1 use clippy_utils::diagnostics::span_lint_and_sugg;
2 use clippy_utils::{is_expr_path_def_path, is_trait_method, path_to_local_id, paths};
3 use if_chain::if_chain;
4 use rustc_errors::Applicability;
6 use rustc_lint::LateContext;
7 use rustc_span::{source_map::Span, sym};
9 use super::FILTER_MAP_IDENTITY;
11 pub(super) fn check(cx: &LateContext<'_>, expr: &hir::Expr<'_>, filter_map_arg: &hir::Expr<'_>, filter_map_span: Span) {
12 if is_trait_method(cx, expr, sym::Iterator) {
13 let apply_lint = |message: &str| {
17 filter_map_span.with_hi(expr.span.hi()),
20 "flatten()".to_string(),
21 Applicability::MachineApplicable,
26 if let hir::ExprKind::Closure(_, _, body_id, _, _) = filter_map_arg.kind;
27 let body = cx.tcx.hir().body(body_id);
29 if let hir::PatKind::Binding(_, binding_id, ..) = body.params[0].pat.kind;
30 if path_to_local_id(&body.value, binding_id);
32 apply_lint("called `filter_map(|x| x)` on an `Iterator`");
36 if is_expr_path_def_path(cx, filter_map_arg, &paths::CONVERT_IDENTITY) {
37 apply_lint("called `filter_map(std::convert::identity)` on an `Iterator`");