Use LangVersion=8 where feasible in testing

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;"], expectedErrors:["CS8627"]} -->
 > ```csharp
 > #nullable enable
 > public T? Find<T>(IEnumerable<T> sequence, Func<T, bool> predicate) { ... }

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 }
 >

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();
 >

tools/example-templates/additional-files/Attr1Attribute.cs

@@ -1,3 +1,5 @@
+using System;
+
 [AttributeUsage(AttributeTargets.Class, AllowMultiple = false)]
 public class Attr1Attribute : Attribute
 {

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; }
 //    }
 }
-

tools/example-templates/additional-files/Attr3Attribute.cs

@@ -1,3 +1,5 @@
+using System;
+
 [AttributeUsage(AttributeTargets.Class, AllowMultiple = false)]
 public class Attr3Attribute : Attribute
 {

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);

tools/example-templates/additional-files/SimpleAttribute.cs

@@ -1,3 +1,5 @@
+using System;
+
 [AttributeUsage(AttributeTargets.Class | AttributeTargets.Interface)]
 public class SimpleAttribute : Attribute
 { 

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>

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>

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>

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>

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>

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>

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>

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>

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>

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>

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>