Add docs for diagnostics emitted by the System.Text.Json source gener…

…ator (#27163)

* Add docs for diagnostics emitted by the System.Text.Json source generator

* Update docs/fundamentals/syslib-diagnostics/source-generator-overview.md

Co-authored-by: Tom Dykstra <tdykstra@microsoft.com>

* Update docs/fundamentals/syslib-diagnostics/source-generator-overview.md

Co-authored-by: Tom Dykstra <tdykstra@microsoft.com>

* Update docs/fundamentals/syslib-diagnostics/source-generator-overview.md

Co-authored-by: Tom Dykstra <tdykstra@microsoft.com>

* Update docs/fundamentals/syslib-diagnostics/source-generator-overview.md

Co-authored-by: Tom Dykstra <tdykstra@microsoft.com>

* Update docs/fundamentals/syslib-diagnostics/source-generator-overview.md

Co-authored-by: Tom Dykstra <tdykstra@microsoft.com>

* Update docs/fundamentals/syslib-diagnostics/syslib1038.md

Co-authored-by: Tom Dykstra <tdykstra@microsoft.com>

* Update docs/fundamentals/syslib-diagnostics/syslib1032.md

Co-authored-by: Tom Dykstra <tdykstra@microsoft.com>

* Update docs/fundamentals/syslib-diagnostics/source-generator-overview.md

Co-authored-by: Tom Dykstra <tdykstra@microsoft.com>

Co-authored-by: Tom Dykstra <tdykstra@microsoft.com>

docs/fundamentals/syslib-diagnostics/source-generator-overview.md

@@ -42,10 +42,14 @@ The following table provides an index to the `SYSLIB1XXX` diagnostics in .NET 6
 | [SYSLIB1021][1021] | Multiple message-template item names differ only by case                                              |
 | [SYSLIB1022][1022] | Can't have malformed format strings (for example, dangling curly braces)                                     |
 | [SYSLIB1023][1023] | Generating more than six arguments is not supported                                                          |
-<!-- commented out for now, as these do not exist.
-| [SYSLIB1030][1030] | [System.Text.Json.SourceGeneration] Did not generate serialization metadata for type.                        |
-| [SYSLIB1031][1031] | [System.Text.Json.SourceGeneration] Duplicate type name.                                                     |
--->
+| [SYSLIB1030][1030] | The `System.Text.Json` source generator did not generate serialization metadata for type |
+| [SYSLIB1031][1031] | The `System.Text.Json` source generator encountered a duplicate `JsonTypeInfo` property name |
+| [SYSLIB1032][1032] | The `System.Text.Json` source generator encountered a context class that is not partial |
+| [SYSLIB1033][1033] | The `System.Text.Json` source generator encountered a type that has multiple `[JsonConstructor]` annotations|
+| [SYSLIB1035][1035] | The `System.Text.Json` source generator encountered a type that has multiple `[JsonExtensionData]` annotations |
+| [SYSLIB1036][1036] | The `System.Text.Json` source generator encountered an invalid `[JsonExtensionData]` annotation |
+| [SYSLIB1037][1037] | The `System.Text.Json` source generator encountered a type with init-only properties for which deserialization is not supported |
+| [SYSLIB1038][1038] | The `System.Text.Json` source generator encountered a property annotated with `[JsonInclude]` that has inaccessible accessors |
 
 <!-- Include adds ## Suppress warnings (H2 heading) -->
 [!INCLUDE [suppress-source-generator-diagnostics](includes/suppress-source-generator-diagnostics.md)]
@@ -72,7 +76,11 @@ The following table provides an index to the `SYSLIB1XXX` diagnostics in .NET 6
 [1021]: syslib1021.md
 [1022]: syslib1022.md
 [1023]: syslib1023.md
-<!--
 [1030]: syslib1030.md
 [1031]: syslib1031.md
--->
+[1032]: syslib1032.md
+[1033]: syslib1033.md
+[1035]: syslib1035.md
+[1036]: syslib1036.md
+[1037]: syslib1037.md
+[1038]: syslib1038.md

docs/fundamentals/syslib-diagnostics/syslib1030.md

@@ -0,0 +1,15 @@
+---
+title: SYSLIB1030 warning
+description: Learn about the diagnostic that generates compile-time warning SYSLIB1030.
+ms.date: 05/07/2021
+---
+
+# SYSLIB1030: `System.Text.Json` source generator did not generate output for type
+
+The `System.Text.Json` source generator did not generate output for a given type in the input object graph. This typically means that the type is not supported by `JsonSerializer`, for example multi-dimensional arrays like `int[,]`.
+
+## Workarounds
+
+Register a [custom converter](../../standard/serialization/system-text-json-converters-how-to.md) for the type.
+
+[!INCLUDE [suppress-syslib-warning](includes/suppress-source-generator-diagnostics.md)]

docs/fundamentals/syslib-diagnostics/syslib1031.md

@@ -0,0 +1,15 @@
+---
+title: SYSLIB1031 warning
+description: Learn about the diagnostic that generates compile-time warning SYSLIB1031.
+ms.date: 05/07/2021
+---
+
+# SYSLIB1031: `System.Text.Json` source generator encountered a duplicate type info property name
+
+The `System.Text.Json` source generator encountered a duplicate type info property name to be generated on the specified partial context type.
+
+## Workarounds
+
+Specify a new type info property name for the duplicate instance using `System.Text.Json.Serialization.JsonSerializableAttribute.TypeInfoPropertyName`.
+
+[!INCLUDE [suppress-syslib-warning](includes/suppress-source-generator-diagnostics.md)]

docs/fundamentals/syslib-diagnostics/syslib1032.md

@@ -0,0 +1,15 @@
+---
+title: SYSLIB1032 error
+description: Learn about the diagnostic that generates compile-time warning SYSLIB1032.
+ms.date: 05/07/2021
+---
+
+# SYSLIB1032: Context classes to be augmented by the `System.Text.Json` source generator must be declared as partial
+
+The `System.Text.Json` source generator encountered a context type included for source generation that is not partial, or whose containing type(s) is not partial.
+
+## Workarounds
+
+Make the context type and all containing types partial.
+
+[!INCLUDE [suppress-syslib-warning](includes/suppress-source-generator-diagnostics.md)]

docs/fundamentals/syslib-diagnostics/syslib1033.md

@@ -0,0 +1,15 @@
+---
+title: SYSLIB1033 error
+description: Learn about the diagnostic that generates compile-time error SYSLIB1033.
+ms.date: 05/07/2021
+---
+
+# SYSLIB1033: `System.Text.Json` source generator encountered a type with multiple `[JsonConstructor]` annotations
+
+The `System.Text.Json` source generator encountered a serializable type with multiple `[JsonConstructor]` annotations.
+
+## Workarounds
+
+Remove duplicate `[JsonConstructor]` annotations.
+
+[!INCLUDE [suppress-syslib-warning](includes/suppress-source-generator-diagnostics.md)]

docs/fundamentals/syslib-diagnostics/syslib1035.md

@@ -0,0 +1,15 @@
+---
+title: SYSLIB1035 error
+description: Learn about the diagnostic that generates compile-time error SYSLIB1035.
+ms.date: 05/07/2021
+---
+
+# SYSLIB1035: `System.Text.Json` source generator encountered a type with multiple `[JsonExtensionData]` annotations
+
+The `System.Text.Json` source generator encountered a serializable type with multiple `[JsonExtensionData]` annotations.
+
+## Workarounds
+
+Remove duplicate `[JsonExtensionData]` annotations.
+
+[!INCLUDE [suppress-syslib-warning](includes/suppress-source-generator-diagnostics.md)]

docs/fundamentals/syslib-diagnostics/syslib1036.md

@@ -0,0 +1,15 @@
+---
+title: SYSLIB1036 error
+description: Learn about the diagnostic that generates compile-time error SYSLIB1036.
+ms.date: 05/07/2021
+---
+
+# SYSLIB1036: `System.Text.Json` source generator encountered an invalid `[JsonExtensionData]` annotation
+
+The `System.Text.Json` source generator encountered a property or field annotated with `[JsonExtensionData]` but whose data type does not implement `IDictionary<string, JsonElement>`, `IDictionary<string, object>`, `IDictionary<string, JsonNode>`, or `JsonNode`.
+
+## Workarounds
+
+Ensure that the data type for any property or field that is annotated with `[JsonExtensionData]` implements `IDictionary<string, JsonElement>`, `IDictionary<string, object>`, `IDictionary<string, JsonNode>`, or `JsonNode`.
+
+[!INCLUDE [suppress-syslib-warning](includes/suppress-source-generator-diagnostics.md)]

docs/fundamentals/syslib-diagnostics/syslib1037.md

@@ -0,0 +1,15 @@
+---
+title: SYSLIB1037 warning
+description: Learn about the diagnostic that generates compile-time warning SYSLIB1037.
+ms.date: 05/07/2021
+---
+
+# SYSLIB1037: `System.Text.Json` source generator encountered a type with init-only properties which are not supported for deserialization
+
+The `System.Text.Json` source generator encountered a type with init-only properties, such as a record type. These properties are currently not supported by the source generator for deserialization.
+
+## Workarounds
+
+If deserialization of init-only properties is required, use the [reflection-based `JsonSerializer` implementation](../../standard/serialization/system-text-json-source-generation-modes.md).
+
+[!INCLUDE [suppress-syslib-warning](includes/suppress-source-generator-diagnostics.md)]

docs/fundamentals/syslib-diagnostics/syslib1038.md

@@ -0,0 +1,15 @@
+---
+title: SYSLIB1038 warning
+description: Learn about the diagnostic that generates compile-time warning SYSLIB1038.
+ms.date: 05/07/2021
+---
+
+# SYSLIB1038: `System.Text.Json` source generator encountered a property annotated with `[JsonInclude]` but with inaccessible accessors
+
+The `System.Text.Json` source generator encountered a property that is annotated with `[JsonInclude]` but has accessors that are inaccessible to the source generator. The property must have `public` or `internal` accessors.
+
+## Workarounds
+
+If serialization or deserialization of properties with accessors that are not `public` or `internal` is required, use the [reflection-based `JsonSerializer` implementation](../../standard/serialization/system-text-json-source-generation-modes.md).
+
+[!INCLUDE [suppress-syslib-warning](includes/suppress-source-generator-diagnostics.md)]