Added "propr" snippet for required properties (#75339)

* added prop snippet

* updated xlf files

* test fixes

* fixed spacing

* reverted localization

* moved snipped name to CSharpSnippetIdentifiers

* addressed PR comments

* handled interface case

* fix formatting

* fixed PR comments

* fixed PR comments

* fixed PR comments

* moved required prop key in CSharpFeaturesResources

src/Features/CSharp/Portable/CSharpFeaturesResources.resx

@@ -619,4 +619,7 @@
     <value>do-while loop</value>
     <comment>{Locked="do"}{Locked="while"} "do" and "while" are C# keywords and should not be localized.</comment>
   </data>
+  <data name="required_property" xml:space="preserve">
+    <value>required property</value>
+  </data>
 </root>

src/Features/CSharp/Portable/Snippets/AbstractCSharpAutoPropertySnippetProvider.cs

@@ -30,6 +30,8 @@ internal abstract class AbstractCSharpAutoPropertySnippetProvider : AbstractProp
     protected virtual AccessorDeclarationSyntax? GenerateSetAccessorDeclaration(CSharpSyntaxContext syntaxContext, SyntaxGenerator generator, CancellationToken cancellationToken)
         => (AccessorDeclarationSyntax)generator.SetAccessorDeclaration();
 
+    protected virtual SyntaxToken[] GetAdditionalPropertyModifiers(CSharpSyntaxContext? syntaxContext) => [];
+
     protected override bool IsValidSnippetLocationCore(SnippetContext context, CancellationToken cancellationToken)
     {
         return context.SyntaxContext.SyntaxTree.IsMemberDeclarationContext(context.Position, (CSharpSyntaxContext)context.SyntaxContext,
@@ -58,6 +60,8 @@ protected override async Task<PropertyDeclarationSyntax> GenerateSnippetSyntaxAs
             modifiers = SyntaxTokenList.Create(PublicKeyword);
         }
 
+        modifiers = modifiers.AddRange(GetAdditionalPropertyModifiers(syntaxContext));
+
         return SyntaxFactory.PropertyDeclaration(
             attributeLists: default,
             modifiers: modifiers,

src/Features/CSharp/Portable/Snippets/CSharpProprSnippetProvider.cs

@@ -0,0 +1,65 @@
+// Licensed to the .NET Foundation under one or more agreements.
+// The .NET Foundation licenses this file to you under the MIT license.
+// See the LICENSE file in the project root for more information.
+
+using System;
+using System.Composition;
+using System.Linq;
+using System.Threading;
+using Microsoft.CodeAnalysis.CSharp.Extensions.ContextQuery;
+using Microsoft.CodeAnalysis.CSharp.Syntax;
+using Microsoft.CodeAnalysis.Editing;
+using Microsoft.CodeAnalysis.Host.Mef;
+using Microsoft.CodeAnalysis.Snippets;
+using Microsoft.CodeAnalysis.Snippets.SnippetProviders;
+using static Microsoft.CodeAnalysis.CSharp.CSharpSyntaxTokens;
+
+namespace Microsoft.CodeAnalysis.CSharp.Snippets;
+
+[ExportSnippetProvider(nameof(ISnippetProvider), LanguageNames.CSharp), Shared]
+[method: ImportingConstructor]
+[method: Obsolete(MefConstruction.ImportingConstructorMessage, error: true)]
+internal sealed class CSharpProprSnippetProvider() : AbstractCSharpAutoPropertySnippetProvider
+{
+    public override string Identifier => CSharpSnippetIdentifiers.RequiredProperty;
+
+    public override string Description => CSharpFeaturesResources.required_property;
+
+    protected override SyntaxToken[] GetAdditionalPropertyModifiers(CSharpSyntaxContext? syntaxContext) => [RequiredKeyword];
+
+    protected override bool IsValidSnippetLocationCore(SnippetContext context, CancellationToken cancellationToken)
+    {
+        if (!base.IsValidSnippetLocationCore(context, cancellationToken))
+            return false;
+
+        var syntaxContext = (CSharpSyntaxContext)context.SyntaxContext;
+        var precedingModifiers = syntaxContext.PrecedingModifiers;
+
+        // The required modifier can't be applied to members of an interface
+        if (syntaxContext.ContainingTypeDeclaration is InterfaceDeclarationSyntax)
+            return false;
+
+        // "protected internal" modifiers are valid for required property
+        if (precedingModifiers.IsSupersetOf([SyntaxKind.ProtectedKeyword, SyntaxKind.InternalKeyword]))
+            return true;
+
+        // "private", "private protected", "protected" and "private protected" modifiers are NOT valid for required property
+        if (precedingModifiers.Any(syntaxKind => syntaxKind is SyntaxKind.PrivateKeyword or SyntaxKind.ProtectedKeyword))
+            return false;
+
+        return true;
+    }
+
+    protected override AccessorDeclarationSyntax? GenerateSetAccessorDeclaration(CSharpSyntaxContext syntaxContext, SyntaxGenerator generator, CancellationToken cancellationToken)
+    {
+        // Having a property with `set` accessor in a readonly struct leads to a compiler error.
+        // So if user executes snippet inside a readonly struct the right thing to do is to not generate `set` accessor at all
+        if (syntaxContext.ContainingTypeDeclaration is StructDeclarationSyntax structDeclaration &&
+            syntaxContext.SemanticModel.GetDeclaredSymbol(structDeclaration, cancellationToken) is { IsReadOnly: true })
+        {
+            return null;
+        }
+
+        return base.GenerateSetAccessorDeclaration(syntaxContext, generator, cancellationToken);
+    }
+}

src/Features/CSharp/Portable/Snippets/CSharpSnippetIdentifiers.cs

@@ -18,6 +18,7 @@ internal static class CSharpSnippetIdentifiers
     public const string ReversedFor = "forr";
     public const string ForEach = "foreach";
     public const string InitOnlyProperty = "propi";
+    public const string RequiredProperty = "propr";
     public const string If = "if";
     public const string Interface = "interface";
     public const string Lock = "lock";

src/Features/CSharpTest/Snippets/AbstractCSharpAutoPropertySnippetProviderTests.cs

@@ -56,11 +56,14 @@ class MyClass
             """);
     }
 
-    [Fact]
-    public async Task InsertSnippetInRecordTest()
+    [Theory]
+    [InlineData("record")]
+    [InlineData("record struct")]
+    [InlineData("record class")]
+    public async Task InsertSnippetInRecordTest(string recordType)
     {
-        await VerifyDefaultPropertyAsync("""
-            record MyRecord
+        await VerifyDefaultPropertyAsync($$"""
+            {{recordType}} MyRecord
             {
                 $$
             }
@@ -90,7 +93,7 @@ struct MyStruct
     // This case might produce non-default results for different snippets (e.g. no `set` accessor in 'propg' snippet),
     // so it is tested separately for all of them
     [Fact]
-    public abstract Task InsertSnippetInInterfaceTest();
+    public abstract Task VerifySnippetInInterfaceTest();
 
     [Fact]
     public async Task InsertSnippetNamingTest()
@@ -143,9 +146,7 @@ public Program()
             """);
     }
 
-    [Theory]
-    [MemberData(nameof(CommonSnippetTestData.AllAccessibilityModifiers), MemberType = typeof(CommonSnippetTestData))]
-    public async Task InsertSnippetAfterAccessibilityModifierTest(string modifier)
+    public virtual async Task InsertSnippetAfterAllowedAccessibilityModifierTest(string modifier)
     {
         await VerifyPropertyAsync($$"""
             class Program
@@ -162,6 +163,6 @@ protected async Task VerifyPropertyAsync([StringSyntax(PredefinedEmbeddedLanguag
         await VerifySnippetAsync(markup, expectedCode);
     }
 
-    protected Task VerifyDefaultPropertyAsync([StringSyntax(PredefinedEmbeddedLanguageNames.CSharpTest)] string markup, string propertyName = "MyProperty")
+    protected virtual Task VerifyDefaultPropertyAsync([StringSyntax(PredefinedEmbeddedLanguageNames.CSharpTest)] string markup, string propertyName = "MyProperty")
         => VerifyPropertyAsync(markup, $$"""public {|0:int|} {|1:{{propertyName}}|} {{DefaultPropertyBlockText}}""");
 }

src/Features/CSharpTest/Snippets/CSharpPropSnippetProviderTests.cs

@@ -3,6 +3,7 @@
 // See the LICENSE file in the project root for more information.
 
 using System.Threading.Tasks;
+using Xunit;
 
 namespace Microsoft.CodeAnalysis.CSharp.UnitTests.Snippets;
 
@@ -56,7 +57,7 @@ readonly partial struct MyStruct
             """, "public {|0:int|} {|1:MyProperty|} { get; }");
     }
 
-    public override async Task InsertSnippetInInterfaceTest()
+    public override async Task VerifySnippetInInterfaceTest()
     {
         await VerifyDefaultPropertyAsync("""
             interface MyInterface
@@ -65,4 +66,9 @@ interface MyInterface
             }
             """);
     }
+
+    [Theory]
+    [MemberData(nameof(CommonSnippetTestData.AllAccessibilityModifiers), MemberType = typeof(CommonSnippetTestData))]
+    public override Task InsertSnippetAfterAllowedAccessibilityModifierTest(string modifier)
+        => base.InsertSnippetAfterAllowedAccessibilityModifierTest(modifier);
 }

src/Features/CSharpTest/Snippets/CSharpPropgSnippetProviderTests.cs

@@ -3,6 +3,7 @@
 // See the LICENSE file in the project root for more information.
 
 using System.Threading.Tasks;
+using Xunit;
 
 namespace Microsoft.CodeAnalysis.CSharp.UnitTests.Snippets;
 
@@ -56,7 +57,7 @@ readonly partial struct MyStruct
             """, "public {|0:int|} {|1:MyProperty|} { get; }");
     }
 
-    public override async Task InsertSnippetInInterfaceTest()
+    public override async Task VerifySnippetInInterfaceTest()
     {
         // Ensure we don't generate redundant `set` accessor when executed in interface
         await VerifyPropertyAsync("""
@@ -66,4 +67,9 @@ interface MyInterface
             }
             """, "public {|0:int|} {|1:MyProperty|} { get; }");
     }
+
+    [Theory]
+    [MemberData(nameof(CommonSnippetTestData.AllAccessibilityModifiers), MemberType = typeof(CommonSnippetTestData))]
+    public override Task InsertSnippetAfterAllowedAccessibilityModifierTest(string modifier)
+        => base.InsertSnippetAfterAllowedAccessibilityModifierTest(modifier);
 }

src/Features/CSharpTest/Snippets/CSharpPropiSnippetProviderTests.cs

@@ -3,6 +3,7 @@
 // See the LICENSE file in the project root for more information.
 
 using System.Threading.Tasks;
+using Xunit;
 
 namespace Microsoft.CodeAnalysis.CSharp.UnitTests.Snippets;
 
@@ -50,7 +51,7 @@ readonly partial struct MyStruct
             """);
     }
 
-    public override async Task InsertSnippetInInterfaceTest()
+    public override async Task VerifySnippetInInterfaceTest()
     {
         await VerifyDefaultPropertyAsync("""
             interface MyInterface
@@ -59,4 +60,9 @@ interface MyInterface
             }
             """);
     }
+
+    [Theory]
+    [MemberData(nameof(CommonSnippetTestData.AllAccessibilityModifiers), MemberType = typeof(CommonSnippetTestData))]
+    public override Task InsertSnippetAfterAllowedAccessibilityModifierTest(string modifier)
+        => base.InsertSnippetAfterAllowedAccessibilityModifierTest(modifier);
 }