diff --git a/config.nims b/config.nims
index 7c9db32..86bd4ef 100644
--- a/config.nims
+++ b/config.nims
@@ -1,3 +1,12 @@
+# json-serialization
+# Copyright (c) 2023 Status Research & Development GmbH
+# Licensed under either of
+#  * Apache License, version 2.0, ([LICENSE-APACHE](LICENSE-APACHE))
+#  * MIT license ([LICENSE-MIT](LICENSE-MIT))
+# at your option.
+# This file may not be copied, modified, or distributed except according to
+# those terms.
+
 # begin Nimble config (version 1)
 when fileExists("nimble.paths"):
   include "nimble.paths"
diff --git a/json_serialization.nim b/json_serialization.nim
index de62396..abde59a 100644
--- a/json_serialization.nim
+++ b/json_serialization.nim
@@ -1,3 +1,12 @@
+# json-serialization
+# Copyright (c) 2023 Status Research & Development GmbH
+# Licensed under either of
+#  * Apache License, version 2.0, ([LICENSE-APACHE](LICENSE-APACHE))
+#  * MIT license ([LICENSE-MIT](LICENSE-MIT))
+# at your option.
+# This file may not be copied, modified, or distributed except according to
+# those terms.
+
 import
   serialization, json_serialization/[format, reader, writer]
 
diff --git a/json_serialization/format.nim b/json_serialization/format.nim
index 0b44d9c..58e1ccc 100644
--- a/json_serialization/format.nim
+++ b/json_serialization/format.nim
@@ -1,3 +1,12 @@
+# json-serialization
+# Copyright (c) 2019-2023 Status Research & Development GmbH
+# Licensed under either of
+#  * Apache License, version 2.0, ([LICENSE-APACHE](LICENSE-APACHE))
+#  * MIT license ([LICENSE-MIT](LICENSE-MIT))
+# at your option.
+# This file may not be copied, modified, or distributed except according to
+# those terms.
+
 import
   serialization/formats
 
diff --git a/json_serialization/lexer.nim b/json_serialization/lexer.nim
index aee603d..b87efe1 100644
--- a/json_serialization/lexer.nim
+++ b/json_serialization/lexer.nim
@@ -1,4 +1,11 @@
-{.push raises: [].}
+# json-serialization
+# Copyright (c) 2019-2023 Status Research & Development GmbH
+# Licensed under either of
+#  * Apache License, version 2.0, ([LICENSE-APACHE](LICENSE-APACHE))
+#  * MIT license ([LICENSE-MIT](LICENSE-MIT))
+# at your option.
+# This file may not be copied, modified, or distributed except according to
+# those terms.
 
 import
   std/[json, unicode],
diff --git a/json_serialization/reader.nim b/json_serialization/reader.nim
index 4e58e4a..5c51c61 100644
--- a/json_serialization/reader.nim
+++ b/json_serialization/reader.nim
@@ -1,3 +1,12 @@
+# json-serialization
+# Copyright (c) 2019-2023 Status Research & Development GmbH
+# Licensed under either of
+#  * Apache License, version 2.0, ([LICENSE-APACHE](LICENSE-APACHE))
+#  * MIT license ([LICENSE-MIT](LICENSE-MIT))
+# at your option.
+# This file may not be copied, modified, or distributed except according to
+# those terms.
+
 {.experimental: "notnil".}
 
 import
@@ -773,4 +782,4 @@ template configureJsonDeserialization*(
     static: doAssert not allowNumericRepr or enumStyle(T) == EnumStyle.Numeric
     r.parseEnum(value, allowNumericRepr, stringNormalizer)
 
-{.pop.}
+{.pop.}
\ No newline at end of file
diff --git a/json_serialization/std/net.nim b/json_serialization/std/net.nim
index 3ae93f4..16a00cd 100644
--- a/json_serialization/std/net.nim
+++ b/json_serialization/std/net.nim
@@ -1,3 +1,12 @@
+# json-serialization
+# Copyright (c) 2019-2023 Status Research & Development GmbH
+# Licensed under either of
+#  * Apache License, version 2.0, ([LICENSE-APACHE](LICENSE-APACHE))
+#  * MIT license ([LICENSE-MIT](LICENSE-MIT))
+# at your option.
+# This file may not be copied, modified, or distributed except according to
+# those terms.
+
 import
   std/strutils, stew/shims/net,
   ../../json_serialization, chronos/transports/common
diff --git a/json_serialization/std/options.nim b/json_serialization/std/options.nim
index 5dd9f24..d4a1300 100644
--- a/json_serialization/std/options.nim
+++ b/json_serialization/std/options.nim
@@ -1,3 +1,12 @@
+# json-serialization
+# Copyright (c) 2019-2023 Status Research & Development GmbH
+# Licensed under either of
+#  * Apache License, version 2.0, ([LICENSE-APACHE](LICENSE-APACHE))
+#  * MIT license ([LICENSE-MIT](LICENSE-MIT))
+# at your option.
+# This file may not be copied, modified, or distributed except according to
+# those terms.
+
 import std/options, ../../json_serialization/[reader, writer, lexer]
 export options
 
diff --git a/json_serialization/std/sets.nim b/json_serialization/std/sets.nim
index 96e50ce..a8c39b0 100644
--- a/json_serialization/std/sets.nim
+++ b/json_serialization/std/sets.nim
@@ -1,3 +1,12 @@
+# json-serialization
+# Copyright (c) 2019-2023 Status Research & Development GmbH
+# Licensed under either of
+#  * Apache License, version 2.0, ([LICENSE-APACHE](LICENSE-APACHE))
+#  * MIT license ([LICENSE-MIT](LICENSE-MIT))
+# at your option.
+# This file may not be copied, modified, or distributed except according to
+# those terms.
+
 import stew/shims/sets, ../../json_serialization/[reader, writer, lexer]
 export sets
 
diff --git a/json_serialization/std/tables.nim b/json_serialization/std/tables.nim
index d71e11b..aa461e6 100644
--- a/json_serialization/std/tables.nim
+++ b/json_serialization/std/tables.nim
@@ -1,3 +1,12 @@
+# json-serialization
+# Copyright (c) 2019-2023 Status Research & Development GmbH
+# Licensed under either of
+#  * Apache License, version 2.0, ([LICENSE-APACHE](LICENSE-APACHE))
+#  * MIT license ([LICENSE-MIT](LICENSE-MIT))
+# at your option.
+# This file may not be copied, modified, or distributed except according to
+# those terms.
+
 import stew/shims/tables, ../../json_serialization/[reader, writer, lexer]
 export tables
 
diff --git a/json_serialization/stew/results.nim b/json_serialization/stew/results.nim
index 0b0a18f..ea8f842 100644
--- a/json_serialization/stew/results.nim
+++ b/json_serialization/stew/results.nim
@@ -1,3 +1,12 @@
+# json-serialization
+# Copyright (c) 2019-2023 Status Research & Development GmbH
+# Licensed under either of
+#  * Apache License, version 2.0, ([LICENSE-APACHE](LICENSE-APACHE))
+#  * MIT license ([LICENSE-MIT](LICENSE-MIT))
+# at your option.
+# This file may not be copied, modified, or distributed except according to
+# those terms.
+
 import
   stew/results, ../../json_serialization/[reader, writer, lexer]
 
diff --git a/json_serialization/types.nim b/json_serialization/types.nim
index 5a366a5..639a5c2 100644
--- a/json_serialization/types.nim
+++ b/json_serialization/types.nim
@@ -1,3 +1,12 @@
+# json-serialization
+# Copyright (c) 2019-2023 Status Research & Development GmbH
+# Licensed under either of
+#  * Apache License, version 2.0, ([LICENSE-APACHE](LICENSE-APACHE))
+#  * MIT license ([LICENSE-MIT](LICENSE-MIT))
+# at your option.
+# This file may not be copied, modified, or distributed except according to
+# those terms.
+
 import
   serialization/errors
 
diff --git a/json_serialization/writer.nim b/json_serialization/writer.nim
index 9280809..dc80c58 100644
--- a/json_serialization/writer.nim
+++ b/json_serialization/writer.nim
@@ -1,3 +1,12 @@
+# json-serialization
+# Copyright (c) 2019-2023 Status Research & Development GmbH
+# Licensed under either of
+#  * Apache License, version 2.0, ([LICENSE-APACHE](LICENSE-APACHE))
+#  * MIT license ([LICENSE-MIT](LICENSE-MIT))
+# at your option.
+# This file may not be copied, modified, or distributed except according to
+# those terms.
+
 import
   std/[json, typetraits],
   faststreams/[outputs, textio], serialization,
@@ -152,6 +161,9 @@ template writeObjectField*[FieldType, RecordType](w: var JsonWriter,
                                                   field: FieldType): bool =
   mixin writeFieldIMPL, writeValue
 
+  type
+    R {.used.} = type record
+
   w.writeFieldName(fieldName)
   when RecordType is tuple:
     w.writeValue(field)
diff --git a/tests/nim.cfg b/tests/nim.cfg
index 9d2b0c6..ab0ea36 100644
--- a/tests/nim.cfg
+++ b/tests/nim.cfg
@@ -1,2 +1,11 @@
+# json-serialization
+# Copyright (c) 2019-2023 Status Research & Development GmbH
+# Licensed under either of
+#  * Apache License, version 2.0, ([LICENSE-APACHE](LICENSE-APACHE))
+#  * MIT license ([LICENSE-MIT](LICENSE-MIT))
+# at your option.
+# This file may not be copied, modified, or distributed except according to
+# those terms.
+
 --threads:on
 
diff --git a/tests/test_all.nim b/tests/test_all.nim
index 01ba09b..fbd2c04 100644
--- a/tests/test_all.nim
+++ b/tests/test_all.nim
@@ -1,3 +1,14 @@
+# json-serialization
+# Copyright (c) 2019-2023 Status Research & Development GmbH
+# Licensed under either of
+#  * Apache License, version 2.0, ([LICENSE-APACHE](LICENSE-APACHE))
+#  * MIT license ([LICENSE-MIT](LICENSE-MIT))
+# at your option.
+# This file may not be copied, modified, or distributed except according to
+# those terms.
+
+{. warning[UnusedImport]:off .}
+
 import
   test_lexer,
   test_serialization
diff --git a/tests/test_json_flavor.nim b/tests/test_json_flavor.nim
index 46a44a6..8bd7a2a 100644
--- a/tests/test_json_flavor.nim
+++ b/tests/test_json_flavor.nim
@@ -1,3 +1,12 @@
+# json-serialization
+# Copyright (c) 2019-2023 Status Research & Development GmbH
+# Licensed under either of
+#  * Apache License, version 2.0, ([LICENSE-APACHE](LICENSE-APACHE))
+#  * MIT license ([LICENSE-MIT](LICENSE-MIT))
+# at your option.
+# This file may not be copied, modified, or distributed except according to
+# those terms.
+
 import
   strutils,
   serialization,
diff --git a/tests/test_lexer.nim b/tests/test_lexer.nim
index c0554d5..ec1642f 100644
--- a/tests/test_lexer.nim
+++ b/tests/test_lexer.nim
@@ -1,4 +1,11 @@
-{.used.}
+# json-serialization
+# Copyright (c) 2019-2023 Status Research & Development GmbH
+# Licensed under either of
+#  * Apache License, version 2.0, ([LICENSE-APACHE](LICENSE-APACHE))
+#  * MIT license ([LICENSE-MIT](LICENSE-MIT))
+# at your option.
+# This file may not be copied, modified, or distributed except according to
+# those terms.
 
 import
   unittest,
diff --git a/tests/test_serialization.nim b/tests/test_serialization.nim
index 40c4e42..23cb5b3 100644
--- a/tests/test_serialization.nim
+++ b/tests/test_serialization.nim
@@ -1,4 +1,11 @@
-{.used.}
+# json-serialization
+# Copyright (c) 2019-2023 Status Research & Development GmbH
+# Licensed under either of
+#  * Apache License, version 2.0, ([LICENSE-APACHE](LICENSE-APACHE))
+#  * MIT license ([LICENSE-MIT](LICENSE-MIT))
+# at your option.
+# This file may not be copied, modified, or distributed except according to
+# those terms.
 
 import
   strutils, unittest2, json,
@@ -746,6 +753,7 @@ suite "toJson tests":
     expect SerializationError:
      let h4 = Json.decode("""{"o":{"distance":3,"x":1,"y":"2"}}""",
                           HoldsOption, requireAllFields = true)
+     discard h4
 
   test "Nested option types":
     let
@@ -824,6 +832,7 @@ suite "toJson tests":
     expect SerializationError:
      let h4 = Json.decode("""{"o":{"distance":3,"x":1,"y":"2"}}""",
                           HoldsResultOpt, requireAllFields = true)
+     discard h4
 
   test "Custom field serialization":
     let obj = WithCustomFieldRule(str: "test", intVal: 10)
diff --git a/tests/utils.nim b/tests/utils.nim
index 3c19ef7..019c9ca 100644
--- a/tests/utils.nim
+++ b/tests/utils.nim
@@ -1,4 +1,14 @@
-import strutils
+# json-serialization
+# Copyright (c) 2019-2023 Status Research & Development GmbH
+# Licensed under either of
+#  * Apache License, version 2.0, ([LICENSE-APACHE](LICENSE-APACHE))
+#  * MIT license ([LICENSE-MIT](LICENSE-MIT))
+# at your option.
+# This file may not be copied, modified, or distributed except according to
+# those terms.
+
+import
+  strutils
 
 # `dedent` exists in newer Nim version and doesn't behave the same
 func test_dedent*(s: string): string =