Dear caml develpers,

I am working on an experimental branch to pass more information from typedtree to lambda to enable ocaml generate user readable javascript code(https://github.com/bobzhang/ocaml/tree/master) (online-demo: http://zhanghongbo.me/js-demo/)

Here I get a segfault, after I change const_block:

Below is my minimal change:

```

type pointer_info =

| NullConstructor of string

| NullVariant of string

| NAPointer

type tag_info =

| Constructor of string

| Tuple

| Variant of string

| Record

| NA

type structured_constant =

Const_base of constant

| Const_pointer of int * pointer_info

| Const_block of int * tag_info * structured_constant list

| Const_float_array of string list

| Const_immstring of string

```

Note that the enriched info is not used in ``emitcode``, now I get a segfault in make world:

```

../../boot/ocamlrun ../../ocamlc -nostdlib -I ../../stdlib -c -w +33..39 -warn-error A -bin-annot -g -safe-string -I ../../stdlib -I ../../utils -I ../../typing -I ../../bytecomp -I ../../asmcomp extract_crc.ml

../../boot/ocamlrun ../../ocamlc -nostdlib -I ../../stdlib -o extract_crc dynlink.cma extract_crc.cmo

make[3]: *** [extract_crc] Segmentation fault: 11

make[3]: *** Deleting file `extract_crc'

make[2]: *** [otherlibraries] Error 2

make[1]: *** [all] Error 2

```

Any help is appreciated : )

Regards
-- Hongbo Zhang