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use clippy_utils::diagnostics::{span_lint, span_lint_and_sugg};
use clippy_utils::source::snippet;
use clippy_utils::{is_trait_method, meets_msrv, msrvs};
use rustc_errors::Applicability;
use rustc_hir as hir;
use rustc_lint::LateContext;
use rustc_semver::RustcVersion;
use rustc_span::sym;
use super::FILTER_MAP_NEXT;
pub(super) fn check<'tcx>(
cx: &LateContext<'tcx>,
expr: &'tcx hir::Expr<'_>,
recv: &'tcx hir::Expr<'_>,
arg: &'tcx hir::Expr<'_>,
msrv: Option<RustcVersion>,
) {
if is_trait_method(cx, expr, sym::Iterator) {
if !meets_msrv(msrv, msrvs::ITERATOR_FIND_MAP) {
return;
}
let msg = "called `filter_map(..).next()` on an `Iterator`. This is more succinctly expressed by calling \
`.find_map(..)` instead";
let filter_snippet = snippet(cx, arg.span, "..");
if filter_snippet.lines().count() <= 1 {
let iter_snippet = snippet(cx, recv.span, "..");
span_lint_and_sugg(
cx,
FILTER_MAP_NEXT,
expr.span,
msg,
"try this",
format!("{iter_snippet}.find_map({filter_snippet})"),
Applicability::MachineApplicable,
);
} else {
span_lint(cx, FILTER_MAP_NEXT, expr.span, msg);
}
}
}
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