1 use clippy_utils::diagnostics::span_lint_and_sugg;
2 use clippy_utils::sugg::Sugg;
3 use clippy_utils::ty::is_type_diagnostic_item;
4 use if_chain::if_chain;
5 use rustc_errors::Applicability;
6 use rustc_hir::{def, Expr, ExprKind, PrimTy, QPath, TyKind};
7 use rustc_lint::{LateContext, LateLintPass};
8 use rustc_middle::ty::Ty;
9 use rustc_session::{declare_lint_pass, declare_tool_lint};
10 use rustc_span::symbol::sym;
12 declare_clippy_lint! {
15 /// Checks for function invocations of the form `primitive::from_str_radix(s, 10)`
17 /// ### Why is this bad?
19 /// This specific common use case can be rewritten as `s.parse::<primitive>()`
20 /// (and in most cases, the turbofish can be removed), which reduces code length
23 /// ### Known problems
25 /// This lint may suggest using (&<expression>).parse() instead of <expression>.parse() directly
26 /// in some cases, which is correct but adds unnecessary complexity to the code.
30 /// let input: &str = get_input();
31 /// let num = u16::from_str_radix(input, 10)?;
35 /// let input: &str = get_input();
36 /// let num: u16 = input.parse()?;
38 pub FROM_STR_RADIX_10,
40 "from_str_radix with radix 10"
43 declare_lint_pass!(FromStrRadix10 => [FROM_STR_RADIX_10]);
45 impl LateLintPass<'tcx> for FromStrRadix10 {
46 fn check_expr(&mut self, cx: &LateContext<'tcx>, exp: &Expr<'tcx>) {
48 if let ExprKind::Call(maybe_path, arguments) = &exp.kind;
49 if let ExprKind::Path(QPath::TypeRelative(ty, pathseg)) = &maybe_path.kind;
51 // check if the first part of the path is some integer primitive
52 if let TyKind::Path(ty_qpath) = &ty.kind;
53 let ty_res = cx.qpath_res(ty_qpath, ty.hir_id);
54 if let def::Res::PrimTy(prim_ty) = ty_res;
55 if matches!(prim_ty, PrimTy::Int(_) | PrimTy::Uint(_));
57 // check if the second part of the path indeed calls the associated
58 // function `from_str_radix`
59 if pathseg.ident.name.as_str() == "from_str_radix";
61 // check if the second argument is a primitive `10`
62 if arguments.len() == 2;
63 if let ExprKind::Lit(lit) = &arguments[1].kind;
64 if let rustc_ast::ast::LitKind::Int(10, _) = lit.node;
67 let expr = if let ExprKind::AddrOf(_, _, expr) = &arguments[0].kind {
68 let ty = cx.typeck_results().expr_ty(expr);
69 if is_ty_stringish(cx, ty) {
78 let sugg = Sugg::hir_with_applicability(
82 &mut Applicability::MachineApplicable
89 "this call to `from_str_radix` can be replaced with a call to `str::parse`",
91 format!("{}.parse::<{}>()", sugg, prim_ty.name_str()),
92 Applicability::MaybeIncorrect
99 /// Checks if a Ty is `String` or `&str`
100 fn is_ty_stringish(cx: &LateContext<'_>, ty: Ty<'_>) -> bool {
101 is_type_diagnostic_item(cx, ty, sym::String) || is_type_diagnostic_item(cx, ty, sym::str)