91 lines
3.3 KiB
Rust
91 lines
3.3 KiB
Rust
use clippy_utils::diagnostics::span_lint_and_sugg;
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use clippy_utils::is_integer_literal;
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use clippy_utils::sugg::Sugg;
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use clippy_utils::ty::{is_type_diagnostic_item, is_type_lang_item};
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use rustc_errors::Applicability;
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use rustc_hir::{def, Expr, ExprKind, LangItem, PrimTy, QPath, TyKind};
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use rustc_lint::{LateContext, LateLintPass};
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use rustc_middle::ty::Ty;
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use rustc_session::declare_lint_pass;
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use rustc_span::symbol::sym;
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declare_clippy_lint! {
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/// ### What it does
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///
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/// Checks for function invocations of the form `primitive::from_str_radix(s, 10)`
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///
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/// ### Why is this bad?
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///
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/// This specific common use case can be rewritten as `s.parse::<primitive>()`
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/// (and in most cases, the turbofish can be removed), which reduces code length
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/// and complexity.
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///
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/// ### Known problems
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///
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/// This lint may suggest using (&<expression>).parse() instead of <expression>.parse() directly
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/// in some cases, which is correct but adds unnecessary complexity to the code.
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///
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/// ### Example
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/// ```ignore
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/// let input: &str = get_input();
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/// let num = u16::from_str_radix(input, 10)?;
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/// ```
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/// Use instead:
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/// ```ignore
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/// let input: &str = get_input();
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/// let num: u16 = input.parse()?;
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/// ```
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#[clippy::version = "1.52.0"]
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pub FROM_STR_RADIX_10,
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style,
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"from_str_radix with radix 10"
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}
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declare_lint_pass!(FromStrRadix10 => [FROM_STR_RADIX_10]);
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impl<'tcx> LateLintPass<'tcx> for FromStrRadix10 {
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fn check_expr(&mut self, cx: &LateContext<'tcx>, exp: &Expr<'tcx>) {
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if let ExprKind::Call(maybe_path, [src, radix]) = &exp.kind
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&& let ExprKind::Path(QPath::TypeRelative(ty, pathseg)) = &maybe_path.kind
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// check if the first part of the path is some integer primitive
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&& let TyKind::Path(ty_qpath) = &ty.kind
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&& let ty_res = cx.qpath_res(ty_qpath, ty.hir_id)
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&& let def::Res::PrimTy(prim_ty) = ty_res
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&& matches!(prim_ty, PrimTy::Int(_) | PrimTy::Uint(_))
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// check if the second part of the path indeed calls the associated
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// function `from_str_radix`
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&& pathseg.ident.name.as_str() == "from_str_radix"
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// check if the second argument is a primitive `10`
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&& is_integer_literal(radix, 10)
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{
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let expr = if let ExprKind::AddrOf(_, _, expr) = &src.kind {
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let ty = cx.typeck_results().expr_ty(expr);
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if is_ty_stringish(cx, ty) { expr } else { &src }
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} else {
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&src
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};
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let sugg =
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Sugg::hir_with_applicability(cx, expr, "<string>", &mut Applicability::MachineApplicable).maybe_par();
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span_lint_and_sugg(
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cx,
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FROM_STR_RADIX_10,
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exp.span,
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"this call to `from_str_radix` can be replaced with a call to `str::parse`",
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"try",
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format!("{sugg}.parse::<{}>()", prim_ty.name_str()),
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Applicability::MaybeIncorrect,
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);
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}
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}
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}
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/// Checks if a Ty is `String` or `&str`
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fn is_ty_stringish(cx: &LateContext<'_>, ty: Ty<'_>) -> bool {
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is_type_lang_item(cx, ty, LangItem::String) || is_type_diagnostic_item(cx, ty, sym::str)
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}
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