diff options
Diffstat (limited to 'src/tools/clippy/clippy_lints/src/methods/iter_skip_next.rs')
-rw-r--r-- | src/tools/clippy/clippy_lints/src/methods/iter_skip_next.rs | 46 |
1 files changed, 46 insertions, 0 deletions
diff --git a/src/tools/clippy/clippy_lints/src/methods/iter_skip_next.rs b/src/tools/clippy/clippy_lints/src/methods/iter_skip_next.rs new file mode 100644 index 000000000..43e9451f7 --- /dev/null +++ b/src/tools/clippy/clippy_lints/src/methods/iter_skip_next.rs @@ -0,0 +1,46 @@ +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::Mutable; + 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, + ); + }, + ); + } +} |