Auto merge of #13540 - GnomedDev:create-dir-single-arg, r=y21

Check MethodCall/Call arg count earlier or at all

This gets rid of a bunch of possible panic spots, as well as bailing out earlier for optimisation reasons.

I started doing this because I saw that a significant amount of time was being spent in the `create_dir` restriction lint when running clippy with `perf`, but this also helps with robustness.

changelog: none

clippy_lints/src/box_default.rs

@@ -47,7 +47,7 @@ impl LateLintPass<'_> for BoxDefault {
             // And the call is that of a `Box` method
             && path_def_id(cx, ty).map_or(false, |id| Some(id) == cx.tcx.lang_items().owned_box())
             // And the single argument to the call is another function call
-            // This is the `T::default()` of `Box::new(T::default())`
+            // This is the `T::default()` (or default equivalent) of `Box::new(T::default())`
             && let ExprKind::Call(arg_path, _) = arg.kind
             // And we are not in a foreign crate's macro
             && !in_external_macro(cx.sess(), expr.span)

clippy_lints/src/casts/cast_abs_to_unsigned.rs

@@ -19,7 +19,7 @@ pub(super) fn check(
     if msrv.meets(msrvs::UNSIGNED_ABS)
         && let ty::Int(from) = cast_from.kind()
         && let ty::Uint(to) = cast_to.kind()
-        && let ExprKind::MethodCall(method_path, receiver, ..) = cast_expr.kind
+        && let ExprKind::MethodCall(method_path, receiver, [], _) = cast_expr.kind
         && method_path.ident.name.as_str() == "abs"
     {
         let span = if from.bit_width() == to.bit_width() {

clippy_lints/src/casts/cast_ptr_alignment.rs

@@ -19,7 +19,7 @@ pub(super) fn check(cx: &LateContext<'_>, expr: &Expr<'_>) {
             cx.typeck_results().expr_ty(expr),
         );
         lint_cast_ptr_alignment(cx, expr, cast_from, cast_to);
-    } else if let ExprKind::MethodCall(method_path, self_arg, ..) = &expr.kind {
+    } else if let ExprKind::MethodCall(method_path, self_arg, [], _) = &expr.kind {
         if method_path.ident.name == sym!(cast)
             && let Some(generic_args) = method_path.args
             && let [GenericArg::Type(cast_to)] = generic_args.args

clippy_lints/src/create_dir.rs

@@ -34,7 +34,7 @@ declare_lint_pass!(CreateDir => [CREATE_DIR]);
 
 impl LateLintPass<'_> for CreateDir {
     fn check_expr(&mut self, cx: &LateContext<'_>, expr: &Expr<'_>) {
-        if let ExprKind::Call(func, [arg, ..]) = expr.kind
+        if let ExprKind::Call(func, [arg]) = expr.kind
             && let ExprKind::Path(ref path) = func.kind
             && let Some(def_id) = cx.qpath_res(path, func.hir_id).opt_def_id()
             && cx.tcx.is_diagnostic_item(sym::fs_create_dir, def_id)

clippy_lints/src/default.rs

@@ -83,7 +83,7 @@ impl<'tcx> LateLintPass<'tcx> for Default {
         if !expr.span.from_expansion()
             // Avoid cases already linted by `field_reassign_with_default`
             && !self.reassigned_linted.contains(&expr.span)
-            && let ExprKind::Call(path, ..) = expr.kind
+            && let ExprKind::Call(path, []) = expr.kind
             && !in_automatically_derived(cx.tcx, expr.hir_id)
             && let ExprKind::Path(ref qpath) = path.kind
             && let Some(def_id) = cx.qpath_res(qpath, path.hir_id).opt_def_id()
@@ -253,7 +253,7 @@ impl<'tcx> LateLintPass<'tcx> for Default {
 
 /// Checks if the given expression is the `default` method belonging to the `Default` trait.
 fn is_expr_default<'tcx>(expr: &'tcx Expr<'tcx>, cx: &LateContext<'tcx>) -> bool {
-    if let ExprKind::Call(fn_expr, _) = &expr.kind
+    if let ExprKind::Call(fn_expr, []) = &expr.kind
         && let ExprKind::Path(qpath) = &fn_expr.kind
         && let Res::Def(_, def_id) = cx.qpath_res(qpath, fn_expr.hir_id)
     {

clippy_lints/src/exit.rs

@@ -43,7 +43,7 @@ declare_lint_pass!(Exit => [EXIT]);
 
 impl<'tcx> LateLintPass<'tcx> for Exit {
     fn check_expr(&mut self, cx: &LateContext<'tcx>, e: &'tcx Expr<'_>) {
-        if let ExprKind::Call(path_expr, _args) = e.kind
+        if let ExprKind::Call(path_expr, [_]) = e.kind
             && let ExprKind::Path(ref path) = path_expr.kind
             && let Some(def_id) = cx.qpath_res(path, path_expr.hir_id).opt_def_id()
             && cx.tcx.is_diagnostic_item(sym::process_exit, def_id)

clippy_lints/src/explicit_write.rs

@@ -57,7 +57,7 @@ impl<'tcx> LateLintPass<'tcx> for ExplicitWrite {
             && unwrap_fun.ident.name == sym::unwrap
             // match call to write_fmt
             && let ExprKind::MethodCall(write_fun, write_recv, [write_arg], _) = *look_in_block(cx, &write_call.kind)
-            && let ExprKind::Call(write_recv_path, _) = write_recv.kind
+            && let ExprKind::Call(write_recv_path, []) = write_recv.kind
             && write_fun.ident.name == sym!(write_fmt)
             && let Some(def_id) = path_def_id(cx, write_recv_path)
         {

clippy_lints/src/floating_point_arithmetic.rs

@@ -436,12 +436,12 @@ fn check_expm1(cx: &LateContext<'_>, expr: &Expr<'_>) {
         lhs,
         rhs,
     ) = expr.kind
+        && let ExprKind::MethodCall(path, self_arg, [], _) = &lhs.kind
+        && path.ident.name.as_str() == "exp"
         && cx.typeck_results().expr_ty(lhs).is_floating_point()
         && let Some(value) = ConstEvalCtxt::new(cx).eval(rhs)
         && (F32(1.0) == value || F64(1.0) == value)
-        && let ExprKind::MethodCall(path, self_arg, ..) = &lhs.kind
         && cx.typeck_results().expr_ty(self_arg).is_floating_point()
-        && path.ident.name.as_str() == "exp"
     {
         span_lint_and_sugg(
             cx,

clippy_lints/src/format_impl.rs

@@ -151,7 +151,7 @@ struct FormatImplExpr<'a, 'tcx> {
 impl FormatImplExpr<'_, '_> {
     fn check_to_string_in_display(&self) {
         if self.format_trait_impl.name == sym::Display
-            && let ExprKind::MethodCall(path, self_arg, ..) = self.expr.kind
+            && let ExprKind::MethodCall(path, self_arg, [], _) = self.expr.kind
             // Get the hir_id of the object we are calling the method on
             // Is the method to_string() ?
             && path.ident.name == sym::to_string

clippy_lints/src/if_let_mutex.rs

@@ -82,7 +82,7 @@ fn mutex_lock_call<'tcx>(
     expr: &'tcx Expr<'_>,
     op_mutex: Option<&'tcx Expr<'_>>,
 ) -> ControlFlow<&'tcx Expr<'tcx>> {
-    if let ExprKind::MethodCall(path, self_arg, ..) = &expr.kind
+    if let ExprKind::MethodCall(path, self_arg, [], _) = &expr.kind
         && path.ident.as_str() == "lock"
         && let ty = cx.typeck_results().expr_ty(self_arg).peel_refs()
         && is_type_diagnostic_item(cx, ty, sym::Mutex)

clippy_lints/src/large_futures.rs

@@ -57,7 +57,7 @@ impl_lint_pass!(LargeFuture => [LARGE_FUTURES]);
 impl<'tcx> LateLintPass<'tcx> for LargeFuture {
     fn check_expr(&mut self, cx: &LateContext<'tcx>, expr: &'tcx Expr<'tcx>) {
         if let ExprKind::Match(scrutinee, _, MatchSource::AwaitDesugar) = expr.kind
-            && let ExprKind::Call(func, [arg, ..]) = scrutinee.kind
+            && let ExprKind::Call(func, [arg]) = scrutinee.kind
             && let ExprKind::Path(QPath::LangItem(LangItem::IntoFutureIntoFuture, ..)) = func.kind
             && !expr.span.from_expansion()
             && let ty = cx.typeck_results().expr_ty(arg)

clippy_lints/src/len_zero.rs

@@ -517,37 +517,25 @@ fn check_cmp(cx: &LateContext<'_>, span: Span, method: &Expr<'_>, lit: &Expr<'_>
         return;
     }
 
-    if let (&ExprKind::MethodCall(method_path, receiver, args, _), ExprKind::Lit(lit)) = (&method.kind, &lit.kind) {
+    if let (&ExprKind::MethodCall(method_path, receiver, [], _), ExprKind::Lit(lit)) = (&method.kind, &lit.kind) {
         // check if we are in an is_empty() method
         if let Some(name) = get_item_name(cx, method) {
             if name.as_str() == "is_empty" {
                 return;
             }
         }
 
-        check_len(
-            cx,
-            span,
-            method_path.ident.name,
-            receiver,
-            args,
-            &lit.node,
-            op,
-            compare_to,
-        );
+        check_len(cx, span, method_path.ident.name, receiver, &lit.node, op, compare_to);
     } else {
         check_empty_expr(cx, span, method, lit, op);
     }
 }
 
-// FIXME(flip1995): Figure out how to reduce the number of arguments
-#[allow(clippy::too_many_arguments)]
 fn check_len(
     cx: &LateContext<'_>,
     span: Span,
     method_name: Symbol,
     receiver: &Expr<'_>,
-    args: &[Expr<'_>],
     lit: &LitKind,
     op: &str,
     compare_to: u32,
@@ -558,7 +546,7 @@ fn check_len(
             return;
         }
 
-        if method_name == sym::len && args.is_empty() && has_is_empty(cx, receiver) {
+        if method_name == sym::len && has_is_empty(cx, receiver) {
             let mut applicability = Applicability::MachineApplicable;
             span_lint_and_sugg(
                 cx,

clippy_lints/src/loops/manual_while_let_some.rs

@@ -47,8 +47,9 @@ fn report_lint(cx: &LateContext<'_>, pop_span: Span, pop_stmt_kind: PopStmt<'_>,
     );
 }
 
-fn match_method_call(cx: &LateContext<'_>, expr: &Expr<'_>, method: Symbol) -> bool {
-    if let ExprKind::MethodCall(..) = expr.kind
+fn match_method_call<const ARGS_COUNT: usize>(cx: &LateContext<'_>, expr: &Expr<'_>, method: Symbol) -> bool {
+    if let ExprKind::MethodCall(_, _, args, _) = expr.kind
+        && args.len() == ARGS_COUNT
         && let Some(id) = cx.typeck_results().type_dependent_def_id(expr.hir_id)
     {
         cx.tcx.is_diagnostic_item(method, id)
@@ -58,9 +59,9 @@ fn match_method_call(cx: &LateContext<'_>, expr: &Expr<'_>, method: Symbol) -> b
 }
 
 fn is_vec_pop_unwrap(cx: &LateContext<'_>, expr: &Expr<'_>, is_empty_recv: &Expr<'_>) -> bool {
-    if (match_method_call(cx, expr, sym::option_unwrap) || match_method_call(cx, expr, sym::option_expect))
+    if (match_method_call::<0>(cx, expr, sym::option_unwrap) || match_method_call::<1>(cx, expr, sym::option_expect))
         && let ExprKind::MethodCall(_, unwrap_recv, ..) = expr.kind
-        && match_method_call(cx, unwrap_recv, sym::vec_pop)
+        && match_method_call::<0>(cx, unwrap_recv, sym::vec_pop)
         && let ExprKind::MethodCall(_, pop_recv, ..) = unwrap_recv.kind
     {
         // make sure they're the same `Vec`
@@ -96,7 +97,7 @@ fn check_call_arguments(cx: &LateContext<'_>, stmt: &Stmt<'_>, is_empty_recv: &E
 pub(super) fn check<'tcx>(cx: &LateContext<'tcx>, full_cond: &'tcx Expr<'_>, body: &'tcx Expr<'_>, loop_span: Span) {
     if let ExprKind::Unary(UnOp::Not, cond) = full_cond.kind
         && let ExprKind::MethodCall(_, is_empty_recv, _, _) = cond.kind
-        && match_method_call(cx, cond, sym::vec_is_empty)
+        && match_method_call::<0>(cx, cond, sym::vec_is_empty)
         && let ExprKind::Block(body, _) = body.kind
         && let Some(stmt) = body.stmts.first()
     {

clippy_lints/src/loops/same_item_push.rs

@@ -172,10 +172,8 @@ fn get_vec_push<'tcx>(
     stmt: &'tcx Stmt<'_>,
 ) -> Option<(&'tcx Expr<'tcx>, &'tcx Expr<'tcx>, SyntaxContext)> {
     if let StmtKind::Semi(semi_stmt) = &stmt.kind
-            // Extract method being called
-            && let ExprKind::MethodCall(path, self_expr, args, _) = &semi_stmt.kind
-            // Figure out the parameters for the method call
-            && let Some(pushed_item) = args.first()
+            // Extract method being called and figure out the parameters for the method call
+            && let ExprKind::MethodCall(path, self_expr, [pushed_item], _) = &semi_stmt.kind
             // Check that the method being called is push() on a Vec
             && is_type_diagnostic_item(cx, cx.typeck_results().expr_ty(self_expr), sym::Vec)
             && path.ident.name.as_str() == "push"

clippy_lints/src/main_recursion.rs

@@ -42,7 +42,7 @@ impl LateLintPass<'_> for MainRecursion {
             return;
         }
 
-        if let ExprKind::Call(func, _) = &expr.kind
+        if let ExprKind::Call(func, []) = &expr.kind
             && let ExprKind::Path(QPath::Resolved(_, path)) = &func.kind
             && let Some(def_id) = path.res.opt_def_id()
             && is_entrypoint_fn(cx, def_id)

clippy_lints/src/manual_bits.rs

@@ -95,7 +95,7 @@ fn get_one_size_of_ty<'tcx>(
 }
 
 fn get_size_of_ty<'tcx>(cx: &LateContext<'tcx>, expr: &'tcx Expr<'_>) -> Option<(&'tcx rustc_hir::Ty<'tcx>, Ty<'tcx>)> {
-    if let ExprKind::Call(count_func, _func_args) = expr.kind
+    if let ExprKind::Call(count_func, []) = expr.kind
         && let ExprKind::Path(ref count_func_qpath) = count_func.kind
         && let QPath::Resolved(_, count_func_path) = count_func_qpath
         && let Some(segment_zero) = count_func_path.segments.first()

clippy_lints/src/manual_is_power_of_two.rs

@@ -41,7 +41,7 @@ impl LateLintPass<'_> for ManualIsPowerOfTwo {
             && bin_op.node == BinOpKind::Eq
         {
             // a.count_ones() == 1
-            if let ExprKind::MethodCall(method_name, reciever, _, _) = left.kind
+            if let ExprKind::MethodCall(method_name, reciever, [], _) = left.kind
                 && method_name.ident.as_str() == "count_ones"
                 && let &Uint(_) = cx.typeck_results().expr_ty(reciever).kind()
                 && check_lit(right, 1)
@@ -50,7 +50,7 @@ impl LateLintPass<'_> for ManualIsPowerOfTwo {
             }
 
             // 1 == a.count_ones()
-            if let ExprKind::MethodCall(method_name, reciever, _, _) = right.kind
+            if let ExprKind::MethodCall(method_name, reciever, [], _) = right.kind
                 && method_name.ident.as_str() == "count_ones"
                 && let &Uint(_) = cx.typeck_results().expr_ty(reciever).kind()
                 && check_lit(left, 1)

clippy_lints/src/manual_slice_size_calculation.rs

@@ -83,12 +83,12 @@ fn simplify_half<'tcx>(
 ) -> Option<&'tcx Expr<'tcx>> {
     if !expr1.span.from_expansion()
         // expr1 is `[T1].len()`?
-        && let ExprKind::MethodCall(method_path, receiver, _, _) = expr1.kind
+        && let ExprKind::MethodCall(method_path, receiver, [], _) = expr1.kind
         && method_path.ident.name == sym::len
         && let receiver_ty = cx.typeck_results().expr_ty(receiver)
         && let ty::Slice(ty1) = receiver_ty.peel_refs().kind()
         // expr2 is `size_of::<T2>()`?
-        && let ExprKind::Call(func, _) = expr2.kind
+        && let ExprKind::Call(func, []) = expr2.kind
         && let ExprKind::Path(ref func_qpath) = func.kind
         && let Some(def_id) = cx.qpath_res(func_qpath, func.hir_id).opt_def_id()
         && cx.tcx.is_diagnostic_item(sym::mem_size_of, def_id)

clippy_lints/src/manual_string_new.rs

@@ -52,8 +52,8 @@ impl LateLintPass<'_> for ManualStringNew {
         }
 
         match expr.kind {
-            ExprKind::Call(func, args) => {
-                parse_call(cx, expr.span, func, args);
+            ExprKind::Call(func, [arg]) => {
+                parse_call(cx, expr.span, func, arg);
             },
             ExprKind::MethodCall(path_segment, receiver, ..) => {
                 parse_method_call(cx, expr.span, path_segment, receiver);
@@ -93,20 +93,15 @@ fn parse_method_call(cx: &LateContext<'_>, span: Span, path_segment: &PathSegmen
     let method_arg_kind = &receiver.kind;
     if ["to_string", "to_owned", "into"].contains(&ident) && is_expr_kind_empty_str(method_arg_kind) {
         warn_then_suggest(cx, span);
-    } else if let ExprKind::Call(func, args) = method_arg_kind {
+    } else if let ExprKind::Call(func, [arg]) = method_arg_kind {
         // If our first argument is a function call itself, it could be an `unwrap`-like function.
         // E.g. String::try_from("hello").unwrap(), TryFrom::try_from("").expect("hello"), etc.
-        parse_call(cx, span, func, args);
+        parse_call(cx, span, func, arg);
     }
 }
 
 /// Tries to parse an expression as a function call, emitting the warning if necessary.
-fn parse_call(cx: &LateContext<'_>, span: Span, func: &Expr<'_>, args: &[Expr<'_>]) {
-    if args.len() != 1 {
-        return;
-    }
-
-    let arg_kind = &args[0].kind;
+fn parse_call(cx: &LateContext<'_>, span: Span, func: &Expr<'_>, arg: &Expr<'_>) {
     if let ExprKind::Path(qpath) = &func.kind {
         // String::from(...) or String::try_from(...)
         if let QPath::TypeRelative(ty, path_seg) = qpath
@@ -115,13 +110,13 @@ fn parse_call(cx: &LateContext<'_>, span: Span, func: &Expr<'_>, args: &[Expr<'_
             && let QPath::Resolved(_, path) = qpath
             && let [path_seg] = path.segments
             && path_seg.ident.name == sym::String
-            && is_expr_kind_empty_str(arg_kind)
+            && is_expr_kind_empty_str(&arg.kind)
         {
             warn_then_suggest(cx, span);
         } else if let QPath::Resolved(_, path) = qpath {
             // From::from(...) or TryFrom::try_from(...)
             if let [path_seg1, path_seg2] = path.segments
-                && is_expr_kind_empty_str(arg_kind)
+                && is_expr_kind_empty_str(&arg.kind)
                 && ((path_seg1.ident.name == sym::From && path_seg2.ident.name == sym::from)
                     || (path_seg1.ident.name == sym::TryFrom && path_seg2.ident.name == sym::try_from))
             {

clippy_lints/src/matches/redundant_pattern_match.rs

@@ -210,7 +210,7 @@ fn find_method_sugg_for_if_let<'tcx>(
 
     // check that `while_let_on_iterator` lint does not trigger
     if keyword == "while"
-        && let ExprKind::MethodCall(method_path, ..) = let_expr.kind
+        && let ExprKind::MethodCall(method_path, _, [], _) = let_expr.kind
         && method_path.ident.name == sym::next
         && is_trait_method(cx, let_expr, sym::Iterator)
     {

clippy_lints/src/matches/try_err.rs

@@ -21,10 +21,10 @@ pub(super) fn check<'tcx>(cx: &LateContext<'tcx>, expr: &'tcx Expr<'_>, scrutine
     //         #[allow(unreachable_code)]
     //         val,
     // };
-    if let ExprKind::Call(match_fun, [try_arg, ..]) = scrutinee.kind
+    if let ExprKind::Call(match_fun, [try_arg]) = scrutinee.kind
         && let ExprKind::Path(ref match_fun_path) = match_fun.kind
         && matches!(match_fun_path, QPath::LangItem(LangItem::TryTraitBranch, ..))
-        && let ExprKind::Call(err_fun, [err_arg, ..]) = try_arg.kind
+        && let ExprKind::Call(err_fun, [err_arg]) = try_arg.kind
         && is_res_lang_ctor(cx, path_res(cx, err_fun), ResultErr)
         && let Some(return_ty) = find_return_type(cx, &expr.kind)
     {

clippy_lints/src/methods/clone_on_copy.rs

@@ -58,7 +58,7 @@ pub(super) fn check(
                     return;
                 },
                 // ? is a Call, makes sure not to rec *x?, but rather (*x)?
-                ExprKind::Call(hir_callee, _) => matches!(
+                ExprKind::Call(hir_callee, [_]) => matches!(
                     hir_callee.kind,
                     ExprKind::Path(QPath::LangItem(rustc_hir::LangItem::TryTraitBranch, ..))
                 ),

clippy_lints/src/methods/iter_filter.rs

@@ -106,9 +106,9 @@ fn is_method(
 
 fn parent_is_map(cx: &LateContext<'_>, expr: &hir::Expr<'_>) -> bool {
     if let Some(expr) = get_parent_expr(cx, expr)
-        && is_trait_method(cx, expr, sym::Iterator)
-        && let ExprKind::MethodCall(path, _, _, _) = expr.kind
+        && let ExprKind::MethodCall(path, _, [_], _) = expr.kind
         && path.ident.name == sym::map
+        && is_trait_method(cx, expr, sym::Iterator)
     {
         return true;
     }

clippy_lints/src/methods/manual_c_str_literals.rs

@@ -87,7 +87,7 @@ pub(super) fn check(cx: &LateContext<'_>, expr: &Expr<'_>, func: &Expr<'_>, args
 
 /// Checks `CStr::from_ptr(b"foo\0".as_ptr().cast())`
 fn check_from_ptr(cx: &LateContext<'_>, expr: &Expr<'_>, arg: &Expr<'_>) {
-    if let ExprKind::MethodCall(method, lit, ..) = peel_ptr_cast(arg).kind
+    if let ExprKind::MethodCall(method, lit, [], _) = peel_ptr_cast(arg).kind
         && method.ident.name == sym::as_ptr
         && !lit.span.from_expansion()
         && let ExprKind::Lit(lit) = lit.kind

clippy_lints/src/methods/manual_saturating_arithmetic.rs

@@ -68,8 +68,7 @@ enum MinMax {
 
 fn is_min_or_max(cx: &LateContext<'_>, expr: &hir::Expr<'_>) -> Option<MinMax> {
     // `T::max_value()` `T::min_value()` inherent methods
-    if let hir::ExprKind::Call(func, args) = &expr.kind
-        && args.is_empty()
+    if let hir::ExprKind::Call(func, []) = &expr.kind
         && let hir::ExprKind::Path(hir::QPath::TypeRelative(_, segment)) = &func.kind
     {
         match segment.ident.as_str() {

clippy_lints/src/methods/map_clone.rs

@@ -86,9 +86,8 @@ pub(super) fn check(cx: &LateContext<'_>, e: &hir::Expr<'_>, recv: &hir::Expr<'_
                                     }
                                 }
                             },
-                            hir::ExprKind::Call(call, args) => {
+                            hir::ExprKind::Call(call, [arg]) => {
                                 if let hir::ExprKind::Path(qpath) = call.kind
-                                    && let [arg] = args
                                     && ident_eq(name, arg)
                                 {
                                     handle_path(cx, call, &qpath, e, recv);