diff --git a/clippy_lints/src/methods/filter_map_identity.rs b/clippy_lints/src/methods/filter_map_identity.rs index 403fe8d3546..d1b5e945dfd 100644 --- a/clippy_lints/src/methods/filter_map_identity.rs +++ b/clippy_lints/src/methods/filter_map_identity.rs @@ -1,6 +1,5 @@ use clippy_utils::diagnostics::span_lint_and_sugg; -use clippy_utils::{is_expr_path_def_path, is_trait_method, path_to_local_id, paths}; -use if_chain::if_chain; +use clippy_utils::{is_expr_identity_function, is_trait_method}; use rustc_errors::Applicability; use rustc_hir as hir; use rustc_lint::LateContext; @@ -9,32 +8,15 @@ use super::FILTER_MAP_IDENTITY; pub(super) fn check(cx: &LateContext<'_>, expr: &hir::Expr<'_>, filter_map_arg: &hir::Expr<'_>, filter_map_span: Span) { - if is_trait_method(cx, expr, sym::Iterator) { - let apply_lint = |message: &str| { - span_lint_and_sugg( - cx, - FILTER_MAP_IDENTITY, - filter_map_span.with_hi(expr.span.hi()), - message, - "try", - "flatten()".to_string(), - Applicability::MachineApplicable, - ); - }; - - if_chain! { - if let hir::ExprKind::Closure(_, _, body_id, _, _) = filter_map_arg.kind; - let body = cx.tcx.hir().body(body_id); - - if let hir::PatKind::Binding(_, binding_id, ..) = body.params[0].pat.kind; - if path_to_local_id(&body.value, binding_id); - then { - apply_lint("called `filter_map(|x| x)` on an `Iterator`"); - } - } - - if is_expr_path_def_path(cx, filter_map_arg, &paths::CONVERT_IDENTITY) { - apply_lint("called `filter_map(std::convert::identity)` on an `Iterator`"); - } + if is_trait_method(cx, expr, sym::Iterator) && is_expr_identity_function(cx, filter_map_arg) { + span_lint_and_sugg( + cx, + FILTER_MAP_IDENTITY, + filter_map_span.with_hi(expr.span.hi()), + "use of `filter_map` with an identity function", + "try", + "flatten()".to_string(), + Applicability::MachineApplicable, + ); } } diff --git a/tests/ui/filter_map_identity.fixed b/tests/ui/filter_map_identity.fixed index 23ce28d8e9b..a5860aa49b3 100644 --- a/tests/ui/filter_map_identity.fixed +++ b/tests/ui/filter_map_identity.fixed @@ -1,6 +1,6 @@ // run-rustfix -#![allow(unused_imports)] +#![allow(unused_imports, clippy::needless_return)] #![warn(clippy::filter_map_identity)] fn main() { @@ -13,4 +13,7 @@ fn main() { use std::convert::identity; let iterator = vec![Some(1), None, Some(2)].into_iter(); let _ = iterator.flatten(); + + let iterator = vec![Some(1), None, Some(2)].into_iter(); + let _ = iterator.flatten(); } diff --git a/tests/ui/filter_map_identity.rs b/tests/ui/filter_map_identity.rs index e698df13eea..7e998b9cdf7 100644 --- a/tests/ui/filter_map_identity.rs +++ b/tests/ui/filter_map_identity.rs @@ -1,6 +1,6 @@ // run-rustfix -#![allow(unused_imports)] +#![allow(unused_imports, clippy::needless_return)] #![warn(clippy::filter_map_identity)] fn main() { @@ -13,4 +13,7 @@ fn main() { use std::convert::identity; let iterator = vec![Some(1), None, Some(2)].into_iter(); let _ = iterator.filter_map(identity); + + let iterator = vec![Some(1), None, Some(2)].into_iter(); + let _ = iterator.filter_map(|x| return x); } diff --git a/tests/ui/filter_map_identity.stderr b/tests/ui/filter_map_identity.stderr index 596a6320608..43c9fdca4fb 100644 --- a/tests/ui/filter_map_identity.stderr +++ b/tests/ui/filter_map_identity.stderr @@ -1,4 +1,4 @@ -error: called `filter_map(|x| x)` on an `Iterator` +error: use of `filter_map` with an identity function --> $DIR/filter_map_identity.rs:8:22 | LL | let _ = iterator.filter_map(|x| x); @@ -6,17 +6,23 @@ LL | let _ = iterator.filter_map(|x| x); | = note: `-D clippy::filter-map-identity` implied by `-D warnings` -error: called `filter_map(std::convert::identity)` on an `Iterator` +error: use of `filter_map` with an identity function --> $DIR/filter_map_identity.rs:11:22 | LL | let _ = iterator.filter_map(std::convert::identity); | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: try: `flatten()` -error: called `filter_map(std::convert::identity)` on an `Iterator` +error: use of `filter_map` with an identity function --> $DIR/filter_map_identity.rs:15:22 | LL | let _ = iterator.filter_map(identity); | ^^^^^^^^^^^^^^^^^^^^ help: try: `flatten()` -error: aborting due to 3 previous errors +error: use of `filter_map` with an identity function + --> $DIR/filter_map_identity.rs:18:22 + | +LL | let _ = iterator.filter_map(|x| return x); + | ^^^^^^^^^^^^^^^^^^^^^^^^ help: try: `flatten()` + +error: aborting due to 4 previous errors