Add new condition to avoid derived code trigger lint

Author: cocodery

clippy_lints/src/no_effect.rs

@@ -1,7 +1,7 @@
 use clippy_utils::diagnostics::{span_lint_hir, span_lint_hir_and_then};
 use clippy_utils::source::snippet_opt;
 use clippy_utils::ty::has_drop;
-use clippy_utils::{get_parent_node, is_lint_allowed, peel_blocks};
+use clippy_utils::{any_parent_is_automatically_derived, get_parent_node, is_lint_allowed, peel_blocks};
 use rustc_errors::Applicability;
 use rustc_hir::def::{DefKind, Res};
 use rustc_hir::{
@@ -144,6 +144,7 @@ fn check_no_effect(cx: &LateContext<'_>, stmt: &Stmt<'_>) -> bool {
         }
     } else if let StmtKind::Local(local) = stmt.kind {
         if !is_lint_allowed(cx, NO_EFFECT_UNDERSCORE_BINDING, local.hir_id)
+            && !any_parent_is_automatically_derived(cx.tcx, local.hir_id)
             && let Some(init) = local.init
             && local.els.is_none()
             && !local.pat.span.from_expansion()