incorporate additional ref struct error conditions

.openpublishing.redirection.csharp.json

@@ -467,6 +467,10 @@
             "source_path_from_root": "/docs/csharp/language-reference/compiler-messages/cs8964.md",
             "redirect_url": "/dotnet/csharp/language-reference/compiler-messages/parameter-argument-mismatch"
         },
+        {
+            "source_path_from_root": "/docs/csharp/language-reference/compiler-messages/cs9050.md",
+            "redirect_url": "/dotnet/csharp/language-reference/compiler-messages/ref-struct-errors"
+        },
         {
             "source_path_from_root": "/docs/csharp/language-reference/compiler-options/addmodule-compiler-option.md",
             "redirect_url": "/dotnet/csharp/language-reference/compiler-options/inputs"

docs/csharp/language-reference/compiler-messages/ref-modifiers-errors.md

@@ -32,7 +32,6 @@ f1_keywords:
   - "CS8332"
   - "CS8337"
   - "CS8338"
-  - "CS8345"
   - "CS8351"
   - "CS8373"
   - "CS8374"
@@ -98,7 +97,6 @@ helpviewer_keywords:
   - "CS8332"
   - "CS8337"
   - "CS8338"
-  - "CS8345"
   - "CS8351"
   - "CS8373"
   - "CS8374"
@@ -172,7 +170,6 @@ That's by design. The text closely matches the text of the compiler error / warn
 - [**CS8332**](#writable-reference-variables-require-a-writable-referent): *Cannot assign to a member of variable or use it as the right hand side of a `ref` assignment because it is a readonly variable*
 - [**CS8337**](#reference-variable-restrictions): *The first parameter of a '`ref`' extension method must be a value type or a generic type constrained to struct.*
 - [**CS8338**](#reference-variable-restrictions): *The first '`in`' or '`ref readonly`' parameter of the extension method must be a concrete (non-generic) value type.*
-- [**CS8345**](#ref-safety-violations): *Field or auto-implemented property cannot be of type unless it is an instance member of a `ref struct`.*
 - [**CS8351**](#ref-safety-violations): *Branches of a `ref` conditional operator cannot refer to variables with incompatible declaration scopes*
 - [**CS8373**](#incorrect-syntax): *The left-hand side of a `ref` assignment must be a ref variable.*
 - [**CS8374**](#ref-safety-violations): *Cannot ref-assign source has a narrower escape scope than destination.*

docs/csharp/language-reference/compiler-messages/ref-struct-errors.md

@@ -4,6 +4,10 @@ description: Learn about errors and warnings related to `ref struct` types. The
 f1_keywords:
   - "CS8343"
   - "CS8344"
+  - "CS8345"
+  - "CS9048"
+  - "CS9050"
+  - "CS9059"
   - "CS9241"
   - "CS9242"
   - "CS9243"
@@ -14,6 +18,10 @@ f1_keywords:
 helpviewer_keywords:
   - "CS8343"
   - "CS8344"
+  - "CS8345"
+  - "CS9048"
+  - "CS9050"
+  - "CS9059"
   - "CS9241"
   - "CS9242"
   - "CS9243"
@@ -27,6 +35,10 @@ ms.date: 07/30/2024
 
 - [**CS8343**](#ref-struct-interface-implementations): *`ref structs` cannot implement interfaces*
 - [**CS8344**](#ref-struct-interface-implementations): *`foreach` statement cannot operate on enumerators in async or iterator methods because type is a `ref struct` or a type parameter that allows `ref struct`.*
+- [**CS8345**](#ref-safety-violations): *Field or auto-implemented property cannot be of type unless it is an instance member of a `ref struct`.*
+- [**CS9048**](#ref-safety-violations): *The `scoped` modifier can be used for refs and `ref struct` values only.*
+- [**CS9050**](#compiler-error-cs9050): *A `ref` field cannot refer to a `ref struct`.*
+- [**CS9059**](#ref-safety-violations): *A ref field can only be declared in a ref struct.*
 - [**CS9241**](#ref-struct-interface-implementations): *'ref struct' is already specified.*
 - [**CS9242**](#ref-struct-interface-implementations): *The 'allows' constraint clause must be the last constraint specified.*
 - [**CS9243**](#ref-struct-interface-implementations): *Cannot allow ref structs for a type parameter known from other constraints to be a class.*
@@ -38,3 +50,40 @@ ms.date: 07/30/2024
 ## ref struct interface implementations
 
 More content here.
+
+## ref safety violations
+
+Even more content goes here.
+
+## Compiler Error CS9050
+
+A `ref` field cannot refer to a `ref struct`.
+
+The compiler does not support the `ref` modifier on a field within a struct (to declare a stack-allocated field) of a type already declared stack-allocated (`ref struct`).
+
+The following sample generates CS9050:
+
+```csharp
+// CS9050.cs (0,0)
+ref struct Color
+{
+    public float r, g, b;
+}
+ref struct Group
+{
+    public ref Color color;
+}
+```
+
+In this example, it is most likely a typo to have included a `ref` modifier on a field of a `ref struct` type within the declaration of a `ref struct`.  Removing the `ref` modifier corrects this error.
+
+```csharp
+ref struct Color
+{
+    public float r, g, b;
+}
+ref struct Group
+{
+    public Color color;
+}
+```

docs/csharp/language-reference/keywords/ref.md

@@ -18,3 +18,4 @@ You use the `ref` keyword in the following contexts:
 - As the part of a [conditional ref expression](../operators/conditional-operator.md#conditional-ref-expression) or a [ref assignment operator](../operators/assignment-operator.md#ref-assignment).
 - In a `struct` declaration, to declare a `ref struct`. For more information, see the [`ref` structure types](../builtin-types/ref-struct.md) article.
 - In a `ref struct` definition, to declare a `ref` field. For more information, see the [`ref` fields](../builtin-types/ref-struct.md#ref-fields) section of the [`ref` structure types](../builtin-types/ref-struct.md) article.
+- In a generic type declaration to specify that a type parameter [`allows ref struct`](../../programming-guide/generics/constraints-on-type-parameters.md#allows-ref-struct) types.

docs/csharp/language-reference/toc.yml

@@ -460,15 +460,15 @@ items:
     displayName: >
       ref safety,
       CS0192, CS0199, CS0206, CS0631, CS0767, CS1510, CS1605, CS1623, CS1649, CS1651, CS1655, CS1657, CS1741, CS1939, CS1988,
-      CS7084, CS8166, CS8167, CS8168, CS8169. CS8325, CS8326, CS8327, CS8329, CS8330, CS8331, CS8332, CS8337, CS8338, CS8345,
-      CS8351, CS8373, CS8374, CS8388, CS8977, CS9072, CS9077, CS9078, CS9079, CS9085, CS9086, CS9087, CS9089, CS9091, CS9092,
-      CS9093, CS9094, CS9095, CS9096, CS9097, CS9101, CS9102, CS9104, CS9190, CS9191, CS9192, CS9193, CS9195, CS9196, CS9197,
-      CS9198, CS9199, CS9200, CS9201
+      CS7084, CS8166, CS8167, CS8168, CS8169. CS8325, CS8326, CS8327, CS8329, CS8330, CS8331, CS8332, CS8337, CS8338, CS8351,
+      CS8373, CS8374, CS8388, CS8977, CS9072, CS9077, CS9078, CS9079, CS9085, CS9086, CS9087, CS9089, CS9091, CS9092, CS9093,
+      CS9094, CS9095, CS9096, CS9097, CS9101, CS9102, CS9104, CS9190, CS9191, CS9192, CS9193, CS9195, CS9196, CS9197, CS9198,
+      CS9199, CS9200, CS9201
   - name: "`ref struct` types"
     href: ./compiler-messages/ref-struct-errors.md
     displayName: > 
       ref struct,
-      CS8343, CS8344, CS9241, CS9242, CS9243, CS9244, CS9245, CS9246, CS9247
+      CS8343, CS8344, CS8345, CS9048, CS9050, CS9059, CS9241, CS9242, CS9243, CS9244, CS9245, CS9246, CS9247
   - name: Iterator methods
     href: ./compiler-messages/iterator-yield.md
     displayName: > 
@@ -2017,8 +2017,6 @@ items:
       href: ./compiler-messages/CS8817.md
     - name: CS9043
       href: ./compiler-messages/cs9043.md
-    - name: CS9050
-      href: ./compiler-messages/cs9050.md
   - name: Level 1 warning messages
     items:
     - name: CS0183

docs/csharp/misc/sorry-we-don-t-have-specifics-on-this-csharp-error.md

@@ -582,15 +582,13 @@ f1_keywords:
   - "CS9045"
   - "CS9046"
   - "CS9047"
-  - "CS9048"
   - "CS9049"
   - "CS9051"
   - "CS9052"
   - "CS9053"
   - "CS9054"
   - "CS9056"
   - "CS9057"
-  - "CS9059"
   - "CS9060"
   - "CS9061"
   - "CS9062"