From 955815fbfa0e4d0b47cef6cb746d360185623158 Mon Sep 17 00:00:00 2001
From: Benoit Blanchon <git@benoitblanchon.fr>
Date: Thu, 7 Dec 2023 15:36:31 +0100
Subject: [PATCH] Fix `function returns incomplete class type` on IAR (issue
 #2001)

Ported from 3e1be980d93e47b2a0073efeeb9a9396fd7a83be
---
 src/ArduinoJson/Variant/VariantRefBase.hpp    | 20 +++----------
 .../Variant/VariantRefBaseImpl.hpp            | 30 +++++++++++++++++++
 2 files changed, 34 insertions(+), 16 deletions(-)

diff --git a/src/ArduinoJson/Variant/VariantRefBase.hpp b/src/ArduinoJson/Variant/VariantRefBase.hpp
index d807f293..0effaf02 100644
--- a/src/ArduinoJson/Variant/VariantRefBase.hpp
+++ b/src/ArduinoJson/Variant/VariantRefBase.hpp
@@ -56,9 +56,7 @@ class VariantRefBase : public VariantTag {
   // https://arduinojson.org/v7/api/jsonvariant/as/
   template <typename T>
   FORCE_INLINE typename enable_if<ConverterNeedsWriteableRef<T>::value, T>::type
-  as() const {
-    return Converter<T>::fromJson(getVariant());
-  }
+  as() const;
 
   template <typename T,
             typename = typename enable_if<!is_same<T, TDerived>::value>::type>
@@ -88,9 +86,7 @@ class VariantRefBase : public VariantTag {
   template <typename T>
   FORCE_INLINE
       typename enable_if<ConverterNeedsWriteableRef<T>::value, bool>::type
-      is() const {
-    return Converter<T>::checkJson(getVariant());
-  }
+      is() const;
 
   // Returns true if the value is of the specified type.
   // https://arduinojson.org/v7/api/jsonvariant/is/
@@ -106,20 +102,12 @@ class VariantRefBase : public VariantTag {
   // Copies the specified value.
   // https://arduinojson.org/v7/api/jsonvariant/set/
   template <typename T>
-  FORCE_INLINE bool set(const T& value) const {
-    Converter<T>::toJson(value, getOrCreateVariant());
-    auto resources = getResourceManager();
-    return resources && !resources->overflowed();
-  }
+  FORCE_INLINE bool set(const T& value) const;
 
   // Copies the specified value.
   // https://arduinojson.org/v7/api/jsonvariant/set/
   template <typename T>
-  FORCE_INLINE bool set(T* value) const {
-    Converter<T*>::toJson(value, getOrCreateVariant());
-    auto resources = getResourceManager();
-    return resources && !resources->overflowed();
-  }
+  FORCE_INLINE bool set(T* value) const;
 
   // Returns the size of the array or object.
   // https://arduinojson.org/v7/api/jsonvariant/size/
diff --git a/src/ArduinoJson/Variant/VariantRefBaseImpl.hpp b/src/ArduinoJson/Variant/VariantRefBaseImpl.hpp
index 7f925746..2db34daa 100644
--- a/src/ArduinoJson/Variant/VariantRefBaseImpl.hpp
+++ b/src/ArduinoJson/Variant/VariantRefBaseImpl.hpp
@@ -15,6 +15,13 @@ inline JsonVariant VariantRefBase<TDerived>::add() const {
   return add<JsonVariant>();
 }
 
+template <typename TDerived>
+template <typename T>
+inline typename enable_if<ConverterNeedsWriteableRef<T>::value, T>::type
+VariantRefBase<TDerived>::as() const {
+  return Converter<T>::fromJson(getVariant());
+}
+
 template <typename TDerived>
 inline JsonArray VariantRefBase<TDerived>::createNestedArray() const {
   return add<JsonArray>();
@@ -93,6 +100,13 @@ inline JsonVariant VariantRefBase<TDerived>::getOrCreateVariant() const {
   return JsonVariant(getOrCreateData(), getResourceManager());
 }
 
+template <typename TDerived>
+template <typename T>
+inline typename enable_if<ConverterNeedsWriteableRef<T>::value, bool>::type
+VariantRefBase<TDerived>::is() const {
+  return Converter<T>::checkJson(getVariant());
+}
+
 template <typename TDerived>
 inline ElementProxy<TDerived> VariantRefBase<TDerived>::operator[](
     size_t index) const {
@@ -115,6 +129,22 @@ VariantRefBase<TDerived>::operator[](const TString& key) const {
   return MemberProxy<TDerived, TString>(derived(), key);
 }
 
+template <typename TDerived>
+template <typename T>
+inline bool VariantRefBase<TDerived>::set(const T& value) const {
+  Converter<T>::toJson(value, getOrCreateVariant());
+  auto resources = getResourceManager();
+  return resources && !resources->overflowed();
+}
+
+template <typename TDerived>
+template <typename T>
+inline bool VariantRefBase<TDerived>::set(T* value) const {
+  Converter<T*>::toJson(value, getOrCreateVariant());
+  auto resources = getResourceManager();
+  return resources && !resources->overflowed();
+}
+
 template <typename TDerived>
 template <typename T>
 inline typename enable_if<is_same<T, JsonArray>::value, JsonArray>::type