95 lines
3.6 KiB
Rust
95 lines
3.6 KiB
Rust
use clippy_utils::diagnostics::span_lint_and_sugg;
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use clippy_utils::match_def_path;
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use clippy_utils::source::snippet_with_applicability;
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use rustc_errors::Applicability;
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use rustc_hir as hir;
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use rustc_lint::{LateContext, LateLintPass};
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use rustc_middle::ty;
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use rustc_session::declare_lint_pass;
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declare_clippy_lint! {
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/// ### What it does
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/// Checks for `.to_digit(..).is_some()` on `char`s.
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///
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/// ### Why is this bad?
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/// This is a convoluted way of checking if a `char` is a digit. It's
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/// more straight forward to use the dedicated `is_digit` method.
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///
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/// ### Example
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/// ```no_run
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/// # let c = 'c';
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/// # let radix = 10;
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/// let is_digit = c.to_digit(radix).is_some();
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/// ```
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/// can be written as:
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/// ```no_run
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/// # let c = 'c';
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/// # let radix = 10;
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/// let is_digit = c.is_digit(radix);
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/// ```
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#[clippy::version = "1.41.0"]
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pub TO_DIGIT_IS_SOME,
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style,
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"`char.is_digit()` is clearer"
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}
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declare_lint_pass!(ToDigitIsSome => [TO_DIGIT_IS_SOME]);
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impl<'tcx> LateLintPass<'tcx> for ToDigitIsSome {
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fn check_expr(&mut self, cx: &LateContext<'tcx>, expr: &'tcx hir::Expr<'_>) {
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if let hir::ExprKind::MethodCall(is_some_path, to_digit_expr, [], _) = &expr.kind
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&& is_some_path.ident.name.as_str() == "is_some"
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{
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let match_result = match &to_digit_expr.kind {
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hir::ExprKind::MethodCall(to_digits_path, char_arg, [radix_arg], _) => {
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if to_digits_path.ident.name.as_str() == "to_digit"
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&& let char_arg_ty = cx.typeck_results().expr_ty_adjusted(char_arg)
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&& *char_arg_ty.kind() == ty::Char
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{
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Some((true, *char_arg, radix_arg))
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} else {
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None
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}
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},
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hir::ExprKind::Call(to_digits_call, to_digit_args) => {
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if let [char_arg, radix_arg] = *to_digit_args
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&& let hir::ExprKind::Path(to_digits_path) = &to_digits_call.kind
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&& let to_digits_call_res = cx.qpath_res(to_digits_path, to_digits_call.hir_id)
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&& let Some(to_digits_def_id) = to_digits_call_res.opt_def_id()
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&& match_def_path(
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cx,
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to_digits_def_id,
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&["core", "char", "methods", "<impl char>", "to_digit"],
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)
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{
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Some((false, char_arg, radix_arg))
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} else {
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None
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}
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},
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_ => None,
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};
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if let Some((is_method_call, char_arg, radix_arg)) = match_result {
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let mut applicability = Applicability::MachineApplicable;
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let char_arg_snip = snippet_with_applicability(cx, char_arg.span, "_", &mut applicability);
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let radix_snip = snippet_with_applicability(cx, radix_arg.span, "_", &mut applicability);
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span_lint_and_sugg(
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cx,
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TO_DIGIT_IS_SOME,
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expr.span,
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"use of `.to_digit(..).is_some()`",
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"try",
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if is_method_call {
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format!("{char_arg_snip}.is_digit({radix_snip})")
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} else {
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format!("char::is_digit({char_arg_snip}, {radix_snip})")
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},
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applicability,
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);
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}
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}
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}
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}
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