24 files changed, 174 insertions, 215 deletions

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/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/fix_visibility.rs b/crates/ra_assists/src/handlers/fix_visibility.rs
index 54601d1f3..19d4dac5e 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.
 
@@ -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/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/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_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/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_ide/src/inlay_hints.rs b/crates/ra_ide/src/inlay_hints.rs
index 98fb34486..c87652555 100644
--- a/crates/ra_ide/src/inlay_hints.rs
+++ b/crates/ra_ide/src/inlay_hints.rs
@@ -313,10 +313,8 @@ fn get_string_representation(expr: &ast::Expr) -> Option<String> {
 }
 
 fn is_obvious_param(param_name: &str) -> bool {
-    let is_obvious_param_name = match param_name {
-        "predicate" | "value" | "pat" | "rhs" | "other" => true,
-        _ => false,
-    };
+    let is_obvious_param_name =
+        matches!(param_name, "predicate" | "value" | "pat" | "rhs" | "other");
     param_name.len() == 1 || is_obvious_param_name
 }
 
diff --git a/crates/ra_ide/src/join_lines.rs b/crates/ra_ide/src/join_lines.rs
index 5036c1fb0..6907c09e8 100644
--- a/crates/ra_ide/src/join_lines.rs
+++ b/crates/ra_ide/src/join_lines.rs
@@ -165,10 +165,7 @@ fn join_single_use_tree(edit: &mut TextEditBuilder, token: &SyntaxToken) -> Opti
 }
 
 fn is_trailing_comma(left: SyntaxKind, right: SyntaxKind) -> bool {
-    match (left, right) {
-        (T![,], T![')']) | (T![,], T![']']) => true,
-        _ => false,
-    }
+    matches!((left, right), (T![,], T![')']) | (T![,], T![']']))
 }
 
 #[cfg(test)]
diff --git a/crates/ra_ide_db/src/symbol_index.rs b/crates/ra_ide_db/src/symbol_index.rs
index 6929055b2..5a09e7d1d 100644
--- a/crates/ra_ide_db/src/symbol_index.rs
+++ b/crates/ra_ide_db/src/symbol_index.rs
@@ -346,10 +346,7 @@ impl Query {
 }
 
 fn is_type(kind: SyntaxKind) -> bool {
-    match kind {
-        STRUCT_DEF | ENUM_DEF | TRAIT_DEF | TYPE_ALIAS_DEF => true,
-        _ => false,
-    }
+    matches!(kind, STRUCT_DEF | ENUM_DEF | TRAIT_DEF | TYPE_ALIAS_DEF)
 }
 
 /// The actual data that is stored in the index. It should be as compact as
diff --git a/crates/ra_mbe/src/parser.rs b/crates/ra_mbe/src/parser.rs
index 034150432..1e5dafbdf 100644
--- a/crates/ra_mbe/src/parser.rs
+++ b/crates/ra_mbe/src/parser.rs
@@ -137,10 +137,7 @@ fn eat_fragment_kind<'a>(
 }
 
 fn is_boolean_literal(lit: &tt::Literal) -> bool {
-    match lit.text.as_str() {
-        "true" | "false" => true,
-        _ => false,
-    }
+    matches!(lit.text.as_str(), "true" | "false")
 }
 
 fn parse_repeat(src: &mut TtIter) -> Result<(Option<Separator>, RepeatKind), ExpandError> {
diff --git a/crates/ra_parser/src/grammar.rs b/crates/ra_parser/src/grammar.rs
index 293baecf6..caedeead0 100644
--- a/crates/ra_parser/src/grammar.rs
+++ b/crates/ra_parser/src/grammar.rs
@@ -73,10 +73,7 @@ pub(crate) mod fragments {
     // Parse a meta item , which excluded [], e.g : #[ MetaItem ]
     pub(crate) fn meta_item(p: &mut Parser) {
         fn is_delimiter(p: &mut Parser) -> bool {
-            match p.current() {
-                T!['{'] | T!['('] | T!['['] => true,
-                _ => false,
-            }
+            matches!(p.current(), T!['{'] | T!['('] | T!['['])
         }
 
         if is_delimiter(p) {
diff --git a/crates/ra_parser/src/grammar/paths.rs b/crates/ra_parser/src/grammar/paths.rs
index fd51189d5..b503af1dc 100644
--- a/crates/ra_parser/src/grammar/paths.rs
+++ b/crates/ra_parser/src/grammar/paths.rs
@@ -41,10 +41,7 @@ fn path(p: &mut Parser, mode: Mode) {
     path_segment(p, mode, true);
     let mut qual = path.complete(p, PATH);
     loop {
-        let use_tree = match p.nth(2) {
-            T![*] | T!['{'] => true,
-            _ => false,
-        };
+        let use_tree = matches!(p.nth(2), T![*] | T!['{']);
         if p.at(T![::]) && !use_tree {
             let path = qual.precede(p);
             p.bump(T![::]);
diff --git a/crates/ra_parser/src/grammar/type_params.rs b/crates/ra_parser/src/grammar/type_params.rs
index 325d566ad..d1330d4b9 100644
--- a/crates/ra_parser/src/grammar/type_params.rs
+++ b/crates/ra_parser/src/grammar/type_params.rs
@@ -169,10 +169,7 @@ fn is_where_predicate(p: &mut Parser) -> bool {
 }
 
 fn is_where_clause_end(p: &mut Parser) -> bool {
-    match p.current() {
-        T!['{'] | T![;] | T![=] => true,
-        _ => false,
-    }
+    matches!(p.current(), T!['{'] | T![;] | T![=])
 }
 
 fn where_predicate(p: &mut Parser) {
diff --git a/crates/ra_parser/src/syntax_kind.rs b/crates/ra_parser/src/syntax_kind.rs
index 8d6bd057b..63204436c 100644
--- a/crates/ra_parser/src/syntax_kind.rs
+++ b/crates/ra_parser/src/syntax_kind.rs
@@ -20,9 +20,6 @@ impl From<SyntaxKind> for u16 {
 
 impl SyntaxKind {
     pub fn is_trivia(self) -> bool {
-        match self {
-            SyntaxKind::WHITESPACE | SyntaxKind::COMMENT => true,
-            _ => false,
-        }
+        matches!(self, SyntaxKind::WHITESPACE | SyntaxKind::COMMENT)
     }
 }
diff --git a/crates/ra_syntax/src/ast/expr_extensions.rs b/crates/ra_syntax/src/ast/expr_extensions.rs
index 7771d6759..db5438d68 100644
--- a/crates/ra_syntax/src/ast/expr_extensions.rs
+++ b/crates/ra_syntax/src/ast/expr_extensions.rs
@@ -399,10 +399,7 @@ impl ast::BlockExpr {
             Some(it) => it,
             None => return true,
         };
-        match parent.kind() {
-            FN_DEF | IF_EXPR | WHILE_EXPR | LOOP_EXPR | EFFECT_EXPR => false,
-            _ => true,
-        }
+        !matches!(parent.kind(), FN_DEF | IF_EXPR | WHILE_EXPR | LOOP_EXPR | EFFECT_EXPR)
     }
 }
 
diff --git a/crates/ra_syntax/src/ast/extensions.rs b/crates/ra_syntax/src/ast/extensions.rs
index 98c38d009..662c6f73e 100644
--- a/crates/ra_syntax/src/ast/extensions.rs
+++ b/crates/ra_syntax/src/ast/extensions.rs
@@ -459,16 +459,16 @@ impl ast::RangePat {
 
 impl ast::TokenTree {
     pub fn left_delimiter_token(&self) -> Option<SyntaxToken> {
-        self.syntax().first_child_or_token()?.into_token().filter(|it| match it.kind() {
-            T!['{'] | T!['('] | T!['['] => true,
-            _ => false,
-        })
+        self.syntax()
+            .first_child_or_token()?
+            .into_token()
+            .filter(|it| matches!(it.kind(), T!['{'] | T!['('] | T!['[']))
     }
 
     pub fn right_delimiter_token(&self) -> Option<SyntaxToken> {
-        self.syntax().last_child_or_token()?.into_token().filter(|it| match it.kind() {
-            T!['}'] | T![')'] | T![']'] => true,
-            _ => false,
-        })
+        self.syntax()
+            .last_child_or_token()?
+            .into_token()
+            .filter(|it| matches!(it.kind(), T!['}'] | T![')'] | T![']']))
     }
 }
diff --git a/crates/ra_syntax/src/parsing/reparsing.rs b/crates/ra_syntax/src/parsing/reparsing.rs
index edbc190f8..ed5a42ea3 100644
--- a/crates/ra_syntax/src/parsing/reparsing.rs
+++ b/crates/ra_syntax/src/parsing/reparsing.rs
@@ -120,10 +120,7 @@ fn get_text_after_edit(element: SyntaxElement, edit: &Indel) -> String {
 }
 
 fn is_contextual_kw(text: &str) -> bool {
-    match text {
-        "auto" | "default" | "union" => true,
-        _ => false,
-    }
+    matches!(text, "auto" | "default" | "union")
 }
 
 fn find_reparsable_node(node: &SyntaxNode, range: TextRange) -> Option<(SyntaxNode, Reparser)> {
diff --git a/crates/ra_tt/src/buffer.rs b/crates/ra_tt/src/buffer.rs
index 5967f44cd..02c771f70 100644
--- a/crates/ra_tt/src/buffer.rs
+++ b/crates/ra_tt/src/buffer.rs
@@ -105,10 +105,7 @@ impl<'a> Eq for Cursor<'a> {}
 impl<'a> Cursor<'a> {
     /// Check whether it is eof
     pub fn eof(self) -> bool {
-        match self.buffer.entry(&self.ptr) {
-            None | Some(Entry::End(None)) => true,
-            _ => false,
-        }
+        matches!(self.buffer.entry(&self.ptr), None | Some(Entry::End(None)))
     }
 
     /// If the cursor is pointing at the end of a subtree, returns
diff --git a/crates/rust-analyzer/src/cli.rs b/crates/rust-analyzer/src/cli.rs
index 39ce77900..c5faec83a 100644
--- a/crates/rust-analyzer/src/cli.rs
+++ b/crates/rust-analyzer/src/cli.rs
@@ -28,16 +28,10 @@ pub enum Verbosity {
 
 impl Verbosity {
     pub fn is_verbose(self) -> bool {
-        match self {
-            Verbosity::Verbose | Verbosity::Spammy => true,
-            _ => false,
-        }
+        matches!(self, Verbosity::Verbose | Verbosity::Spammy)
     }
     pub fn is_spammy(self) -> bool {
-        match self {
-            Verbosity::Spammy => true,
-            _ => false,
-        }
+        matches!(self, Verbosity::Spammy)
     }
 }
 
diff --git a/crates/rust-analyzer/src/cli/analysis_bench.rs b/crates/rust-analyzer/src/cli/analysis_bench.rs
index 4fe99ff68..930375d3e 100644
--- a/crates/rust-analyzer/src/cli/analysis_bench.rs
+++ b/crates/rust-analyzer/src/cli/analysis_bench.rs
@@ -78,10 +78,7 @@ pub fn analysis_bench(
             }
         }
         BenchWhat::Complete(pos) | BenchWhat::GotoDef(pos) => {
-            let is_completion = match what {
-                BenchWhat::Complete(..) => true,
-                _ => false,
-            };
+            let is_completion = matches!(what, BenchWhat::Complete(..));
 
             let offset = host
                 .analysis()
diff --git a/crates/rust-analyzer/src/main_loop.rs b/crates/rust-analyzer/src/main_loop.rs
index e5194fe41..9fd16ef3b 100644
--- a/crates/rust-analyzer/src/main_loop.rs
+++ b/crates/rust-analyzer/src/main_loop.rs
@@ -216,7 +216,11 @@ impl GlobalState {
                         flycheck::Progress::DidCheckCrate(target) => {
                             (Progress::Report, Some(target))
                         }
-                        flycheck::Progress::DidFinish | flycheck::Progress::DidCancel => {
+                        flycheck::Progress::DidCancel => (Progress::End, None),
+                        flycheck::Progress::DidFinish(result) => {
+                            if let Err(err) = result {
+                                log::error!("cargo check failed: {}", err)
+                            }
                             (Progress::End, None)
                         }
                     };
diff --git a/crates/vfs-notify/src/lib.rs b/crates/vfs-notify/src/lib.rs
index 25ba8d798..b1ea298ae 100644
--- a/crates/vfs-notify/src/lib.rs
+++ b/crates/vfs-notify/src/lib.rs
@@ -10,7 +10,7 @@ mod include;
 
 use std::convert::{TryFrom, TryInto};
 
-use crossbeam_channel::{select, unbounded, Receiver};
+use crossbeam_channel::{select, unbounded, Receiver, Sender};
 use notify::{RecommendedWatcher, RecursiveMode, Watcher};
 use paths::{AbsPath, AbsPathBuf};
 use rustc_hash::FxHashSet;
@@ -22,8 +22,8 @@ use crate::include::Include;
 #[derive(Debug)]
 pub struct NotifyHandle {
     // Relative order of fields below is significant.
-    sender: crossbeam_channel::Sender<Message>,
-    _thread: jod_thread::JoinHandle,
+    sender: Sender<Message>,
+    thread: jod_thread::JoinHandle,
 }
 
 #[derive(Debug)]
@@ -37,7 +37,7 @@ impl loader::Handle for NotifyHandle {
         let actor = NotifyActor::new(sender);
         let (sender, receiver) = unbounded::<Message>();
         let thread = jod_thread::spawn(move || actor.run(receiver));
-        NotifyHandle { sender, _thread: thread }
+        NotifyHandle { sender, thread }
     }
     fn set_config(&mut self, config: loader::Config) {
         self.sender.send(Message::Config(config)).unwrap()