Add test for use of global type shadowed by local namespace

Without `global::` types in interfaces, the generated interface will resolve to the locally-defined type instead of the global one

AutomaticInterface/Tests/GeneratorTests.TypeResolution.cs

@@ -232,6 +232,52 @@ public partial interface IModelManager
         GenerateCode(code).Should().Be(expected);
     }
 
+    [Fact]
+    public void WorksWithShadowedGlobalNamespace()
+    {
+        const string code = """
+            using AutomaticInterface;
+            using Task = System.Threading.Tasks.Task;
+
+            namespace AutomaticInterfaceExample
+            {
+                namespace System.Threading.Tasks
+                {
+                    public class Task;
+                }
+
+                [GenerateAutomaticInterface]
+                public class DemoClass
+                {
+                    public Task GetTask() => null!;
+                }
+            }
+            """;
+
+        const string expected = """
+            //--------------------------------------------------------------------------------------------------
+            // <auto-generated>
+            //     This code was generated by a tool.
+            //
+            //     Changes to this file may cause incorrect behavior and will be lost if the code is regenerated.
+            // </auto-generated>
+            //--------------------------------------------------------------------------------------------------
+
+            namespace AutomaticInterfaceExample
+            {
+                [global::System.CodeDom.Compiler.GeneratedCode("AutomaticInterface", "")]
+                public partial interface IDemoClass
+                {
+                    /// <inheritdoc />
+                    global::System.Threading.Tasks.Task GetTask();
+                    
+                }
+            }
+
+            """;
+        GenerateCode(code).Should().Be(expected);
+    }
+
     [Fact]
     public void WorksWithGlobalUsing()
     {