Add build-only diagnostic note to CS0169 documentation (#47309)

Copilot · BillWagner · web-flow · commit a715096c6ed0 · 2025-07-21T09:47:30.000-05:00
* Initial plan

* Add build-only diagnostic note to CS0169 documentation

Co-authored-by: BillWagner &lt;493969+BillWagner@users.noreply.github.com&gt;

* Add build-only diagnostic note to all relevant CS error documentation

Co-authored-by: BillWagner &lt;493969+BillWagner@users.noreply.github.com&gt;

* Add build-only diagnostic note to remaining CS error documentation files

Co-authored-by: BillWagner &lt;493969+BillWagner@users.noreply.github.com&gt;

---------

Co-authored-by: copilot-swe-agent[bot] &lt;198982749+Copilot@users.noreply.github.com&gt;
Co-authored-by: BillWagner &lt;493969+BillWagner@users.noreply.github.com&gt;
diff --git a/docs/csharp/language-reference/compiler-messages/cs0518.md b/docs/csharp/language-reference/compiler-messages/cs0518.md
@@ -12,7 +12,9 @@ ms.assetid: b0b61cbb-c9a7-48c9-9e60-7cdd5ecb3e6c
 
 Predefined type 'type' is not defined or imported  
   
- The main cause for this problem is that the project is not importing mscorlib.dll, which defines the entire System namespace. This can be caused by one of the following:  
+The main cause for this problem is that the project is not importing mscorlib.dll, which defines the entire System namespace. This can be caused by one of the following:  
+
+[!INCLUDE[csharp-build-only-diagnostic-note](~/includes/csharp-build-only-diagnostic-note.md)]
   
 - The [**NoStandardLib**](../compiler-options/advanced.md#nostandardlib) option from the command line compiler has been specified. The **NoStandardLib** option prevents the import of mscorlib.dll. Use this option if you want to define or create a user-specific System namespace.  
   
diff --git a/docs/csharp/language-reference/compiler-messages/cs0570.md b/docs/csharp/language-reference/compiler-messages/cs0570.md
@@ -12,7 +12,9 @@ ms.assetid: 6b378974-fdd9-451b-b595-6b5b19b4ab48
 
 Property, indexer, or event 'name' is not supported by the language; try directly calling accessor method 'name!'  
   
- This error occurs when using imported metadata that was generated by another compiler. Your code attempted to use a class member that the compiler cannot process.  
+This error occurs when using imported metadata that was generated by another compiler. Your code attempted to use a class member that the compiler cannot process.
+
+[!INCLUDE[csharp-build-only-diagnostic-note](~/includes/csharp-build-only-diagnostic-note.md)]  
   
 ## Example 1
 
diff --git a/docs/csharp/language-reference/compiler-messages/cs1607.md b/docs/csharp/language-reference/compiler-messages/cs1607.md
@@ -13,6 +13,8 @@ ms.assetid: 7ad8e1a4-40c2-41cc-b4ee-cc4d7beb4372
 Assembly generation -- reason  
   
  A warning was generated from the assembly-creation phase of the compilation.  
+
+[!INCLUDE[csharp-build-only-diagnostic-note](~/includes/csharp-build-only-diagnostic-note.md)]
   
  If you are building a 64-bit application on a 32-bit operating system, you must ensure that 64-bit versions of all referenced assemblies are installed on the target operating system.  
   
diff --git a/docs/csharp/language-reference/compiler-messages/cs8178.md b/docs/csharp/language-reference/compiler-messages/cs8178.md
@@ -11,6 +11,8 @@ helpviewer_keywords:
 
 'await' cannot be used in an expression containing a call to because it returns by reference
 
+[!INCLUDE[csharp-build-only-diagnostic-note](~/includes/csharp-build-only-diagnostic-note.md)]
+
 ## Example
 
  The following sample generates CS8178:
diff --git a/docs/csharp/misc/cs0017.md b/docs/csharp/misc/cs0017.md
@@ -13,6 +13,8 @@ ms.assetid: 5e2a3eb3-6f6e-485d-8293-ceabea4d6905
 Program 'output file name' has more than one entry point defined. Compile with /main to specify the type that contains the entry point.  
   
  A program can only have one [Main](../fundamentals/program-structure/main-command-line.md) method.  
+
+[!INCLUDE[csharp-build-only-diagnostic-note](~/includes/csharp-build-only-diagnostic-note.md)]
   
  To resolve this error, you can either delete all Main methods in your code, except one, or you can use the [**StartupObject**](../language-reference/compiler-options/advanced.md#mainentrypoint-or-startupobject) compiler option to specify which Main method you want to use.  
   
diff --git a/docs/csharp/misc/cs0028.md b/docs/csharp/misc/cs0028.md
@@ -13,6 +13,8 @@ ms.assetid: 47df919f-01fa-45ae-a4b7-912445e679e2
 'function declaration' has the wrong signature to be an entry point  
   
  The method declaration for `Main` was invalid: it was declared with an invalid signature. `Main` must be declared as static and it must return either [int](../language-reference/builtin-types/integral-numeric-types.md) or [void](../language-reference/builtin-types/void.md). For more information, see [Main() and Command-Line Arguments](../fundamentals/program-structure/main-command-line.md).  
+
+[!INCLUDE[csharp-build-only-diagnostic-note](~/includes/csharp-build-only-diagnostic-note.md)]
   
  The following sample generates CS0028:  
   
diff --git a/docs/csharp/misc/cs0067.md b/docs/csharp/misc/cs0067.md
@@ -13,6 +13,8 @@ ms.assetid: df75220b-0b93-45ec-8655-98d9333b0bb7
 The event 'event' is never used  
   
  An [event](../language-reference/keywords/event.md) was declared but never used in the class in which it was declared.  
+
+[!INCLUDE[csharp-build-only-diagnostic-note](~/includes/csharp-build-only-diagnostic-note.md)]
   
  The following sample generates CS0067:  
   
diff --git a/docs/csharp/misc/cs0148.md b/docs/csharp/misc/cs0148.md
@@ -12,4 +12,6 @@ ms.assetid: d199afbf-02e1-4a1c-9e36-07bf86f1a2fb
 
 The delegate 'delegate' does not have a valid constructor  
   
- You imported and used a managed program (one that uses the .NET runtime) that was created with another compiler. That compiler allowed an ill-formed [delegate](../language-reference/builtin-types/reference-types.md) constructor. For more information, see [Delegates](../programming-guide/delegates/index.md).
+You imported and used a managed program (one that uses the .NET runtime) that was created with another compiler. That compiler allowed an ill-formed [delegate](../language-reference/builtin-types/reference-types.md) constructor. For more information, see [Delegates](../programming-guide/delegates/index.md).
+
+[!INCLUDE[csharp-build-only-diagnostic-note](~/includes/csharp-build-only-diagnostic-note.md)]
diff --git a/docs/csharp/misc/cs0169.md b/docs/csharp/misc/cs0169.md
@@ -13,6 +13,8 @@ ms.assetid: 04b0015f-658d-440a-b9ba-831178f1a180
 The private field 'class member' is never used  
   
  A private variable was declared but never referenced. A common way to generate this warning is when you declare a private member of a class and do not use it.  
+
+[!INCLUDE[csharp-build-only-diagnostic-note](~/includes/csharp-build-only-diagnostic-note.md)]
   
  The following sample generates CS0169:  
   
diff --git a/docs/csharp/misc/cs0204.md b/docs/csharp/misc/cs0204.md
@@ -12,4 +12,6 @@ ms.assetid: c1811479-41b3-4a0b-9160-ecc14bf255a3
 
 Only 65534 locals are allowed  
   
- The limit of 65534 local variables has been exceeded in a method.
+The limit of 65534 local variables has been exceeded in a method.
+
+[!INCLUDE[csharp-build-only-diagnostic-note](~/includes/csharp-build-only-diagnostic-note.md)]
diff --git a/docs/csharp/misc/cs0402.md b/docs/csharp/misc/cs0402.md
@@ -13,6 +13,8 @@ ms.assetid: 5a252c95-18c7-4569-bae0-e1f7b582cf6a
 'identifier' : an entry point cannot be generic or in a generic type  
   
  The entry point was found in a generic type. To remove this warning, implement Main in a non-generic class or struct.  
+
+[!INCLUDE[csharp-build-only-diagnostic-note](~/includes/csharp-build-only-diagnostic-note.md)]
   
 ```csharp  
 // CS0402.cs  
diff --git a/docs/csharp/misc/cs0414.md b/docs/csharp/misc/cs0414.md
@@ -12,6 +12,8 @@ ms.assetid: 6a0a80be-799b-4d9c-a7e0-6b91e9ce7be0
 
 The private field 'field' is assigned but its value is never used
 
+[!INCLUDE[csharp-build-only-diagnostic-note](~/includes/csharp-build-only-diagnostic-note.md)]
+
 This warning can occur in several scenarios in which the compiler can verify that a variable is never referenced:
 
 - A private field is assigned a constant value but is never subsequently read. The unnecessary assignment could effect performance. Consider removing the field.
diff --git a/docs/csharp/misc/cs0649.md b/docs/csharp/misc/cs0649.md
@@ -13,6 +13,8 @@ ms.assetid: 37137b18-12ed-4a0f-92e6-ee5fb0532ef3
 Field 'field' is never assigned to, and will always have its default value 'value'  
   
  The compiler detected an uninitialized private or internal field declaration that is never assigned a value.  
+
+[!INCLUDE[csharp-build-only-diagnostic-note](~/includes/csharp-build-only-diagnostic-note.md)]
   
  The following sample generates CS0649:  
   
diff --git a/docs/csharp/misc/cs0656.md b/docs/csharp/misc/cs0656.md
@@ -12,7 +12,9 @@ ms.assetid: e695280a-e75d-4e8c-aec2-1f3fb455544a
 
 Missing compiler required member 'object.member'  
   
- One of the following problems exists:  
+One of the following problems exists:  
+
+[!INCLUDE[csharp-build-only-diagnostic-note](~/includes/csharp-build-only-diagnostic-note.md)]
   
 - Your installation of the common language runtime is corrupt.  
   
diff --git a/docs/csharp/misc/cs1555.md b/docs/csharp/misc/cs1555.md
@@ -12,4 +12,6 @@ ms.assetid: 1919c8b8-d72c-44af-91d0-674ccde77c3f
 
 Could not find 'class' specified for Main method  
   
- A class was specified to the [**MainEntryPoint**](../language-reference/compiler-options/advanced.md#mainentrypoint-or-startupobject) compiler option, but the class name was not found in the source code.
+A class was specified to the [**MainEntryPoint**](../language-reference/compiler-options/advanced.md#mainentrypoint-or-startupobject) compiler option, but the class name was not found in the source code.
+
+[!INCLUDE[csharp-build-only-diagnostic-note](~/includes/csharp-build-only-diagnostic-note.md)]
diff --git a/docs/csharp/misc/cs1556.md b/docs/csharp/misc/cs1556.md
@@ -12,4 +12,6 @@ ms.assetid: 960307d2-d815-4d7a-8f96-e3e78c038ade
 
 'construct' specified for Main method must be a valid class or struct  
   
- The [**MainEntryPoint**](../language-reference/compiler-options/advanced.md#mainentrypoint-or-startupobject) compiler option was passed an identifier that was not a class name.
+The [**MainEntryPoint**](../language-reference/compiler-options/advanced.md#mainentrypoint-or-startupobject) compiler option was passed an identifier that was not a class name.
+
+[!INCLUDE[csharp-build-only-diagnostic-note](~/includes/csharp-build-only-diagnostic-note.md)]
diff --git a/docs/csharp/misc/cs1558.md b/docs/csharp/misc/cs1558.md
@@ -12,9 +12,11 @@ ms.assetid: ee603d66-007e-4782-9285-7ff031975f0f
 
 'class' does not have a suitable static Main method  
   
- The [**MainEntryPoint**](../language-reference/compiler-options/advanced.md#mainentrypoint-or-startupobject) compiler option specified a class in which to look for a **Main** method. However, the [Main](../fundamentals/program-structure/main-command-line.md) method was not defined correctly.  
+The [**MainEntryPoint**](../language-reference/compiler-options/advanced.md#mainentrypoint-or-startupobject) compiler option specified a class in which to look for a **Main** method. However, the [Main](../fundamentals/program-structure/main-command-line.md) method was not defined correctly.  
+
+[!INCLUDE[csharp-build-only-diagnostic-note](~/includes/csharp-build-only-diagnostic-note.md)]
   
- The following example generates CS1558 because of invalid return type.  
+The following example generates CS1558 because of invalid return type.  
   
 ```csharp  
 // CS1558.cs  
diff --git a/docs/csharp/misc/cs5001.md b/docs/csharp/misc/cs5001.md
@@ -14,6 +14,8 @@ Program does not contain a static 'Main' method suitable for an entry point
 
 This error occurs when no static `Main` method with a correct signature is found in the code that produces an executable file. It also occurs if the entry point function, `Main`, is defined with the wrong case, such as lower-case `main`. For information about the rules that apply to the `Main` method, see [Main() and Command-Line Arguments](../fundamentals/program-structure/main-command-line.md).
 
+[!INCLUDE[csharp-build-only-diagnostic-note](~/includes/csharp-build-only-diagnostic-note.md)]
+
 If the `Main` method has an `async` modifier, make sure that the [selected C# language version](../language-reference/configure-language-version.md) is 7.1 or higher and to use `Task` or `Task<int>` as the return type.
 
 The `Main` method is only required when compiling an executable file, that is, when the **exe** or **winexe** element of the [**TargetType**](../language-reference/compiler-options/output.md#targettype) compiler option is specified. The following Visual Studio project types specify one of these options by default:
diff --git a/includes/csharp-build-only-diagnostic-note.md b/includes/csharp-build-only-diagnostic-note.md
@@ -0,0 +1,2 @@
+> [!NOTE]
+> This warning is only reported during explicit **Build** or **Rebuild** operations. It does not appear during typing in the IDE as part of IntelliSense diagnostics. This means that if you fix the warning by using the field or removing it, the warning might persist in the error list until you build or rebuild the project again.
