diff --git a/crates/hir_ty/src/lower.rs b/crates/hir_ty/src/lower.rs
index 13785e3a6cd..28b21fc5b8f 100644
--- a/crates/hir_ty/src/lower.rs
+++ b/crates/hir_ty/src/lower.rs
@@ -410,52 +410,60 @@ impl<'a> TyLoweringContext<'a> {
     ) -> (Ty, Option<TypeNs>) {
         let ty = match resolution {
             TypeNs::TraitId(trait_) => {
-                let ty = if remaining_segments.len() == 1 {
-                    let trait_ref =
-                        self.lower_trait_ref_from_resolved_path(trait_, resolved_segment, None);
-                    let segment = remaining_segments.first().unwrap();
-                    let found = self
-                        .db
-                        .trait_data(trait_ref.hir_trait_id())
-                        .associated_type_by_name(segment.name);
-                    match found {
-                        Some(associated_ty) => {
-                            // FIXME handle type parameters on the segment
-                            TyKind::Alias(AliasTy::Projection(ProjectionTy {
-                                associated_ty_id: to_assoc_type_id(associated_ty),
-                                substitution: trait_ref.substitution,
-                            }))
-                            .intern(&Interner)
-                        }
-                        None => {
-                            // FIXME: report error (associated type not found)
-                            TyKind::Error.intern(&Interner)
+                let ty = match remaining_segments.len() {
+                    1 => {
+                        let trait_ref =
+                            self.lower_trait_ref_from_resolved_path(trait_, resolved_segment, None);
+                        let segment = remaining_segments.first().unwrap();
+                        let found = self
+                            .db
+                            .trait_data(trait_ref.hir_trait_id())
+                            .associated_type_by_name(segment.name);
+                        match found {
+                            Some(associated_ty) => {
+                                // FIXME handle type parameters on the segment
+                                TyKind::Alias(AliasTy::Projection(ProjectionTy {
+                                    associated_ty_id: to_assoc_type_id(associated_ty),
+                                    substitution: trait_ref.substitution,
+                                }))
+                                .intern(&Interner)
+                            }
+                            None => {
+                                // FIXME: report error (associated type not found)
+                                TyKind::Error.intern(&Interner)
+                            }
                         }
                     }
-                } else if remaining_segments.len() > 1 {
-                    // FIXME report error (ambiguous associated type)
-                    TyKind::Error.intern(&Interner)
-                } else {
-                    let self_ty = Some(
-                        TyKind::BoundVar(BoundVar::new(DebruijnIndex::INNERMOST, 0))
-                            .intern(&Interner),
-                    );
-                    let trait_ref = self.with_shifted_in(DebruijnIndex::ONE, |ctx| {
-                        ctx.lower_trait_ref_from_resolved_path(trait_, resolved_segment, self_ty)
-                    });
-                    let dyn_ty = DynTy {
-                        bounds: crate::make_only_type_binders(
-                            1,
-                            QuantifiedWhereClauses::from_iter(
-                                &Interner,
-                                Some(crate::wrap_empty_binders(WhereClause::Implemented(
-                                    trait_ref,
-                                ))),
+                    0 => {
+                        let self_ty = Some(
+                            TyKind::BoundVar(BoundVar::new(DebruijnIndex::INNERMOST, 0))
+                                .intern(&Interner),
+                        );
+                        let trait_ref = self.with_shifted_in(DebruijnIndex::ONE, |ctx| {
+                            ctx.lower_trait_ref_from_resolved_path(
+                                trait_,
+                                resolved_segment,
+                                self_ty,
+                            )
+                        });
+                        let dyn_ty = DynTy {
+                            bounds: crate::make_only_type_binders(
+                                1,
+                                QuantifiedWhereClauses::from_iter(
+                                    &Interner,
+                                    Some(crate::wrap_empty_binders(WhereClause::Implemented(
+                                        trait_ref,
+                                    ))),
+                                ),
                             ),
-                        ),
-                        lifetime: static_lifetime(),
-                    };
-                    TyKind::Dyn(dyn_ty).intern(&Interner)
+                            lifetime: static_lifetime(),
+                        };
+                        TyKind::Dyn(dyn_ty).intern(&Interner)
+                    }
+                    _ => {
+                        // FIXME report error (ambiguous associated type)
+                        TyKind::Error.intern(&Interner)
+                    }
                 };
                 return (ty, None);
             }
diff --git a/crates/hir_ty/src/method_resolution.rs b/crates/hir_ty/src/method_resolution.rs
index 3533d2010c5..c88a8b65358 100644
--- a/crates/hir_ty/src/method_resolution.rs
+++ b/crates/hir_ty/src/method_resolution.rs
@@ -697,7 +697,7 @@ fn iterate_trait_method_candidates(
             }
             known_implemented = true;
             // FIXME: we shouldn't be ignoring the binders here
-            callback(&self_ty, *item)?
+            callback(self_ty, *item)?
         }
     }
     ControlFlow::Continue(())
@@ -773,7 +773,7 @@ fn iterate_inherent_methods(
                     cov_mark::hit!(impl_self_type_match_without_receiver);
                     continue;
                 }
-                let receiver_ty = receiver_ty.unwrap_or(&self_ty);
+                let receiver_ty = receiver_ty.unwrap_or(self_ty);
                 callback(receiver_ty, item)?;
             }
         }
diff --git a/crates/ide_assists/src/assist_context.rs b/crates/ide_assists/src/assist_context.rs
index 0244f5fb291..2b1f3d1633e 100644
--- a/crates/ide_assists/src/assist_context.rs
+++ b/crates/ide_assists/src/assist_context.rs
@@ -167,7 +167,7 @@ impl Assists {
             None
         };
 
-        let label = Label::new(label.into());
+        let label = Label::new(label);
         let group = group.cloned();
         self.buf.push(Assist { id, label, group, target, source_change });
         Some(())
diff --git a/crates/ide_assists/src/handlers/convert_bool_then.rs b/crates/ide_assists/src/handlers/convert_bool_then.rs
index 5adb3f5a1b3..497e7c2546d 100644
--- a/crates/ide_assists/src/handlers/convert_bool_then.rs
+++ b/crates/ide_assists/src/handlers/convert_bool_then.rs
@@ -198,7 +198,7 @@ fn option_variants(
     sema: &Semantics<RootDatabase>,
     expr: &SyntaxNode,
 ) -> Option<(hir::Variant, hir::Variant)> {
-    let fam = FamousDefs(&sema, sema.scope(expr).krate());
+    let fam = FamousDefs(sema, sema.scope(expr).krate());
     let option_variants = fam.core_option_Option()?.variants(sema.db);
     match &*option_variants {
         &[variant0, variant1] => Some(if variant0.name(sema.db) == known::None {
@@ -224,7 +224,7 @@ fn is_invalid_body(
         invalid
     });
     if !invalid {
-        for_each_tail_expr(&expr, &mut |e| {
+        for_each_tail_expr(expr, &mut |e| {
             if invalid {
                 return;
             }
diff --git a/crates/ide_assists/src/handlers/convert_tuple_struct_to_named_struct.rs b/crates/ide_assists/src/handlers/convert_tuple_struct_to_named_struct.rs
index fc5a17f052c..bb0382e15f9 100644
--- a/crates/ide_assists/src/handlers/convert_tuple_struct_to_named_struct.rs
+++ b/crates/ide_assists/src/handlers/convert_tuple_struct_to_named_struct.rs
@@ -110,7 +110,9 @@ fn edit_struct_def(
         } else {
             edit.insert(tuple_fields_text_range.start(), ast::make::tokens::single_space().text());
         }
-        strukt.semicolon_token().map(|t| edit.delete(t.text_range()));
+        if let Some(t) = strukt.semicolon_token() {
+            edit.delete(t.text_range());
+        }
     } else {
         edit.insert(tuple_fields_text_range.start(), ast::make::tokens::single_space().text());
     }
diff --git a/crates/ide_assists/src/handlers/expand_glob_import.rs b/crates/ide_assists/src/handlers/expand_glob_import.rs
index aedb2f95f92..6a07136cc89 100644
--- a/crates/ide_assists/src/handlers/expand_glob_import.rs
+++ b/crates/ide_assists/src/handlers/expand_glob_import.rs
@@ -227,14 +227,12 @@ fn find_imported_defs(ctx: &AssistContext, star: SyntaxToken) -> Option<Vec<Def>
     Some(
         [Direction::Prev, Direction::Next]
             .iter()
-            .map(|dir| {
+            .flat_map(|dir| {
                 parent_use_item_syntax
                     .siblings(dir.to_owned())
                     .filter(|n| ast::Use::can_cast(n.kind()))
             })
-            .flatten()
-            .filter_map(|n| Some(n.descendants().filter_map(ast::NameRef::cast)))
-            .flatten()
+            .flat_map(|n| n.descendants().filter_map(ast::NameRef::cast))
             .filter_map(|r| match NameRefClass::classify(&ctx.sema, &r)? {
                 NameRefClass::Definition(Definition::ModuleDef(def)) => Some(Def::ModuleDef(def)),
                 NameRefClass::Definition(Definition::Macro(def)) => Some(Def::MacroDef(def)),
diff --git a/crates/ide_assists/src/handlers/extract_function.rs b/crates/ide_assists/src/handlers/extract_function.rs
index 1e21050911d..c0cf3fac039 100644
--- a/crates/ide_assists/src/handlers/extract_function.rs
+++ b/crates/ide_assists/src/handlers/extract_function.rs
@@ -885,12 +885,9 @@ fn reference_is_exclusive(
 
 /// checks if this expr requires `&mut` access, recurses on field access
 fn expr_require_exclusive_access(ctx: &AssistContext, expr: &ast::Expr) -> Option<bool> {
-    match expr {
-        ast::Expr::MacroCall(_) => {
-            // FIXME: expand macro and check output for mutable usages of the variable?
-            return None;
-        }
-        _ => (),
+    if let ast::Expr::MacroCall(_) = expr {
+        // FIXME: expand macro and check output for mutable usages of the variable?
+        return None;
     }
 
     let parent = expr.syntax().parent()?;
diff --git a/crates/ide_assists/src/handlers/extract_struct_from_enum_variant.rs b/crates/ide_assists/src/handlers/extract_struct_from_enum_variant.rs
index 96115881103..3bc347b1e2e 100644
--- a/crates/ide_assists/src/handlers/extract_struct_from_enum_variant.rs
+++ b/crates/ide_assists/src/handlers/extract_struct_from_enum_variant.rs
@@ -231,7 +231,7 @@ fn create_struct_def(
     let variant_attrs = attrs_and_docs(variant.syntax())
         .map(|tok| match tok.kind() {
             WHITESPACE => make::tokens::single_newline().into(),
-            _ => tok.into(),
+            _ => tok,
         })
         .collect();
     ted::insert_all(Position::first_child_of(strukt.syntax()), variant_attrs);
@@ -251,12 +251,14 @@ fn update_variant(variant: &ast::Variant, generic: Option<ast::GenericParamList>
         Some(gpl) => {
             let gpl = gpl.clone_for_update();
             gpl.generic_params().for_each(|gp| {
-                match gp {
+                let tbl = match gp {
                     ast::GenericParam::LifetimeParam(it) => it.type_bound_list(),
                     ast::GenericParam::TypeParam(it) => it.type_bound_list(),
                     ast::GenericParam::ConstParam(_) => return,
+                };
+                if let Some(tbl) = tbl {
+                    tbl.remove();
                 }
-                .map(|it| it.remove());
             });
             make::ty(&format!("{}<{}>", name.text(), gpl.generic_params().join(", ")))
         }
diff --git a/crates/ide_assists/src/handlers/extract_variable.rs b/crates/ide_assists/src/handlers/extract_variable.rs
index c72ed324237..9398b84b3fc 100644
--- a/crates/ide_assists/src/handlers/extract_variable.rs
+++ b/crates/ide_assists/src/handlers/extract_variable.rs
@@ -79,7 +79,7 @@ pub(crate) fn extract_variable(acc: &mut Assists, ctx: &AssistContext) -> Option
             if let Anchor::Replace(stmt) = anchor {
                 cov_mark::hit!(test_extract_var_expr_stmt);
                 if stmt.semicolon_token().is_none() {
-                    buf.push_str(";");
+                    buf.push(';');
                 }
                 match ctx.config.snippet_cap {
                     Some(cap) => {
@@ -92,7 +92,7 @@ pub(crate) fn extract_variable(acc: &mut Assists, ctx: &AssistContext) -> Option
                 return;
             }
 
-            buf.push_str(";");
+            buf.push(';');
 
             // We want to maintain the indent level,
             // but we do not want to duplicate possible
diff --git a/crates/ide_assists/src/handlers/generate_function.rs b/crates/ide_assists/src/handlers/generate_function.rs
index 8feae78126f..55c5c46e695 100644
--- a/crates/ide_assists/src/handlers/generate_function.rs
+++ b/crates/ide_assists/src/handlers/generate_function.rs
@@ -109,7 +109,7 @@ fn gen_fn(acc: &mut Assists, ctx: &AssistContext) -> Option<()> {
     };
     let function_builder = FunctionBuilder::from_call(ctx, &call, &path, target_module, target)?;
     let text_range = call.syntax().text_range();
-    let label = format!("Generate {} function", function_builder.fn_name.clone());
+    let label = format!("Generate {} function", function_builder.fn_name);
     add_func_to_accumulator(
         acc,
         ctx,
@@ -139,7 +139,7 @@ fn gen_method(acc: &mut Assists, ctx: &AssistContext) -> Option<()> {
         FunctionBuilder::from_method_call(ctx, &call, &fn_name, target_module, target)?;
     let text_range = call.syntax().text_range();
     let adt_name = if impl_.is_none() { Some(adt.name(ctx.sema.db)) } else { None };
-    let label = format!("Generate {} method", function_builder.fn_name.clone());
+    let label = format!("Generate {} method", function_builder.fn_name);
     add_func_to_accumulator(
         acc,
         ctx,
@@ -369,7 +369,7 @@ fn make_return_type(
             }
         }
     };
-    let ret_type = ret_ty.map(|rt| make::ret_type(rt));
+    let ret_type = ret_ty.map(make::ret_type);
     (ret_type, should_focus_return_type)
 }
 
@@ -386,7 +386,7 @@ fn get_fn_target(
             file = in_file;
             target
         }
-        None => next_space_for_fn_after_call_site(FuncExpr::Func(call.clone()))?,
+        None => next_space_for_fn_after_call_site(FuncExpr::Func(call))?,
     };
     Some((target.clone(), file, get_insert_offset(&target)))
 }
@@ -397,7 +397,7 @@ fn get_method_target(
     impl_: &Option<ast::Impl>,
 ) -> Option<(GeneratedFunctionTarget, TextSize)> {
     let target = match impl_ {
-        Some(impl_) => next_space_for_fn_in_impl(&impl_)?,
+        Some(impl_) => next_space_for_fn_in_impl(impl_)?,
         None => {
             next_space_for_fn_in_module(ctx.sema.db, &target_module.definition_source(ctx.sema.db))?
                 .1
@@ -448,7 +448,7 @@ fn fn_args(
         });
         arg_types.push(match fn_arg_type(ctx, target_module, &arg) {
             Some(ty) => {
-                if ty.len() > 0 && ty.starts_with('&') {
+                if !ty.is_empty() && ty.starts_with('&') {
                     if let Some((new_ty, _)) = useless_type_special_case("", &ty[1..].to_owned()) {
                         new_ty
                     } else {
diff --git a/crates/ide_assists/src/handlers/inline_call.rs b/crates/ide_assists/src/handlers/inline_call.rs
index 9cab0487e15..33e029c236f 100644
--- a/crates/ide_assists/src/handlers/inline_call.rs
+++ b/crates/ide_assists/src/handlers/inline_call.rs
@@ -199,7 +199,7 @@ pub(crate) fn inline_(
                             .sema
                             .type_of_expr(&expr)
                             .filter(TypeInfo::has_adjustment)
-                            .and_then(|_| param_ty);
+                            .and(param_ty);
                         body.push_front(
                             make::let_stmt(pat, ty, Some(expr)).clone_for_update().into(),
                         )
diff --git a/crates/ide_assists/src/handlers/introduce_named_lifetime.rs b/crates/ide_assists/src/handlers/introduce_named_lifetime.rs
index aa32c698a2b..8077f73d1ea 100644
--- a/crates/ide_assists/src/handlers/introduce_named_lifetime.rs
+++ b/crates/ide_assists/src/handlers/introduce_named_lifetime.rs
@@ -77,7 +77,7 @@ fn generate_fn_def_assist(
             })
             .collect();
         match fn_params_without_lifetime.len() {
-            1 => Some(fn_params_without_lifetime.into_iter().nth(0)?),
+            1 => Some(fn_params_without_lifetime.into_iter().next()?),
             0 => None,
             // multiple unnnamed is invalid. assist is not applicable
             _ => return None,
@@ -93,8 +93,9 @@ fn generate_fn_def_assist(
             make::lifetime_param(new_lifetime_param.clone()).clone_for_update().into(),
         );
         ted::replace(lifetime.syntax(), new_lifetime_param.clone_for_update().syntax());
-        loc_needing_lifetime
-            .map(|position| ted::insert(position, new_lifetime_param.clone_for_update().syntax()));
+        if let Some(position) = loc_needing_lifetime {
+            ted::insert(position, new_lifetime_param.clone_for_update().syntax());
+        }
     })
 }
 
diff --git a/crates/ide_assists/src/handlers/raw_string.rs b/crates/ide_assists/src/handlers/raw_string.rs
index d98a55ae4ab..acd0829570c 100644
--- a/crates/ide_assists/src/handlers/raw_string.rs
+++ b/crates/ide_assists/src/handlers/raw_string.rs
@@ -35,7 +35,7 @@ pub(crate) fn make_raw_string(acc: &mut Assists, ctx: &AssistContext) -> Option<
             if matches!(value, Cow::Borrowed(_)) {
                 // Avoid replacing the whole string to better position the cursor.
                 edit.insert(token.syntax().text_range().start(), format!("r{}", hashes));
-                edit.insert(token.syntax().text_range().end(), format!("{}", hashes));
+                edit.insert(token.syntax().text_range().end(), hashes);
             } else {
                 edit.replace(
                     token.syntax().text_range(),
diff --git a/crates/ide_assists/src/handlers/remove_unused_param.rs b/crates/ide_assists/src/handlers/remove_unused_param.rs
index 9aa33e39bae..75b9f827d7a 100644
--- a/crates/ide_assists/src/handlers/remove_unused_param.rs
+++ b/crates/ide_assists/src/handlers/remove_unused_param.rs
@@ -137,7 +137,7 @@ fn process_usage(
         return Some(range_to_remove(arg.syntax()));
     }
 
-    return None;
+    None
 }
 
 fn range_to_remove(node: &SyntaxNode) -> TextRange {
diff --git a/crates/ide_assists/src/handlers/replace_if_let_with_match.rs b/crates/ide_assists/src/handlers/replace_if_let_with_match.rs
index 5ce2ad3193e..96a8c783929 100644
--- a/crates/ide_assists/src/handlers/replace_if_let_with_match.rs
+++ b/crates/ide_assists/src/handlers/replace_if_let_with_match.rs
@@ -126,7 +126,7 @@ fn make_else_arm(
     if let Some(else_block) = else_block {
         let pattern = if let [(Either::Left(pat), _)] = conditionals {
             ctx.sema
-                .type_of_pat(&pat)
+                .type_of_pat(pat)
                 .and_then(|ty| TryEnum::from_ty(&ctx.sema, &ty.adjusted()))
                 .zip(Some(pat))
         } else {
@@ -134,7 +134,7 @@ fn make_else_arm(
         };
         let pattern = match pattern {
             Some((it, pat)) => {
-                if does_pat_match_variant(&pat, &it.sad_pattern()) {
+                if does_pat_match_variant(pat, &it.sad_pattern()) {
                     it.happy_pattern()
                 } else {
                     it.sad_pattern()
@@ -144,7 +144,7 @@ fn make_else_arm(
         };
         make::match_arm(iter::once(pattern), None, unwrap_trivial_block(else_block))
     } else {
-        make::match_arm(iter::once(make::wildcard_pat().into()), None, make::expr_unit().into())
+        make::match_arm(iter::once(make::wildcard_pat().into()), None, make::expr_unit())
     }
 }
 
@@ -257,7 +257,7 @@ fn is_empty_expr(expr: &ast::Expr) -> bool {
 }
 
 fn binds_name(sema: &hir::Semantics<RootDatabase>, pat: &ast::Pat) -> bool {
-    let binds_name_v = |pat| binds_name(&sema, &pat);
+    let binds_name_v = |pat| binds_name(sema, &pat);
     match pat {
         ast::Pat::IdentPat(pat) => !matches!(
             pat.name().and_then(|name| NameClass::classify(sema, &name)),
diff --git a/crates/ide_assists/src/handlers/replace_qualified_name_with_use.rs b/crates/ide_assists/src/handlers/replace_qualified_name_with_use.rs
index 13367df807f..47600be7638 100644
--- a/crates/ide_assists/src/handlers/replace_qualified_name_with_use.rs
+++ b/crates/ide_assists/src/handlers/replace_qualified_name_with_use.rs
@@ -141,10 +141,7 @@ fn path_eq_no_generics(lhs: ast::Path, rhs: ast::Path) -> bool {
                     && lhs
                         .name_ref()
                         .zip(rhs.name_ref())
-                        .map_or(false, |(lhs, rhs)| lhs.text() == rhs.text()) =>
-            {
-                ()
-            }
+                        .map_or(false, |(lhs, rhs)| lhs.text() == rhs.text()) => {}
             _ => return false,
         }
 
diff --git a/crates/ide_assists/src/handlers/toggle_ignore.rs b/crates/ide_assists/src/handlers/toggle_ignore.rs
index 33e12a7d0ca..4da6089cacc 100644
--- a/crates/ide_assists/src/handlers/toggle_ignore.rs
+++ b/crates/ide_assists/src/handlers/toggle_ignore.rs
@@ -33,7 +33,7 @@ pub(crate) fn toggle_ignore(acc: &mut Assists, ctx: &AssistContext) -> Option<()
             AssistId("toggle_ignore", AssistKind::None),
             "Ignore this test",
             attr.syntax().text_range(),
-            |builder| builder.insert(attr.syntax().text_range().end(), &format!("\n#[ignore]")),
+            |builder| builder.insert(attr.syntax().text_range().end(), "\n#[ignore]"),
         ),
         Some(ignore_attr) => acc.add(
             AssistId("toggle_ignore", AssistKind::None),
diff --git a/crates/proc_macro_api/src/lib.rs b/crates/proc_macro_api/src/lib.rs
index 20c5ffaebd1..b03a029f8ad 100644
--- a/crates/proc_macro_api/src/lib.rs
+++ b/crates/proc_macro_api/src/lib.rs
@@ -130,7 +130,7 @@ impl ProcMacroServer {
                 .into_iter()
                 .map(|(name, kind)| ProcMacro {
                     process: self.process.clone(),
-                    name: name.into(),
+                    name,
                     kind,
                     dylib_path: dylib.path.clone(),
                 })