91 lines
3.4 KiB
Rust
91 lines
3.4 KiB
Rust
use clippy_utils::diagnostics::span_lint_and_sugg;
|
|
use clippy_utils::higher;
|
|
use clippy_utils::method_chain_args;
|
|
use clippy_utils::source::snippet_with_applicability;
|
|
use clippy_utils::ty::is_type_diagnostic_item;
|
|
use if_chain::if_chain;
|
|
use rustc_errors::Applicability;
|
|
use rustc_hir::{Expr, ExprKind, PatKind, QPath};
|
|
use rustc_lint::{LateContext, LateLintPass};
|
|
use rustc_session::{declare_lint_pass, declare_tool_lint};
|
|
use rustc_span::sym;
|
|
|
|
declare_clippy_lint! {
|
|
/// ### What it does
|
|
/// Checks for unnecessary `ok()` in `while let`.
|
|
///
|
|
/// ### Why is this bad?
|
|
/// Calling `ok()` in `while let` is unnecessary, instead match
|
|
/// on `Ok(pat)`
|
|
///
|
|
/// ### Example
|
|
/// ```ignore
|
|
/// while let Some(value) = iter.next().ok() {
|
|
/// vec.push(value)
|
|
/// }
|
|
///
|
|
/// if let Some(valie) = iter.next().ok() {
|
|
/// vec.push(value)
|
|
/// }
|
|
/// ```
|
|
/// Use instead:
|
|
/// ```ignore
|
|
/// while let Ok(value) = iter.next() {
|
|
/// vec.push(value)
|
|
/// }
|
|
///
|
|
/// if let Ok(value) = iter.next() {
|
|
/// vec.push(value)
|
|
/// }
|
|
/// ```
|
|
#[clippy::version = "1.57.0"]
|
|
pub MATCH_RESULT_OK,
|
|
style,
|
|
"usage of `ok()` in `let Some(pat)` statements is unnecessary, match on `Ok(pat)` instead"
|
|
}
|
|
|
|
declare_lint_pass!(MatchResultOk => [MATCH_RESULT_OK]);
|
|
|
|
impl<'tcx> LateLintPass<'tcx> for MatchResultOk {
|
|
fn check_expr(&mut self, cx: &LateContext<'tcx>, expr: &'tcx Expr<'_>) {
|
|
let (let_pat, let_expr, ifwhile) =
|
|
if let Some(higher::IfLet { let_pat, let_expr, .. }) = higher::IfLet::hir(cx, expr) {
|
|
(let_pat, let_expr, "if")
|
|
} else if let Some(higher::WhileLet { let_pat, let_expr, .. }) = higher::WhileLet::hir(expr) {
|
|
(let_pat, let_expr, "while")
|
|
} else {
|
|
return;
|
|
};
|
|
|
|
if_chain! {
|
|
if let ExprKind::MethodCall(_, ok_span, [ref result_types_0, ..], _) = let_expr.kind; //check is expr.ok() has type Result<T,E>.ok(, _)
|
|
if let PatKind::TupleStruct(QPath::Resolved(_, x), y, _) = let_pat.kind; //get operation
|
|
if method_chain_args(let_expr, &["ok"]).is_some(); //test to see if using ok() methoduse std::marker::Sized;
|
|
if is_type_diagnostic_item(cx, cx.typeck_results().expr_ty(result_types_0), sym::Result);
|
|
if rustc_hir_pretty::to_string(rustc_hir_pretty::NO_ANN, |s| s.print_path(x, false)) == "Some";
|
|
|
|
then {
|
|
|
|
let mut applicability = Applicability::MachineApplicable;
|
|
let some_expr_string = snippet_with_applicability(cx, y[0].span, "", &mut applicability);
|
|
let trimmed_ok = snippet_with_applicability(cx, let_expr.span.until(ok_span), "", &mut applicability);
|
|
let sugg = format!(
|
|
"{} let Ok({}) = {}",
|
|
ifwhile,
|
|
some_expr_string,
|
|
trimmed_ok.trim().trim_end_matches('.'),
|
|
);
|
|
span_lint_and_sugg(
|
|
cx,
|
|
MATCH_RESULT_OK,
|
|
expr.span.with_hi(let_expr.span.hi()),
|
|
"matching on `Some` with `ok()` is redundant",
|
|
&format!("consider matching on `Ok({})` and removing the call to `ok` instead", some_expr_string),
|
|
sugg,
|
|
applicability,
|
|
);
|
|
}
|
|
}
|
|
}
|
|
}
|