Adding upstream version 1.64.0+dfsg1.upstream/1.64.0+dfsg1

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 146 insertions, 0 deletions

diff --git a/src/tools/clippy/clippy_lints/src/manual_bits.rs b/src/tools/clippy/clippy_lints/src/manual_bits.rs
new file mode 100644
index 000000000..60bbcde4f
--- /dev/null
+++ b/src/tools/clippy/clippy_lints/src/manual_bits.rs
@@ -0,0 +1,146 @@
+use clippy_utils::diagnostics::span_lint_and_sugg;
+use clippy_utils::source::snippet_with_applicability;
+use clippy_utils::{get_parent_expr, meets_msrv, msrvs};
+use rustc_ast::ast::LitKind;
+use rustc_errors::Applicability;
+use rustc_hir::{BinOpKind, Expr, ExprKind, GenericArg, QPath};
+use rustc_lint::{LateContext, LateLintPass};
+use rustc_middle::ty::{self, Ty};
+use rustc_semver::RustcVersion;
+use rustc_session::{declare_tool_lint, impl_lint_pass};
+use rustc_span::sym;
+
+declare_clippy_lint! {
+    /// ### What it does
+    /// Checks for uses of `std::mem::size_of::<T>() * 8` when
+    /// `T::BITS` is available.
+    ///
+    /// ### Why is this bad?
+    /// Can be written as the shorter `T::BITS`.
+    ///
+    /// ### Example
+    /// ```rust
+    /// std::mem::size_of::<usize>() * 8;
+    /// ```
+    /// Use instead:
+    /// ```rust
+    /// usize::BITS as usize;
+    /// ```
+    #[clippy::version = "1.60.0"]
+    pub MANUAL_BITS,
+    style,
+    "manual implementation of `size_of::<T>() * 8` can be simplified with `T::BITS`"
+}
+
+#[derive(Clone)]
+pub struct ManualBits {
+    msrv: Option<RustcVersion>,
+}
+
+impl ManualBits {
+    #[must_use]
+    pub fn new(msrv: Option<RustcVersion>) -> Self {
+        Self { msrv }
+    }
+}
+
+impl_lint_pass!(ManualBits => [MANUAL_BITS]);
+
+impl<'tcx> LateLintPass<'tcx> for ManualBits {
+    fn check_expr(&mut self, cx: &LateContext<'tcx>, expr: &'tcx Expr<'_>) {
+        if !meets_msrv(self.msrv, msrvs::MANUAL_BITS) {
+            return;
+        }
+
+        if_chain! {
+            if let ExprKind::Binary(bin_op, left_expr, right_expr) = expr.kind;
+            if let BinOpKind::Mul = &bin_op.node;
+            if let Some((real_ty, resolved_ty, other_expr)) = get_one_size_of_ty(cx, left_expr, right_expr);
+            if matches!(resolved_ty.kind(), ty::Int(_) | ty::Uint(_));
+            if let ExprKind::Lit(lit) = &other_expr.kind;
+            if let LitKind::Int(8, _) = lit.node;
+            then {
+                let mut app = Applicability::MachineApplicable;
+                let ty_snip = snippet_with_applicability(cx, real_ty.span, "..", &mut app);
+                let sugg = create_sugg(cx, expr, format!("{ty_snip}::BITS"));
+
+                span_lint_and_sugg(
+                    cx,
+                    MANUAL_BITS,
+                    expr.span,
+                    "usage of `mem::size_of::<T>()` to obtain the size of `T` in bits",
+                    "consider using",
+                    sugg,
+                    app,
+                );
+            }
+        }
+    }
+
+    extract_msrv_attr!(LateContext);
+}
+
+fn get_one_size_of_ty<'tcx>(
+    cx: &LateContext<'tcx>,
+    expr1: &'tcx Expr<'_>,
+    expr2: &'tcx Expr<'_>,
+) -> Option<(&'tcx rustc_hir::Ty<'tcx>, Ty<'tcx>, &'tcx Expr<'tcx>)> {
+    match (get_size_of_ty(cx, expr1), get_size_of_ty(cx, expr2)) {
+        (Some((real_ty, resolved_ty)), None) => Some((real_ty, resolved_ty, expr2)),
+        (None, Some((real_ty, resolved_ty))) => Some((real_ty, resolved_ty, expr1)),
+        _ => None,
+    }
+}
+
+fn get_size_of_ty<'tcx>(cx: &LateContext<'tcx>, expr: &'tcx Expr<'_>) -> Option<(&'tcx rustc_hir::Ty<'tcx>, Ty<'tcx>)> {
+    if_chain! {
+        if let ExprKind::Call(count_func, _func_args) = expr.kind;
+        if let ExprKind::Path(ref count_func_qpath) = count_func.kind;
+
+        if let QPath::Resolved(_, count_func_path) = count_func_qpath;
+        if let Some(segment_zero) = count_func_path.segments.get(0);
+        if let Some(args) = segment_zero.args;
+        if let Some(GenericArg::Type(real_ty)) = args.args.get(0);
+
+        if let Some(def_id) = cx.qpath_res(count_func_qpath, count_func.hir_id).opt_def_id();
+        if cx.tcx.is_diagnostic_item(sym::mem_size_of, def_id);
+        then {
+            cx.typeck_results().node_substs(count_func.hir_id).types().next().map(|resolved_ty| (real_ty, resolved_ty))
+        } else {
+            None
+        }
+    }
+}
+
+fn create_sugg(cx: &LateContext<'_>, expr: &Expr<'_>, base_sugg: String) -> String {
+    if let Some(parent_expr) = get_parent_expr(cx, expr) {
+        if is_ty_conversion(parent_expr) {
+            return base_sugg;
+        }
+
+        // These expressions have precedence over casts, the suggestion therefore
+        // needs to be wrapped into parentheses
+        match parent_expr.kind {
+            ExprKind::Unary(..) | ExprKind::AddrOf(..) | ExprKind::MethodCall(..) => {
+                return format!("({base_sugg} as usize)");
+            },
+            _ => {},
+        }
+    }
+
+    format!("{base_sugg} as usize")
+}
+
+fn is_ty_conversion(expr: &Expr<'_>) -> bool {
+    if let ExprKind::Cast(..) = expr.kind {
+        true
+    } else if let ExprKind::MethodCall(path, [_], _) = expr.kind
+        && path.ident.name == rustc_span::sym::try_into
+    {
+        // This is only called for `usize` which implements `TryInto`. Therefore,
+        // we don't have to check here if `self` implements the `TryInto` trait.
+        true
+    } else {
+        false
+    }
+}