Fixes creating constraint string from type parameter symbol

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

@@ -3893,6 +3893,220 @@ public class Column<TItem> : ComponentBase
         CompileToAssembly(generated);
     }
 
+    [Fact]
+    public void CascadingGenericInference_Inferred_WithConstraints()
+    {
+        // Arrange
+        AdditionalSyntaxTrees.Add(Parse(@"
+using Microsoft.AspNetCore.Components;
+
+namespace Test
+{
+    [CascadingTypeParameter(nameof(TItem))]
+    public class Grid<TItem> : ComponentBase
+    {
+        [Parameter] public RenderFragment ColumnsTemplate { get; set; }
+    }
+
+    public abstract partial class BaseColumn<TItem> : ComponentBase where TItem : class
+    {
+        [CascadingParameter]
+        internal Grid<TItem> Grid { get; set; }
+    }
+
+    public class Column<TItem> : BaseColumn<TItem>, IGridFieldColumn<TItem> where TItem : class
+    {
+        [Parameter]
+        public string FieldName { get; set; }
+    }
+
+    internal interface IGridFieldColumn<TItem> where TItem : class
+    {
+    }
+
+    public class WeatherForecast { }
+}
+"));
+
+        // Act
+        var generated = CompileToCSharp(@"
+<Grid TItem=""WeatherForecast"" Items=""@(Array.Empty<WeatherForecast>())"">
+    <ColumnsTemplate>
+        <Column Title=""Date"" FieldName=""Date"" Format=""d"" Width=""10rem"" />
+    </ColumnsTemplate>
+</Grid>
+");
+
+        // Assert
+        AssertDocumentNodeMatchesBaseline(generated.CodeDocument);
+        AssertCSharpDocumentMatchesBaseline(generated.CodeDocument);
+        CompileToAssembly(generated);
+    }
+
+    [Fact]
+    public void CascadingGenericInference_Inferred_MultipleConstraints()
+    {
+        // Arrange
+        AdditionalSyntaxTrees.Add(Parse(@"
+using Microsoft.AspNetCore.Components;
+
+namespace Test
+{
+    [CascadingTypeParameter(nameof(TItem))]
+    public class Grid<TItem> : ComponentBase
+    {
+        [Parameter] public RenderFragment ColumnsTemplate { get; set; }
+    }
+
+    public abstract partial class BaseColumn<TItem> : ComponentBase where TItem : class, new()
+    {
+        [CascadingParameter]
+        internal Grid<TItem> Grid { get; set; }
+    }
+
+    public class Column<TItem> : BaseColumn<TItem>, IGridFieldColumn<TItem> where TItem : class, new()
+    {
+        [Parameter]
+        public string FieldName { get; set; }
+    }
+
+    internal interface IGridFieldColumn<TItem> where TItem : class
+    {
+    }
+
+    public class WeatherForecast { }
+}
+"));
+
+        // Act
+        var generated = CompileToCSharp(@"
+<Grid TItem=""WeatherForecast"" Items=""@(Array.Empty<WeatherForecast>())"">
+    <ColumnsTemplate>
+        <Column Title=""Date"" FieldName=""Date"" Format=""d"" Width=""10rem"" />
+    </ColumnsTemplate>
+</Grid>
+");
+
+        // Assert
+        AssertDocumentNodeMatchesBaseline(generated.CodeDocument);
+        AssertCSharpDocumentMatchesBaseline(generated.CodeDocument);
+        CompileToAssembly(generated);
+    }
+
+    [Fact]
+    public void CascadingGenericInference_Inferred_MultipleConstraints_ClassesAndInterfaces()
+    {
+        // Arrange
+        AdditionalSyntaxTrees.Add(Parse(@"
+using Microsoft.AspNetCore.Components;
+using Models;
+
+namespace Test
+{
+    [CascadingTypeParameter(nameof(TItem))]
+    public class Grid<TItem> : ComponentBase
+    {
+        [Parameter] public RenderFragment ColumnsTemplate { get; set; }
+    }
+
+    public abstract partial class BaseColumn<TItem> : ComponentBase where TItem : WeatherForecast, new()
+    {
+        [CascadingParameter]
+        internal Grid<TItem> Grid { get; set; }
+    }
+
+    public class Column<TItem> : BaseColumn<TItem>, IGridFieldColumn<TItem> where TItem : WeatherForecast, new()
+    {
+        [Parameter]
+        public string FieldName { get; set; }
+    }
+
+    internal interface IGridFieldColumn<TItem> where TItem : class
+    {
+    }
+}
+namespace Models {
+    public class WeatherForecast { }
+}"));
+
+        // Act
+        var generated = CompileToCSharp(@"
+@using Models;
+
+<Grid TItem=""WeatherForecast"" Items=""@(Array.Empty<WeatherForecast>())"">
+    <ColumnsTemplate>
+        <Column Title=""Date"" FieldName=""Date"" Format=""d"" Width=""10rem"" />
+    </ColumnsTemplate>
+</Grid>
+");
+
+        // Assert
+        AssertDocumentNodeMatchesBaseline(generated.CodeDocument);
+        AssertCSharpDocumentMatchesBaseline(generated.CodeDocument);
+        CompileToAssembly(generated);
+    }
+
+    [Fact]
+    public void CascadingGenericInference_Inferred_MultipleConstraints_GenericClassConstraints()
+    {
+        // Arrange
+        AdditionalSyntaxTrees.Add(Parse(@"
+using Microsoft.AspNetCore.Components;
+
+namespace Test
+{
+    [CascadingTypeParameter(nameof(TItem))]
+    public class Grid<TItem> : ComponentBase
+    {
+        [Parameter] public RenderFragment ColumnsTemplate { get; set; }
+    }
+
+    public abstract partial class BaseColumn<TItem> : ComponentBase where TItem : System.Collections.Generic.IEnumerable<TItem>
+    {
+        [CascadingParameter]
+        internal Grid<TItem> Grid { get; set; }
+    }
+
+    public class Column<TItem> : BaseColumn<TItem> where TItem : System.Collections.Generic.IEnumerable<TItem>
+    {
+        [Parameter]
+        public string FieldName { get; set; }
+    }
+}
+
+namespace Models {
+    using System;
+    using System.Collections;
+    using System.Collections.Generic;
+    public class WeatherForecast : IEnumerable<WeatherForecast> {
+        public IEnumerator<WeatherForecast> GetEnumerator()
+        {
+            throw new NotImplementedException();
+        }
+
+        IEnumerator IEnumerable.GetEnumerator()
+        {
+            throw new NotImplementedException();
+        }
+    }
+}"));
+
+        // Act
+        var generated = CompileToCSharp(@"
+@using Models;
+<Grid TItem=""WeatherForecast"" Items=""@(Array.Empty<WeatherForecast>())"">
+    <ColumnsTemplate>
+        <Column Title=""Date"" FieldName=""Date"" Format=""d"" Width=""10rem"" />
+    </ColumnsTemplate>
+</Grid>
+");
+
+        // Assert
+        AssertDocumentNodeMatchesBaseline(generated.CodeDocument);
+        AssertCSharpDocumentMatchesBaseline(generated.CodeDocument);
+        CompileToAssembly(generated);
+    }
+
     [Fact]
     public void CascadingGenericInference_Partial_CreatesError()
     {

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

@@ -0,0 +1,80 @@
+// <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 System.Object __o = null;
+        #pragma warning restore 0414
+        #pragma warning disable 1998
+        protected override void BuildRenderTree(global::Microsoft.AspNetCore.Components.Rendering.RenderTreeBuilder __builder)
+        {
+            __o = typeof(
+#nullable restore
+#line 1 "x:\dir\subdir\Test\TestComponent.cshtml"
+             WeatherForecast
+
+#line default
+#line hidden
+#nullable disable
+            );
+            __o = 
+#nullable restore
+#line 1 "x:\dir\subdir\Test\TestComponent.cshtml"
+                                       Array.Empty<WeatherForecast>()
+
+#line default
+#line hidden
+#nullable disable
+            ;
+            __builder.AddAttribute(-1, "ColumnsTemplate", (global::Microsoft.AspNetCore.Components.RenderFragment)((__builder2) => {
+                global::__Blazor.Test.TestComponent.TypeInference.CreateColumn_0(__builder2, -1, default(WeatherForecast), -1, "", -1, "", -1, "", -1, "");
+#nullable restore
+#line 3 "x:\dir\subdir\Test\TestComponent.cshtml"
+__o = typeof(global::Test.Column<>);
+
+#line default
+#line hidden
+#nullable disable
+            }
+            ));
+#nullable restore
+#line 1 "x:\dir\subdir\Test\TestComponent.cshtml"
+__o = typeof(global::Test.Grid<>);
+
+#line default
+#line hidden
+#nullable disable
+        }
+        #pragma warning restore 1998
+    }
+}
+namespace __Blazor.Test.TestComponent
+{
+    #line hidden
+    internal static class TypeInference
+    {
+        public static void CreateColumn_0<TItem>(global::Microsoft.AspNetCore.Components.Rendering.RenderTreeBuilder __builder, int seq, TItem __syntheticArg0, int __seq0, global::System.Object __arg0, int __seq1, global::System.String __arg1, int __seq2, global::System.Object __arg2, int __seq3, global::System.Object __arg3)
+            where TItem : class, new()
+        {
+        __builder.OpenComponent<global::Test.Column<TItem>>(seq);
+        __builder.AddAttribute(__seq0, "Title", __arg0);
+        __builder.AddAttribute(__seq1, "FieldName", __arg1);
+        __builder.AddAttribute(__seq2, "Format", __arg2);
+        __builder.AddAttribute(__seq3, "Width", __arg3);
+        __builder.CloseComponent();
+        }
+    }
+}
+#pragma warning restore 1591

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

@@ -0,0 +1,45 @@
+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 System.Object __o = null;
+            CSharpCode - 
+                IntermediateToken -  - CSharp - #pragma warning restore 0414
+            MethodDeclaration -  - protected override - void - BuildRenderTree
+                Component - (0:0,0 [203] x:\dir\subdir\Test\TestComponent.cshtml) - Grid
+                    ComponentChildContent - (78:1,4 [116] x:\dir\subdir\Test\TestComponent.cshtml) - ColumnsTemplate - context
+                        HtmlContent - (95:1,21 [10] x:\dir\subdir\Test\TestComponent.cshtml)
+                            LazyIntermediateToken - (95:1,21 [10] x:\dir\subdir\Test\TestComponent.cshtml) - Html - \n        
+                        Component - (105:2,8 [65] x:\dir\subdir\Test\TestComponent.cshtml) - Column
+                            ComponentAttribute -  - Title -  - AttributeStructure.DoubleQuotes
+                                HtmlContent - (120:2,23 [4] x:\dir\subdir\Test\TestComponent.cshtml)
+                                    LazyIntermediateToken - (120:2,23 [4] x:\dir\subdir\Test\TestComponent.cshtml) - Html - Date
+                            ComponentAttribute - (137:2,40 [4] x:\dir\subdir\Test\TestComponent.cshtml) - FieldName - FieldName - AttributeStructure.DoubleQuotes
+                                HtmlContent - (137:2,40 [4] x:\dir\subdir\Test\TestComponent.cshtml)
+                                    LazyIntermediateToken - (137:2,40 [4] x:\dir\subdir\Test\TestComponent.cshtml) - Html - Date
+                            ComponentAttribute -  - Format -  - AttributeStructure.DoubleQuotes
+                                HtmlContent - (151:2,54 [1] x:\dir\subdir\Test\TestComponent.cshtml)
+                                    LazyIntermediateToken - (151:2,54 [1] x:\dir\subdir\Test\TestComponent.cshtml) - Html - d
+                            ComponentAttribute -  - Width -  - AttributeStructure.DoubleQuotes
+                                HtmlContent - (161:2,64 [5] x:\dir\subdir\Test\TestComponent.cshtml)
+                                    LazyIntermediateToken - (161:2,64 [5] x:\dir\subdir\Test\TestComponent.cshtml) - Html - 10rem
+                        HtmlContent - (170:2,73 [6] x:\dir\subdir\Test\TestComponent.cshtml)
+                            LazyIntermediateToken - (170:2,73 [6] x:\dir\subdir\Test\TestComponent.cshtml) - Html - \n    
+                    ComponentTypeArgument - (13:0,13 [15] x:\dir\subdir\Test\TestComponent.cshtml) - TItem
+                        LazyIntermediateToken - (13:0,13 [15] x:\dir\subdir\Test\TestComponent.cshtml) - CSharp - WeatherForecast
+                    ComponentAttribute -  - Items -  - AttributeStructure.DoubleQuotes
+                        CSharpExpression - (37:0,37 [33] x:\dir\subdir\Test\TestComponent.cshtml)
+                            LazyIntermediateToken - (39:0,39 [30] x:\dir\subdir\Test\TestComponent.cshtml) - CSharp - Array.Empty<WeatherForecast>()
+                HtmlContent - (203:4,7 [2] x:\dir\subdir\Test\TestComponent.cshtml)
+                    LazyIntermediateToken - (203:4,7 [2] x:\dir\subdir\Test\TestComponent.cshtml) - Html - \n
+    NamespaceDeclaration -  - __Blazor.Test.TestComponent
+        ClassDeclaration -  - internal static - TypeInference -  - 
+            ComponentTypeInferenceMethod -  - __Blazor.Test.TestComponent.TypeInference - CreateColumn_0

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

@@ -0,0 +1,10 @@
+Source Location: (13:0,13 [15] x:\dir\subdir\Test\TestComponent.cshtml)
+|WeatherForecast|
+Generated Location: (908:25,13 [15] )
+|WeatherForecast|
+
+Source Location: (39:0,39 [30] x:\dir\subdir\Test\TestComponent.cshtml)
+|Array.Empty<WeatherForecast>()|
+Generated Location: (1120:34,39 [30] )
+|Array.Empty<WeatherForecast>()|
+