🔄 synced local 'docs/guide/' with remote 'docs/guide/'

Author: chaokunyang

docs/guide/cpp/field-configuration.md

@@ -527,12 +527,10 @@ FORY_FIELD_CONFIG(DataV2,
 | **Cross-lang compat**   | Limited               | Limited           | Full                      |
 | **Recommended for**     | Simple structs        | Third-party types | Complex/xlang structs     |
 
-## Xlang Mode Defaults
+## Default Values
 
-C++ only supports xlang (cross-language) mode. The defaults are strict due to type system differences between languages:
-
-- **Nullable**: Fields are non-nullable by default
-- **Ref tracking**: Disabled by default (except `std::shared_ptr` which tracks refs by default)
+- **Nullable**: Only `std::optional<T>` is nullable by default; all other types (including `std::shared_ptr`) are non-nullable
+- **Ref tracking**: Disabled by default for all types (including `std::shared_ptr`)
 
 You **need to configure fields** when:
 

docs/guide/go/struct-tags.md

@@ -282,11 +282,18 @@ err := f.RegisterStruct(BadStruct{}, 1)
 // Error: ErrKindInvalidTag
 ```
 
-## Xlang Mode Defaults
+## Native Mode vs Xlang Mode
 
-Go only supports xlang (cross-language) mode. The defaults are strict due to type system differences between languages:
+Field configuration behaves differently depending on the serialization mode:
 
-- **Nullable**: Fields are non-nullable by default
+**Native Mode**:
+
+- **Nullable**: Pointer, slice, map, and interface types are nullable by default
+- **Ref tracking**: Disabled by default (`ref` tag not set)
+
+**Xlang Mode**:
+
+- **Nullable**: Only pointer types are nullable by default (slices and maps are NOT nullable)
 - **Ref tracking**: Disabled by default (`ref` tag not set)
 
 You **need to configure fields** when:

docs/guide/rust/field-configuration.md

@@ -397,12 +397,10 @@ struct Data {
 }
 ```
 
-## Xlang Mode Defaults
+## Default Values
 
-Rust only supports xlang (cross-language) mode. The defaults are strict due to type system differences between languages:
-
-- **Nullable**: Fields are non-nullable by default (except `Option<T>`)
-- **Ref tracking**: Disabled by default (except `Rc<T>`, `Arc<T>`, weak types)
+- **Nullable**: `Option<T>`, `RcWeak<T>`, and `ArcWeak<T>` are nullable by default; all other types are non-nullable
+- **Ref tracking**: `Rc<T>`, `Arc<T>`, `RcWeak<T>`, and `ArcWeak<T>` enable ref tracking by default; all other types are disabled
 
 You **need to configure fields** when: