change lint type to complexity & check ident earlier

Author: Jacherr

clippy_lints/src/unnecessary_indexing.rs

@@ -34,7 +34,7 @@ declare_clippy_lint! {
     /// ```
     #[clippy::version = "1.78.0"]
     pub UNNECESSARY_INDEXING,
-    style,
+    complexity,
     "unnecessary use of `seq.is_empty()` in a conditional when if..let is more appropriate"
 }
 
@@ -48,9 +48,9 @@ impl LateLintPass<'_> for UnnecessaryIndexing {
             && UnOp::Not == op
             // check for call of is_empty
             && let ExprKind::MethodCall(method, conditional_receiver, _, _) = unary_inner.kind
+            && method.ident.as_str() == "is_empty"
             && let expr_ty = cx.typeck_results().expr_ty(conditional_receiver).peel_refs()
             && (expr_ty.is_array_slice() || expr_ty.is_array() || is_type_diagnostic_item(cx, expr_ty, sym::Vec))
-            && method.ident.as_str() == "is_empty"
             && let ExprKind::Block(block, _) = if_expr.then.kind
         {
             // checked if conditional is calling `is_empty` on a sequence, now check if the first