Document C# diagnostics

tutorials/scripting/c_sharp/diagnostics/GD0001.rst

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+GD0001: Missing partial modifier on declaration of type which is a subclass of GodotObject
+==========================================================================================
+
+====================================  ======================================
+                                      Value
+====================================  ======================================
+**Rule ID**                           GD0001
+**Category**                          Usage
+**Fix is breaking or non-breaking**   Non-breaking
+**Enabled by default**                Yes
+====================================  ======================================
+
+Cause
+-----
+
+A type that derives from ``GodotObject`` is not declared partial.
+
+Rule description
+----------------
+
+Godot source generators add generated code to user-defined types to implement
+the integration with the engine. Source generators can't add generated code to
+types that aren't declared partial.
+
+.. code-block:: csharp
+
+    // The source generators can't enhance this type to work with Godot.
+    public class InvalidNode : Node { }
+
+    // The source generators can enhance this type to work with Godot.
+    public partial class ValidNode { }
+
+How to fix violations
+---------------------
+
+To fix a violation of this rule, add the ``partial`` keyword to the type
+declaration.
+
+When to suppress warnings
+-------------------------
+
+Do not suppress a warning from this rule. Types that derive from ``GodotObject``
+but aren't partial can't be enhanced by the source generators, resulting in
+unexpected runtime errors.

tutorials/scripting/c_sharp/diagnostics/GD0002.rst

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+GD0002: Missing partial modifier on declaration of type which contains one or more subclasses of GodotObject
+============================================================================================================
+
+====================================  ======================================
+                                      Value
+====================================  ======================================
+**Rule ID**                           GD0002
+**Category**                          Usage
+**Fix is breaking or non-breaking**   Non-breaking
+**Enabled by default**                Yes
+====================================  ======================================
+
+Cause
+-----
+
+A type that derives from ``GodotObject`` is contained in a non-partial type declaration.
+
+Rule description
+----------------
+
+Godot source generators add generated code to user-defined types to implement
+the integration with the engine. Source generators can't add generated code to
+types that aren't declared partial.
+
+.. code-block:: csharp
+
+    public class InvalidParentType
+    {
+        // MyNode is contained in a non-partial type so the source generators
+        // can't enhance this type to work with Godot.
+        public partial class MyNode : Node { }
+    }
+
+    public partial class ValidParentType
+    {
+        // MyNode is contained in a partial type so the source generators
+        // can enhance this type to work with Godot.
+        public partial class MyNode : Node { }
+    }
+
+How to fix violations
+---------------------
+
+To fix a violation of this rule, add the ``partial`` keyword to the type
+declaration.
+
+When to suppress warnings
+-------------------------
+
+Do not suppress a warning from this rule. Types that derive from ``GodotObject``
+but aren't partial can't be enhanced by the source generators, resulting in
+unexpected runtime errors.

tutorials/scripting/c_sharp/diagnostics/GD0101.rst

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+GD0101: Attempted to export static member
+=========================================
+
+====================================  ======================================
+                                      Value
+====================================  ======================================
+**Rule ID**                           GD0101
+**Category**                          Usage
+**Fix is breaking or non-breaking**   Breaking - If the ``static`` keyword is removed
+
+                                      Non-breaking - If the ``[Export]`` attribute is removed
+**Enabled by default**                Yes
+====================================  ======================================
+
+Cause
+-----
+
+A static member is annotated with the ``[Export]`` attribute. Static members
+can't be exported.
+
+Rule description
+----------------
+
+Godot doesn't allow exporting static members.
+
+.. code-block:: csharp
+
+    // Static members can't be exported.
+    [Export]
+    public static int InvalidProperty { get; set; }
+
+    // Instance members can be exported.
+    [Export]
+    public int ValidProperty { get; set; }
+
+How to fix violations
+---------------------
+
+To fix a violation of this rule, remove the ``[Export]`` attribute or remove the
+``static`` keyword.
+
+When to suppress warnings
+-------------------------
+
+Do not suppress a warning from this rule. Static members can't be exported so
+they will be ignored by Godot, resulting in runtime errors.

tutorials/scripting/c_sharp/diagnostics/GD0102.rst

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+GD0102: The type of the exported member is not supported
+========================================================
+
+====================================  ======================================
+                                      Value
+====================================  ======================================
+**Rule ID**                           GD0102
+**Category**                          Usage
+**Fix is breaking or non-breaking**   Breaking - If the member type is changed
+
+                                      Non-breaking - If the ``[Export]`` attribute is removed
+**Enabled by default**                Yes
+====================================  ======================================
+
+Cause
+-----
+
+An unsupported type is specified for a member annotated with the ``[Export]``
+attribute when a :ref:`Variant-compatible <doc_c_sharp_variant>` type is expected.
+
+Rule description
+----------------
+
+Every exported member must be Variant-compatible so it can be marshalled by
+the engine.
+
+.. code-block:: csharp
+
+    class SomeType { }
+
+    // SomeType is not a valid member type because it doesn't derive from GodotObject,
+    // so it's not compatible with Variant.
+    [Export]
+    public SomeType InvalidProperty { get; set; }
+
+    // System.Int32 is a valid type because it's compatible with Variant.
+    [Export]
+    public int ValidProperty { get; set; }
+
+How to fix violations
+---------------------
+
+To fix a violation of this rule, change the member's type to be Variant-compatible
+or remove the ``[Export]`` attribute.
+
+When to suppress warnings
+-------------------------
+
+Do not suppress a warning from this rule. Members with types that can't be marshalled
+will result in runtime errors.

tutorials/scripting/c_sharp/diagnostics/GD0103.rst

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+GD0103: The exported member is read-only
+========================================
+
+====================================  ======================================
+                                      Value
+====================================  ======================================
+**Rule ID**                           GD0103
+**Category**                          Usage
+**Fix is breaking or non-breaking**   Non-breaking
+**Enabled by default**                Yes
+====================================  ======================================
+
+Cause
+-----
+
+A read-only member is annotated with the ``[Export]`` attribute. Read-only members
+can't be exported.
+
+Rule description
+----------------
+
+Godot doesn't allow exporting read-only members.
+
+.. code-block:: csharp
+
+    // Read-only fields can't be exported.
+    [Export]
+    public readonly int invalidField;
+
+    // This field can be exported because it's not declared 'readonly'.
+    [Export]
+    public int validField;
+
+    // Read-only properties can't be exported.
+    [Export]
+    public int InvalidProperty { get; }
+
+    // This property can be exported because it has both a getter and a setter.
+    [Export]
+    public int ValidProperty { get; set; }
+
+How to fix violations
+---------------------
+
+To fix a violation of this rule for fields, remove the ``readonly`` keyword or
+remove the ``[Export]`` attribute.
+
+To fix a violation of this rule for properties, make sure the property declares
+both a getter and a setter, or remove the ``[Export]`` attribute.
+
+When to suppress warnings
+-------------------------
+
+Do not suppress a warning from this rule. Read-only members can't be exported so
+they will be ignored by Godot, resulting in runtime errors.

tutorials/scripting/c_sharp/diagnostics/GD0104.rst

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+GD0104: The exported property is write-only
+===========================================
+
+====================================  ======================================
+                                      Value
+====================================  ======================================
+**Rule ID**                           GD0104
+**Category**                          Usage
+**Fix is breaking or non-breaking**   Non-breaking
+**Enabled by default**                Yes
+====================================  ======================================
+
+Cause
+-----
+
+A write-only property is annotated with the ``[Export]`` attribute. Write-only properties
+can't be exported.
+
+Rule description
+----------------
+
+Godot doesn't allow exporting write-only properties.
+
+.. code-block:: csharp
+
+    private int _backingField;
+
+    // Write-only properties can't be exported.
+    [Export]
+    public int InvalidProperty { set => _backingField = value; }
+
+    // This property can be exported because it has both a getter and a setter.
+    [Export]
+    public int ValidProperty { get; set; }
+
+How to fix violations
+---------------------
+
+To fix a violation of this rule, make sure the property declares
+both a getter and a setter, or remove the ``[Export]`` attribute.
+
+When to suppress warnings
+-------------------------
+
+Do not suppress a warning from this rule. Write-only members can't be exported so
+they will be ignored by Godot, resulting in runtime errors.

tutorials/scripting/c_sharp/diagnostics/GD0105.rst

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+GD0105: Attempted to export indexer property
+============================================
+
+====================================  ======================================
+                                      Value
+====================================  ======================================
+**Rule ID**                           GD0105
+**Category**                          Usage
+**Fix is breaking or non-breaking**   Non-breaking
+**Enabled by default**                Yes
+====================================  ======================================
+
+Cause
+-----
+
+An indexer is annotated with the ``[Export]`` attribute. Indexers can't be exported.
+
+Rule description
+----------------
+
+Godot doesn't allow exporting indexer properties.
+
+.. code-block:: csharp
+
+    private int[] _backingField;
+
+    // Indexers can't be exported.
+    [Export]
+    public int this[int index]
+    {
+        get => _backingField[index];
+        set => _backingField[index] = value;
+    }
+
+How to fix violations
+---------------------
+
+To fix a violation of this rule, remove the ``[Export]`` attribute.
+
+When to suppress warnings
+-------------------------
+
+Do not suppress a warning from this rule. Indexers can't be exported so
+they will be ignored by Godot, resulting in runtime errors.