From 5253595b3bb6a3cc6502bb2327590e582d1d27e9 Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Matthias=20Kr=C3=BCger?= Date: Fri, 6 Nov 2020 19:34:34 +0100 Subject: [PATCH] FROM_ITER_INSTEAD_OF_COLLECT: avoid unwrapping unconditionally Fixes #6302 --- clippy_lints/src/methods/mod.rs | 31 +++++++++++++++++-------------- 1 file changed, 17 insertions(+), 14 deletions(-) diff --git a/clippy_lints/src/methods/mod.rs b/clippy_lints/src/methods/mod.rs index 7186656f4e11a..a3fa3bdd36a56 100644 --- a/clippy_lints/src/methods/mod.rs +++ b/clippy_lints/src/methods/mod.rs @@ -3901,21 +3901,24 @@ fn lint_from_iter(cx: &LateContext<'_>, expr: &hir::Expr<'_>, args: &[hir::Expr< let ty = cx.typeck_results().expr_ty(expr); let arg_ty = cx.typeck_results().expr_ty(&args[0]); - let from_iter_id = get_trait_def_id(cx, &paths::FROM_ITERATOR).unwrap(); - let iter_id = get_trait_def_id(cx, &paths::ITERATOR).unwrap(); + if_chain! { + if let Some(from_iter_id) = get_trait_def_id(cx, &paths::FROM_ITERATOR); + if let Some(iter_id) = get_trait_def_id(cx, &paths::ITERATOR); - if implements_trait(cx, ty, from_iter_id, &[]) && implements_trait(cx, arg_ty, iter_id, &[]) { - // `expr` implements `FromIterator` trait - let iter_expr = snippet(cx, args[0].span, ".."); - span_lint_and_sugg( - cx, - FROM_ITER_INSTEAD_OF_COLLECT, - expr.span, - "usage of `FromIterator::from_iter`", - "use `.collect()` instead of `::from_iter()`", - format!("{}.collect()", iter_expr), - Applicability::MaybeIncorrect, - ); + if implements_trait(cx, ty, from_iter_id, &[]) && implements_trait(cx, arg_ty, iter_id, &[]); + then { + // `expr` implements `FromIterator` trait + let iter_expr = snippet(cx, args[0].span, ".."); + span_lint_and_sugg( + cx, + FROM_ITER_INSTEAD_OF_COLLECT, + expr.span, + "usage of `FromIterator::from_iter`", + "use `.collect()` instead of `::from_iter()`", + format!("{}.collect()", iter_expr), + Applicability::MaybeIncorrect, + ); + } } }