[foreign-jextract] Duplicated interface declarations when using typedefs for function pointers

[Filip Krakowski]

Hi,

I just noticed that jextract generates duplicate code (interfaces) for 
function pointers within each struct instead at the top-level.
Each interface's name seems to have a suffix based on the occurrence of 
the declaration in the source file.

    typedef void (*callback_t)(void *arg);

    typedef struct first_handler {
         callback_t cb;
    } first_handler_t;

    typedef struct second_handler {
         callback_t cb;
    } second_handler_t;

This code generates the following java source code.

    @C("struct first_handler")public static class first_handler {
    ...
         public static interface cb {

                 void apply(jdk.incubator.foreign.MemoryAddress x0);

                 public static  @C("callback_t") MemorySegment
    allocate(cb fi) {
                     return RuntimeHelper.upcallStub(cb.class, fi,
    ucx_h_constants_0.cb$FUNC(),
    "(Ljdk/incubator/foreign/MemoryAddress;)V");
                 }

                 public static  @C("callback_t") MemorySegment
    allocate(cb fi, NativeScope scope) {
                     return allocate(fi).handoff(scope);
                 }
             }
    ...
    }

    @C("struct second_handler")public static class second_handler {
    ...
         public static interface cb$0 {

                 void apply(jdk.incubator.foreign.MemoryAddress x0);

                 public static  @C("callback_t") MemorySegment
    allocate(cb$0 fi) {
                     return RuntimeHelper.upcallStub(cb$0.class, fi,
    ucx_h_constants_0.cb$0$FUNC(),
    "(Ljdk/incubator/foreign/MemoryAddress;)V");
                 }

                 public static  @C("callback_t") MemorySegment
    allocate(cb$0 fi, NativeScope scope) {
                     return allocate(fi).handoff(scope);
                 }
             }
    ...
    }

 From my point of view both interfaces are identical. Is there a reason 
for placing them inside the struct class?


Best regards
Filip