closures have an object type field so that we can perform correct deepCopy() for the BoehmGC target

lib/system.nim

@@ -413,7 +413,7 @@ type
     ## is an int type ranging from one to the maximum value
     ## of an int. This type is often useful for documentation and debugging.
 
-  RootObj* {.exportc: "TNimObject", inheritable.} =
+  RootObj* {.compilerProc, inheritable.} =
     object ## the root of Nim's object hierarchy. Objects should
            ## inherit from RootObj or one of its descendants. However,
            ## objects that have no ancestor are allowed.
@@ -3269,7 +3269,7 @@ when not defined(JS): #and not defined(nimscript):
     proc finished*[T: proc](x: T): bool {.noSideEffect, inline.} =
       ## can be used to determine if a first class iterator has finished.
       {.emit: """
-      `result` = *((NI*) `x`.ClE_0) < 0;
+      `result` = ((NI*) `x`.ClE_0)[1] < 0;
       """.}
 
 elif defined(JS):

lib/system/deepcopy.nim

@@ -148,11 +148,11 @@ proc genericDeepCopyAux(dest, src: pointer, mt: PNimType; tab: var PtrTable) =
             let realType = x.typ
             sysAssert realType == mt, " types do differ"
           # this version should work for any possible GC:
-          let size = if mt.base.kind == tyObject: cast[ptr PNimType](s2)[].size else: mt.base.size
-          let z = newObj(mt, size)
+          let typ = if mt.base.kind == tyObject: cast[ptr PNimType](s2)[] else: mt.base
+          let z = newObj(mt, typ.size)
           unsureAsgnRef(cast[PPointer](dest), z)
           tab.put(s2, z)
-          genericDeepCopyAux(z, s2, mt.base, tab)
+          genericDeepCopyAux(z, s2, typ, tab)
       else:
         unsureAsgnRef(cast[PPointer](dest), z)
   of tyPtr: