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use clippy_utils::diagnostics::span_lint_and_then;
use clippy_utils::is_trait_method;
use clippy_utils::path_to_local;
use clippy_utils::source::snippet;
use rustc_errors::Applicability;
use rustc_hir as hir;
use rustc_hir::{BindingAnnotation, Node, PatKind};
use rustc_lint::LateContext;
use rustc_span::sym;
use super::ITER_SKIP_NEXT;
pub(super) fn check(cx: &LateContext<'_>, expr: &hir::Expr<'_>, recv: &hir::Expr<'_>, arg: &hir::Expr<'_>) {
// lint if caller of skip is an Iterator
if is_trait_method(cx, expr, sym::Iterator) {
let mut application = Applicability::MachineApplicable;
span_lint_and_then(
cx,
ITER_SKIP_NEXT,
expr.span.trim_start(recv.span).unwrap(),
"called `skip(..).next()` on an iterator",
|diag| {
if_chain! {
if let Some(id) = path_to_local(recv);
if let Node::Pat(pat) = cx.tcx.hir().get(id);
if let PatKind::Binding(ann, _, _, _) = pat.kind;
if ann != BindingAnnotation::MUT;
then {
application = Applicability::Unspecified;
diag.span_help(
pat.span,
&format!("for this change `{}` has to be mutable", snippet(cx, pat.span, "..")),
);
}
}
diag.span_suggestion(
expr.span.trim_start(recv.span).unwrap(),
"use `nth` instead",
format!(".nth({})", snippet(cx, arg.span, "..")),
application,
);
},
);
}
}
|
