use clippy_utils::diagnostics::span_lint_and_sugg;
-use clippy_utils::source::snippet_opt;
-use clippy_utils::{match_def_path, meets_msrv, msrvs, paths};
+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_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
/// ```
/// Use instead:
/// ```rust
- /// usize::BITS;
+ /// usize::BITS as usize;
/// ```
#[clippy::version = "1.60.0"]
pub MANUAL_BITS,
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",
- format!("{}::BITS", snippet_opt(cx, real_ty.span).unwrap()),
- Applicability::MachineApplicable,
+ sugg,
+ app,
);
}
}
}
+
+ extract_msrv_attr!(LateContext);
}
fn get_one_size_of_ty<'tcx>(
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 match_def_path(cx, def_id, &paths::MEM_SIZE_OF);
+ 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 {
}
}
}
+
+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
+ }
+}