ocaml: phase 5 HM with user type declarations (+6 tests, 363 total)

ocaml-hm-ctors is now a mutable list cell; user type-defs register
their constructors via ocaml-hm-register-type-def!. New
ocaml-type-of-program processes top-level decls in order:
- type-def: register ctors with the scheme inferred from PARAMS+CTORS
- def/def-rec: generalize and bind in the type env
- exception-def: no-op for typing
- expr: return inferred type

Examples:
  type color = Red | Green | Blue;; Red : color
  type shape = Circle of int | Square of int;;
  let area s = match s with
    | Circle r -> r * r
    | Square s -> s * s;;
  area : shape -> Int

Caveat: ctor arg types parsed as raw source strings; registry defaults
to int for any single-arg ctor. Proper type-source parsing pending.

lib/ocaml/test.sh

@@ -886,6 +886,20 @@ cat > "$TMPFILE" << 'EPOCHS'
 (epoch 2005)
 (eval "(ocaml-type-of \"let rec sum lst = match lst with | [] -> 0 | h :: t -> h + sum t in sum [1; 2; 3]\")")
 
+;; ── HM with user type declarations ─────────────────────────────
+(epoch 2100)
+(eval "(ocaml-type-of-program \"type color = Red | Green | Blue;; Red\")")
+(epoch 2101)
+(eval "(ocaml-type-of-program \"type shape = Circle of int | Square of int;; Circle 5\")")
+(epoch 2102)
+(eval "(ocaml-type-of-program \"type color = Red | Green;; let c = Red;; c\")")
+(epoch 2103)
+(eval "(ocaml-type-of-program \"type shape = Circle of int | Square of int;; let area s = match s with | Circle r -> r * r | Square s -> s * s;; area\")")
+(epoch 2104)
+(eval "(ocaml-type-of-program \"let x = 1;; let y = 2;; x + y\")")
+(epoch 2105)
+(eval "(ocaml-type-of-program \"let rec fact n = if n = 0 then 1 else n * fact (n - 1);; fact 5\")")
+
 EPOCHS
 
 OUTPUT=$(timeout 180 "$SX_SERVER" < "$TMPFILE" 2>/dev/null)
@@ -1401,6 +1415,14 @@ check 2003 "type 1::list"                 '"Int list"'
 check 2004 "type [1] @ [2;3]"             '"Int list"'
 check 2005 "type sum"                     '"Int"'
 
+# ── HM with user type-defs ──────────────────────────────────────
+check 2100 "user type Red : color"        '"color"'
+check 2101 "user type Circle 5 : shape"   '"shape"'
+check 2102 "let c = Red; c"               '"color"'
+check 2103 "shape -> Int"                 '"shape -> Int"'
+check 2104 "program x+y"                  '"Int"'
+check 2105 "program fact 5"               '"Int"'
+
 TOTAL=$((PASS + FAIL))
 if [ $FAIL -eq 0 ]; then
   echo "ok $PASS/$TOTAL OCaml-on-SX tests passed"