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

Author: bors

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)