101 lines
3.6 KiB
Rust
101 lines
3.6 KiB
Rust
use if_chain::if_chain;
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use rustc_errors::Applicability;
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use rustc_hir::{def, Expr, ExprKind, 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, declare_tool_lint};
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use rustc_span::symbol::sym;
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use crate::utils::is_type_diagnostic_item;
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use crate::utils::span_lint_and_sugg;
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use crate::utils::sugg::Sugg;
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declare_clippy_lint! {
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/// **What it does:**
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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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/// 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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/// 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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///
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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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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 LateLintPass<'tcx> for FromStrRadix10 {
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fn check_expr(&mut self, cx: &LateContext<'tcx>, exp: &Expr<'tcx>) {
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if_chain! {
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if let ExprKind::Call(maybe_path, arguments) = &exp.kind;
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if 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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if 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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if let def::Res::PrimTy(prim_ty) = ty_res;
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if 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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if 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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if arguments.len() == 2;
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if let ExprKind::Lit(lit) = &arguments[1].kind;
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if let rustc_ast::ast::LitKind::Int(10, _) = lit.node;
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then {
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let expr = if let ExprKind::AddrOf(_, _, expr) = &arguments[0].kind {
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let ty = cx.typeck_results().expr_ty(expr);
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if is_ty_stringish(cx, ty) {
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expr
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} else {
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&arguments[0]
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}
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} else {
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&arguments[0]
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};
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let sugg = Sugg::hir_with_applicability(
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cx,
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expr,
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"<string>",
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&mut Applicability::MachineApplicable
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).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!("{}.parse::<{}>()", sugg, 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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}
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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_diagnostic_item(cx, ty, sym::string_type) || is_type_diagnostic_item(cx, ty, sym::str)
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}
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