From b9f621b561e96bdc3b4a7afc6895d7df06dd8031 Mon Sep 17 00:00:00 2001
From: Jon Skeet <skeet@pobox.com>
Date: Thu, 21 Nov 2024 11:12:07 +0000
Subject: [PATCH 1/4] Remove accidentally-nested template directory

---
 .../standalone-lib/standalone-lib-without-using/Library.cs       | 1 -
 1 file changed, 1 deletion(-)
 delete mode 100644 tools/example-templates/standalone-lib/standalone-lib-without-using/Library.cs

diff --git a/tools/example-templates/standalone-lib/standalone-lib-without-using/Library.cs b/tools/example-templates/standalone-lib/standalone-lib-without-using/Library.cs
deleted file mode 100644
index bb8d3f010..000000000
--- a/tools/example-templates/standalone-lib/standalone-lib-without-using/Library.cs
+++ /dev/null
@@ -1 +0,0 @@
-$example-code

From a567d41c3cd0d73be3d5001940e2f9e358630886 Mon Sep 17 00:00:00 2001
From: Jon Skeet <skeet@pobox.com>
Date: Thu, 21 Nov 2024 11:13:24 +0000
Subject: [PATCH 2/4] Use LangVersion=8 where feasible in testing

This should allow us to avoid accidentally using C# 9+ features, at least in most cases.

The standalone-console and standalone-console-without-using templates are unchanged, as many examples using them expect to use top-level statements.
(Once we've got as far as C# 10, we should be able to use LangVersion for all projects.)
---
 standard/attributes.md                                     | 7 +++++--
 standard/conversions.md                                    | 2 +-
 standard/statements.md                                     | 2 +-
 tools/example-templates/additional-files/Attr1Attribute.cs | 2 ++
 tools/example-templates/additional-files/Attr2Attribute.cs | 3 ++-
 tools/example-templates/additional-files/Attr3Attribute.cs | 2 ++
 tools/example-templates/additional-files/Extensions.cs     | 2 ++
 .../example-templates/additional-files/SimpleAttribute.cs  | 2 ++
 .../code-in-class-lib-without-using/Project.csproj         | 2 +-
 tools/example-templates/code-in-class-lib/Project.csproj   | 2 +-
 .../code-in-main-without-using/Project.csproj              | 2 +-
 tools/example-templates/code-in-main/Project.csproj        | 2 +-
 .../example-templates/code-in-partial-class/Project.csproj | 2 +-
 tools/example-templates/extern-lib/ExampleProject.csproj   | 1 +
 tools/example-templates/extern-lib/ExternN2.csproj         | 1 +
 tools/example-templates/extern-lib/ExternR1.csproj         | 1 +
 tools/example-templates/extern-lib/ExternX.csproj          | 1 +
 tools/example-templates/extern-lib/ExternY.csproj          | 1 +
 tools/example-templates/standalone-lib/Project.csproj      | 2 +-
 19 files changed, 28 insertions(+), 11 deletions(-)

diff --git a/standard/attributes.md b/standard/attributes.md
index 21d681e30..2a60a3a4a 100644
--- a/standard/attributes.md
+++ b/standard/attributes.md
@@ -20,7 +20,7 @@ A generic class declaration shall not use `System.Attribute` as a direct or indi
 
 > *Example*:
 >
-> <!-- Example: {template:"standalone-lib", name:"AttributeCantBeGeneric", expectedErrors:["CS8936"], ignoredWarnings:["CS0169"]} -->
+> <!-- Example: {template:"standalone-lib", name:"AttributeCantBeGeneric", expectedErrors:["CS8400"], ignoredWarnings:["CS0169"]} -->
 > ```csharp
 > public class B : Attribute {}
 > public class C<T> : B {} // Error – generic cannot be an attribute
@@ -617,6 +617,7 @@ It is important to understand that the inclusion or exclusion of a call to a con
 > <!-- Example: {template:"standalone-lib", name:"ConditionalMethods3"} -->
 > ```csharp
 > // File Class1.cs:
+> using System;
 > using System.Diagnostics;
 > class Class1
 > {
@@ -659,6 +660,7 @@ The use of conditional methods in an inheritance chain can be confusing. Calls m
 > <!-- Example: {template:"standalone-console", name:"ConditionalMethods4", expectedOutput:["Class2.M executed"]} -->
 > ```csharp
 > // File Class1.cs
+> using System;
 > using System.Diagnostics;
 > class Class1
 > {
@@ -718,6 +720,7 @@ It is important to note that the inclusion or exclusion of an attribute specific
 > <!-- Example: {template:"standalone-lib", name:"ConditionalAttributeClasses2"} -->
 > ```csharp
 > // File Test.cs:
+> using System;
 > using System.Diagnostics;
 > [Conditional("DEBUG")]
 > public class TestAttribute : Attribute {}
@@ -1009,7 +1012,7 @@ Specifies that a non-nullable return value may be null.
 
 > *Example*: Consider the following generic method:
 >
-> <!-- Example: {template:"code-in-class-lib-without-using", name:"MaybeNull1Attribute", replaceEllipsis:true, customEllipsisReplacements: ["return default;"]} -->
+> <!-- Example: {template:"code-in-class-lib", name:"MaybeNull1Attribute", replaceEllipsis:true, customEllipsisReplacements: ["return default;"]} -->
 > ```csharp
 > #nullable enable
 > public T? Find<T>(IEnumerable<T> sequence, Func<T, bool> predicate) { ... }
diff --git a/standard/conversions.md b/standard/conversions.md
index 3cb4557bf..0b2cf680b 100644
--- a/standard/conversions.md
+++ b/standard/conversions.md
@@ -21,7 +21,7 @@ Some conversions in the language are defined from expressions to types, others f
 
 > *Example*:
 >
-> <!-- Example: {template:"code-in-class-lib-without-using", name:"Conversions2", ignoredWarnings:["CS0414"]} -->
+> <!-- Example: {template:"code-in-class-lib", name:"Conversions2", ignoredWarnings:["CS0414"]} -->
 > ```csharp
 > enum Color { Red, Blue, Green }
 >
diff --git a/standard/statements.md b/standard/statements.md
index 245bb6d55..6d7ce6bb5 100644
--- a/standard/statements.md
+++ b/standard/statements.md
@@ -1960,7 +1960,7 @@ There are several restrictions on where a `yield` statement can appear, as descr
 
 > *Example*: The following example shows some valid and invalid uses of `yield` statements.
 >
-> <!-- Example: {template:"code-in-class-lib-without-using", name:"YieldStatement", expectedErrors:["CS1625","CS1625","CS1626","CS1631","CS1643","CS1621","CS1624"], expectedWarnings:["CS0162"]} -->
+> <!-- Example: {template:"code-in-class-lib", name:"YieldStatement", expectedErrors:["CS1625","CS1625","CS1626","CS1631","CS1643","CS1621","CS1624"], expectedWarnings:["CS0162"]} -->
 > ```csharp
 > delegate IEnumerable<int> D();
 >
diff --git a/tools/example-templates/additional-files/Attr1Attribute.cs b/tools/example-templates/additional-files/Attr1Attribute.cs
index 7dc9f8de3..0bafe99b0 100644
--- a/tools/example-templates/additional-files/Attr1Attribute.cs
+++ b/tools/example-templates/additional-files/Attr1Attribute.cs
@@ -1,3 +1,5 @@
+using System;
+
 [AttributeUsage(AttributeTargets.Class, AllowMultiple = false)]
 public class Attr1Attribute : Attribute
 {
diff --git a/tools/example-templates/additional-files/Attr2Attribute.cs b/tools/example-templates/additional-files/Attr2Attribute.cs
index f8e9893d6..564b7d7e0 100644
--- a/tools/example-templates/additional-files/Attr2Attribute.cs
+++ b/tools/example-templates/additional-files/Attr2Attribute.cs
@@ -1,3 +1,5 @@
+using System;
+
 [AttributeUsage(AttributeTargets.Class, AllowMultiple = true)]
 public class Attr2Attribute : Attribute
 {
@@ -11,4 +13,3 @@ public Attr2Attribute(string name)
 //        get { return name; }
 //    }
 }
-
diff --git a/tools/example-templates/additional-files/Attr3Attribute.cs b/tools/example-templates/additional-files/Attr3Attribute.cs
index 94a078814..55cf6c47b 100644
--- a/tools/example-templates/additional-files/Attr3Attribute.cs
+++ b/tools/example-templates/additional-files/Attr3Attribute.cs
@@ -1,3 +1,5 @@
+using System;
+
 [AttributeUsage(AttributeTargets.Class, AllowMultiple = false)]
 public class Attr3Attribute : Attribute
 {
diff --git a/tools/example-templates/additional-files/Extensions.cs b/tools/example-templates/additional-files/Extensions.cs
index 6535f1e3b..0ff912aed 100644
--- a/tools/example-templates/additional-files/Extensions.cs
+++ b/tools/example-templates/additional-files/Extensions.cs
@@ -1,3 +1,5 @@
+using System;
+
 public static class Extensions
 {
     public static int ToInt32(this string s) => Int32.Parse(s);
diff --git a/tools/example-templates/additional-files/SimpleAttribute.cs b/tools/example-templates/additional-files/SimpleAttribute.cs
index 3c0ea5d99..fba4e008d 100644
--- a/tools/example-templates/additional-files/SimpleAttribute.cs
+++ b/tools/example-templates/additional-files/SimpleAttribute.cs
@@ -1,3 +1,5 @@
+using System;
+
 [AttributeUsage(AttributeTargets.Class | AttributeTargets.Interface)]
 public class SimpleAttribute : Attribute
 { 
diff --git a/tools/example-templates/code-in-class-lib-without-using/Project.csproj b/tools/example-templates/code-in-class-lib-without-using/Project.csproj
index 19e60edae..722c71426 100644
--- a/tools/example-templates/code-in-class-lib-without-using/Project.csproj
+++ b/tools/example-templates/code-in-class-lib-without-using/Project.csproj
@@ -2,10 +2,10 @@
 
   <PropertyGroup>
     <TargetFramework>net6.0</TargetFramework>
-    <ImplicitUsings>enable</ImplicitUsings>
     <AssemblyName>$example-name</AssemblyName>
     <AllowUnsafeBlocks>true</AllowUnsafeBlocks>
     <Nullable>annotations</Nullable>
+    <LangVersion>8</LangVersion>
   </PropertyGroup>
 
 </Project>
diff --git a/tools/example-templates/code-in-class-lib/Project.csproj b/tools/example-templates/code-in-class-lib/Project.csproj
index 19e60edae..722c71426 100644
--- a/tools/example-templates/code-in-class-lib/Project.csproj
+++ b/tools/example-templates/code-in-class-lib/Project.csproj
@@ -2,10 +2,10 @@
 
   <PropertyGroup>
     <TargetFramework>net6.0</TargetFramework>
-    <ImplicitUsings>enable</ImplicitUsings>
     <AssemblyName>$example-name</AssemblyName>
     <AllowUnsafeBlocks>true</AllowUnsafeBlocks>
     <Nullable>annotations</Nullable>
+    <LangVersion>8</LangVersion>
   </PropertyGroup>
 
 </Project>
diff --git a/tools/example-templates/code-in-main-without-using/Project.csproj b/tools/example-templates/code-in-main-without-using/Project.csproj
index b6e934c80..3b12870e9 100644
--- a/tools/example-templates/code-in-main-without-using/Project.csproj
+++ b/tools/example-templates/code-in-main-without-using/Project.csproj
@@ -3,10 +3,10 @@
   <PropertyGroup>
     <OutputType>Exe</OutputType>
     <TargetFramework>net6.0</TargetFramework>
-    <ImplicitUsings>enable</ImplicitUsings>
     <Nullable>annotations</Nullable>
     <AssemblyName>$example-name</AssemblyName>
     <AllowUnsafeBlocks>true</AllowUnsafeBlocks>
+    <LangVersion>8</LangVersion>
   </PropertyGroup>
 
 </Project>
diff --git a/tools/example-templates/code-in-main/Project.csproj b/tools/example-templates/code-in-main/Project.csproj
index b6e934c80..3b12870e9 100644
--- a/tools/example-templates/code-in-main/Project.csproj
+++ b/tools/example-templates/code-in-main/Project.csproj
@@ -3,10 +3,10 @@
   <PropertyGroup>
     <OutputType>Exe</OutputType>
     <TargetFramework>net6.0</TargetFramework>
-    <ImplicitUsings>enable</ImplicitUsings>
     <Nullable>annotations</Nullable>
     <AssemblyName>$example-name</AssemblyName>
     <AllowUnsafeBlocks>true</AllowUnsafeBlocks>
+    <LangVersion>8</LangVersion>
   </PropertyGroup>
 
 </Project>
diff --git a/tools/example-templates/code-in-partial-class/Project.csproj b/tools/example-templates/code-in-partial-class/Project.csproj
index f329dbdd9..a11586be9 100644
--- a/tools/example-templates/code-in-partial-class/Project.csproj
+++ b/tools/example-templates/code-in-partial-class/Project.csproj
@@ -3,10 +3,10 @@
   <PropertyGroup>
     <OutputType>Exe</OutputType>
     <TargetFramework>net6.0</TargetFramework>
-    <ImplicitUsings>enable</ImplicitUsings>
     <AssemblyName>$example-name</AssemblyName>
     <AllowUnsafeBlocks>true</AllowUnsafeBlocks>
     <Nullable>annotations</Nullable>
+    <LangVersion>8</LangVersion>
   </PropertyGroup>
 
 </Project>
diff --git a/tools/example-templates/extern-lib/ExampleProject.csproj b/tools/example-templates/extern-lib/ExampleProject.csproj
index cc9bba375..eb01f5963 100644
--- a/tools/example-templates/extern-lib/ExampleProject.csproj
+++ b/tools/example-templates/extern-lib/ExampleProject.csproj
@@ -5,6 +5,7 @@
     <EnableDefaultItems>false</EnableDefaultItems>
     <NoWarn>CS0169</NoWarn>
     <Nullable>annotations</Nullable>
+    <LangVersion>8</LangVersion>
   </PropertyGroup>
 
   <ItemGroup>
diff --git a/tools/example-templates/extern-lib/ExternN2.csproj b/tools/example-templates/extern-lib/ExternN2.csproj
index c310d27de..4604791c8 100644
--- a/tools/example-templates/extern-lib/ExternN2.csproj
+++ b/tools/example-templates/extern-lib/ExternN2.csproj
@@ -4,6 +4,7 @@
     <TargetFramework>net6.0</TargetFramework>
     <EnableDefaultItems>false</EnableDefaultItems>
     <Nullable>annotations</Nullable>
+    <LangVersion>8</LangVersion>
   </PropertyGroup>
 
   <ItemGroup>
diff --git a/tools/example-templates/extern-lib/ExternR1.csproj b/tools/example-templates/extern-lib/ExternR1.csproj
index 40ef94d27..f3524c968 100644
--- a/tools/example-templates/extern-lib/ExternR1.csproj
+++ b/tools/example-templates/extern-lib/ExternR1.csproj
@@ -4,6 +4,7 @@
     <TargetFramework>net6.0</TargetFramework>
     <EnableDefaultItems>false</EnableDefaultItems>
     <Nullable>annotations</Nullable>
+    <LangVersion>8</LangVersion>
   </PropertyGroup>
 
   <ItemGroup>
diff --git a/tools/example-templates/extern-lib/ExternX.csproj b/tools/example-templates/extern-lib/ExternX.csproj
index 296993cc6..0e11dd005 100644
--- a/tools/example-templates/extern-lib/ExternX.csproj
+++ b/tools/example-templates/extern-lib/ExternX.csproj
@@ -4,6 +4,7 @@
     <TargetFramework>net6.0</TargetFramework>
     <EnableDefaultItems>false</EnableDefaultItems>
     <Nullable>annotations</Nullable>
+    <LangVersion>8</LangVersion>
   </PropertyGroup>
 
   <ItemGroup>
diff --git a/tools/example-templates/extern-lib/ExternY.csproj b/tools/example-templates/extern-lib/ExternY.csproj
index e7ea5519d..351eb409b 100644
--- a/tools/example-templates/extern-lib/ExternY.csproj
+++ b/tools/example-templates/extern-lib/ExternY.csproj
@@ -4,6 +4,7 @@
     <TargetFramework>net6.0</TargetFramework>
     <EnableDefaultItems>false</EnableDefaultItems>
     <Nullable>annotations</Nullable>
+    <LangVersion>8</LangVersion>
   </PropertyGroup>
 
   <ItemGroup>
diff --git a/tools/example-templates/standalone-lib/Project.csproj b/tools/example-templates/standalone-lib/Project.csproj
index 19e60edae..722c71426 100644
--- a/tools/example-templates/standalone-lib/Project.csproj
+++ b/tools/example-templates/standalone-lib/Project.csproj
@@ -2,10 +2,10 @@
 
   <PropertyGroup>
     <TargetFramework>net6.0</TargetFramework>
-    <ImplicitUsings>enable</ImplicitUsings>
     <AssemblyName>$example-name</AssemblyName>
     <AllowUnsafeBlocks>true</AllowUnsafeBlocks>
     <Nullable>annotations</Nullable>
+    <LangVersion>8</LangVersion>
   </PropertyGroup>
 
 </Project>

From 95855d9dcc6d73c802124f61d676755b6f413fd0 Mon Sep 17 00:00:00 2001
From: Jon Skeet <skeet@pobox.com>
Date: Fri, 22 Nov 2024 15:48:04 +0000
Subject: [PATCH 3/4] Expect an error for an unconstrained use of T?

Co-authored-by: Bill Wagner <wiwagn@microsoft.com>
---
 standard/attributes.md | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/standard/attributes.md b/standard/attributes.md
index 2a60a3a4a..2995471f1 100644
--- a/standard/attributes.md
+++ b/standard/attributes.md
@@ -1012,7 +1012,7 @@ Specifies that a non-nullable return value may be null.
 
 > *Example*: Consider the following generic method:
 >
-> <!-- Example: {template:"code-in-class-lib", name:"MaybeNull1Attribute", replaceEllipsis:true, customEllipsisReplacements: ["return default;"]} -->
+> <!-- Example: {template:"code-in-class-lib", name:"MaybeNull1Attribute", replaceEllipsis:true, customEllipsisReplacements: ["return default;"]", expectedErrors:["CS8627"]} -->
 > ```csharp
 > #nullable enable
 > public T? Find<T>(IEnumerable<T> sequence, Func<T, bool> predicate) { ... }

From bfdf15fda400032688dd65bedad15d5ca7c5ae31 Mon Sep 17 00:00:00 2001
From: Jon Skeet <skeet@pobox.com>
Date: Fri, 22 Nov 2024 16:36:29 +0000
Subject: [PATCH 4/4] Fix typo in example specification

---
 standard/attributes.md | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/standard/attributes.md b/standard/attributes.md
index 2995471f1..3d9d4737e 100644
--- a/standard/attributes.md
+++ b/standard/attributes.md
@@ -1012,7 +1012,7 @@ Specifies that a non-nullable return value may be null.
 
 > *Example*: Consider the following generic method:
 >
-> <!-- Example: {template:"code-in-class-lib", name:"MaybeNull1Attribute", replaceEllipsis:true, customEllipsisReplacements: ["return default;"]", expectedErrors:["CS8627"]} -->
+> <!-- Example: {template:"code-in-class-lib", name:"MaybeNull1Attribute", replaceEllipsis:true, customEllipsisReplacements: ["return default;"], expectedErrors:["CS8627"]} -->
 > ```csharp
 > #nullable enable
 > public T? Find<T>(IEnumerable<T> sequence, Func<T, bool> predicate) { ... }