Dynamically typed ProjectedRasterTile expressions don't deserialize to Tile

[metasim]

If minus and one are ProjectedRasterTiles, the following code will throw a runtime cast exception.

val df = Seq((minus, one)).toDF("minus", "one")
assertEqual(df.select(rf_abs($"minus")).first(), one)

error:

cannot resolve 'CAST(`rf_abs(minus)` AS STRUCT<`cell_context`: STRUCT<`cellType`: STRUCT<`cellTypeName`: STRING>, `dimensions`: STRUCT<`cols`: SMALLINT, `rows`: SMALLINT>>, `cell_data`: STRUCT<`cells`: BINARY, `ref`: STRUCT<`source`: STRUCT<`raster_source_kryo`: BINARY>, `bandIndex`: INT, `subextent`: STRUCT<`xmin`: DOUBLE, `ymin`: DOUBLE, `xmax`: DOUBLE, `ymax`: DOUBLE>>>>)' due to data type mismatch: cannot cast struct<tile_context:struct<extent:struct<xmin:double,ymin:double,xmax:double,ymax:double>,crs:struct<crsProj4:string>>,tile:tile> to tile;

[metasim]

Taking the path of making overloaded tile methods return an untyped column since specific type. guarantee can't be made.