Nested Structs lose `partial` keyword

[Soaryn]

Problem:

PolymorphicStructs that are created in a nested structs, according to the IDE (Rider), don't have a partial sibling related to it.. This breaks compilation.

Example

namespace Playground.ExamplePoly {
 [PolymorphicStruct]
 public interface IPoly {
 public void DoThing();
 }
}

namespace Playground.ExamplePoly {
 public class NestedExample {
 public partial struct PolyB : IPoly {
 public void DoThing() { }
 }
 }
}

Potential Related Issues

Static or type definition using statements are lost on source generation. Examples below of what is written vs what is generated.

using static Playground.ExamplePoly.NestedExample.PolyB; //This example is not using both at the same time, but the result is the same.
using PolyB = Playground.ExamplePoly.NestedExample.PolyB;

Result:

using Playground.ExamplePoly.NestedExample.PolyB;