Merge tag 'debian/1.52.1+dfsg1-1_exp2' into proxmox/buster

[rustc.git] / src / tools / clippy / clippy_lints / src / methods / iter_skip_next.rs

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 (file)
index 0000000..5f59691
--- /dev/null
+++ b/src/tools/clippy/clippy_lints/src/methods/iter_skip_next.rs
@@ -0,0 +1,24 @@
+use crate::utils::{match_trait_method, paths, snippet, span_lint_and_sugg};
+use rustc_errors::Applicability;
+use rustc_hir as hir;
+use rustc_lint::LateContext;
+
+use super::ITER_SKIP_NEXT;
+
+pub(super) fn check(cx: &LateContext<'_>, expr: &hir::Expr<'_>, skip_args: &[hir::Expr<'_>]) {
+    // lint if caller of skip is an Iterator
+    if match_trait_method(cx, expr, &paths::ITERATOR) {
+        if let [caller, n] = skip_args {
+            let hint = format!(".nth({})", snippet(cx, n.span, ".."));
+            span_lint_and_sugg(
+                cx,
+                ITER_SKIP_NEXT,
+                expr.span.trim_start(caller.span).unwrap(),
+                "called `skip(..).next()` on an iterator",
+                "use `nth` instead",
+                hint,
+                Applicability::MachineApplicable,
+            );
+        }
+    }
+}