs");
 
 fn main() {
-    0<|>
-}
+    0
+} //^ i32
 "#,
     );
-    assert_eq!("i32", type_at_pos(&db, pos));
 }
 
 #[test]
@@ -686,14 +671,14 @@ fn main() {
 
 #[test]
 fn infer_derive_clone_simple() {
-    let (db, pos) = TestDB::with_position(
+    check_types(
         r#"
 //- /main.rs crate:main deps:core
 #[derive(Clone)]
 struct S;
 fn test() {
-    S.clone()<|>;
-}
+    S.clone();
+}         //^ S
 
 //- /lib.rs crate:core
 #[prelude_import]
@@ -705,12 +690,11 @@ mod clone {
 }
 "#,
     );
-    assert_eq!("S", type_at_pos(&db, pos));
 }
 
 #[test]
 fn infer_derive_clone_in_core() {
-    let (db, pos) = TestDB::with_position(
+    check_types(
         r#"
 //- /lib.rs crate:core
 #[prelude_import]
@@ -726,16 +710,15 @@ pub struct S;
 //- /main.rs crate:main deps:core
 use core::S;
 fn test() {
-    S.clone()<|>;
-}
+    S.clone();
+}         //^ S
 "#,
     );
-    assert_eq!("S", type_at_pos(&db, pos));
 }
 
 #[test]
 fn infer_derive_clone_with_params() {
-    let (db, pos) = TestDB::with_position(
+    check_types(
         r#"
 //- /main.rs crate:main deps:core
 #[derive(Clone)]
@@ -744,7 +727,8 @@ struct S;
 struct Wrapper<T>(T);
 struct NonClone;
 fn test() {
-    (Wrapper(S).clone(), Wrapper(NonClone).clone())<|>;
+    (Wrapper(S).clone(), Wrapper(NonClone).clone());
+  //^ (Wrapper<S>, {unknown})
 }
 
 //- /lib.rs crate:core
@@ -757,13 +741,12 @@ mod clone {
 }
 "#,
     );
-    assert_eq!("(Wrapper<S>, {unknown})", type_at_pos(&db, pos));
 }
 
 #[test]
 fn infer_custom_derive_simple() {
     // FIXME: this test current now do nothing
-    let (db, pos) = TestDB::with_position(
+    check_types(
         r#"
 //- /main.rs crate:main
 use foo::Foo;
@@ -772,11 +755,10 @@ use foo::Foo;
 struct S{}
 
 fn test() {
-    S{}<|>;
-}
+    S{};
+}   //^ S
 "#,
     );
-    assert_eq!("S", type_at_pos(&db, pos));
 }
 
 #[test]
diff --git a/crates/ra_hir_ty/src/tests/method_resolution.rs b/crates/ra_hir_ty/src/tests/method_resolution.rs
index 20329bae4..9c8f22314 100644
--- a/crates/ra_hir_ty/src/tests/method_resolution.rs
+++ b/crates/ra_hir_ty/src/tests/method_resolution.rs
@@ -1,7 +1,6 @@
-use super::{infer, type_at, type_at_pos};
-use crate::test_db::TestDB;
 use insta::assert_snapshot;
-use ra_db::fixture::WithFixture;
+
+use super::{check_types, infer};
 
 #[test]
 fn infer_slice_method() {
@@ -246,13 +245,13 @@ fn test() {
 
 #[test]
 fn cross_crate_associated_method_call() {
-    let (db, pos) = TestDB::with_position(
+    check_types(
         r#"
 //- /main.rs crate:main deps:other_crate
 fn test() {
     let x = other_crate::foo::S::thing();
-    x<|>;
-}
+    x;
+} //^ i128
 
 //- /lib.rs crate:other_crate
 mod foo {
@@ -263,7 +262,6 @@ mod foo {
 }
 "#,
     );
-    assert_eq!("i128", type_at_pos(&db, pos));
 }
 
 #[test]
@@ -684,135 +682,127 @@ fn test() {
 
 #[test]
 fn method_resolution_unify_impl_self_type() {
-    let t = type_at(
+    check_types(
         r#"
-//- /main.rs
 struct S<T>;
 impl S<u32> { fn foo(&self) -> u8 {} }
 impl S<i32> { fn foo(&self) -> i8 {} }
-fn test() { (S::<u32>.foo(), S::<i32>.foo())<|>; }
+fn test() { (S::<u32>.foo(), S::<i32>.foo()); }
+          //^ (u8, i8)
 "#,
     );
-    assert_eq!(t, "(u8, i8)");
 }
 
 #[test]
 fn method_resolution_trait_before_autoref() {
-    let t = type_at(
+    check_types(
         r#"
-//- /main.rs
 trait Trait { fn foo(self) -> u128; }
 struct S;
 impl S { fn foo(&self) -> i8 { 0 } }
 impl Trait for S { fn foo(self) -> u128 { 0 } }
-fn test() { S.foo()<|>; }
+fn test() { S.foo(); }
+                //^ u128
 "#,
     );
-    assert_eq!(t, "u128");
 }
 
 #[test]
 fn method_resolution_by_value_before_autoref() {
-    let t = type_at(
+    check_types(
         r#"
-//- /main.rs
 trait Clone { fn clone(&self) -> Self; }
 struct S;
 impl Clone for S {}
 impl Clone for &S {}
-fn test() { (S.clone(), (&S).clone(), (&&S).clone())<|>; }
+fn test() { (S.clone(), (&S).clone(), (&&S).clone()); }
+          //^ (S, S, &S)
 "#,
     );
-    assert_eq!(t, "(S, S, &S)");
 }
 
 #[test]
 fn method_resolution_trait_before_autoderef() {
-    let t = type_at(
+    check_types(
         r#"
-//- /main.rs
 trait Trait { fn foo(self) -> u128; }
 struct S;
 impl S { fn foo(self) -> i8 { 0 } }
 impl Trait for &S { fn foo(self) -> u128 { 0 } }
-fn test() { (&S).foo()<|>; }
+fn test() { (&S).foo(); }
+                   //^ u128
 "#,
     );
-    assert_eq!(t, "u128");
 }
 
 #[test]
 fn method_resolution_impl_before_trait() {
-    let t = type_at(
+    check_types(
         r#"
-//- /main.rs
 trait Trait { fn foo(self) -> u128; }
 struct S;
 impl S { fn foo(self) -> i8 { 0 } }
 impl Trait for S { fn foo(self) -> u128 { 0 } }
-fn test() { S.foo()<|>; }
+fn test() { S.foo(); }
+                //^ i8
 "#,
     );
-    assert_eq!(t, "i8");
 }
 
 #[test]
 fn method_resolution_impl_ref_before_trait() {
-    let t = type_at(
+    check_types(
         r#"
-//- /main.rs
 trait Trait { fn foo(self) -> u128; }
 struct S;
 impl S { fn foo(&self) -> i8 { 0 } }
 impl Trait for &S { fn foo(self) -> u128 { 0 } }
-fn test() { S.foo()<|>; }
+fn test() { S.foo(); }
+                //^ i8
 "#,
     );
-    assert_eq!(t, "i8");
 }
 
 #[test]
 fn method_resolution_trait_autoderef() {
-    let t = type_at(
+    check_types(
         r#"
-//- /main.rs
 trait Trait { fn foo(self) -> u128; }
 struct S;
 impl Trait for S { fn foo(self) -> u128 { 0 } }
-fn test() { (&S).foo()<|>; }
+fn test() { (&S).foo(); }
+                   //^ u128
 "#,
     );
-    assert_eq!(t, "u128");
 }
 
 #[test]
 fn method_resolution_unsize_array() {
-    let t = type_at(
+    check_types(
         r#"
-//- /main.rs
 #[lang = "slice"]
 impl<T> [T] {
     fn len(&self) -> usize { loop {} }
 }
 fn test() {
     let a = [1, 2, 3];
-    a.len()<|>;
-}
+    a.len();
+}       //^ usize
 "#,
     );
-    assert_eq!(t, "usize");
 }
 
 #[test]
 fn method_resolution_trait_from_prelude() {
-    let (db, pos) = TestDB::with_position(
+    check_types(
         r#"
 //- /main.rs crate:main deps:other_crate
 struct S;
 impl Clone for S {}
 
 fn test() {
-    S.clone()<|>;
+    S.clone();
+          //^ S
 }
 
 //- /lib.rs crate:other_crate
@@ -825,115 +815,107 @@ mod foo {
 }
 "#,
     );
-    assert_eq!("S", type_at_pos(&db, pos));
 }
 
 #[test]
 fn method_resolution_where_clause_for_unknown_trait() {
     // The blanket impl currently applies because we ignore the unresolved where clause
-    let t = type_at(
+    check_types(
         r#"
-//- /main.rs
 trait Trait { fn foo(self) -> u128; }
 struct S;
 impl<T> Trait for T where T: UnknownTrait {}
-fn test() { (&S).foo()<|>; }
+fn test() { (&S).foo(); }
+                   //^ u128
 "#,
     );
-    assert_eq!(t, "u128");
 }
 
 #[test]
 fn method_resolution_where_clause_not_met() {
     // The blanket impl shouldn't apply because we can't prove S: Clone
-    let t = type_at(
+    // This is also to make sure that we don't resolve to the foo method just
+    // because that's the only method named foo we can find, which would make
+    // the below tests not work
+    check_types(
         r#"
-//- /main.rs
 trait Clone {}
 trait Trait { fn foo(self) -> u128; }
 struct S;
 impl<T> Trait for T where T: Clone {}
-fn test() { (&S).foo()<|>; }
+fn test() { (&S).foo(); }
+                   //^ {unknown}
 "#,
     );
-    // This is also to make sure that we don't resolve to the foo method just
-    // because that's the only method named foo we can find, which would make
-    // the below tests not work
-    assert_eq!(t, "{unknown}");
 }
 
 #[test]
 fn method_resolution_where_clause_inline_not_met() {
     // The blanket impl shouldn't apply because we can't prove S: Clone
-    let t = type_at(
+    check_types(
         r#"
-//- /main.rs
 trait Clone {}
 trait Trait { fn foo(self) -> u128; }
 struct S;
 impl<T: Clone> Trait for T {}
-fn test() { (&S).foo()<|>; }
+fn test() { (&S).foo(); }
+                   //^ {unknown}
 "#,
     );
-    assert_eq!(t, "{unknown}");
 }
 
 #[test]
 fn method_resolution_where_clause_1() {
-    let t = type_at(
+    check_types(
         r#"
-//- /main.rs
 trait Clone {}
 trait Trait { fn foo(self) -> u128; }
 struct S;
 impl Clone for S {}
 impl<T> Trait for T where T: Clone {}
-fn test() { S.foo()<|>; }
+fn test() { S.foo(); }
+                //^ u128
 "#,
     );
-    assert_eq!(t, "u128");
 }
 
 #[test]
 fn method_resolution_where_clause_2() {
-    let t = type_at(
+    check_types(
         r#"
-//- /main.rs
 trait Into<T> { fn into(self) -> T; }
 trait From<T> { fn from(other: T) -> Self; }
 struct S1;
 struct S2;
 impl From<S2> for S1 {}
 impl<T, U> Into<U> for T where U: From<T> {}
-fn test() { S2.into()<|>; }
+fn test() { S2.into(); }
+                  //^ {unknown}
 "#,
     );
-    assert_eq!(t, "{unknown}");
 }
 
 #[test]
 fn method_resolution_where_clause_inline() {
-    let t = type_at(
+    check_types(
         r#"
-//- /main.rs
 trait Into<T> { fn into(self) -> T; }
 trait From<T> { fn from(other: T) -> Self; }
 struct S1;
 struct S2;
 impl From<S2> for S1 {}
 impl<T, U: From<T>> Into<U> for T {}
-fn test() { S2.into()<|>; }
+fn test() { S2.into(); }
+                  //^ {unknown}
 "#,
     );
-    assert_eq!(t, "{unknown}");
 }
 
 #[test]
 fn method_resolution_overloaded_method() {
     test_utils::mark::check!(impl_self_type_match_without_receiver);
-    let t = type_at(
+    check_types(
         r#"
-//- /main.rs
 struct Wrapper<T>(T);
 struct Foo<T>(T);
 struct Bar<T>(T);
@@ -953,30 +935,30 @@ impl<T> Wrapper<Bar<T>> {
 fn main() {
     let a = Wrapper::<Foo<f32>>::new(1.0);
     let b = Wrapper::<Bar<f32>>::new(1.0);
-    (a, b)<|>;
+    (a, b);
+  //^ (Wrapper<Foo<f32>>, Wrapper<Bar<f32>>)
 }
 "#,
     );
-    assert_eq!(t, "(Wrapper<Foo<f32>>, Wrapper<Bar<f32>>)")
 }
 
 #[test]
 fn method_resolution_encountering_fn_type() {
-    type_at(
+    check_types(
         r#"
 //- /main.rs
 fn foo() {}
 trait FnOnce { fn call(self); }
-fn test() { foo.call()<|>; }
+fn test() { foo.call(); }
+                   //^ {unknown}
 "#,
     );
 }
 
 #[test]
 fn method_resolution_non_parameter_type() {
-    let t = type_at(
+    check_types(
         r#"
-//- /main.rs
 mod a {
     pub trait Foo {
         fn foo(&self);
@@ -988,18 +970,16 @@ fn foo<T>(t: Wrapper<T>)
 where
     Wrapper<T>: a::Foo,
 {
-    t.foo()<|>;
-}
+    t.foo();
+}       //^ {unknown}
 "#,
     );
-    assert_eq!(t, "{unknown}");
 }
 
 #[test]
 fn method_resolution_3373() {
-    let t = type_at(
+    check_types(
         r#"
-//- /main.rs
 struct A<T>(T);