Misc refactorings part 2

clippy_lints/src/double_parens.rs

@@ -40,35 +40,29 @@ declare_lint_pass!(DoubleParens => [DOUBLE_PARENS]);
 
 impl EarlyLintPass for DoubleParens {
     fn check_expr(&mut self, cx: &EarlyContext<'_>, expr: &Expr) {
-        if expr.span.from_expansion() {
-            return;
-        }
-
-        let msg: &str = "consider removing unnecessary double parentheses";
-
-        match expr.kind {
-            ExprKind::Paren(ref in_paren) => match in_paren.kind {
-                ExprKind::Paren(_) | ExprKind::Tup(_) => {
-                    span_lint(cx, DOUBLE_PARENS, expr.span, msg);
-                },
-                _ => {},
-            },
-            ExprKind::Call(_, ref params) => {
-                if params.len() == 1 {
-                    let param = &params[0];
-                    if let ExprKind::Paren(_) = param.kind {
-                        span_lint(cx, DOUBLE_PARENS, param.span, msg);
-                    }
-                }
+        let span = match &expr.kind {
+            ExprKind::Paren(in_paren) if matches!(in_paren.kind, ExprKind::Paren(_) | ExprKind::Tup(_)) => expr.span,
+            ExprKind::Call(_, params)
+                if let [param] = &**params
+                    && let ExprKind::Paren(_) = param.kind =>
+            {
+                param.span
             },
-            ExprKind::MethodCall(ref call) => {
-                if let [ref arg] = call.args[..] {
-                    if let ExprKind::Paren(_) = arg.kind {
-                        span_lint(cx, DOUBLE_PARENS, arg.span, msg);
-                    }
-                }
+            ExprKind::MethodCall(call)
+                if let [arg] = &*call.args
+                    && let ExprKind::Paren(_) = arg.kind =>
+            {
+                arg.span
             },
-            _ => {},
+            _ => return,
+        };
+        if !expr.span.from_expansion() {
+            span_lint(
+                cx,
+                DOUBLE_PARENS,
+                span,
+                "consider removing unnecessary double parentheses",
+            );
         }
     }
 }

clippy_lints/src/endian_bytes.rs

@@ -109,32 +109,27 @@ impl LintKind {
 
 impl LateLintPass<'_> for EndianBytes {
     fn check_expr(&mut self, cx: &LateContext<'_>, expr: &Expr<'_>) {
-        if in_external_macro(cx.sess(), expr.span) {
-            return;
-        }
-
-        if let ExprKind::MethodCall(method_name, receiver, args, ..) = expr.kind
-            && args.is_empty()
-            && let ty = cx.typeck_results().expr_ty(receiver)
+        let (prefix, name, ty_expr) = match expr.kind {
+            ExprKind::MethodCall(method_name, receiver, [], ..) => (Prefix::To, method_name.ident.name, receiver),
+            ExprKind::Call(function, ..)
+                if let ExprKind::Path(qpath) = function.kind
+                    && let Some(def_id) = cx.qpath_res(&qpath, function.hir_id).opt_def_id()
+                    && let Some(function_name) = cx.get_def_path(def_id).last() =>
+            {
+                (Prefix::From, *function_name, expr)
+            },
+            _ => return,
+        };
+        if !in_external_macro(cx.sess(), expr.span)
+            && let ty = cx.typeck_results().expr_ty(ty_expr)
             && ty.is_primitive_ty()
-            && maybe_lint_endian_bytes(cx, expr, Prefix::To, method_name.ident.name, ty)
         {
-            return;
-        }
-
-        if let ExprKind::Call(function, ..) = expr.kind
-            && let ExprKind::Path(qpath) = function.kind
-            && let Some(def_id) = cx.qpath_res(&qpath, function.hir_id).opt_def_id()
-            && let Some(function_name) = cx.get_def_path(def_id).last()
-            && let ty = cx.typeck_results().expr_ty(expr)
-            && ty.is_primitive_ty()
-        {
-            maybe_lint_endian_bytes(cx, expr, Prefix::From, *function_name, ty);
+            maybe_lint_endian_bytes(cx, expr, prefix, name, ty);
         }
     }
 }
 
-fn maybe_lint_endian_bytes(cx: &LateContext<'_>, expr: &Expr<'_>, prefix: Prefix, name: Symbol, ty: Ty<'_>) -> bool {
+fn maybe_lint_endian_bytes(cx: &LateContext<'_>, expr: &Expr<'_>, prefix: Prefix, name: Symbol, ty: Ty<'_>) {
     let ne = LintKind::Host.as_name(prefix);
     let le = LintKind::Little.as_name(prefix);
     let be = LintKind::Big.as_name(prefix);
@@ -143,7 +138,7 @@ fn maybe_lint_endian_bytes(cx: &LateContext<'_>, expr: &Expr<'_>, prefix: Prefix
         name if name == ne => ((&LintKind::Host), [(&LintKind::Little), (&LintKind::Big)]),
         name if name == le => ((&LintKind::Little), [(&LintKind::Host), (&LintKind::Big)]),
         name if name == be => ((&LintKind::Big), [(&LintKind::Host), (&LintKind::Little)]),
-        _ => return false,
+        _ => return,
     };
 
     let mut help = None;
@@ -208,6 +203,4 @@ fn maybe_lint_endian_bytes(cx: &LateContext<'_>, expr: &Expr<'_>, prefix: Prefix
             }
         },
     );
-
-    true
 }

clippy_lints/src/excessive_bools.rs

@@ -87,12 +87,6 @@ pub struct ExcessiveBools {
     max_fn_params_bools: u64,
 }
 
-#[derive(Eq, PartialEq, Debug, Copy, Clone)]
-enum Kind {
-    Struct,
-    Fn,
-}
-
 impl ExcessiveBools {
     #[must_use]
     pub fn new(max_struct_bools: u64, max_fn_params_bools: u64) -> Self {
@@ -101,64 +95,60 @@ impl ExcessiveBools {
             max_fn_params_bools,
         }
     }
+}
 
-    fn too_many_bools<'tcx>(&self, tys: impl Iterator<Item = &'tcx Ty<'tcx>>, kind: Kind) -> bool {
-        if let Ok(bools) = tys.filter(|ty| is_bool(ty)).count().try_into() {
-            (if Kind::Fn == kind {
-                self.max_fn_params_bools
-            } else {
-                self.max_struct_bools
-            }) < bools
-        } else {
-            false
-        }
-    }
+impl_lint_pass!(ExcessiveBools => [STRUCT_EXCESSIVE_BOOLS, FN_PARAMS_EXCESSIVE_BOOLS]);
 
-    fn check_fn_sig(&self, cx: &LateContext<'_>, fn_decl: &FnDecl<'_>, span: Span) {
-        if !span.from_expansion() && self.too_many_bools(fn_decl.inputs.iter(), Kind::Fn) {
-            span_lint_and_help(
-                cx,
-                FN_PARAMS_EXCESSIVE_BOOLS,
-                span,
-                format!("more than {} bools in function parameters", self.max_fn_params_bools),
-                None,
-                "consider refactoring bools into two-variant enums",
-            );
-        }
-    }
+fn has_n_bools<'tcx>(iter: impl Iterator<Item = &'tcx Ty<'tcx>>, mut count: u64) -> bool {
+    iter.filter(|ty| is_bool(ty)).any(|_| {
+        let (x, overflow) = count.overflowing_sub(1);
+        count = x;
+        overflow
+    })
 }
 
-impl_lint_pass!(ExcessiveBools => [STRUCT_EXCESSIVE_BOOLS, FN_PARAMS_EXCESSIVE_BOOLS]);
+fn check_fn_decl(cx: &LateContext<'_>, decl: &FnDecl<'_>, sp: Span, max: u64) {
+    if has_n_bools(decl.inputs.iter(), max) && !sp.from_expansion() {
+        span_lint_and_help(
+            cx,
+            FN_PARAMS_EXCESSIVE_BOOLS,
+            sp,
+            format!("more than {max} bools in function parameters"),
+            None,
+            "consider refactoring bools into two-variant enums",
+        );
+    }
+}
 
 impl<'tcx> LateLintPass<'tcx> for ExcessiveBools {
     fn check_item(&mut self, cx: &LateContext<'tcx>, item: &'tcx Item<'tcx>) {
-        if item.span.from_expansion() {
-            return;
-        }
-        if let ItemKind::Struct(variant_data, _) = &item.kind {
-            if has_repr_attr(cx, item.hir_id()) {
-                return;
-            }
-
-            if self.too_many_bools(variant_data.fields().iter().map(|field| field.ty), Kind::Struct) {
-                span_lint_and_help(
-                    cx,
-                    STRUCT_EXCESSIVE_BOOLS,
-                    item.span,
-                    format!("more than {} bools in a struct", self.max_struct_bools),
-                    None,
-                    "consider using a state machine or refactoring bools into two-variant enums",
-                );
-            }
+        if let ItemKind::Struct(variant_data, _) = &item.kind
+            && variant_data.fields().len() as u64 > self.max_struct_bools
+            && has_n_bools(
+                variant_data.fields().iter().map(|field| field.ty),
+                self.max_struct_bools,
+            )
+            && !has_repr_attr(cx, item.hir_id())
+            && !item.span.from_expansion()
+        {
+            span_lint_and_help(
+                cx,
+                STRUCT_EXCESSIVE_BOOLS,
+                item.span,
+                format!("more than {} bools in a struct", self.max_struct_bools),
+                None,
+                "consider using a state machine or refactoring bools into two-variant enums",
+            );
         }
     }
 
     fn check_trait_item(&mut self, cx: &LateContext<'tcx>, trait_item: &'tcx TraitItem<'tcx>) {
         // functions with a body are already checked by `check_fn`
         if let TraitItemKind::Fn(fn_sig, TraitFn::Required(_)) = &trait_item.kind
             && fn_sig.header.abi == Abi::Rust
+            && fn_sig.decl.inputs.len() as u64 > self.max_fn_params_bools
         {
-            self.check_fn_sig(cx, fn_sig.decl, fn_sig.span);
+            check_fn_decl(cx, fn_sig.decl, fn_sig.span, self.max_fn_params_bools);
         }
     }
 
@@ -171,12 +161,13 @@ impl<'tcx> LateLintPass<'tcx> for ExcessiveBools {
         span: Span,
         def_id: LocalDefId,
     ) {
-        let hir_id = cx.tcx.local_def_id_to_hir_id(def_id);
         if let Some(fn_header) = fn_kind.header()
             && fn_header.abi == Abi::Rust
-            && get_parent_as_impl(cx.tcx, hir_id).map_or(true, |impl_item| impl_item.of_trait.is_none())
+            && fn_decl.inputs.len() as u64 > self.max_fn_params_bools
+            && get_parent_as_impl(cx.tcx, cx.tcx.local_def_id_to_hir_id(def_id))
+                .map_or(true, |impl_item| impl_item.of_trait.is_none())
         {
-            self.check_fn_sig(cx, fn_decl, span);
+            check_fn_decl(cx, fn_decl, span, self.max_fn_params_bools);
         }
     }
 }

clippy_lints/src/extra_unused_type_parameters.rs

@@ -50,21 +50,6 @@ impl ExtraUnusedTypeParameters {
             avoid_breaking_exported_api,
         }
     }
-
-    /// Don't lint external macros or functions with empty bodies. Also, don't lint exported items
-    /// if the `avoid_breaking_exported_api` config option is set.
-    fn is_empty_exported_or_macro(
-        &self,
-        cx: &LateContext<'_>,
-        span: Span,
-        def_id: LocalDefId,
-        body_id: BodyId,
-    ) -> bool {
-        let body = cx.tcx.hir().body(body_id).value;
-        let fn_empty = matches!(&body.kind, ExprKind::Block(blk, None) if blk.stmts.is_empty() && blk.expr.is_none());
-        let is_exported = cx.effective_visibilities.is_exported(def_id);
-        in_external_macro(cx.sess(), span) || fn_empty || (is_exported && self.avoid_breaking_exported_api)
-    }
 }
 
 impl_lint_pass!(ExtraUnusedTypeParameters => [EXTRA_UNUSED_TYPE_PARAMETERS]);
@@ -266,10 +251,17 @@ impl<'cx, 'tcx> Visitor<'tcx> for TypeWalker<'cx, 'tcx> {
     }
 }
 
+fn is_empty_body(cx: &LateContext<'_>, body: BodyId) -> bool {
+    matches!(cx.tcx.hir().body(body).value.kind, ExprKind::Block(b, _) if b.stmts.is_empty() && b.expr.is_none())
+}
+
 impl<'tcx> LateLintPass<'tcx> for ExtraUnusedTypeParameters {
     fn check_item(&mut self, cx: &LateContext<'tcx>, item: &'tcx Item<'tcx>) {
         if let ItemKind::Fn(_, generics, body_id) = item.kind
-            && !self.is_empty_exported_or_macro(cx, item.span, item.owner_id.def_id, body_id)
+            && !generics.params.is_empty()
+            && !is_empty_body(cx, body_id)
+            && (!self.avoid_breaking_exported_api || !cx.effective_visibilities.is_exported(item.owner_id.def_id))
+            && !in_external_macro(cx.sess(), item.span)
             && !is_from_proc_macro(cx, item)
         {
             let mut walker = TypeWalker::new(cx, generics);
@@ -281,8 +273,12 @@ impl<'tcx> LateLintPass<'tcx> for ExtraUnusedTypeParameters {
     fn check_impl_item(&mut self, cx: &LateContext<'tcx>, item: &'tcx ImplItem<'tcx>) {
         // Only lint on inherent methods, not trait methods.
         if let ImplItemKind::Fn(.., body_id) = item.kind
+            && !item.generics.params.is_empty()
             && trait_ref_of_method(cx, item.owner_id.def_id).is_none()
-            && !self.is_empty_exported_or_macro(cx, item.span, item.owner_id.def_id, body_id)
+            && !is_empty_body(cx, body_id)
+            && (!self.avoid_breaking_exported_api || !cx.effective_visibilities.is_exported(item.owner_id.def_id))
+            && !in_external_macro(cx.sess(), item.span)
+            && !is_from_proc_macro(cx, item)
         {
             let mut walker = TypeWalker::new(cx, item.generics);
             walk_impl_item(&mut walker, item);

clippy_lints/src/future_not_send.rs

@@ -66,15 +66,11 @@ impl<'tcx> LateLintPass<'tcx> for FutureNotSend {
         let ret_ty = return_ty(cx, cx.tcx.local_def_id_to_hir_id(fn_def_id).expect_owner());
         if let ty::Alias(ty::Opaque, AliasTy { def_id, args, .. }) = *ret_ty.kind() {
             let preds = cx.tcx.explicit_item_super_predicates(def_id);
-            let mut is_future = false;
-            for (p, _span) in preds.iter_instantiated_copied(cx.tcx, args) {
-                if let Some(trait_pred) = p.as_trait_clause() {
-                    if Some(trait_pred.skip_binder().trait_ref.def_id) == cx.tcx.lang_items().future_trait() {
-                        is_future = true;
-                        break;
-                    }
-                }
-            }
+            let is_future = preds.iter_instantiated_copied(cx.tcx, args).any(|(p, _)| {
+                p.as_trait_clause().is_some_and(|trait_pred| {
+                    Some(trait_pred.skip_binder().trait_ref.def_id) == cx.tcx.lang_items().future_trait()
+                })
+            });
             if is_future {
                 let send_trait = cx.tcx.get_diagnostic_item(sym::Send).unwrap();
                 let span = decl.output.span();