Add null suppression to component reference capture

src/Compiler/Microsoft.AspNetCore.Razor.Language/src/Components/ComponentDesignTimeNodeWriter.cs

@@ -1119,6 +1119,7 @@ protected override void WriteReferenceCaptureInnards(CodeRenderingContext contex
             var captureTypeName = node.IsComponentCapture
                 ? TypeNameHelper.GetGloballyQualifiedNameIfNeeded(node.ComponentCaptureTypeName)
                 : ComponentsApi.ElementReference.FullTypeName;
+            var nullSuppression = !context.Options.SuppressNullabilityEnforcement ? "!" : string.Empty;
             WriteCSharpCode(context, new CSharpCodeIntermediateNode
             {
                 Source = node.Source,
@@ -1128,7 +1129,7 @@ protected override void WriteReferenceCaptureInnards(CodeRenderingContext contex
                         new IntermediateToken
                         {
                             Kind = TokenKind.CSharp,
-                            Content = $" = default({captureTypeName});"
+                            Content = $" = default({captureTypeName}){nullSuppression};"
                         }
                     }
             });

src/Compiler/Microsoft.AspNetCore.Razor.Language/test/IntegrationTests/ComponentCodeGenerationTestBase.cs

@@ -7628,6 +7628,58 @@ public class MyComponent : ComponentBase
         CompileToAssembly(generated);
     }
 
+    [Fact] // https://github.com/dotnet/razor/issues/8170
+    public void Component_WithRef_Nullable()
+    {
+        // Act
+        var generated = CompileToCSharp("""
+            <TestComponent @ref="myComponent" />
+
+            @code {
+                private TestComponent myComponent = null!;
+                public void Use() { System.GC.KeepAlive(myComponent); }
+            }
+            """,
+            nullableEnable: true);
+
+        // Assert
+        AssertDocumentNodeMatchesBaseline(generated.CodeDocument);
+        AssertCSharpDocumentMatchesBaseline(generated.CodeDocument);
+        CompileToAssembly(generated);
+    }
+
+    [Fact] // https://github.com/dotnet/razor/issues/8170
+    public void Component_WithRef_Nullable_Generic()
+    {
+        // Arrange
+        AdditionalSyntaxTrees.Add(Parse("""
+            using Microsoft.AspNetCore.Components;
+
+            namespace Test;
+
+            public class MyComponent<T> : ComponentBase
+            {
+                [Parameter] public T MyParameter { get; set; } = default!;
+            }
+            """));
+
+        // Act
+        var generated = CompileToCSharp("""
+            <MyComponent @ref="myComponent" MyParameter="1" />
+
+            @code {
+                private MyComponent<int> myComponent = null!;
+                public void Use() { System.GC.KeepAlive(myComponent); }
+            }
+            """,
+            nullableEnable: true);
+
+        // Assert
+        AssertDocumentNodeMatchesBaseline(generated.CodeDocument);
+        AssertCSharpDocumentMatchesBaseline(generated.CodeDocument);
+        CompileToAssembly(generated);
+    }
+
     [Fact]
     public void Component_WithRef_WithChildContent()
     {

src/Compiler/Microsoft.AspNetCore.Razor.Language/test/TestFiles/IntegrationTests/ComponentDesignTimeCodeGenerationTest/Component_WithCssScope/TestComponent.codegen.cs

@@ -48,7 +48,7 @@ protected override void BuildRenderTree(global::Microsoft.AspNetCore.Components.
             ));
 #nullable restore
 #line 7 "x:\dir\subdir\Test\TestComponent.cshtml"
-                              myComponentReference = default(global::Test.TemplatedComponent);
+                              myComponentReference = default(global::Test.TemplatedComponent)!;
 
 #line default
 #line hidden
@@ -71,7 +71,7 @@ protected override void BuildRenderTree(global::Microsoft.AspNetCore.Components.
 #nullable disable
 #nullable restore
 #line 13 "x:\dir\subdir\Test\TestComponent.cshtml"
-                                      myElementReference = default(Microsoft.AspNetCore.Components.ElementReference);
+                                      myElementReference = default(Microsoft.AspNetCore.Components.ElementReference)!;
 
 #line default
 #line hidden

src/Compiler/Microsoft.AspNetCore.Razor.Language/test/TestFiles/IntegrationTests/ComponentDesignTimeCodeGenerationTest/Component_WithCssScope/TestComponent.mappings.txt

@@ -22,32 +22,32 @@ Source Location: (439:10,1 [38] x:\dir\subdir\Test\TestComponent.cshtml)
 |if (DateTime.Now.Year > 1950)
 {
     |
-Generated Location: (1965:64,1 [38] )
+Generated Location: (1966:64,1 [38] )
 |if (DateTime.Now.Year > 1950)
 {
     |
 
 Source Location: (511:12,38 [18] x:\dir\subdir\Test\TestComponent.cshtml)
 |myElementReference|
-Generated Location: (2164:73,38 [18] )
+Generated Location: (2165:73,38 [18] )
 |myElementReference|
 
 Source Location: (557:12,84 [6] x:\dir\subdir\Test\TestComponent.cshtml)
 |
     |
-Generated Location: (2379:78,84 [6] )
+Generated Location: (2381:78,84 [6] )
 |
     |
 
 Source Location: (589:13,30 [10] x:\dir\subdir\Test\TestComponent.cshtml)
 |myVariable|
-Generated Location: (2574:83,30 [10] )
+Generated Location: (2576:83,30 [10] )
 |myVariable|
 
 Source Location: (637:13,78 [3] x:\dir\subdir\Test\TestComponent.cshtml)
 |
 }|
-Generated Location: (2947:92,78 [3] )
+Generated Location: (2949:92,78 [3] )
 |
 }|
 
@@ -62,7 +62,7 @@ Source Location: (651:16,7 [245] x:\dir\subdir\Test\TestComponent.cshtml)
         for (var i = 0; i < 10; i++)
         {
             |
-Generated Location: (3129:102,7 [245] )
+Generated Location: (3131:102,7 [245] )
 |
     ElementReference myElementReference;
     TemplatedComponent myComponentReference;
@@ -76,12 +76,12 @@ Generated Location: (3129:102,7 [245] )
 
 Source Location: (912:25,28 [1] x:\dir\subdir\Test\TestComponent.cshtml)
 |i|
-Generated Location: (3541:119,28 [1] )
+Generated Location: (3543:119,28 [1] )
 |i|
 
 Source Location: (925:25,41 [1] x:\dir\subdir\Test\TestComponent.cshtml)
 |i|
-Generated Location: (3717:127,41 [1] )
+Generated Location: (3719:127,41 [1] )
 |i|
 
 Source Location: (931:25,47 [166] x:\dir\subdir\Test\TestComponent.cshtml)
@@ -93,7 +93,7 @@ Source Location: (931:25,47 [166] x:\dir\subdir\Test\TestComponent.cshtml)
         System.GC.KeepAlive(myVariable);
     }
 |
-Generated Location: (3889:134,47 [166] )
+Generated Location: (3891:134,47 [166] )
 |
         }
 

src/Compiler/Microsoft.AspNetCore.Razor.Language/test/TestFiles/IntegrationTests/ComponentDesignTimeCodeGenerationTest/Component_WithRef/TestComponent.codegen.cs

@@ -27,7 +27,7 @@ protected override void BuildRenderTree(global::Microsoft.AspNetCore.Components.
             ));
 #nullable restore
 #line 1 "x:\dir\subdir\Test\TestComponent.cshtml"
-                                        myInstance = default(global::Test.MyComponent);
+                                        myInstance = default(global::Test.MyComponent)!;
 
 #line default
 #line hidden

src/Compiler/Microsoft.AspNetCore.Razor.Language/test/TestFiles/IntegrationTests/ComponentDesignTimeCodeGenerationTest/Component_WithRef/TestComponent.mappings.txt

@@ -8,7 +8,7 @@ Source Location: (84:2,7 [104] x:\dir\subdir\Test\TestComponent.cshtml)
     private Test.MyComponent myInstance;
     public void Foo() { System.GC.KeepAlive(myInstance); }
 |
-Generated Location: (1496:45,7 [104] )
+Generated Location: (1497:45,7 [104] )
 |
     private Test.MyComponent myInstance;
     public void Foo() { System.GC.KeepAlive(myInstance); }

src/Compiler/Microsoft.AspNetCore.Razor.Language/test/TestFiles/IntegrationTests/ComponentDesignTimeCodeGenerationTest/Component_WithRef_Nullable/TestComponent.codegen.cs

@@ -0,0 +1,53 @@
+// <auto-generated/>
+#pragma warning disable 1591
+namespace Test
+{
+    #line hidden
+    using System;
+    using System.Collections.Generic;
+    using System.Linq;
+    using System.Threading.Tasks;
+    using Microsoft.AspNetCore.Components;
+    public partial class TestComponent : global::Microsoft.AspNetCore.Components.ComponentBase
+    {
+        #pragma warning disable 219
+        private void __RazorDirectiveTokenHelpers__() {
+        }
+        #pragma warning restore 219
+        #pragma warning disable 0414
+        private static object __o = null;
+        #pragma warning restore 0414
+        #pragma warning disable 1998
+        protected override void BuildRenderTree(global::Microsoft.AspNetCore.Components.Rendering.RenderTreeBuilder __builder)
+        {
+            __builder.AddAttribute(-1, "ChildContent", (global::Microsoft.AspNetCore.Components.RenderFragment)((__builder2) => {
+            }
+            ));
+#nullable restore
+#line 1 "x:\dir\subdir\Test\TestComponent.cshtml"
+                     myComponent = default(global::Test.TestComponent)!;
+
+#line default
+#line hidden
+#nullable disable
+#nullable restore
+#line 1 "x:\dir\subdir\Test\TestComponent.cshtml"
+__o = typeof(global::Test.TestComponent);
+
+#line default
+#line hidden
+#nullable disable
+        }
+        #pragma warning restore 1998
+#nullable restore
+#line 3 "x:\dir\subdir\Test\TestComponent.cshtml"
+
+    private TestComponent myComponent = null!;
+    public void Use() { System.GC.KeepAlive(myComponent); }
+
+#line default
+#line hidden
+#nullable disable
+    }
+}
+#pragma warning restore 1591

src/Compiler/Microsoft.AspNetCore.Razor.Language/test/TestFiles/IntegrationTests/ComponentDesignTimeCodeGenerationTest/Component_WithRef_Nullable/TestComponent.ir.txt

@@ -0,0 +1,22 @@
+Document - 
+    NamespaceDeclaration -  - Test
+        UsingDirective - (3:1,1 [12] ) - System
+        UsingDirective - (18:2,1 [32] ) - System.Collections.Generic
+        UsingDirective - (53:3,1 [17] ) - System.Linq
+        UsingDirective - (73:4,1 [28] ) - System.Threading.Tasks
+        UsingDirective - (104:5,1 [37] ) - Microsoft.AspNetCore.Components
+        ClassDeclaration -  - public partial - TestComponent - global::Microsoft.AspNetCore.Components.ComponentBase - 
+            DesignTimeDirective - 
+            CSharpCode - 
+                IntermediateToken -  - CSharp - #pragma warning disable 0414
+            CSharpCode - 
+                IntermediateToken -  - CSharp - private static object __o = null;
+            CSharpCode - 
+                IntermediateToken -  - CSharp - #pragma warning restore 0414
+            MethodDeclaration -  - protected override - void - BuildRenderTree
+                Component - (0:0,0 [36] x:\dir\subdir\Test\TestComponent.cshtml) - TestComponent
+                    ReferenceCapture - (21:0,21 [11] x:\dir\subdir\Test\TestComponent.cshtml) - myComponent
+                HtmlContent - (36:0,36 [4] x:\dir\subdir\Test\TestComponent.cshtml)
+                    LazyIntermediateToken - (36:0,36 [4] x:\dir\subdir\Test\TestComponent.cshtml) - Html - \n\n
+            CSharpCode - (47:2,7 [111] x:\dir\subdir\Test\TestComponent.cshtml)
+                LazyIntermediateToken - (47:2,7 [111] x:\dir\subdir\Test\TestComponent.cshtml) - CSharp - \n    private TestComponent myComponent = null!;\n    public void Use() { System.GC.KeepAlive(myComponent); }\n

src/Compiler/Microsoft.AspNetCore.Razor.Language/test/TestFiles/IntegrationTests/ComponentDesignTimeCodeGenerationTest/Component_WithRef_Nullable/TestComponent.mappings.txt

@@ -0,0 +1,16 @@
+Source Location: (21:0,21 [11] x:\dir\subdir\Test\TestComponent.cshtml)
+|myComponent|
+Generated Location: (1045:27,21 [11] )
+|myComponent|
+
+Source Location: (47:2,7 [111] x:\dir\subdir\Test\TestComponent.cshtml)
+|
+    private TestComponent myComponent = null!;
+    public void Use() { System.GC.KeepAlive(myComponent); }
+|
+Generated Location: (1437:43,7 [111] )
+|
+    private TestComponent myComponent = null!;
+    public void Use() { System.GC.KeepAlive(myComponent); }
+|
+

src/Compiler/Microsoft.AspNetCore.Razor.Language/test/TestFiles/IntegrationTests/ComponentDesignTimeCodeGenerationTest/Component_WithRef_Nullable_Generic/TestComponent.codegen.cs

@@ -0,0 +1,85 @@
+// <auto-generated/>
+#pragma warning disable 1591
+namespace Test
+{
+    #line hidden
+    using System;
+    using System.Collections.Generic;
+    using System.Linq;
+    using System.Threading.Tasks;
+    using Microsoft.AspNetCore.Components;
+    public partial class TestComponent : global::Microsoft.AspNetCore.Components.ComponentBase
+    {
+        #pragma warning disable 219
+        private void __RazorDirectiveTokenHelpers__() {
+        }
+        #pragma warning restore 219
+        #pragma warning disable 0414
+        private static object __o = null;
+        #pragma warning restore 0414
+        #pragma warning disable 1998
+        protected override void BuildRenderTree(global::Microsoft.AspNetCore.Components.Rendering.RenderTreeBuilder __builder)
+        {
+            var __typeInference_CreateMyComponent_0 = global::__Blazor.Test.TestComponent.TypeInference.CreateMyComponent_0(__builder, -1, -1, 
+#nullable restore
+#line 1 "x:\dir\subdir\Test\TestComponent.cshtml"
+                                             1
+
+#line default
+#line hidden
+#nullable disable
+            , -1, (__value) => {
+#nullable restore
+#line 1 "x:\dir\subdir\Test\TestComponent.cshtml"
+                   myComponent = __value;
+
+#line default
+#line hidden
+#nullable disable
+            }
+            );
+            __o = __typeInference_CreateMyComponent_0.
+#nullable restore
+#line 1 "x:\dir\subdir\Test\TestComponent.cshtml"
+                                MyParameter
+
+#line default
+#line hidden
+#nullable disable
+            ;
+#nullable restore
+#line 1 "x:\dir\subdir\Test\TestComponent.cshtml"
+__o = typeof(global::Test.MyComponent<>);
+
+#line default
+#line hidden
+#nullable disable
+        }
+        #pragma warning restore 1998
+#nullable restore
+#line 3 "x:\dir\subdir\Test\TestComponent.cshtml"
+
+    private MyComponent<int> myComponent = null!;
+    public void Use() { System.GC.KeepAlive(myComponent); }
+
+#line default
+#line hidden
+#nullable disable
+    }
+}
+namespace __Blazor.Test.TestComponent
+{
+    #line hidden
+    internal static class TypeInference
+    {
+        public static global::Test.MyComponent<T> CreateMyComponent_0<T>(global::Microsoft.AspNetCore.Components.Rendering.RenderTreeBuilder __builder, int seq, int __seq0, T __arg0, int __seq1, System.Action<global::Test.MyComponent<T>> __arg1)
+        {
+        __builder.OpenComponent<global::Test.MyComponent<T>>(seq);
+        __builder.AddAttribute(__seq0, "MyParameter", __arg0);
+        __builder.AddComponentReferenceCapture(__seq1, (__value) => { __arg1((global::Test.MyComponent<T>)__value); });
+        __builder.CloseComponent();
+        return default;
+        }
+    }
+}
+#pragma warning restore 1591

src/Compiler/Microsoft.AspNetCore.Razor.Language/test/TestFiles/IntegrationTests/ComponentDesignTimeCodeGenerationTest/Component_WithRef_Nullable_Generic/TestComponent.ir.txt

@@ -0,0 +1,27 @@
+Document - 
+    NamespaceDeclaration -  - Test
+        UsingDirective - (3:1,1 [12] ) - System
+        UsingDirective - (18:2,1 [32] ) - System.Collections.Generic
+        UsingDirective - (53:3,1 [17] ) - System.Linq
+        UsingDirective - (73:4,1 [28] ) - System.Threading.Tasks
+        UsingDirective - (104:5,1 [37] ) - Microsoft.AspNetCore.Components
+        ClassDeclaration -  - public partial - TestComponent - global::Microsoft.AspNetCore.Components.ComponentBase - 
+            DesignTimeDirective - 
+            CSharpCode - 
+                IntermediateToken -  - CSharp - #pragma warning disable 0414
+            CSharpCode - 
+                IntermediateToken -  - CSharp - private static object __o = null;
+            CSharpCode - 
+                IntermediateToken -  - CSharp - #pragma warning restore 0414
+            MethodDeclaration -  - protected override - void - BuildRenderTree
+                Component - (0:0,0 [50] x:\dir\subdir\Test\TestComponent.cshtml) - MyComponent
+                    ReferenceCapture - (19:0,19 [11] x:\dir\subdir\Test\TestComponent.cshtml) - myComponent
+                    ComponentAttribute - (45:0,45 [1] x:\dir\subdir\Test\TestComponent.cshtml) - MyParameter - MyParameter - AttributeStructure.DoubleQuotes
+                        LazyIntermediateToken - (45:0,45 [1] x:\dir\subdir\Test\TestComponent.cshtml) - CSharp - 1
+                HtmlContent - (50:0,50 [4] x:\dir\subdir\Test\TestComponent.cshtml)
+                    LazyIntermediateToken - (50:0,50 [4] x:\dir\subdir\Test\TestComponent.cshtml) - Html - \n\n
+            CSharpCode - (61:2,7 [114] x:\dir\subdir\Test\TestComponent.cshtml)
+                LazyIntermediateToken - (61:2,7 [114] x:\dir\subdir\Test\TestComponent.cshtml) - CSharp - \n    private MyComponent<int> myComponent = null!;\n    public void Use() { System.GC.KeepAlive(myComponent); }\n
+    NamespaceDeclaration -  - __Blazor.Test.TestComponent
+        ClassDeclaration -  - internal static - TypeInference -  - 
+            ComponentTypeInferenceMethod -  - __Blazor.Test.TestComponent.TypeInference - CreateMyComponent_0