Merge #10440

10440: Fix Clippy warnings and replace some `if let`s with `match` r=Veykril a=arzg

I decided to try fixing a bunch of Clippy warnings. I am aware of this project’s opinion of Clippy (I have read both [rust-lang/clippy#5537](https://github.com/rust-lang/rust-clippy/issues/5537) and [rust-analyzer/rowan#57 (comment)](https://github.com/rust-analyzer/rowan/pull/57#discussion_r415676159)), so I totally understand if part of or the entirety of this PR is rejected. In particular, I can see how the semicolons and `if let` vs `match` commits provide comparatively little benefit when compared to the ensuing churn.

I tried to separate each kind of change into its own commit to make it easier to discard certain changes. I also only applied Clippy suggestions where I thought they provided a definite improvement to the code (apart from semicolons, which is IMO more of a formatting/consistency question than a linting question). In the end I accumulated a list of 28 Clippy lints I ignored entirely.

Sidenote: I should really have asked about this on Zulip before going through all 1,555 `if let`s in the codebase to decide which ones definitely look better as `match` :P

Co-authored-by: Aramis Razzaghipour <aramisnoah@gmail.com>

crates/flycheck/src/lib.rs

@@ -179,7 +179,7 @@ impl FlycheckActor {
                         tracing::error!(
                             "Flycheck failed to run the following command: {:?}",
                             self.check_command()
-                        )
+                        );
                     }
                     self.progress(Progress::DidFinish(res));
                 }
@@ -253,14 +253,14 @@ impl FlycheckActor {
     }
 
     fn send(&self, check_task: Message) {
-        (self.sender)(check_task)
+        (self.sender)(check_task);
     }
 }
 
 struct CargoHandle {
     child: JodChild,
     #[allow(unused)]
-    thread: jod_thread::JoinHandle<io::Result<bool>>,
+    thread: jod_thread::JoinHandle<bool>,
     receiver: Receiver<CargoMessage>,
 }
 
@@ -279,7 +279,7 @@ impl CargoHandle {
         // 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()?;
+        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
@@ -304,7 +304,7 @@ impl CargoActor {
     fn new(child_stdout: process::ChildStdout, sender: Sender<CargoMessage>) -> CargoActor {
         CargoActor { child_stdout, sender }
     }
-    fn run(self) -> io::Result<bool> {
+    fn run(self) -> 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
@@ -334,20 +334,20 @@ impl CargoActor {
                     // Skip certain kinds of messages to only spend time on what's useful
                     JsonMessage::Cargo(message) => match message {
                         cargo_metadata::Message::CompilerArtifact(artifact) if !artifact.fresh => {
-                            self.sender.send(CargoMessage::CompilerArtifact(artifact)).unwrap()
+                            self.sender.send(CargoMessage::CompilerArtifact(artifact)).unwrap();
                         }
                         cargo_metadata::Message::CompilerMessage(msg) => {
-                            self.sender.send(CargoMessage::Diagnostic(msg.message)).unwrap()
+                            self.sender.send(CargoMessage::Diagnostic(msg.message)).unwrap();
                         }
                         _ => (),
                     },
                     JsonMessage::Rustc(message) => {
-                        self.sender.send(CargoMessage::Diagnostic(message)).unwrap()
+                        self.sender.send(CargoMessage::Diagnostic(message)).unwrap();
                     }
                 }
             }
         }
-        Ok(read_at_least_one_message)
+        read_at_least_one_message
     }
 }
 

crates/hir/src/lib.rs

@@ -1119,7 +1119,7 @@ impl DefWithBody {
                                 if let ast::Expr::RecordExpr(record_expr) =
                                     &source_ptr.value.to_node(&root)
                                 {
-                                    if let Some(_) = record_expr.record_expr_field_list() {
+                                    if record_expr.record_expr_field_list().is_some() {
                                         acc.push(
                                             MissingFields {
                                                 file: source_ptr.file_id,
@@ -1143,7 +1143,7 @@ impl DefWithBody {
                                 if let Some(expr) = source_ptr.value.as_ref().left() {
                                     let root = source_ptr.file_syntax(db.upcast());
                                     if let ast::Pat::RecordPat(record_pat) = expr.to_node(&root) {
-                                        if let Some(_) = record_pat.record_pat_field_list() {
+                                        if record_pat.record_pat_field_list().is_some() {
                                             acc.push(
                                                 MissingFields {
                                                     file: source_ptr.file_id,
@@ -2119,10 +2119,9 @@ impl Impl {
         };
 
         let fp = TyFingerprint::for_inherent_impl(&ty);
-        let fp = if let Some(fp) = fp {
+        let fp = match fp {
-            fp
+            Some(fp) => fp,
-        } else {
+            None => return Vec::new(),
-            return Vec::new();
         };
 
         let mut all = Vec::new();

crates/hir_def/src/body/lower.rs

@@ -474,10 +474,9 @@ impl ExprCollector<'_> {
             }
             ast::Expr::PrefixExpr(e) => {
                 let expr = self.collect_expr_opt(e.expr());
-                if let Some(op) = e.op_kind() {
+                match e.op_kind() {
-                    self.alloc_expr(Expr::UnaryOp { expr, op }, syntax_ptr)
+                    Some(op) => self.alloc_expr(Expr::UnaryOp { expr, op }, syntax_ptr),
-                } else {
+                    None => self.alloc_expr(Expr::Missing, syntax_ptr),
-                    self.alloc_expr(Expr::Missing, syntax_ptr)
                 }
             }
             ast::Expr::ClosureExpr(e) => {
@@ -624,10 +623,9 @@ impl ExprCollector<'_> {
     }
 
     fn collect_expr_opt(&mut self, expr: Option<ast::Expr>) -> ExprId {
-        if let Some(expr) = expr {
+        match expr {
-            self.collect_expr(expr)
+            Some(expr) => self.collect_expr(expr),
-        } else {
+            None => self.missing_expr(),
-            self.missing_expr()
         }
     }
 
@@ -724,10 +722,9 @@ impl ExprCollector<'_> {
     }
 
     fn collect_block_opt(&mut self, expr: Option<ast::BlockExpr>) -> ExprId {
-        if let Some(block) = expr {
+        match expr {
-            self.collect_block(block)
+            Some(block) => self.collect_block(block),
-        } else {
+            None => self.missing_expr(),
-            self.missing_expr()
         }
     }
 
@@ -890,10 +887,9 @@ impl ExprCollector<'_> {
     }
 
     fn collect_pat_opt(&mut self, pat: Option<ast::Pat>) -> PatId {
-        if let Some(pat) = pat {
+        match pat {
-            self.collect_pat(pat)
+            Some(pat) => self.collect_pat(pat),
-        } else {
+            None => self.missing_pat(),
-            self.missing_pat()
         }
     }
 

crates/hir_def/src/find_path.rs

@@ -209,10 +209,9 @@ fn find_path_inner(
             ) {
                 path.push_segment(name);
 
-                let new_path = if let Some(best_path) = best_path {
+                let new_path = match best_path {
-                    select_best_path(best_path, path, prefer_no_std)
+                    Some(best_path) => select_best_path(best_path, path, prefer_no_std),
-                } else {
+                    None => path,
-                    path
                 };
                 best_path_len = new_path.len();
                 best_path = Some(new_path);
@@ -243,10 +242,9 @@ fn find_path_inner(
         });
 
         for path in extern_paths {
-            let new_path = if let Some(best_path) = best_path {
+            let new_path = match best_path {
-                select_best_path(best_path, path, prefer_no_std)
+                Some(best_path) => select_best_path(best_path, path, prefer_no_std),
-            } else {
+                None => path,
-                path
             };
             best_path = Some(new_path);
         }
@@ -261,12 +259,11 @@ fn find_path_inner(
         }
     }
 
-    if let Some(prefix) = prefixed.map(PrefixKind::prefix) {
+    match prefixed.map(PrefixKind::prefix) {
-        best_path.or_else(|| {
+        Some(prefix) => best_path.or_else(|| {
             scope_name.map(|scope_name| ModPath::from_segments(prefix, vec![scope_name]))
-        })
+        }),
-    } else {
+        None => best_path,
-        best_path
     }
 }
 
@@ -346,15 +343,13 @@ fn find_local_import_locations(
 
         if let Some((name, vis)) = data.scope.name_of(item) {
             if vis.is_visible_from(db, from) {
-                let is_private = if let Visibility::Module(private_to) = vis {
+                let is_private = match vis {
-                    private_to.local_id == module.local_id
+                    Visibility::Module(private_to) => private_to.local_id == module.local_id,
-                } else {
+                    Visibility::Public => false,
-                    false
                 };
-                let is_original_def = if let Some(module_def_id) = item.as_module_def_id() {
+                let is_original_def = match item.as_module_def_id() {
-                    data.scope.declarations().any(|it| it == module_def_id)
+                    Some(module_def_id) => data.scope.declarations().any(|it| it == module_def_id),
-                } else {
+                    None => false,
-                    false
                 };
 
                 // Ignore private imports. these could be used if we are

crates/hir_def/src/item_tree.rs

@@ -475,10 +475,9 @@ macro_rules! mod_items {
                 }
 
                 fn id_from_mod_item(mod_item: ModItem) -> Option<FileItemTreeId<Self>> {
-                    if let ModItem::$typ(id) = mod_item {
+                    match mod_item {
-                        Some(id)
+                        ModItem::$typ(id) => Some(id),
-                    } else {
+                        _ => None,
-                        None
                     }
                 }
 

crates/hir_def/src/nameres/path_resolution.rs

@@ -400,13 +400,10 @@ impl DefMap {
         };
         let from_scope_or_builtin = match shadow {
             BuiltinShadowMode::Module => from_scope.or(from_builtin),
-            BuiltinShadowMode::Other => {
+            BuiltinShadowMode::Other => match from_scope.take_types() {
-                if let Some(ModuleDefId::ModuleId(_)) = from_scope.take_types() {
+                Some(ModuleDefId::ModuleId(_)) => from_builtin.or(from_scope),
-                    from_builtin.or(from_scope)
+                Some(_) | None => from_scope.or(from_builtin),
-                } else {
+            },
-                    from_scope.or(from_builtin)
-                }
-            }
         };
         let from_extern_prelude = self
             .extern_prelude

crates/hir_def/src/path/lower/lower_use.rs

@@ -18,10 +18,9 @@ pub(crate) fn convert_path(
     path: ast::Path,
     hygiene: &Hygiene,
 ) -> Option<ModPath> {
-    let prefix = if let Some(qual) = path.qualifier() {
+    let prefix = match path.qualifier() {
-        Some(convert_path(db, prefix, qual, hygiene)?)
+        Some(qual) => Some(convert_path(db, prefix, qual, hygiene)?),
-    } else {
+        None => prefix,
-        prefix
     };
 
     let segment = path.segment()?;

crates/hir_def/src/type_ref.rs

@@ -214,10 +214,9 @@ impl TypeRef {
     }
 
     pub(crate) fn from_ast_opt(ctx: &LowerCtx, node: Option<ast::Type>) -> Self {
-        if let Some(node) = node {
+        match node {
-            TypeRef::from_ast(ctx, node)
+            Some(node) => TypeRef::from_ast(ctx, node),
-        } else {
+            None => TypeRef::Error,
-            TypeRef::Error
         }
     }
 

crates/hir_expand/src/name.rs

@@ -48,10 +48,9 @@ impl Name {
 
     /// Resolve a name from the text of token.
     fn resolve(raw_text: &str) -> Name {
-        if let Some(text) = raw_text.strip_prefix("r#") {
+        match raw_text.strip_prefix("r#") {
-            Name::new_text(SmolStr::new(text))
+            Some(text) => Name::new_text(SmolStr::new(text)),
-        } else {
+            None => Name::new_text(raw_text.into()),
-            Name::new_text(raw_text.into())
         }
     }
 

crates/hir_ty/src/autoderef.rs

@@ -109,10 +109,9 @@ pub(crate) fn deref(
     ty: InEnvironment<&Canonical<Ty>>,
 ) -> Option<Canonical<Ty>> {
     let _p = profile::span("deref");
-    if let Some(derefed) = builtin_deref(&ty.goal.value) {
+    match builtin_deref(&ty.goal.value) {
-        Some(Canonical { value: derefed, binders: ty.goal.binders.clone() })
+        Some(derefed) => Some(Canonical { value: derefed, binders: ty.goal.binders.clone() }),
-    } else {
+        None => deref_by_trait(db, krate, ty),
-        deref_by_trait(db, krate, ty)
     }
 }
 

crates/hir_ty/src/chalk_ext.rs

@@ -104,10 +104,9 @@ impl TyExt for Ty {
     }
 
     fn as_fn_def(&self, db: &dyn HirDatabase) -> Option<FunctionId> {
-        if let Some(CallableDefId::FunctionId(func)) = self.callable_def(db) {
+        match self.callable_def(db) {
-            Some(func)
+            Some(CallableDefId::FunctionId(func)) => Some(func),
-        } else {
+            Some(CallableDefId::StructId(_) | CallableDefId::EnumVariantId(_)) | None => None,
-            None
         }
     }
     fn as_reference(&self) -> Option<(&Ty, Lifetime, Mutability)> {

crates/hir_ty/src/diagnostics/match_check/deconstruct_pat.rs

@@ -105,10 +105,9 @@ impl IntRange {
 
     #[inline]
     fn from_range(lo: u128, hi: u128, scalar_ty: Scalar) -> IntRange {
-        if let Scalar::Bool = scalar_ty {
+        match scalar_ty {
-            IntRange { range: lo..=hi }
+            Scalar::Bool => IntRange { range: lo..=hi },
-        } else {
+            _ => unimplemented!(),
-            unimplemented!()
         }
     }
 

crates/hir_ty/src/display.rs

@@ -167,10 +167,9 @@ impl<'a> HirFormatter<'a> {
     }
 
     pub fn should_truncate(&self) -> bool {
-        if let Some(max_size) = self.max_size {
+        match self.max_size {
-            self.curr_size >= max_size
+            Some(max_size) => self.curr_size >= max_size,
-        } else {
+            None => false,
-            false
         }
     }
 

crates/hir_ty/src/infer/expr.rs

@@ -264,10 +264,9 @@ impl<'a> InferenceContext<'a> {
 
                 // collect explicitly written argument types
                 for arg_type in arg_types.iter() {
-                    let arg_ty = if let Some(type_ref) = arg_type {
+                    let arg_ty = match arg_type {
-                        self.make_ty(type_ref)
+                        Some(type_ref) => self.make_ty(type_ref),
-                    } else {
+                        None => self.table.new_type_var(),
-                        self.table.new_type_var()
                     };
                     sig_tys.push(arg_ty);
                 }

crates/hir_ty/src/infer/pat.rs

@@ -204,10 +204,9 @@ impl<'a> InferenceContext<'a> {
                 } else {
                     BindingMode::convert(*mode)
                 };
-                let inner_ty = if let Some(subpat) = subpat {
+                let inner_ty = match subpat {
-                    self.infer_pat(*subpat, &expected, default_bm)
+                    Some(subpat) => self.infer_pat(*subpat, &expected, default_bm),
-                } else {
+                    None => expected,
-                    expected
                 };
                 let inner_ty = self.insert_type_vars_shallow(inner_ty);
 

crates/hir_ty/src/infer/unify.rs

@@ -324,10 +324,9 @@ impl<'a> InferenceTable<'a> {
 
     /// Unify two types and register new trait goals that arise from that.
     pub(crate) fn unify(&mut self, ty1: &Ty, ty2: &Ty) -> bool {
-        let result = if let Ok(r) = self.try_unify(ty1, ty2) {
+        let result = match self.try_unify(ty1, ty2) {
-            r
+            Ok(r) => r,
-        } else {
+            Err(_) => return false,
-            return false;
         };
         self.register_infer_ok(result);
         true

crates/hir_ty/src/lower.rs

@@ -369,10 +369,9 @@ impl<'a> TyLoweringContext<'a> {
                 Some((it, None)) => it,
                 _ => return None,
             };
-        if let TypeNs::GenericParam(param_id) = resolution {
+        match resolution {
-            Some(param_id)
+            TypeNs::GenericParam(param_id) => Some(param_id),
-        } else {
+            _ => None,
-            None
         }
     }
 

crates/hir_ty/src/method_resolution.rs

@@ -82,10 +82,9 @@ impl TyFingerprint {
             TyKind::Ref(_, _, ty) => return TyFingerprint::for_trait_impl(ty),
             TyKind::Tuple(_, subst) => {
                 let first_ty = subst.interned().get(0).map(|arg| arg.assert_ty_ref(&Interner));
-                if let Some(ty) = first_ty {
+                match first_ty {
-                    return TyFingerprint::for_trait_impl(ty);
+                    Some(ty) => return TyFingerprint::for_trait_impl(ty),
-                } else {
+                    None => TyFingerprint::Unit,
-                    TyFingerprint::Unit
                 }
             }
             TyKind::AssociatedType(_, _)

crates/hir_ty/src/tests.rs

@@ -195,10 +195,9 @@ fn check_impl(ra_fixture: &str, allow_none: bool, only_types: bool, display_sour
                 mismatch.expected.display_test(&db),
                 mismatch.actual.display_test(&db)
             );
-            if let Some(annotation) = mismatches.remove(&range) {
+            match mismatches.remove(&range) {
-                assert_eq!(actual, annotation);
+                Some(annotation) => assert_eq!(actual, annotation),
-            } else {
+                None => format_to!(unexpected_type_mismatches, "{:?}: {}\n", range.range, actual),
-                format_to!(unexpected_type_mismatches, "{:?}: {}\n", range.range, actual);
             }
         }
         for (expr, mismatch) in inference_result.expr_type_mismatches() {
@@ -215,10 +214,9 @@ fn check_impl(ra_fixture: &str, allow_none: bool, only_types: bool, display_sour
                 mismatch.expected.display_test(&db),
                 mismatch.actual.display_test(&db)
             );
-            if let Some(annotation) = mismatches.remove(&range) {
+            match mismatches.remove(&range) {
-                assert_eq!(actual, annotation);
+                Some(annotation) => assert_eq!(actual, annotation),
-            } else {
+                None => format_to!(unexpected_type_mismatches, "{:?}: {}\n", range.range, actual),
-                format_to!(unexpected_type_mismatches, "{:?}: {}\n", range.range, actual);
             }
         }
     }

crates/ide/src/display/navigation_target.rs

@@ -292,10 +292,9 @@ impl TryToNav for hir::Impl {
     fn try_to_nav(&self, db: &RootDatabase) -> Option<NavigationTarget> {
         let src = self.source(db)?;
         let derive_attr = self.is_builtin_derive(db);
-        let frange = if let Some(item) = &derive_attr {
+        let frange = match &derive_attr {
-            item.syntax().original_file_range(db)
+            Some(item) => item.syntax().original_file_range(db),
-        } else {
+            None => src.syntax().original_file_range(db),
-            src.syntax().original_file_range(db)
         };
         let focus_range = if derive_attr.is_some() {
             None

crates/ide/src/join_lines.rs

@@ -136,10 +136,9 @@ fn remove_newline(
             }
             T!['}'] => {
                 // Removes: comma, newline (incl. surrounding whitespace)
-                let space = if let Some(left) = prev.prev_sibling_or_token() {
+                let space = match prev.prev_sibling_or_token() {
-                    compute_ws(left.kind(), next.kind())
+                    Some(left) => compute_ws(left.kind(), next.kind()),
-                } else {
+                    None => " ",
-                    " "
                 };
                 edit.replace(
                     TextRange::new(prev.text_range().start(), token.text_range().end()),

crates/ide/src/rename.rs

@@ -156,7 +156,7 @@ fn rename_to_self(sema: &Semantics<RootDatabase>, local: hir::Local) -> RenameRe
         _ => bail!("Cannot rename local to self outside of function"),
     };
 
-    if let Some(_) = fn_def.self_param(sema.db) {
+    if fn_def.self_param(sema.db).is_some() {
         bail!("Method already has a self parameter");
     }
 

crates/ide/src/static_index.rs

@@ -103,10 +103,9 @@ impl StaticIndex<'_> {
         for token in tokens {
             let range = token.text_range();
             let node = token.parent().unwrap();
-            let def = if let Some(x) = get_definition(&sema, token.clone()) {
+            let def = match get_definition(&sema, token.clone()) {
-                x
+                Some(x) => x,
-            } else {
+                None => continue,
-                continue;
             };
             let id = if let Some(x) = self.def_map.get(&def) {
                 *x
@@ -124,10 +123,9 @@ impl StaticIndex<'_> {
             let token = self.tokens.get_mut(id).unwrap();
             token.references.push(ReferenceData {
                 range: FileRange { range, file_id },
-                is_definition: if let Some(x) = def.try_to_nav(self.db) {
+                is_definition: match def.try_to_nav(self.db) {
-                    x.file_id == file_id && x.focus_or_full_range() == range
+                    Some(x) => x.file_id == file_id && x.focus_or_full_range() == range,
-                } else {
+                    None => false,
-                    false
                 },
             });
             result.tokens.push((range, id));

crates/ide/src/syntax_highlighting.rs

@@ -330,7 +330,7 @@ fn traverse(
             }
         }
 
-        if let Some(_) = macro_highlighter.highlight(element_to_highlight.clone()) {
+        if macro_highlighter.highlight(element_to_highlight.clone()).is_some() {
             continue;
         }
 

crates/ide_assists/src/handlers/convert_while_to_loop.rs

@@ -44,7 +44,7 @@ pub(crate) fn convert_while_to_loop(acc: &mut Assists, ctx: &AssistContext) -> O
     let cond = while_expr.condition()?;
 
     // Don't handle while let
-    if let Some(_) = cond.pat() {
+    if cond.pat().is_some() {
         return None;
     };
 

crates/ide_assists/src/handlers/extract_function.rs

@@ -827,10 +827,9 @@ impl FunctionBody {
         locals
             .map(|local| (local, local.source(ctx.db())))
             .filter(|(_, src)| is_defined_outside_of_body(ctx, self, src))
-            .filter_map(|(local, src)| {
+            .filter_map(|(local, src)| match src.value {
-                if let Either::Left(src) = src.value {
+                Either::Left(src) => Some((local, src)),
-                    Some((local, src))
+                Either::Right(_) => {
-                } else {
                     stdx::never!(false, "Local::is_self returned false, but source is SelfParam");
                     None
                 }

crates/ide_assists/src/handlers/extract_variable.rs

@@ -76,10 +76,11 @@ pub(crate) fn extract_variable(acc: &mut Assists, ctx: &AssistContext) -> Option
                 None => to_extract.syntax().text_range(),
             };
 
-            if let Anchor::WrapInBlock(_) = anchor {
+            match anchor {
-                format_to!(buf, "{{ let {} = ", var_name);
+                Anchor::Before(_) | Anchor::Replace(_) => {
-            } else {
+                    format_to!(buf, "let {} = ", var_name)
-                format_to!(buf, "let {} = ", var_name);
+                }
+                Anchor::WrapInBlock(_) => format_to!(buf, "{{ let {} = ", var_name),
             };
             format_to!(buf, "{}", to_extract.syntax());
 

crates/ide_assists/src/handlers/generate_function.rs

@@ -192,10 +192,9 @@ impl FunctionTemplate {
             Some(cap) => {
                 let cursor = if self.should_focus_return_type {
                     // Focus the return type if there is one
-                    if let Some(ref ret_type) = self.ret_type {
+                    match self.ret_type {
-                        ret_type.syntax()
+                        Some(ref ret_type) => ret_type.syntax(),
-                    } else {
+                        None => self.tail_expr.syntax(),
-                        self.tail_expr.syntax()
                     }
                 } else {
                     self.tail_expr.syntax()
@@ -428,10 +427,9 @@ fn fn_args(
         arg_types.push(match fn_arg_type(ctx, target_module, &arg) {
             Some(ty) => {
                 if !ty.is_empty() && ty.starts_with('&') {
-                    if let Some((new_ty, _)) = useless_type_special_case("", &ty[1..].to_owned()) {
+                    match useless_type_special_case("", &ty[1..].to_owned()) {
-                        new_ty
+                        Some((new_ty, _)) => new_ty,
-                    } else {
+                        None => ty,
-                        ty
                     }
                 } else {
                     ty
@@ -523,11 +521,7 @@ fn fn_arg_type(
         return None;
     }
 
-    if let Ok(rendered) = ty.display_source_code(ctx.db(), target_module.into()) {
+    ty.display_source_code(ctx.db(), target_module.into()).ok()
-        Some(rendered)
-    } else {
-        None
-    }
 }
 
 /// Returns the position inside the current mod or file
@@ -560,20 +554,14 @@ fn next_space_for_fn_in_module(
 ) -> Option<(FileId, GeneratedFunctionTarget)> {
     let file = module_source.file_id.original_file(db);
     let assist_item = match &module_source.value {
-        hir::ModuleSource::SourceFile(it) => {
+        hir::ModuleSource::SourceFile(it) => match it.items().last() {
-            if let Some(last_item) = it.items().last() {
+            Some(last_item) => GeneratedFunctionTarget::BehindItem(last_item.syntax().clone()),
-                GeneratedFunctionTarget::BehindItem(last_item.syntax().clone())
+            None => GeneratedFunctionTarget::BehindItem(it.syntax().clone()),
-            } else {
+        },
-                GeneratedFunctionTarget::BehindItem(it.syntax().clone())
+        hir::ModuleSource::Module(it) => match it.item_list().and_then(|it| it.items().last()) {
-            }
+            Some(last_item) => GeneratedFunctionTarget::BehindItem(last_item.syntax().clone()),
-        }
+            None => GeneratedFunctionTarget::InEmptyItemList(it.item_list()?.syntax().clone()),
-        hir::ModuleSource::Module(it) => {
+        },
-            if let Some(last_item) = it.item_list().and_then(|it| it.items().last()) {
-                GeneratedFunctionTarget::BehindItem(last_item.syntax().clone())
-            } else {
-                GeneratedFunctionTarget::InEmptyItemList(it.item_list()?.syntax().clone())
-            }
-        }
         hir::ModuleSource::BlockExpr(it) => {
             if let Some(last_item) =
                 it.statements().take_while(|stmt| matches!(stmt, ast::Stmt::Item(_))).last()

crates/ide_assists/src/handlers/inline_call.rs

@@ -141,10 +141,9 @@ pub(crate) fn inline_into_callers(acc: &mut Assists, ctx: &AssistContext) -> Opt
             for (file_id, refs) in usages.into_iter() {
                 inline_refs_for_file(file_id, refs);
             }
-            if let Some(refs) = current_file_usage {
+            match current_file_usage {
-                inline_refs_for_file(def_file, refs);
+                Some(refs) => inline_refs_for_file(def_file, refs),
-            } else {
+                None => builder.edit_file(def_file),
-                builder.edit_file(def_file);
             }
             if remove_def {
                 builder.delete(ast_func.syntax().text_range());

crates/ide_assists/src/handlers/pull_assignment_up.rs

@@ -127,12 +127,9 @@ impl<'a> AssignmentsCollector<'a> {
         }
     }
     fn collect_block(&mut self, block: &ast::BlockExpr) -> Option<()> {
-        let last_expr = block.tail_expr().or_else(|| {
+        let last_expr = block.tail_expr().or_else(|| match block.statements().last()? {
-            if let ast::Stmt::ExprStmt(stmt) = block.statements().last()? {
+            ast::Stmt::ExprStmt(stmt) => stmt.expr(),
-                stmt.expr()
+            ast::Stmt::Item(_) | ast::Stmt::LetStmt(_) => None,
-            } else {
-                None
-            }
         })?;
 
         if let ast::Expr::BinExpr(expr) = last_expr {

crates/ide_assists/src/handlers/qualify_path.rs

@@ -181,10 +181,9 @@ fn find_trait_method(
 fn item_as_trait(db: &RootDatabase, item: hir::ItemInNs) -> Option<hir::Trait> {
     let item_module_def = item.as_module_def()?;
 
-    if let hir::ModuleDef::Trait(trait_) = item_module_def {
+    match item_module_def {
-        Some(trait_)
+        hir::ModuleDef::Trait(trait_) => Some(trait_),
-    } else {
+        _ => item_module_def.as_assoc_item(db)?.containing_trait(db),
-        item_module_def.as_assoc_item(db)?.containing_trait(db)
     }
 }
 

crates/ide_assists/src/utils.rs

@@ -250,13 +250,10 @@ fn invert_special_case(expr: &ast::Expr) -> Option<ast::Expr> {
             };
             Some(make::expr_method_call(receiver, make::name_ref(method), arg_list))
         }
-        ast::Expr::PrefixExpr(pe) if pe.op_kind()? == ast::UnaryOp::Not => {
+        ast::Expr::PrefixExpr(pe) if pe.op_kind()? == ast::UnaryOp::Not => match pe.expr()? {
-            if let ast::Expr::ParenExpr(parexpr) = pe.expr()? {
+            ast::Expr::ParenExpr(parexpr) => parexpr.expr(),
-                parexpr.expr()
+            _ => pe.expr(),
-            } else {
+        },
-                pe.expr()
-            }
-        }
         ast::Expr::Literal(lit) => match lit.kind() {
             ast::LiteralKind::Bool(b) => match b {
                 true => Some(ast::Expr::Literal(make::expr_literal("false"))),
@@ -276,13 +273,10 @@ pub(crate) fn does_pat_match_variant(pat: &ast::Pat, var: &ast::Pat) -> bool {
     let first_node_text = |pat: &ast::Pat| pat.syntax().first_child().map(|node| node.text());
 
     let pat_head = match pat {
-        ast::Pat::IdentPat(bind_pat) => {
+        ast::Pat::IdentPat(bind_pat) => match bind_pat.pat() {
-            if let Some(p) = bind_pat.pat() {
+            Some(p) => first_node_text(&p),
-                first_node_text(&p)
+            None => return pat.syntax().text() == var.syntax().text(),
-            } else {
+        },
-                return pat.syntax().text() == var.syntax().text();
-            }
-        }
         pat => first_node_text(pat),
     };
 

crates/ide_assists/src/utils/suggest_name.rs

@@ -144,10 +144,9 @@ fn is_valid_name(name: &str) -> bool {
 fn is_useless_method(method: &ast::MethodCallExpr) -> bool {
     let ident = method.name_ref().and_then(|it| it.ident_token());
 
-    if let Some(ident) = ident {
+    match ident {
-        USELESS_METHODS.contains(&ident.text())
+        Some(ident) => USELESS_METHODS.contains(&ident.text()),
-    } else {
+        None => false,
-        false
     }
 }
 

crates/ide_completion/src/context.rs

@@ -509,10 +509,9 @@ impl<'a> CompletionContext<'a> {
                             .and_then(|pat| self.sema.type_of_pat(&pat))
                             .or_else(|| it.initializer().and_then(|it| self.sema.type_of_expr(&it)))
                             .map(TypeInfo::original);
-                        let name = if let Some(ast::Pat::IdentPat(ident)) = it.pat() {
+                        let name = match it.pat() {
-                            ident.name().map(NameOrNameRef::Name)
+                            Some(ast::Pat::IdentPat(ident)) => ident.name().map(NameOrNameRef::Name),
-                        } else {
+                            Some(_) | None => None,
-                            None
                         };
 
                         (ty, name)

crates/ide_completion/src/render/function.rs

@@ -74,10 +74,9 @@ impl<'a> FunctionRender<'a> {
 
     fn render(self, import_to_add: Option<ImportEdit>) -> CompletionItem {
         let params = self.params();
-        let call = if let Some(receiver) = &self.receiver {
+        let call = match &self.receiver {
-            format!("{}.{}", receiver, &self.name)
+            Some(receiver) => format!("{}.{}", receiver, &self.name),
-        } else {
+            None => self.name.clone(),
-            self.name.clone()
         };
         let mut item =
             CompletionItem::new(CompletionKind::Reference, self.ctx.source_range(), call.clone());

crates/ide_completion/src/render/pattern.rs

@@ -63,10 +63,9 @@ fn build_completion(
         .set_documentation(ctx.docs(def))
         .set_deprecated(ctx.is_deprecated(def))
         .detail(&pat);
-    if let Some(snippet_cap) = ctx.snippet_cap() {
+    match ctx.snippet_cap() {
-        item.insert_snippet(snippet_cap, pat);
+        Some(snippet_cap) => item.insert_snippet(snippet_cap, pat),
-    } else {
+        None => item.insert_text(pat),
-        item.insert_text(pat);
     };
     item.build()
 }

crates/ide_completion/src/render/struct_literal.rs

@@ -38,10 +38,9 @@ fn build_completion(
         .set_documentation(ctx.docs(def))
         .set_deprecated(ctx.is_deprecated(def))
         .detail(&literal);
-    if let Some(snippet_cap) = ctx.snippet_cap() {
+    match ctx.snippet_cap() {
-        item.insert_snippet(snippet_cap, literal);
+        Some(snippet_cap) => item.insert_snippet(snippet_cap, literal),
-    } else {
+        None => item.insert_text(literal),
-        item.insert_text(literal);
     };
     item.build()
 }

crates/ide_db/src/rename.rs

@@ -318,7 +318,7 @@ pub fn source_edit_from_references(
 }
 
 fn source_edit_from_name(edit: &mut TextEditBuilder, name: &ast::Name, new_name: &str) -> bool {
-    if let Some(_) = ast::RecordPatField::for_field_name(name) {
+    if ast::RecordPatField::for_field_name(name).is_some() {
         if let Some(ident_pat) = name.syntax().parent().and_then(ast::IdentPat::cast) {
             cov_mark::hit!(rename_record_pat_field_name_split);
             // Foo { ref mut field } -> Foo { new_name: ref mut field }

crates/ide_ssr/src/resolving.rs

@@ -47,10 +47,9 @@ impl ResolvedRule {
     ) -> Result<ResolvedRule, SsrError> {
         let resolver =
             Resolver { resolution_scope, placeholders_by_stand_in: rule.placeholders_by_stand_in };
-        let resolved_template = if let Some(template) = rule.template {
+        let resolved_template = match rule.template {
-            Some(resolver.resolve_pattern_tree(template)?)
+            Some(template) => Some(resolver.resolve_pattern_tree(template)?),
-        } else {
+            None => None,
-            None
         };
         Ok(ResolvedRule {
             pattern: resolver.resolve_pattern_tree(rule.pattern)?,

crates/parser/src/grammar.rs

@@ -67,11 +67,11 @@ pub(crate) mod entry_points {
     }
 
     pub(crate) fn stmt(p: &mut Parser) {
-        expressions::stmt(p, expressions::StmtWithSemi::No, true)
+        expressions::stmt(p, expressions::StmtWithSemi::No, true);
     }
 
     pub(crate) fn stmt_optional_semi(p: &mut Parser) {
-        expressions::stmt(p, expressions::StmtWithSemi::Optional, false)
+        expressions::stmt(p, expressions::StmtWithSemi::Optional, false);
     }
 
     pub(crate) fn visibility(p: &mut Parser) {
@@ -84,7 +84,7 @@ pub(crate) mod entry_points {
     }
 
     pub(crate) fn item(p: &mut Parser) {
-        items::item_or_macro(p, true)
+        items::item_or_macro(p, true);
     }
 
     pub(crate) fn macro_items(p: &mut Parser) {
@@ -109,7 +109,7 @@ pub(crate) mod entry_points {
     }
 
     pub(crate) fn attr(p: &mut Parser) {
-        attributes::outer_attrs(p)
+        attributes::outer_attrs(p);
     }
 }
 
@@ -128,8 +128,7 @@ pub(crate) fn reparser(
         EXTERN_ITEM_LIST => items::extern_item_list,
         TOKEN_TREE if first_child? == T!['{'] => items::token_tree,
         ASSOC_ITEM_LIST => match parent? {
-            IMPL => items::assoc_item_list,
+            IMPL | TRAIT => items::assoc_item_list,
-            TRAIT => items::assoc_item_list,
             _ => return None,
         },
         ITEM_LIST => items::item_list,
@@ -246,7 +245,7 @@ fn name_r(p: &mut Parser, recovery: TokenSet) {
 }
 
 fn name(p: &mut Parser) {
-    name_r(p, TokenSet::EMPTY)
+    name_r(p, TokenSet::EMPTY);
 }
 
 fn name_ref(p: &mut Parser) {

crates/parser/src/grammar/attributes.rs

@@ -2,13 +2,13 @@ use super::*;
 
 pub(super) fn inner_attrs(p: &mut Parser) {
     while p.at(T![#]) && p.nth(1) == T![!] {
-        attr(p, true)
+        attr(p, true);
     }
 }
 
 pub(super) fn outer_attrs(p: &mut Parser) {
     while p.at(T![#]) {
-        attr(p, false)
+        attr(p, false);
     }
 }
 

crates/parser/src/grammar/expressions.rs

@@ -139,7 +139,7 @@ pub(super) fn expr_block_contents(p: &mut Parser) {
             continue;
         }
 
-        stmt(p, StmtWithSemi::Yes, false)
+        stmt(p, StmtWithSemi::Yes, false);
     }
 }
 
@@ -311,7 +311,7 @@ fn lhs(p: &mut Parser, r: Restrictions) -> Option<(CompletedMarker, BlockLike)>
         _ => {
             // test full_range_expr
             // fn foo() { xs[..]; }
-            for &op in [T![..=], T![..]].iter() {
+            for op in [T![..=], T![..]] {
                 if p.at(op) {
                     m = p.start();
                     p.bump(op);
@@ -468,12 +468,12 @@ fn field_expr(p: &mut Parser, lhs: CompletedMarker) -> CompletedMarker {
     let m = lhs.precede(p);
     p.bump(T![.]);
     if p.at(IDENT) || p.at(INT_NUMBER) {
-        name_ref_or_index(p)
+        name_ref_or_index(p);
     } else if p.at(FLOAT_NUMBER) {
         // FIXME: How to recover and instead parse INT + T![.]?
         p.bump_any();
     } else {
-        p.error("expected field name or number")
+        p.error("expected field name or number");
     }
     m.complete(p, FIELD_EXPR)
 }

crates/parser/src/grammar/expressions/atom.rs

@@ -374,7 +374,7 @@ fn match_expr(p: &mut Parser) -> CompletedMarker {
     if p.at(T!['{']) {
         match_arm_list(p);
     } else {
-        p.error("expected `{`")
+        p.error("expected `{`");
     }
     m.complete(p, MATCH_EXPR)
 }
@@ -602,7 +602,7 @@ fn try_block_expr(p: &mut Parser, m: Option<Marker>) -> CompletedMarker {
     if p.at(T!['{']) {
         stmt_list(p);
     } else {
-        p.error("expected a block")
+        p.error("expected a block");
     }
     m.complete(p, BLOCK_EXPR)
 }
@@ -639,7 +639,7 @@ fn meta_var_expr(p: &mut Parser) -> CompletedMarker {
         }
         _ => {
             while !p.at(R_DOLLAR) {
-                p.bump_any()
+                p.bump_any();
             }
             p.bump(R_DOLLAR);
             m.complete(p, ERROR)

crates/parser/src/grammar/generic_params.rs

@@ -34,7 +34,7 @@ fn generic_param(p: &mut Parser) {
         T![const] => const_param(p, m),
         _ => {
             m.abandon(p);
-            p.err_and_bump("expected type parameter")
+            p.err_and_bump("expected type parameter");
         }
     }
 }
@@ -62,7 +62,7 @@ fn type_param(p: &mut Parser, m: Marker) {
         // test type_param_default
         // struct S<T = i32>;
         p.bump(T![=]);
-        types::type_(p)
+        types::type_(p);
     }
     m.complete(p, TYPE_PARAM);
 }

crates/parser/src/grammar/items.rs

@@ -20,7 +20,7 @@ use super::*;
 pub(super) fn mod_contents(p: &mut Parser, stop_on_r_curly: bool) {
     attributes::inner_attrs(p);
     while !p.at(EOF) && !(p.at(T!['}']) && stop_on_r_curly) {
-        item_or_macro(p, stop_on_r_curly)
+        item_or_macro(p, stop_on_r_curly);
     }
 }
 
@@ -165,7 +165,7 @@ pub(super) fn opt_item(p: &mut Parser, m: Marker) -> Result<(), Marker> {
                     p.bump_remap(T![default]);
                     p.bump(T![async]);
                     if is_unsafe {
-                        p.bump(T![unsafe])
+                        p.bump(T![unsafe]);
                     }
                     has_mods = true;
                 }
@@ -404,7 +404,7 @@ fn fn_(p: &mut Parser, m: Marker) {
         // trait T { fn foo(); }
         p.bump(T![;]);
     } else {
-        expressions::block_expr(p)
+        expressions::block_expr(p);
     }
     m.complete(p, FN);
 }

crates/parser/src/grammar/items/adt.rs

@@ -58,7 +58,7 @@ pub(super) fn enum_(p: &mut Parser, m: Marker) {
     if p.at(T!['{']) {
         variant_list(p);
     } else {
-        p.error("expected `{`")
+        p.error("expected `{`");
     }
     m.complete(p, ENUM);
 }

crates/parser/src/grammar/items/consts.rs

@@ -4,12 +4,12 @@ use super::*;
 // const C: u32 = 92;
 pub(super) fn konst(p: &mut Parser, m: Marker) {
     p.bump(T![const]);
-    const_or_static(p, m, true)
+    const_or_static(p, m, true);
 }
 
 pub(super) fn static_(p: &mut Parser, m: Marker) {
     p.bump(T![static]);
-    const_or_static(p, m, false)
+    const_or_static(p, m, false);
 }
 
 fn const_or_static(p: &mut Parser, m: Marker, is_const: bool) {
@@ -27,7 +27,7 @@ fn const_or_static(p: &mut Parser, m: Marker, is_const: bool) {
     if p.at(T![:]) {
         types::ascription(p);
     } else {
-        p.error("missing type for `const` or `static`")
+        p.error("missing type for `const` or `static`");
     }
     if p.eat(T![=]) {
         expressions::expr(p);

crates/parser/src/grammar/params.rs

@@ -6,21 +6,21 @@ use super::*;
 // fn c(x: i32, ) {}
 // fn d(x: i32, y: ()) {}
 pub(super) fn param_list_fn_def(p: &mut Parser) {
-    list_(p, Flavor::FnDef)
+    list_(p, Flavor::FnDef);
 }
 
 // test param_list_opt_patterns
 // fn foo<F: FnMut(&mut Foo<'a>)>(){}
 pub(super) fn param_list_fn_trait(p: &mut Parser) {
-    list_(p, Flavor::FnTrait)
+    list_(p, Flavor::FnTrait);
 }
 
 pub(super) fn param_list_fn_ptr(p: &mut Parser) {
-    list_(p, Flavor::FnPointer)
+    list_(p, Flavor::FnPointer);
 }
 
 pub(super) fn param_list_closure(p: &mut Parser) {
-    list_(p, Flavor::Closure)
+    list_(p, Flavor::Closure);
 }
 
 #[derive(Debug, Clone, Copy)]
@@ -104,13 +104,13 @@ fn param(p: &mut Parser, m: Marker, flavor: Flavor) -> Variadic {
         Flavor::FnDef => {
             patterns::pattern(p);
             if variadic_param(p) {
-                res = Variadic(true)
+                res = Variadic(true);
             } else if p.at(T![:]) {
-                types::ascription(p)
+                types::ascription(p);
             } else {
                 // test_err missing_fn_param_type
                 // fn f(x y: i32, z, t: i32) {}
-                p.error("missing type for function parameter")
+                p.error("missing type for function parameter");
             }
         }
         // test value_parameters_no_patterns
@@ -128,11 +128,11 @@ fn param(p: &mut Parser, m: Marker, flavor: Flavor) -> Variadic {
             if (p.at(IDENT) || p.at(UNDERSCORE)) && p.nth(1) == T![:] && !p.nth_at(1, T![::]) {
                 patterns::pattern_single(p);
                 if variadic_param(p) {
-                    res = Variadic(true)
+                    res = Variadic(true);
                 } else if p.at(T![:]) {
-                    types::ascription(p)
+                    types::ascription(p);
                 } else {
-                    p.error("missing type for function parameter")
+                    p.error("missing type for function parameter");
                 }
             } else {
                 types::type_(p);

crates/parser/src/grammar/paths.rs

@@ -16,15 +16,15 @@ pub(super) fn is_use_path_start(p: &Parser) -> bool {
 }
 
 pub(super) fn use_path(p: &mut Parser) {
-    path(p, Mode::Use)
+    path(p, Mode::Use);
 }
 
 pub(crate) fn type_path(p: &mut Parser) {
-    path(p, Mode::Type)
+    path(p, Mode::Type);
 }
 
 pub(super) fn expr_path(p: &mut Parser) {
-    path(p, Mode::Expr)
+    path(p, Mode::Expr);
 }
 
 pub(crate) fn type_path_for_qualifier(p: &mut Parser, qual: CompletedMarker) -> CompletedMarker {
@@ -117,7 +117,7 @@ fn opt_path_type_args(p: &mut Parser, mode: Mode) {
                 params::param_list_fn_trait(p);
                 opt_ret_type(p);
             } else {
-                generic_args::opt_generic_arg_list(p, false)
+                generic_args::opt_generic_arg_list(p, false);
             }
         }
         Mode::Expr => generic_args::opt_generic_arg_list(p, true),

crates/parser/src/grammar/patterns.rs

@@ -19,7 +19,7 @@ pub(crate) fn pattern(p: &mut Parser) {
 
 /// Parses a pattern list separated by pipes `|`.
 pub(super) fn pattern_top(p: &mut Parser) {
-    pattern_top_r(p, PAT_RECOVERY_SET)
+    pattern_top_r(p, PAT_RECOVERY_SET);
 }
 
 pub(crate) fn pattern_single(p: &mut Parser) {
@@ -78,7 +78,7 @@ fn pattern_single_r(p: &mut Parser, recovery_set: TokenSet) {
 
         // FIXME: support half_open_range_patterns (`..=2`),
         // exclusive_range_pattern (`..5`) with missing lhs
-        for &range_op in [T![...], T![..=], T![..]].iter() {
+        for range_op in [T![...], T![..=], T![..]] {
             if p.at(range_op) {
                 let m = lhs.precede(p);
                 p.bump(range_op);

crates/parser/src/grammar/types.rs

@@ -57,7 +57,7 @@ fn type_with_bounds_cond(p: &mut Parser, allow_bounds: bool) {
 pub(super) fn ascription(p: &mut Parser) {
     assert!(p.at(T![:]));
     p.bump(T![:]);
-    type_(p)
+    type_(p);
 }
 
 fn paren_or_tuple_type(p: &mut Parser) {
@@ -204,7 +204,7 @@ fn fn_ptr_type(p: &mut Parser) {
     if p.at(T!['(']) {
         params::param_list_fn_ptr(p);
     } else {
-        p.error("expected parameters")
+        p.error("expected parameters");
     }
     // test fn_pointer_type_with_ret
     // type F = fn() -> ();
@@ -274,7 +274,7 @@ fn dyn_trait_type(p: &mut Parser) {
 // type C = self::Foo;
 // type D = super::Foo;
 pub(super) fn path_type(p: &mut Parser) {
-    path_type_(p, true)
+    path_type_(p, true);
 }
 
 // test macro_call_type

crates/parser/src/parser.rs

@@ -177,7 +177,7 @@ impl<'t> Parser<'t> {
         if kind == EOF {
             return;
         }
-        self.do_bump(kind, 1)
+        self.do_bump(kind, 1);
     }
 
     /// Advances the parser by one token, remapping its kind.
@@ -200,7 +200,7 @@ impl<'t> Parser<'t> {
     /// does.
     pub(crate) fn error<T: Into<String>>(&mut self, message: T) {
         let msg = ParseError(Box::new(message.into()));
-        self.push_event(Event::Error { msg })
+        self.push_event(Event::Error { msg });
     }
 
     /// Consume the next token if it is `kind` or emit an error
@@ -258,7 +258,7 @@ impl<'t> Parser<'t> {
     }
 
     fn push_event(&mut self, event: Event) {
-        self.events.push(event)
+        self.events.push(event);
     }
 }
 

crates/parser/src/token_set.rs

@@ -14,7 +14,7 @@ impl TokenSet {
         let mut i = 0;
         while i < kinds.len() {
             res |= mask(kinds[i]);
-            i += 1
+            i += 1;
         }
         TokenSet(res)
     }

crates/paths/src/lib.rs

@@ -271,7 +271,7 @@ impl RelPath {
 /// Taken from <https://github.com/rust-lang/cargo/blob/79c769c3d7b4c2cf6a93781575b7f592ef974255/src/cargo/util/paths.rs#L60-L85>
 fn normalize_path(path: &Path) -> PathBuf {
     let mut components = path.components().peekable();
-    let mut ret = if let Some(c @ Component::Prefix(..)) = components.peek().cloned() {
+    let mut ret = if let Some(c @ Component::Prefix(..)) = components.peek().copied() {
         components.next();
         PathBuf::from(c.as_os_str())
     } else {

crates/proc_macro_api/src/msg/flat.rs

@@ -246,7 +246,7 @@ impl<'a> Writer<'a> {
 
     fn enqueue(&mut self, subtree: &'a tt::Subtree) -> u32 {
         let idx = self.subtree.len();
-        let delimiter_id = subtree.delimiter.map(|it| it.id).unwrap_or_else(TokenId::unspecified);
+        let delimiter_id = subtree.delimiter.map_or(TokenId::unspecified(), |it| it.id);
         let delimiter_kind = subtree.delimiter.map(|it| it.kind);
         self.subtree.push(SubtreeRepr { id: delimiter_id, kind: delimiter_kind, tt: [!0, !0] });
         self.work.push_back((idx, subtree));
@@ -320,7 +320,7 @@ impl Reader {
                     })
                     .collect(),
             };
-            res[i] = Some(s)
+            res[i] = Some(s);
         }
 
         res[0].take().unwrap()

crates/proc_macro_srv/src/abis/abi_1_47/rustc_server.rs

@@ -497,10 +497,9 @@ impl server::Literal for Rustc {
     }
 
     fn integer(&mut self, n: &str) -> Self::Literal {
-        let n = if let Ok(n) = n.parse::<i128>() {
+        let n = match n.parse::<i128>() {
-            n.to_string()
+            Ok(n) => n.to_string(),
-        } else {
+            Err(_) => n.parse::<u128>().unwrap().to_string(),
-            n.parse::<u128>().unwrap().to_string()
         };
         Literal { text: n.into(), id: tt::TokenId::unspecified() }
     }

crates/proc_macro_srv/src/abis/abi_1_55/rustc_server.rs

@@ -500,10 +500,9 @@ impl server::Literal for Rustc {
     }
 
     fn integer(&mut self, n: &str) -> Self::Literal {
-        let n = if let Ok(n) = n.parse::<i128>() {
+        let n = match n.parse::<i128>() {
-            n.to_string()
+            Ok(n) => n.to_string(),
-        } else {
+            Err(_) => n.parse::<u128>().unwrap().to_string(),
-            n.parse::<u128>().unwrap().to_string()
         };
         Literal { text: n.into(), id: tt::TokenId::unspecified() }
     }

crates/proc_macro_srv/src/abis/abi_1_56/rustc_server.rs

@@ -504,10 +504,9 @@ impl server::Literal for Rustc {
     }
 
     fn integer(&mut self, n: &str) -> Self::Literal {
-        let n = if let Ok(n) = n.parse::<i128>() {
+        let n = match n.parse::<i128>() {
-            n.to_string()
+            Ok(n) => n.to_string(),
-        } else {
+            Err(_) => n.parse::<u128>().unwrap().to_string(),
-            n.parse::<u128>().unwrap().to_string()
         };
         Literal { text: n.into(), id: tt::TokenId::unspecified() }
     }

crates/profile/src/hprof.rs

@@ -93,7 +93,7 @@ struct ProfilerImpl {
 impl ProfileSpan {
     pub fn detail(mut self, detail: impl FnOnce() -> String) -> ProfileSpan {
         if let Some(profiler) = &mut self.0 {
-            profiler.detail = Some(detail())
+            profiler.detail = Some(detail());
         }
         self
     }
@@ -114,7 +114,7 @@ impl HeartbeatSpan {
     #[inline]
     pub fn new(enabled: bool) -> Self {
         if enabled {
-            with_profile_stack(|it| it.heartbeats(true))
+            with_profile_stack(|it| it.heartbeats(true));
         }
         Self { enabled }
     }
@@ -123,7 +123,7 @@ impl HeartbeatSpan {
 impl Drop for HeartbeatSpan {
     fn drop(&mut self) {
         if self.enabled {
-            with_profile_stack(|it| it.heartbeats(false))
+            with_profile_stack(|it| it.heartbeats(false));
         }
     }
 }
@@ -238,7 +238,7 @@ impl ProfileStack {
             self.heartbeat(frame.heartbeats);
             let avg_span = duration / (frame.heartbeats + 1);
             if avg_span > self.filter.heartbeat_longer_than {
-                eprintln!("Too few heartbeats {} ({}/{:?})?", label, frame.heartbeats, duration)
+                eprintln!("Too few heartbeats {} ({}/{:?})?", label, frame.heartbeats, duration);
             }
         }
 
@@ -292,7 +292,7 @@ fn print(
         accounted_for += tree[child].duration;
 
         if tree[child].duration.as_millis() > longer_than.as_millis() {
-            print(tree, child, level + 1, longer_than, out)
+            print(tree, child, level + 1, longer_than, out);
         } else {
             let (total_duration, cnt) =
                 short_children.entry(tree[child].label).or_insert((Duration::default(), 0));
@@ -301,7 +301,7 @@ fn print(
         }
     }
 
-    for (child_msg, (duration, count)) in short_children.iter() {
+    for (child_msg, (duration, count)) in &short_children {
         writeln!(out, "    {}{} - {} ({} calls)", current_indent, ms(*duration), child_msg, count)
             .expect("printing profiling info");
     }

crates/profile/src/lib.rs

@@ -92,7 +92,7 @@ pub fn cpu_span() -> CpuSpan {
     {
         eprintln!(
             r#"cpu profiling is disabled, uncomment `default = [ "cpu_profiler" ]` in Cargo.toml to enable."#
-        )
+        );
     }
 
     CpuSpan { _private: () }

crates/profile/src/stop_watch.rs

@@ -70,15 +70,15 @@ impl fmt::Display for StopWatchSpan {
             let mut prefix = "";
             if instructions > 10000 {
                 instructions /= 1000;
-                prefix = "k"
+                prefix = "k";
             }
             if instructions > 10000 {
                 instructions /= 1000;
-                prefix = "m"
+                prefix = "m";
             }
             if instructions > 10000 {
                 instructions /= 1000;
-                prefix = "g"
+                prefix = "g";
             }
             write!(f, ", {}{}instr", instructions, prefix)?;
         }

crates/rust-analyzer/build.rs

@@ -4,7 +4,7 @@ use std::{env, path::PathBuf, process::Command};
 
 fn main() {
     set_rerun();
-    println!("cargo:rustc-env=REV={}", rev())
+    println!("cargo:rustc-env=REV={}", rev());
 }
 
 fn set_rerun() {

crates/rust-analyzer/src/handlers.rs

@@ -427,10 +427,9 @@ pub(crate) fn handle_workspace_symbol(
         // If no explicit marker was set, check request params. If that's also empty
         // use global config.
         if !all_symbols {
-            let search_kind = if let Some(ref search_kind) = params.search_kind {
+            let search_kind = match params.search_kind {
-                search_kind
+                Some(ref search_kind) => search_kind,
-            } else {
+                None => &config.search_kind,
-                &config.search_kind
             };
             all_symbols = match search_kind {
                 lsp_ext::WorkspaceSymbolSearchKind::OnlyTypes => false,
@@ -439,10 +438,9 @@ pub(crate) fn handle_workspace_symbol(
         }
 
         if !libs {
-            let search_scope = if let Some(ref search_scope) = params.search_scope {
+            let search_scope = match params.search_scope {
-                search_scope
+                Some(ref search_scope) => search_scope,
-            } else {
+                None => &config.search_scope,
-                &config.search_scope
             };
             libs = match search_scope {
                 lsp_ext::WorkspaceSymbolSearchScope::Workspace => false,

crates/sourcegen/src/lib.rs

@@ -33,9 +33,9 @@ pub fn list_files(dir: &Path) -> Vec<PathBuf> {
                 path.file_name().unwrap_or_default().to_str().unwrap_or_default().starts_with('.');
             if !is_hidden {
                 if file_type.is_dir() {
-                    work.push(path)
+                    work.push(path);
                 } else if file_type.is_file() {
-                    res.push(path)
+                    res.push(path);
                 }
             }
         }
@@ -66,7 +66,7 @@ impl CommentBlock {
                         panic!(
                             "Use plain (non-doc) comments with tags like {}:\n    {}",
                             tag, first
-                        )
+                        );
                     }
 
                     block.id = id.trim().to_string();
@@ -106,7 +106,7 @@ impl CommentBlock {
             }
         }
         if !block.contents.is_empty() {
-            res.push(block)
+            res.push(block);
         }
         res
     }
@@ -139,7 +139,7 @@ fn ensure_rustfmt() {
         panic!(
             "Failed to run rustfmt from toolchain 'stable'. \
                  Please run `rustup component add rustfmt --toolchain stable` to install it.",
-        )
+        );
     }
 }
 
@@ -185,7 +185,7 @@ pub fn ensure_file_contents(file: &Path, contents: &str) {
         let _ = fs::create_dir_all(parent);
     }
     fs::write(file, contents).unwrap();
-    panic!("some file was not up to date and has been updated, simply re-run the tests")
+    panic!("some file was not up to date and has been updated, simply re-run the tests");
 }
 
 fn normalize_newlines(s: &str) -> String {

crates/stdx/src/lib.rs

@@ -45,7 +45,7 @@ fn to_snake_case<F: Fn(&char) -> char>(s: &str, change_case: F) -> String {
         if c.is_ascii_uppercase() && prev {
             // This check is required to not translate `Weird_Case` into `weird__case`.
             if !buf.ends_with('_') {
-                buf.push('_')
+                buf.push('_');
             }
         }
         prev = true;
@@ -60,7 +60,7 @@ pub fn replace(buf: &mut String, from: char, to: &str) {
         return;
     }
     // FIXME: do this in place.
-    *buf = buf.replace(from, to)
+    *buf = buf.replace(from, to);
 }
 
 pub fn trim_indent(mut text: &str) -> String {
@@ -101,7 +101,7 @@ pub fn defer<F: FnOnce()>(f: F) -> impl Drop {
     impl<F: FnOnce()> Drop for D<F> {
         fn drop(&mut self) {
             if let Some(f) = self.0.take() {
-                f()
+                f();
             }
         }
     }

crates/stdx/src/panic_context.rs

@@ -25,19 +25,19 @@ impl PanicContext {
                 if !ctx.is_empty() {
                     eprintln!("Panic context:");
                     for frame in ctx.iter() {
-                        eprintln!("> {}\n", frame)
+                        eprintln!("> {}\n", frame);
                     }
                 }
-                default_hook(panic_info)
+                default_hook(panic_info);
-            })
+            });
         };
-        panic::set_hook(Box::new(hook))
+        panic::set_hook(Box::new(hook));
     }
 }
 
 impl Drop for PanicContext {
     fn drop(&mut self) {
-        with_ctx(|ctx| assert!(ctx.pop().is_some()))
+        with_ctx(|ctx| assert!(ctx.pop().is_some()));
     }
 }
 
@@ -45,5 +45,5 @@ fn with_ctx(f: impl FnOnce(&mut Vec<String>)) {
     thread_local! {
         static CTX: RefCell<Vec<String>> = RefCell::new(Vec::new());
     }
-    CTX.with(|ctx| f(&mut *ctx.borrow_mut()))
+    CTX.with(|ctx| f(&mut *ctx.borrow_mut()));
 }

crates/stdx/src/process.rs

@@ -42,9 +42,9 @@ pub fn streaming_output(
                 };
                 for line in String::from_utf8_lossy(new_lines).lines() {
                     if is_out {
-                        on_stdout_line(line)
+                        on_stdout_line(line);
                     } else {
-                        on_stderr_line(line)
+                        on_stderr_line(line);
                     }
                 }
             }

crates/syntax/src/algo.rs

@@ -112,15 +112,15 @@ impl TreeDiff {
     pub fn into_text_edit(&self, builder: &mut TextEditBuilder) {
         let _p = profile::span("into_text_edit");
 
-        for (anchor, to) in self.insertions.iter() {
+        for (anchor, to) in &self.insertions {
             let offset = match anchor {
                 TreeDiffInsertPos::After(it) => it.text_range().end(),
                 TreeDiffInsertPos::AsFirstChild(it) => it.text_range().start(),
             };
             to.iter().for_each(|to| builder.insert(offset, to.to_string()));
         }
-        for (from, to) in self.replacements.iter() {
+        for (from, to) in &self.replacements {
-            builder.replace(from.text_range(), to.to_string())
+            builder.replace(from.text_range(), to.to_string());
         }
         for text_range in self.deletions.iter().map(SyntaxElement::text_range) {
             builder.delete(text_range);
@@ -217,9 +217,8 @@ pub fn diff(from: &SyntaxNode, to: &SyntaxNode) -> TreeDiff {
                             cov_mark::hit!(diff_insertions);
                             insert = true;
                             break;
-                        } else {
-                            look_ahead_scratch.push(rhs_child);
                         }
+                        look_ahead_scratch.push(rhs_child);
                     }
                     let drain = look_ahead_scratch.drain(..);
                     if insert {
@@ -233,7 +232,7 @@ pub fn diff(from: &SyntaxNode, to: &SyntaxNode) -> TreeDiff {
                         diff.insertions.entry(insert_pos).or_insert_with(Vec::new).extend(drain);
                         rhs_children = rhs_children_clone;
                     } else {
-                        go(diff, lhs_ele, rhs_ele)
+                        go(diff, lhs_ele, rhs_ele);
                     }
                 }
             }

crates/syntax/src/ast/edit.rs

@@ -126,7 +126,7 @@ impl IndentLevel {
             if let Some(ws) = ast::Whitespace::cast(token) {
                 if ws.text().contains('\n') {
                     let new_ws = make::tokens::whitespace(&format!("{}{}", ws.syntax(), self));
-                    ted::replace(ws.syntax(), &new_ws)
+                    ted::replace(ws.syntax(), &new_ws);
                 }
             }
         }
@@ -143,7 +143,7 @@ impl IndentLevel {
                     let new_ws = make::tokens::whitespace(
                         &ws.syntax().text().replace(&format!("\n{}", self), "\n"),
                     );
-                    ted::replace(ws.syntax(), &new_ws)
+                    ted::replace(ws.syntax(), &new_ws);
                 }
             }
         }

crates/syntax/src/ast/edit_in_place.rs

@@ -49,7 +49,7 @@ impl GenericParamsOwnerEdit for ast::Fn {
             } else {
                 Position::last_child_of(self.syntax())
             };
-            create_where_clause(position)
+            create_where_clause(position);
         }
         self.where_clause().unwrap()
     }
@@ -60,10 +60,9 @@ impl GenericParamsOwnerEdit for ast::Impl {
         match self.generic_param_list() {
             Some(it) => it,
             None => {
-                let position = if let Some(imp_token) = self.impl_token() {
+                let position = match self.impl_token() {
-                    Position::after(imp_token)
+                    Some(imp_token) => Position::after(imp_token),
-                } else {
+                    None => Position::last_child_of(self.syntax()),
-                    Position::last_child_of(self.syntax())
                 };
                 create_generic_param_list(position)
             }
@@ -72,12 +71,11 @@ impl GenericParamsOwnerEdit for ast::Impl {
 
     fn get_or_create_where_clause(&self) -> ast::WhereClause {
         if self.where_clause().is_none() {
-            let position = if let Some(items) = self.assoc_item_list() {
+            let position = match self.assoc_item_list() {
-                Position::before(items.syntax())
+                Some(items) => Position::before(items.syntax()),
-            } else {
+                None => Position::last_child_of(self.syntax()),
-                Position::last_child_of(self.syntax())
             };
-            create_where_clause(position)
+            create_where_clause(position);
         }
         self.where_clause().unwrap()
     }
@@ -102,12 +100,11 @@ impl GenericParamsOwnerEdit for ast::Trait {
 
     fn get_or_create_where_clause(&self) -> ast::WhereClause {
         if self.where_clause().is_none() {
-            let position = if let Some(items) = self.assoc_item_list() {
+            let position = match self.assoc_item_list() {
-                Position::before(items.syntax())
+                Some(items) => Position::before(items.syntax()),
-            } else {
+                None => Position::last_child_of(self.syntax()),
-                Position::last_child_of(self.syntax())
             };
-            create_where_clause(position)
+            create_where_clause(position);
         }
         self.where_clause().unwrap()
     }
@@ -145,7 +142,7 @@ impl GenericParamsOwnerEdit for ast::Struct {
             } else {
                 Position::last_child_of(self.syntax())
             };
-            create_where_clause(position)
+            create_where_clause(position);
         }
         self.where_clause().unwrap()
     }
@@ -177,7 +174,7 @@ impl GenericParamsOwnerEdit for ast::Enum {
             } else {
                 Position::last_child_of(self.syntax())
             };
-            create_where_clause(position)
+            create_where_clause(position);
         }
         self.where_clause().unwrap()
     }
@@ -234,7 +231,7 @@ impl ast::GenericParamList {
             }
             None => {
                 let after_l_angle = Position::after(self.l_angle_token().unwrap());
-                ted::insert(after_l_angle, generic_param.syntax())
+                ted::insert(after_l_angle, generic_param.syntax());
             }
         }
     }
@@ -247,18 +244,15 @@ impl ast::WhereClause {
                 ted::append_child_raw(self.syntax(), make::token(T![,]));
             }
         }
-        ted::append_child(self.syntax(), predicate.syntax())
+        ted::append_child(self.syntax(), predicate.syntax());
     }
 }
 
 impl ast::TypeBoundList {
     pub fn remove(&self) {
-        if let Some(colon) =
+        match self.syntax().siblings_with_tokens(Direction::Prev).find(|it| it.kind() == T![:]) {
-            self.syntax().siblings_with_tokens(Direction::Prev).find(|it| it.kind() == T![:])
+            Some(colon) => ted::remove_all(colon..=self.syntax().clone().into()),
-        {
+            None => ted::remove(self.syntax()),
-            ted::remove_all(colon..=self.syntax().clone().into())
-        } else {
-            ted::remove(self.syntax())
         }
     }
 }
@@ -267,7 +261,7 @@ impl ast::PathSegment {
     pub fn get_or_create_generic_arg_list(&self) -> ast::GenericArgList {
         if self.generic_arg_list().is_none() {
             let arg_list = make::generic_arg_list().clone_for_update();
-            ted::append_child(self.syntax(), arg_list.syntax())
+            ted::append_child(self.syntax(), arg_list.syntax());
         }
         self.generic_arg_list().unwrap()
     }
@@ -275,7 +269,7 @@ impl ast::PathSegment {
 
 impl ast::UseTree {
     pub fn remove(&self) {
-        for &dir in [Direction::Next, Direction::Prev].iter() {
+        for dir in [Direction::Next, Direction::Prev] {
             if let Some(next_use_tree) = neighbor(self, dir) {
                 let separators = self
                     .syntax()
@@ -286,7 +280,7 @@ impl ast::UseTree {
                 break;
             }
         }
-        ted::remove(self.syntax())
+        ted::remove(self.syntax());
     }
 }
 
@@ -301,13 +295,13 @@ impl ast::Use {
             let ws_text = next_ws.syntax().text();
             if let Some(rest) = ws_text.strip_prefix('\n') {
                 if rest.is_empty() {
-                    ted::remove(next_ws.syntax())
+                    ted::remove(next_ws.syntax());
                 } else {
-                    ted::replace(next_ws.syntax(), make::tokens::whitespace(rest))
+                    ted::replace(next_ws.syntax(), make::tokens::whitespace(rest));
                 }
             }
         }
-        ted::remove(self.syntax())
+        ted::remove(self.syntax());
     }
 }
 
@@ -455,7 +449,7 @@ impl ast::RecordExprField {
     /// This will either replace the initializer, or in the case that this is a shorthand convert
     /// the initializer into the name ref and insert the expr as the new initializer.
     pub fn replace_expr(&self, expr: ast::Expr) {
-        if let Some(_) = self.name_ref() {
+        if self.name_ref().is_some() {
             match self.expr() {
                 Some(prev) => ted::replace(prev.syntax(), expr.syntax()),
                 None => ted::append_child(self.syntax(), expr.syntax()),
@@ -525,7 +519,7 @@ pub trait Indent: AstNode + Clone + Sized {
     fn reindent_to(&self, target_level: IndentLevel) {
         let current_level = IndentLevel::from_node(self.syntax());
         self.dedent(current_level);
-        self.indent(target_level)
+        self.indent(target_level);
     }
 }
 

crates/syntax/src/ast/make.rs

@@ -257,7 +257,7 @@ pub fn block_expr(
         format_to!(buf, "    {}\n", stmt);
     }
     if let Some(tail_expr) = tail_expr {
-        format_to!(buf, "    {}\n", tail_expr)
+        format_to!(buf, "    {}\n", tail_expr);
     }
     buf += "}";
     ast_from_text(&format!("fn f() {}", buf))
@@ -644,9 +644,14 @@ pub fn fn_(
     ret_type: Option<ast::RetType>,
     is_async: bool,
 ) -> ast::Fn {
-    let type_params =
+    let type_params = match type_params {
-        if let Some(type_params) = type_params { format!("<{}>", type_params) } else { "".into() };
+        Some(type_params) => format!("<{}>", type_params),
-    let ret_type = if let Some(ret_type) = ret_type { format!("{} ", ret_type) } else { "".into() };
+        None => "".into(),
+    };
+    let ret_type = match ret_type {
+        Some(ret_type) => format!("{} ", ret_type),
+        None => "".into(),
+    };
     let visibility = match visibility {
         None => String::new(),
         Some(it) => format!("{} ", it),

crates/syntax/src/ast/node_ext.rs

@@ -276,9 +276,9 @@ impl ast::Path {
 
 impl ast::Use {
     pub fn is_simple_glob(&self) -> bool {
-        self.use_tree()
+        self.use_tree().map_or(false, |use_tree| {
-            .map(|use_tree| use_tree.use_tree_list().is_none() && use_tree.star_token().is_some())
+            use_tree.use_tree_list().is_none() && use_tree.star_token().is_some()
-            .unwrap_or(false)
+        })
     }
 }
 
@@ -549,10 +549,9 @@ impl ast::FieldExpr {
     }
 
     pub fn field_access(&self) -> Option<FieldKind> {
-        if let Some(nr) = self.name_ref() {
+        match self.name_ref() {
-            Some(FieldKind::Name(nr))
+            Some(nr) => Some(FieldKind::Name(nr)),
-        } else {
+            None => self.index_token().map(FieldKind::Index),
-            self.index_token().map(FieldKind::Index)
         }
     }
 }

crates/syntax/src/ast/token_ext.rs

@@ -283,10 +283,9 @@ pub trait HasFormatSpecifier: AstToken {
     where
         F: FnMut(TextRange, FormatSpecifier),
     {
-        let char_ranges = if let Some(char_ranges) = self.char_ranges() {
+        let char_ranges = match self.char_ranges() {
-            char_ranges
+            Some(char_ranges) => char_ranges,
-        } else {
+            None => return,
-            return;
         };
         let mut chars = char_ranges.iter().peekable();
 
@@ -528,10 +527,11 @@ pub trait HasFormatSpecifier: AstToken {
                         }
                     }
 
-                    if let Some((_, Ok('}'))) = chars.peek() {
+                    match chars.peek() {
+                        Some((_, Ok('}'))) => {
                             skip_char_and_emit(&mut chars, FormatSpecifier::Close, &mut callback);
-                    } else {
+                        }
-                        continue;
+                        Some((_, _)) | None => continue,
                     }
                 }
                 _ => {
@@ -609,7 +609,7 @@ impl HasFormatSpecifier for ast::String {
                 TextRange::new(range.start.try_into().unwrap(), range.end.try_into().unwrap())
                     + offset,
                 unescaped_char,
-            ))
+            ));
         });
 
         Some(res)
@@ -631,7 +631,7 @@ impl ast::IntNumber {
 
         let mut text = token.text();
         if let Some(suffix) = self.suffix() {
-            text = &text[..text.len() - suffix.len()]
+            text = &text[..text.len() - suffix.len()];
         }
 
         let radix = self.radix();
@@ -688,7 +688,7 @@ impl Radix {
     pub const ALL: &'static [Radix] =
         &[Radix::Binary, Radix::Octal, Radix::Decimal, Radix::Hexadecimal];
 
-    const fn prefix_len(&self) -> usize {
+    const fn prefix_len(self) -> usize {
         match self {
             Self::Decimal => 0,
             _ => 2,

crates/syntax/src/display.rs

@@ -28,7 +28,7 @@ pub fn function_declaration(node: &ast::Fn) -> String {
         format_to!(buf, "{} ", abi);
     }
     if let Some(name) = node.name() {
-        format_to!(buf, "fn {}", name)
+        format_to!(buf, "fn {}", name);
     }
     if let Some(type_params) = node.generic_param_list() {
         format_to!(buf, "{}", type_params);

crates/syntax/src/parsing/text_token_source.rs

@@ -44,8 +44,7 @@ impl<'t> TokenSource for TextTokenSource<'t> {
     fn is_keyword(&self, kw: &str) -> bool {
         self.token_offset_pairs
             .get(self.curr.1)
-            .map(|(token, offset)| &self.text[TextRange::at(*offset, token.len)] == kw)
+            .map_or(false, |(token, offset)| &self.text[TextRange::at(*offset, token.len)] == kw)
-            .unwrap_or(false)
     }
 }
 
@@ -55,8 +54,7 @@ fn mk_token(pos: usize, token_offset_pairs: &[(Token, TextSize)]) -> parser::Tok
             token.kind,
             token_offset_pairs
                 .get(pos + 1)
-                .map(|(_, next_offset)| offset + token.len == *next_offset)
+                .map_or(false, |(_, next_offset)| offset + token.len == *next_offset),
-                .unwrap_or(false),
         ),
         None => (EOF, false),
     };

crates/syntax/src/parsing/text_tree_sink.rs

@@ -88,7 +88,7 @@ impl<'a> TreeSink for TextTreeSink<'a> {
     }
 
     fn error(&mut self, error: ParseError) {
-        self.inner.error(error, self.text_pos)
+        self.inner.error(error, self.text_pos);
     }
 }
 
@@ -108,7 +108,7 @@ impl<'a> TextTreeSink<'a> {
         match mem::replace(&mut self.state, State::Normal) {
             State::PendingFinish => {
                 self.eat_trivias();
-                self.inner.finish_node()
+                self.inner.finish_node();
             }
             State::PendingStart | State::Normal => unreachable!(),
         }

crates/syntax/src/ptr.rs

@@ -81,7 +81,7 @@ impl<N: AstNode> PartialEq for AstPtr<N> {
 
 impl<N: AstNode> Hash for AstPtr<N> {
     fn hash<H: Hasher>(&self, state: &mut H) {
-        self.raw.hash(state)
+        self.raw.hash(state);
     }
 }
 

crates/syntax/src/syntax_node.rs

@@ -56,19 +56,19 @@ impl SyntaxTreeBuilder {
 
     pub fn token(&mut self, kind: SyntaxKind, text: &str) {
         let kind = RustLanguage::kind_to_raw(kind);
-        self.inner.token(kind, text)
+        self.inner.token(kind, text);
     }
 
     pub fn start_node(&mut self, kind: SyntaxKind) {
         let kind = RustLanguage::kind_to_raw(kind);
-        self.inner.start_node(kind)
+        self.inner.start_node(kind);
     }
 
     pub fn finish_node(&mut self) {
-        self.inner.finish_node()
+        self.inner.finish_node();
     }
 
     pub fn error(&mut self, error: parser::ParseError, text_pos: TextSize) {
-        self.errors.push(SyntaxError::new_at_offset(*error.0, text_pos))
+        self.errors.push(SyntaxError::new_at_offset(*error.0, text_pos));
     }
 }

crates/syntax/src/ted.rs

@@ -77,23 +77,23 @@ impl Position {
 }
 
 pub fn insert(position: Position, elem: impl Element) {
-    insert_all(position, vec![elem.syntax_element()])
+    insert_all(position, vec![elem.syntax_element()]);
 }
 pub fn insert_raw(position: Position, elem: impl Element) {
-    insert_all_raw(position, vec![elem.syntax_element()])
+    insert_all_raw(position, vec![elem.syntax_element()]);
 }
 pub fn insert_all(position: Position, mut elements: Vec<SyntaxElement>) {
     if let Some(first) = elements.first() {
         if let Some(ws) = ws_before(&position, first) {
-            elements.insert(0, ws.into())
+            elements.insert(0, ws.into());
         }
     }
     if let Some(last) = elements.last() {
         if let Some(ws) = ws_after(&position, last) {
-            elements.push(ws.into())
+            elements.push(ws.into());
         }
     }
-    insert_all_raw(position, elements)
+    insert_all_raw(position, elements);
 }
 pub fn insert_all_raw(position: Position, elements: Vec<SyntaxElement>) {
     let (parent, index) = match position.repr {
@@ -104,10 +104,10 @@ pub fn insert_all_raw(position: Position, elements: Vec<SyntaxElement>) {
 }
 
 pub fn remove(elem: impl Element) {
-    elem.syntax_element().detach()
+    elem.syntax_element().detach();
 }
 pub fn remove_all(range: RangeInclusive<SyntaxElement>) {
-    replace_all(range, Vec::new())
+    replace_all(range, Vec::new());
 }
 pub fn remove_all_iter(range: impl IntoIterator<Item = SyntaxElement>) {
     let mut it = range.into_iter();
@@ -115,9 +115,9 @@ pub fn remove_all_iter(range: impl IntoIterator<Item = SyntaxElement>) {
         match it.last() {
             Some(mut last) => {
                 if first.index() > last.index() {
-                    mem::swap(&mut first, &mut last)
+                    mem::swap(&mut first, &mut last);
                 }
-                remove_all(first..=last)
+                remove_all(first..=last);
             }
             None => remove(first),
         }
@@ -125,26 +125,26 @@ pub fn remove_all_iter(range: impl IntoIterator<Item = SyntaxElement>) {
 }
 
 pub fn replace(old: impl Element, new: impl Element) {
-    replace_with_many(old, vec![new.syntax_element()])
+    replace_with_many(old, vec![new.syntax_element()]);
 }
 pub fn replace_with_many(old: impl Element, new: Vec<SyntaxElement>) {
     let old = old.syntax_element();
-    replace_all(old.clone()..=old, new)
+    replace_all(old.clone()..=old, new);
 }
 pub fn replace_all(range: RangeInclusive<SyntaxElement>, new: Vec<SyntaxElement>) {
     let start = range.start().index();
     let end = range.end().index();
     let parent = range.start().parent().unwrap();
-    parent.splice_children(start..end + 1, new)
+    parent.splice_children(start..end + 1, new);
 }
 
 pub fn append_child(node: &(impl Into<SyntaxNode> + Clone), child: impl Element) {
     let position = Position::last_child_of(node);
-    insert(position, child)
+    insert(position, child);
 }
 pub fn append_child_raw(node: &(impl Into<SyntaxNode> + Clone), child: impl Element) {
     let position = Position::last_child_of(node);
-    insert_raw(position, child)
+    insert_raw(position, child);
 }
 
 fn ws_before(position: &Position, new: &SyntaxElement) -> Option<SyntaxToken> {

crates/syntax/src/tests.rs

@@ -227,12 +227,9 @@ where
     T: crate::AstNode,
     F: Fn(&str) -> Result<T, ()>,
 {
-    dir_tests(&test_data_dir(), ok_paths, "rast", |text, path| {
+    dir_tests(&test_data_dir(), ok_paths, "rast", |text, path| match f(text) {
-        if let Ok(node) = f(text) {
+        Ok(node) => format!("{:#?}", crate::ast::AstNode::syntax(&node)),
-            format!("{:#?}", crate::ast::AstNode::syntax(&node))
+        Err(_) => panic!("Failed to parse '{:?}'", path),
-        } else {
-            panic!("Failed to parse '{:?}'", path);
-        }
     });
     dir_tests(&test_data_dir(), err_paths, "rast", |text, path| {
         if f(text).is_ok() {

crates/syntax/src/tests/sourcegen_ast.rs

@@ -215,7 +215,7 @@ fn generate_nodes(kinds: KindsSrc<'_>, grammar: &AstSrc) -> String {
         .flat_map(|node| node.traits.iter().map(move |t| (t, node)))
         .into_group_map()
         .into_iter()
-        .sorted_by_key(|(k, _)| k.clone())
+        .sorted_by_key(|(k, _)| *k)
         .map(|(trait_name, nodes)| {
             let name = format_ident!("Any{}", trait_name);
             let trait_name = format_ident!("{}", trait_name);
@@ -558,12 +558,13 @@ impl Field {
 }
 
 fn lower(grammar: &Grammar) -> AstSrc {
-    let mut res = AstSrc::default();
+    let mut res = AstSrc {
-
+        tokens: "Whitespace Comment String ByteString IntNumber FloatNumber"
-    res.tokens = "Whitespace Comment String ByteString IntNumber FloatNumber"
             .split_ascii_whitespace()
             .map(|it| it.to_string())
-        .collect::<Vec<_>>();
+            .collect::<Vec<_>>(),
+        ..Default::default()
+    };
 
     let nodes = grammar.iter().collect::<Vec<_>>();
 

crates/syntax/src/validation.rs

@@ -137,7 +137,7 @@ fn validate_literal(literal: ast::Literal, acc: &mut Vec<SyntaxError>) {
                         if let Err(err) = char {
                             push_err(1, (range.start, err));
                         }
-                    })
+                    });
                 }
             }
         }
@@ -148,7 +148,7 @@ fn validate_literal(literal: ast::Literal, acc: &mut Vec<SyntaxError>) {
                         if let Err(err) = char {
                             push_err(2, (range.start, err));
                         }
-                    })
+                    });
                 }
             }
         }

crates/syntax/src/validation/block.rs

@@ -19,6 +19,6 @@ pub(crate) fn validate_block_expr(block: ast::BlockExpr, errors: &mut Vec<Syntax
                 "A block in this position cannot accept inner attributes",
                 attr.syntax().text_range(),
             )
-        }))
+        }));
     }
 }

crates/test_utils/src/assert_linear.rs

@@ -43,7 +43,7 @@ impl AssertLinear {
     }
 
     pub fn sample(&mut self, x: f64, y: f64) {
-        self.rounds.last_mut().unwrap().samples.push((x, y))
+        self.rounds.last_mut().unwrap().samples.push((x, y));
     }
 }
 
@@ -54,7 +54,7 @@ impl Drop for AssertLinear {
             for round in &self.rounds {
                 eprintln!("\n{}", round.plot);
             }
-            panic!("Doesn't look linear!")
+            panic!("Doesn't look linear!");
         }
     }
 }

crates/test_utils/src/fixture.rs

@@ -142,14 +142,14 @@ impl Fixture {
 
             if line.starts_with("//-") {
                 let meta = Fixture::parse_meta_line(line);
-                res.push(meta)
+                res.push(meta);
             } else {
                 if line.starts_with("// ")
                     && line.contains(':')
                     && !line.contains("::")
                     && line.chars().all(|it| !it.is_uppercase())
                 {
-                    panic!("looks like invalid metadata line: {:?}", line)
+                    panic!("looks like invalid metadata line: {:?}", line);
                 }
 
                 if let Some(entry) = res.last_mut() {
@@ -256,9 +256,9 @@ impl MiniCore {
         let line = line.strip_prefix("//- minicore:").unwrap().trim();
         for entry in line.split(", ") {
             if res.has_flag(entry) {
-                panic!("duplicate minicore flag: {:?}", entry)
+                panic!("duplicate minicore flag: {:?}", entry);
             }
-            res.activated_flags.push(entry.to_string())
+            res.activated_flags.push(entry.to_string());
         }
 
         res
@@ -310,7 +310,7 @@ impl MiniCore {
         // Fixed point loop to compute transitive closure of flags.
         loop {
             let mut changed = false;
-            for &(u, v) in implications.iter() {
+            for &(u, v) in &implications {
                 if self.has_flag(u) && !self.has_flag(v) {
                     self.activated_flags.push(v.to_string());
                     changed = true;
@@ -354,7 +354,7 @@ impl MiniCore {
             }
 
             if keep {
-                buf.push_str(line)
+                buf.push_str(line);
             }
             if line_region {
                 active_regions.pop().unwrap();

crates/test_utils/src/lib.rs

@@ -244,7 +244,7 @@ pub fn extract_annotations(text: &str) -> Vec<(TextRange, String)> {
 
                             range + line_start.1
                         };
-                        res.push((range, content))
+                        res.push((range, content));
                     }
                     LineAnnotation::Continuation { mut offset, content } => {
                         offset += annotation_offset;
@@ -301,7 +301,7 @@ fn extract_line_annotations(mut line: &str) -> Vec<LineAnnotation> {
         let mut file = false;
         if !continuation && content.starts_with("file") {
             file = true;
-            content = &content["file".len()..]
+            content = &content["file".len()..];
         }
 
         let content = content.trim().to_string();
@@ -371,7 +371,7 @@ fn main() {
 pub fn skip_slow_tests() -> bool {
     let should_skip = std::env::var("CI").is_err() && std::env::var("RUN_SLOW_TESTS").is_err();
     if should_skip {
-        eprintln!("ignoring slow test")
+        eprintln!("ignoring slow test");
     } else {
         let path = project_root().join("./target/.slow_tests_cookie");
         fs::write(&path, ".").unwrap();
@@ -432,7 +432,7 @@ pub fn bench(label: &'static str) -> impl Drop {
 
     impl Drop for Bencher {
         fn drop(&mut self) {
-            eprintln!("{}: {}", self.label, self.sw.elapsed())
+            eprintln!("{}: {}", self.label, self.sw.elapsed());
         }
     }
 

crates/text_edit/src/lib.rs

@@ -90,13 +90,13 @@ impl TextEdit {
         }
 
         let mut total_len = TextSize::of(&*text);
-        for indel in self.indels.iter() {
+        for indel in &self.indels {
             total_len += TextSize::of(&indel.insert);
             total_len -= indel.delete.end() - indel.delete.start();
         }
         let mut buf = String::with_capacity(total_len.into());
         let mut prev = 0;
-        for indel in self.indels.iter() {
+        for indel in &self.indels {
             let start: usize = indel.delete.start().into();
             let end: usize = indel.delete.end().into();
             if start > prev {
@@ -110,7 +110,7 @@ impl TextEdit {
 
         // FIXME: figure out a way to mutate the text in-place or reuse the
         // memory in some other way
-        *text = buf
+        *text = buf;
     }
 
     pub fn union(&mut self, other: TextEdit) -> Result<(), TextEdit> {
@@ -126,7 +126,7 @@ impl TextEdit {
 
     pub fn apply_to_offset(&self, offset: TextSize) -> Option<TextSize> {
         let mut res = offset;
-        for indel in self.indels.iter() {
+        for indel in &self.indels {
             if indel.delete.start() >= offset {
                 break;
             }
@@ -163,13 +163,13 @@ impl TextEditBuilder {
         self.indels.is_empty()
     }
     pub fn replace(&mut self, range: TextRange, replace_with: String) {
-        self.indel(Indel::replace(range, replace_with))
+        self.indel(Indel::replace(range, replace_with));
     }
     pub fn delete(&mut self, range: TextRange) {
-        self.indel(Indel::delete(range))
+        self.indel(Indel::delete(range));
     }
     pub fn insert(&mut self, offset: TextSize, text: String) {
-        self.indel(Indel::insert(offset, text))
+        self.indel(Indel::insert(offset, text));
     }
     pub fn finish(self) -> TextEdit {
         let mut indels = self.indels;

crates/tt/src/buffer.rs

@@ -194,8 +194,7 @@ impl<'a> Cursor<'a> {
                 TokenTree::Subtree(subtree) => Some(TokenTreeRef::Subtree(subtree, Some(tt))),
             },
             Some(Entry::Subtree(tt, subtree, _)) => Some(TokenTreeRef::Subtree(subtree, *tt)),
-            Some(Entry::End(_)) => None,
+            Some(Entry::End(_)) | None => None,
-            None => None,
         }
     }
 
@@ -206,10 +205,9 @@ impl<'a> Cursor<'a> {
     /// Bump the cursor
     pub fn bump(self) -> Cursor<'a> {
         if let Some(Entry::End(exit)) = self.buffer.entry(&self.ptr) {
-            if let Some(exit) = exit {
+            match exit {
-                Cursor::create(self.buffer, *exit)
+                Some(exit) => Cursor::create(self.buffer, *exit),
-            } else {
+                None => self,
-                self
             }
         } else {
             Cursor::create(self.buffer, EntryPtr(self.ptr.0, self.ptr.1 + 1))

crates/tt/src/lib.rs

@@ -161,7 +161,7 @@ impl fmt::Display for Subtree {
         };
         f.write_str(l)?;
         let mut needs_space = false;
-        for tt in self.token_trees.iter() {
+        for tt in &self.token_trees {
             if needs_space {
                 f.write_str(" ")?;
             }
@@ -169,7 +169,7 @@ impl fmt::Display for Subtree {
             match tt {
                 TokenTree::Leaf(Leaf::Punct(p)) => {
                     needs_space = p.spacing == Spacing::Alone;
-                    fmt::Display::fmt(p, f)?
+                    fmt::Display::fmt(p, f)?;
                 }
                 tt => fmt::Display::fmt(tt, f)?,
             }
@@ -215,7 +215,7 @@ impl Subtree {
             .iter()
             .map(|c| match c {
                 TokenTree::Subtree(c) => c.count(),
-                _ => 0,
+                TokenTree::Leaf(_) => 0,
             })
             .sum::<usize>();
 

crates/vfs-notify/src/lib.rs

@@ -38,7 +38,7 @@ impl loader::Handle for NotifyHandle {
         NotifyHandle { sender, _thread: thread }
     }
     fn set_config(&mut self, config: loader::Config) {
-        self.sender.send(Message::Config(config)).unwrap()
+        self.sender.send(Message::Config(config)).unwrap();
     }
     fn invalidate(&mut self, path: AbsPathBuf) {
         self.sender.send(Message::Invalidate(path)).unwrap();
@@ -84,7 +84,7 @@ impl NotifyActor {
                         if !config.watch.is_empty() {
                             let (watcher_sender, watcher_receiver) = unbounded();
                             let watcher = log_notify_error(RecommendedWatcher::new(move |event| {
-                                watcher_sender.send(event).unwrap()
+                                watcher_sender.send(event).unwrap();
                             }));
                             self.watcher = watcher.map(|it| (it, watcher_receiver));
                         }
@@ -99,7 +99,7 @@ impl NotifyActor {
                         for (i, entry) in config.load.into_iter().enumerate() {
                             let watch = config.watch.contains(&i);
                             if watch {
-                                self.watched_entries.push(entry.clone())
+                                self.watched_entries.push(entry.clone());
                             }
                             let files = self.load_entry(entry, watch);
                             self.send(loader::Message::Loaded { files });
@@ -149,7 +149,7 @@ impl NotifyActor {
                                 Some((path, contents))
                             })
                             .collect();
-                        self.send(loader::Message::Loaded { files })
+                        self.send(loader::Message::Loaded { files });
                     }
                 }
             }
@@ -165,7 +165,7 @@ impl NotifyActor {
                 .into_iter()
                 .map(|file| {
                     if watch {
-                        self.watch(file.clone())
+                        self.watch(file.clone());
                     }
                     let contents = read(file.as_path());
                     (file, contents)
@@ -174,7 +174,7 @@ impl NotifyActor {
             loader::Entry::Directories(dirs) => {
                 let mut res = Vec::new();
 
-                for root in dirs.include.iter() {
+                for root in &dirs.include {
                     let walkdir =
                         WalkDir::new(root).follow_links(true).into_iter().filter_entry(|entry| {
                             if !entry.file_type().is_dir() {
@@ -218,7 +218,7 @@ impl NotifyActor {
         }
     }
     fn send(&mut self, msg: loader::Message) {
-        (self.sender)(msg)
+        (self.sender)(msg);
     }
 }
 

crates/vfs/src/file_set.rs

@@ -112,7 +112,7 @@ impl FileSetConfig {
         let mut res = vec![FileSet::default(); self.len()];
         for (file_id, path) in vfs.iter() {
             let root = self.classify(path, &mut scratch_space);
-            res[root].insert(file_id, path.clone())
+            res[root].insert(file_id, path.clone());
         }
         res
     }
@@ -157,7 +157,7 @@ impl FileSetConfigBuilder {
 
     /// Add a new set of paths prefixes.
     pub fn add_file_set(&mut self, roots: Vec<VfsPath>) {
-        self.roots.push(roots)
+        self.roots.push(roots);
     }
 
     /// Build the `FileSetConfig`.

crates/vfs/src/vfs_path.rs

@@ -73,9 +73,8 @@ impl VfsPath {
     pub fn starts_with(&self, other: &VfsPath) -> bool {
         match (&self.0, &other.0) {
             (VfsPathRepr::PathBuf(lhs), VfsPathRepr::PathBuf(rhs)) => lhs.starts_with(rhs),
-            (VfsPathRepr::PathBuf(_), _) => false,
             (VfsPathRepr::VirtualPath(lhs), VfsPathRepr::VirtualPath(rhs)) => lhs.starts_with(rhs),
-            (VfsPathRepr::VirtualPath(_), _) => false,
+            (VfsPathRepr::PathBuf(_) | VfsPathRepr::VirtualPath(_), _) => false,
         }
     }
 
@@ -357,7 +356,7 @@ impl VirtualPath {
             if !res.pop() {
                 return None;
             }
-            path = &path["../".len()..]
+            path = &path["../".len()..];
         }
         path = path.trim_start_matches("./");
         res.0 = format!("{}/{}", res.0, path);

lib/arena/src/lib.rs

@@ -63,7 +63,7 @@ impl<T> Eq for Idx<T> {}
 
 impl<T> Hash for Idx<T> {
     fn hash<H: Hasher>(&self, state: &mut H) {
-        self.raw.hash(state)
+        self.raw.hash(state);
     }
 }
 
@@ -71,7 +71,7 @@ impl<T> fmt::Debug for Idx<T> {
     fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
         let mut type_name = std::any::type_name::<T>();
         if let Some(idx) = type_name.rfind(':') {
-            type_name = &type_name[idx + 1..]
+            type_name = &type_name[idx + 1..];
         }
         write!(f, "Idx::<{}>({})", type_name, self.raw)
     }

xtask/src/install.rs

@@ -13,7 +13,7 @@ const REQUIRED_RUST_VERSION: u32 = 55;
 impl flags::Install {
     pub(crate) fn run(self) -> Result<()> {
         if cfg!(target_os = "macos") {
-            fix_path_for_mac().context("Fix path for mac")?
+            fix_path_for_mac().context("Fix path for mac")?;
         }
         if let Some(server) = self.server() {
             install_server(server).context("install server")?;
@@ -148,7 +148,7 @@ fn install_server(opts: ServerOpt) -> Result<()> {
         eprintln!(
             "\nWARNING: at least rust 1.{}.0 is required to compile rust-analyzer\n",
             REQUIRED_RUST_VERSION,
-        )
+        );
     }
     let features = match opts.malloc {
         Malloc::System => &[][..],

xtask/src/release.rs

@@ -33,15 +33,13 @@ impl flags::Release {
         let commit = cmd!("git rev-parse HEAD").read()?;
         let changelog_n = read_dir(changelog_dir.as_path())?.len();
 
-        for &adoc in [
+        for adoc in [
             "manual.adoc",
             "generated_assists.adoc",
             "generated_config.adoc",
             "generated_diagnostic.adoc",
             "generated_features.adoc",
-        ]
+        ] {
-        .iter()
-        {
             let src = project_root().join("./docs/user/").join(adoc);
             let dst = website_root.join(adoc);