Avoid ambiguous object reference in generic component recovery

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

@@ -9002,6 +9002,29 @@ public class MyComponent<TService, TKey> : ComponentBase
         CompileToAssembly(generated);
     }
 
+    [IntegrationTestFact]
+    public void GenericComponent_MissingTypeParameter_SystemInNamespace()
+    {
+        // Arrange
+        AdditionalSyntaxTrees.Add(Parse("""
+            using Microsoft.AspNetCore.Components;
+            namespace Test;
+            public class MyComponent<TItem> : ComponentBase;
+            """));
+
+        // Act
+        var generated = CompileToCSharp("""
+            @namespace Test.System
+            <MyComponent />
+            """);
+
+        // Assert
+        CompileToAssembly(generated);
+        generated.RazorDiagnostics.Verify(
+            // x:\dir\subdir\Test\TestComponent.cshtml(2,1): error RZ10001: The type of component 'MyComponent' cannot be inferred based on the values provided. Consider specifying the type arguments directly using the following attributes: 'TItem'.
+            Diagnostic("RZ10001").WithLocation(2, 1));
+    }
+
     [IntegrationTestFact, WorkItem("https://github.com/dotnet/razor/issues/10827")]
     public void GenericTypeCheck()
     {

src/Compiler/Microsoft.CodeAnalysis.Razor.Compiler/src/CSharp/GenericTypeNameRewriter.cs

@@ -48,7 +48,7 @@ public override SyntaxNode Visit(SyntaxNode node)
                     // compared to leaving the type parameter in place.
                     //
                     // We add our own diagnostics for missing/invalid type parameters anyway.
-                    var replacement = binding == null ? typeof(object).FullName : binding;
+                    var replacement = binding ?? "object";
                     return identifier.Update(SyntaxFactory.Identifier(replacement).WithTriviaFrom(identifier.Identifier));
                 }
             }