dont trigger in macro expansions

Author: y21

clippy_lints/src/missing_fields_in_debug.rs

@@ -263,6 +263,10 @@ impl<'tcx> LateLintPass<'tcx> for MissingFieldInDebug {
             if let TyKind::Path(QPath::Resolved(_, self_path)) = &self_ty.kind;
             if cx.match_def_path(trait_def_id, &[sym::core, sym::fmt, sym::Debug]);
 
+            // don't trigger if this impl was derived
+            if !cx.tcx.has_attr(item.owner_id, sym::automatically_derived);
+            if !item.span.from_expansion();
+
             // find `Debug::fmt` function
             if let Some(fmt_item) = items.iter().find(|i| i.ident.name == sym::fmt);
             if let ImplItem { kind: ImplItemKind::Fn(_, body_id), .. } = cx.tcx.hir().impl_item(fmt_item.id);

tests/ui/missing_field_in_debug.rs

@@ -217,4 +217,16 @@ impl fmt::Debug for Empty {
     }
 }
 
+#[derive(Debug)]
+struct DerivedStruct {
+    a: u8,
+    b: i32,
+}
+
+#[derive(Debug)]
+enum DerivedEnum {
+    A(i32),
+    B { a: String },
+}
+
 fn main() {}