1 files changed, 45 insertions, 0 deletions
diff --git a/src/tools/clippy/clippy_lints/src/methods/vec_resize_to_zero.rs b/src/tools/clippy/clippy_lints/src/methods/vec_resize_to_zero.rs
new file mode 100644
index 000000000..02d8364cb
--- /dev/null
+++ b/src/tools/clippy/clippy_lints/src/methods/vec_resize_to_zero.rs
@@ -0,0 +1,45 @@
+use clippy_utils::diagnostics::span_lint_and_then;
+use clippy_utils::ty::is_type_diagnostic_item;
+use if_chain::if_chain;
+use rustc_ast::LitKind;
+use rustc_errors::Applicability;
+use rustc_hir::{Expr, ExprKind};
+use rustc_lint::LateContext;
+use rustc_span::source_map::Spanned;
+use rustc_span::{sym, Span};
+
+use super::VEC_RESIZE_TO_ZERO;
+
+pub(super) fn check<'tcx>(
+    cx: &LateContext<'tcx>,
+    expr: &'tcx Expr<'_>,
+    count_arg: &'tcx Expr<'_>,
+    default_arg: &'tcx Expr<'_>,
+    name_span: Span,
+) {
+    if_chain! {
+        if let Some(method_id) = cx.typeck_results().type_dependent_def_id(expr.hir_id);
+        if let Some(impl_id) = cx.tcx.impl_of_method(method_id);
+        if is_type_diagnostic_item(cx, cx.tcx.type_of(impl_id), sym::Vec);
+        if let ExprKind::Lit(Spanned { node: LitKind::Int(0, _), .. }) = count_arg.kind;
+        if let ExprKind::Lit(Spanned { node: LitKind::Int(..), .. }) = default_arg.kind;
+        then {
+            let method_call_span = expr.span.with_lo(name_span.lo());
+            span_lint_and_then(
+                cx,
+                VEC_RESIZE_TO_ZERO,
+                expr.span,
+                "emptying a vector with `resize`",
+                |db| {
+                    db.help("the arguments may be inverted...");
+                    db.span_suggestion(
+                        method_call_span,
+                        "...or you can empty the vector with",
+                        "clear()".to_string(),
+                        Applicability::MaybeIncorrect,
+                    );
+                },
+            );
+        }
+    }
+}