Merge pull request #43083 from faso/master

CanAddNullCheck update for nullable reference types

src/EditorFeatures/CSharpTest/GenerateConstructor/GenerateConstructorTests.cs

@@ -3751,7 +3751,7 @@ void M()
         }
 
         [Fact, Trait(Traits.Feature, Traits.Features.CodeActionsGenerateConstructor)]
-        public async Task TestWitNestedNullability()
+        public async Task TestWithNestedNullability()
         {
             await TestInRegularAndScriptAsync(
 @"#nullable enable

src/EditorFeatures/CSharpTest/GenerateFromMembers/GenerateConstructorFromMembers/GenerateConstructorFromMembersTests.cs

@@ -1002,6 +1002,84 @@ class Z
 optionsCallback: options => options[0].Value = true);
         }
 
+        [WorkItem(41428, "https://github.com/dotnet/roslyn/issues/41428")]
+        [Fact, Trait(Traits.Feature, Traits.Features.CodeActionsGenerateConstructorFromMembers)]
+        public async Task TestAddNullChecksWithNullableReferenceType()
+        {
+            await TestWithPickMembersDialogAsync(
+@"
+using System;
+using System.Collections.Generic;
+#nullable enable
+
+class Z
+{
+    int a;
+    string b;
+    string? c;
+    [||]
+}",
+@"
+using System;
+using System.Collections.Generic;
+#nullable enable
+
+class Z
+{
+    int a;
+    string b;
+    string? c;
+
+    public Z(int a, string b, string? c{|Navigation:)|}
+    {
+        this.a = a;
+        this.b = b ?? throw new ArgumentNullException(nameof(b));
+        this.c = c;
+    }
+}",
+chosenSymbols: new string[] { "a", "b", "c" },
+optionsCallback: options => options[0].Value = true);
+        }
+
+        [WorkItem(41428, "https://github.com/dotnet/roslyn/issues/41428")]
+        [Fact, Trait(Traits.Feature, Traits.Features.CodeActionsGenerateConstructorFromMembers)]
+        public async Task TestAddNullChecksWithNullableReferenceTypeForGenerics()
+        {
+            await TestWithPickMembersDialogAsync(
+@"
+using System;
+using System.Collections.Generic;
+#nullable enable
+
+class Z<T> where T : class
+{
+    int a;
+    string b;
+    T? c;
+    [||]
+}",
+@"
+using System;
+using System.Collections.Generic;
+#nullable enable
+
+class Z<T> where T : class
+{
+    int a;
+    string b;
+    T? c;
+
+    public Z(int a, string b, T c{|Navigation:)|}
+    {
+        this.a = a;
+        this.b = b ?? throw new ArgumentNullException(nameof(b));
+        this.c = c;
+    }
+}",
+chosenSymbols: new string[] { "a", "b", "c" },
+optionsCallback: options => options[0].Value = true);
+        }
+
         [Fact, Trait(Traits.Feature, Traits.Features.CodeActionsGenerateConstructorFromMembers)]
         public async Task TestAddNullChecks2()
         {

src/Workspaces/SharedUtilitiesAndExtensions/Compiler/Core/Extensions/ITypeSymbolExtensions.cs

@@ -23,7 +23,19 @@ internal static partial class ITypeSymbolExtensions
         private const string DefaultBuiltInParameterName = "v";
 
         public static bool CanAddNullCheck([NotNullWhen(returnValue: true)] this ITypeSymbol? type)
+#if CODE_STYLE // TODO: Remove this #if once 'WithNullableAnnotation' and 'NullableAnnotation' are available in CodeStyle layer.
             => type != null && (type.IsReferenceType || type.IsNullable());
+#else
+        {
+            if (type == null)
+                return false;
+
+            var isNullableValueType = type.IsNullable();
+            var isNonNullableReferenceType = type.IsReferenceType && type.NullableAnnotation != NullableAnnotation.Annotated;
+
+            return isNullableValueType || isNonNullableReferenceType;
+        }
+#endif
 
         public static IList<INamedTypeSymbol> GetAllInterfacesIncludingThis(this ITypeSymbol type)
         {