CLI generator will use the pointee type for indexed properties which have a setter.

src/Generator/Passes/CheckOperatorsOverloads.cs

@@ -100,9 +100,18 @@ namespace CppSharp.Passes
             if (!@operator.ReturnType.Qualifiers.IsConst && @operator.ReturnType.Type.IsAddress())
                 property.SetMethod = @operator;
 
-            // C++/CLI uses "default" as the indexer property name.
             if (Driver.Options.IsCLIGenerator)
+            {
+                // If we've a setter use the pointee as the type of the property.
+                var pointerType = property.Type as PointerType;
+                if (pointerType != null && property.HasSetter)
+                {
+                    property.QualifiedType = new QualifiedType(pointerType.Pointee, property.QualifiedType.Qualifiers);
+                    property.GetMethod.ReturnType = property.QualifiedType;
+                }
+                // C++/CLI uses "default" as the indexer property name.
                 property.Name = "default";
+            }
 
             property.Parameters.AddRange(@operator.Parameters);
 

tests/Basic/Basic.Tests.cs

@@ -235,6 +235,8 @@ public class BasicTests : GeneratorTestFixture
         var someStruct = new SomeStruct();
         Assert.That(someStruct[0], Is.EqualTo(1));
         Assert.That(someStruct["foo"], Is.EqualTo(1));
+        someStruct[0] = 2;
+        Assert.That(someStruct[0], Is.EqualTo(2));
     }
 
     [Test]

tests/Basic/Basic.h

@@ -315,8 +315,8 @@ typedef unsigned long foo_t;
 typedef struct DLL_API SomeStruct
 {
 	SomeStruct() : p(1) {}
-	const foo_t& operator[](int i) const { return p; }
+	foo_t& operator[](int i) { return p; }
-	foo_t operator[](int i) { return p; }
+    // CSharp backend can't deal with a setter here
     foo_t operator[](const char* name) { return p; }
 	foo_t p;
 }