Merge pull request #53 from AeneasVerif/son/casts

Add support for casts between integers and booleans

1 files changed, 71 insertions, 61 deletions

diff --git a/tests/lean/NoNestedBorrows.lean b/tests/lean/NoNestedBorrows.lean
index 8ee8ad9e..0bce3a64 100644
--- a/tests/lean/NoNestedBorrows.lean
+++ b/tests/lean/NoNestedBorrows.lean
@@ -146,13 +146,23 @@ def const0_c : Usize := eval_global const0_body (by simp)
 def const1_body : Result Usize := 2#usize * 2#usize
 def const1_c : Usize := eval_global const1_body (by simp)
 
-/- [no_nested_borrows::cast_test]: forward function
-   Source: 'src/no_nested_borrows.rs', lines 128:0-128:31 -/
-def cast_test (x : U32) : Result I32 :=
+/- [no_nested_borrows::cast_u32_to_i32]: forward function
+   Source: 'src/no_nested_borrows.rs', lines 128:0-128:37 -/
+def cast_u32_to_i32 (x : U32) : Result I32 :=
   Scalar.cast .I32 x
 
+/- [no_nested_borrows::cast_bool_to_i32]: forward function
+   Source: 'src/no_nested_borrows.rs', lines 132:0-132:39 -/
+def cast_bool_to_i32 (x : Bool) : Result I32 :=
+  Scalar.cast_bool .I32 x
+
+/- [no_nested_borrows::cast_bool_to_bool]: forward function
+   Source: 'src/no_nested_borrows.rs', lines 137:0-137:41 -/
+def cast_bool_to_bool (x : Bool) : Result Bool :=
+  Result.ret x
+
 /- [no_nested_borrows::test2]: forward function
-   Source: 'src/no_nested_borrows.rs', lines 133:0-133:14 -/
+   Source: 'src/no_nested_borrows.rs', lines 142:0-142:14 -/
 def test2 : Result Unit :=
   do
     let _ ← 23#u32 + 44#u32
@@ -162,14 +172,14 @@ def test2 : Result Unit :=
 #assert (test2 == Result.ret ())
 
 /- [no_nested_borrows::get_max]: forward function
-   Source: 'src/no_nested_borrows.rs', lines 145:0-145:37 -/
+   Source: 'src/no_nested_borrows.rs', lines 154:0-154:37 -/
 def get_max (x : U32) (y : U32) : Result U32 :=
   if x >= y
   then Result.ret x
   else Result.ret y
 
 /- [no_nested_borrows::test3]: forward function
-   Source: 'src/no_nested_borrows.rs', lines 153:0-153:14 -/
+   Source: 'src/no_nested_borrows.rs', lines 162:0-162:14 -/
 def test3 : Result Unit :=
   do
     let x ← get_max 4#u32 3#u32
@@ -183,7 +193,7 @@ def test3 : Result Unit :=
 #assert (test3 == Result.ret ())
 
 /- [no_nested_borrows::test_neg1]: forward function
-   Source: 'src/no_nested_borrows.rs', lines 160:0-160:18 -/
+   Source: 'src/no_nested_borrows.rs', lines 169:0-169:18 -/
 def test_neg1 : Result Unit :=
   do
     let y ← - 3#i32
@@ -195,7 +205,7 @@ def test_neg1 : Result Unit :=
 #assert (test_neg1 == Result.ret ())
 
 /- [no_nested_borrows::refs_test1]: forward function
-   Source: 'src/no_nested_borrows.rs', lines 167:0-167:19 -/
+   Source: 'src/no_nested_borrows.rs', lines 176:0-176:19 -/
 def refs_test1 : Result Unit :=
   if not (1#i32 = 1#i32)
   then Result.fail .panic
@@ -205,7 +215,7 @@ def refs_test1 : Result Unit :=
 #assert (refs_test1 == Result.ret ())
 
 /- [no_nested_borrows::refs_test2]: forward function
-   Source: 'src/no_nested_borrows.rs', lines 178:0-178:19 -/
+   Source: 'src/no_nested_borrows.rs', lines 187:0-187:19 -/
 def refs_test2 : Result Unit :=
   if not (2#i32 = 2#i32)
   then Result.fail .panic
@@ -223,7 +233,7 @@ def refs_test2 : Result Unit :=
 #assert (refs_test2 == Result.ret ())
 
 /- [no_nested_borrows::test_list1]: forward function
-   Source: 'src/no_nested_borrows.rs', lines 194:0-194:19 -/
+   Source: 'src/no_nested_borrows.rs', lines 203:0-203:19 -/
 def test_list1 : Result Unit :=
   Result.ret ()
 
@@ -231,7 +241,7 @@ def test_list1 : Result Unit :=
 #assert (test_list1 == Result.ret ())
 
 /- [no_nested_borrows::test_box1]: forward function
-   Source: 'src/no_nested_borrows.rs', lines 199:0-199:18 -/
+   Source: 'src/no_nested_borrows.rs', lines 208:0-208:18 -/
 def test_box1 : Result Unit :=
   do
     let b := 0#i32
@@ -245,26 +255,26 @@ def test_box1 : Result Unit :=
 #assert (test_box1 == Result.ret ())
 
 /- [no_nested_borrows::copy_int]: forward function
-   Source: 'src/no_nested_borrows.rs', lines 209:0-209:30 -/
+   Source: 'src/no_nested_borrows.rs', lines 218:0-218:30 -/
 def copy_int (x : I32) : Result I32 :=
   Result.ret x
 
 /- [no_nested_borrows::test_unreachable]: forward function
-   Source: 'src/no_nested_borrows.rs', lines 215:0-215:32 -/
+   Source: 'src/no_nested_borrows.rs', lines 224:0-224:32 -/
 def test_unreachable (b : Bool) : Result Unit :=
   if b
   then Result.fail .panic
   else Result.ret ()
 
 /- [no_nested_borrows::test_panic]: forward function
-   Source: 'src/no_nested_borrows.rs', lines 223:0-223:26 -/
+   Source: 'src/no_nested_borrows.rs', lines 232:0-232:26 -/
 def test_panic (b : Bool) : Result Unit :=
   if b
   then Result.fail .panic
   else Result.ret ()
 
 /- [no_nested_borrows::test_copy_int]: forward function
-   Source: 'src/no_nested_borrows.rs', lines 230:0-230:22 -/
+   Source: 'src/no_nested_borrows.rs', lines 239:0-239:22 -/
 def test_copy_int : Result Unit :=
   do
     let y ← copy_int 0#i32
@@ -276,14 +286,14 @@ def test_copy_int : Result Unit :=
 #assert (test_copy_int == Result.ret ())
 
 /- [no_nested_borrows::is_cons]: forward function
-   Source: 'src/no_nested_borrows.rs', lines 237:0-237:38 -/
+   Source: 'src/no_nested_borrows.rs', lines 246:0-246:38 -/
 def is_cons (T : Type) (l : List T) : Result Bool :=
   match l with
   | List.Cons t l0 => Result.ret true
   | List.Nil => Result.ret false
 
 /- [no_nested_borrows::test_is_cons]: forward function
-   Source: 'src/no_nested_borrows.rs', lines 244:0-244:21 -/
+   Source: 'src/no_nested_borrows.rs', lines 253:0-253:21 -/
 def test_is_cons : Result Unit :=
   do
     let l := List.Nil
@@ -296,14 +306,14 @@ def test_is_cons : Result Unit :=
 #assert (test_is_cons == Result.ret ())
 
 /- [no_nested_borrows::split_list]: forward function
-   Source: 'src/no_nested_borrows.rs', lines 250:0-250:48 -/
+   Source: 'src/no_nested_borrows.rs', lines 259:0-259:48 -/
 def split_list (T : Type) (l : List T) : Result (T × (List T)) :=
   match l with
   | List.Cons hd tl => Result.ret (hd, tl)
   | List.Nil => Result.fail .panic
 
 /- [no_nested_borrows::test_split_list]: forward function
-   Source: 'src/no_nested_borrows.rs', lines 258:0-258:24 -/
+   Source: 'src/no_nested_borrows.rs', lines 267:0-267:24 -/
 def test_split_list : Result Unit :=
   do
     let l := List.Nil
@@ -317,14 +327,14 @@ def test_split_list : Result Unit :=
 #assert (test_split_list == Result.ret ())
 
 /- [no_nested_borrows::choose]: forward function
-   Source: 'src/no_nested_borrows.rs', lines 265:0-265:70 -/
+   Source: 'src/no_nested_borrows.rs', lines 274:0-274:70 -/
 def choose (T : Type) (b : Bool) (x : T) (y : T) : Result T :=
   if b
   then Result.ret x
   else Result.ret y
 
 /- [no_nested_borrows::choose]: backward function 0
-   Source: 'src/no_nested_borrows.rs', lines 265:0-265:70 -/
+   Source: 'src/no_nested_borrows.rs', lines 274:0-274:70 -/
 def choose_back
   (T : Type) (b : Bool) (x : T) (y : T) (ret : T) : Result (T × T) :=
   if b
@@ -332,7 +342,7 @@ def choose_back
   else Result.ret (x, ret)
 
 /- [no_nested_borrows::choose_test]: forward function
-   Source: 'src/no_nested_borrows.rs', lines 273:0-273:20 -/
+   Source: 'src/no_nested_borrows.rs', lines 282:0-282:20 -/
 def choose_test : Result Unit :=
   do
     let z ← choose I32 true 0#i32 0#i32
@@ -352,20 +362,20 @@ def choose_test : Result Unit :=
 #assert (choose_test == Result.ret ())
 
 /- [no_nested_borrows::test_char]: forward function
-   Source: 'src/no_nested_borrows.rs', lines 285:0-285:26 -/
+   Source: 'src/no_nested_borrows.rs', lines 294:0-294:26 -/
 def test_char : Result Char :=
   Result.ret 'a'
 
 mutual
 
 /- [no_nested_borrows::Tree]
-   Source: 'src/no_nested_borrows.rs', lines 290:0-290:16 -/
+   Source: 'src/no_nested_borrows.rs', lines 299:0-299:16 -/
 inductive Tree (T : Type) :=
 | Leaf : T → Tree T
 | Node : T → NodeElem T → Tree T → Tree T
 
 /- [no_nested_borrows::NodeElem]
-   Source: 'src/no_nested_borrows.rs', lines 295:0-295:20 -/
+   Source: 'src/no_nested_borrows.rs', lines 304:0-304:20 -/
 inductive NodeElem (T : Type) :=
 | Cons : Tree T → NodeElem T → NodeElem T
 | Nil : NodeElem T
@@ -373,7 +383,7 @@ inductive NodeElem (T : Type) :=
 end
 
 /- [no_nested_borrows::list_length]: forward function
-   Source: 'src/no_nested_borrows.rs', lines 330:0-330:48 -/
+   Source: 'src/no_nested_borrows.rs', lines 339:0-339:48 -/
 divergent def list_length (T : Type) (l : List T) : Result U32 :=
   match l with
   | List.Cons t l1 => do
@@ -382,7 +392,7 @@ divergent def list_length (T : Type) (l : List T) : Result U32 :=
   | List.Nil => Result.ret 0#u32
 
 /- [no_nested_borrows::list_nth_shared]: forward function
-   Source: 'src/no_nested_borrows.rs', lines 338:0-338:62 -/
+   Source: 'src/no_nested_borrows.rs', lines 347:0-347:62 -/
 divergent def list_nth_shared (T : Type) (l : List T) (i : U32) : Result T :=
   match l with
   | List.Cons x tl =>
@@ -394,7 +404,7 @@ divergent def list_nth_shared (T : Type) (l : List T) (i : U32) : Result T :=
   | List.Nil => Result.fail .panic
 
 /- [no_nested_borrows::list_nth_mut]: forward function
-   Source: 'src/no_nested_borrows.rs', lines 354:0-354:67 -/
+   Source: 'src/no_nested_borrows.rs', lines 363:0-363:67 -/
 divergent def list_nth_mut (T : Type) (l : List T) (i : U32) : Result T :=
   match l with
   | List.Cons x tl =>
@@ -406,7 +416,7 @@ divergent def list_nth_mut (T : Type) (l : List T) (i : U32) : Result T :=
   | List.Nil => Result.fail .panic
 
 /- [no_nested_borrows::list_nth_mut]: backward function 0
-   Source: 'src/no_nested_borrows.rs', lines 354:0-354:67 -/
+   Source: 'src/no_nested_borrows.rs', lines 363:0-363:67 -/
 divergent def list_nth_mut_back
   (T : Type) (l : List T) (i : U32) (ret : T) : Result (List T) :=
   match l with
@@ -421,7 +431,7 @@ divergent def list_nth_mut_back
   | List.Nil => Result.fail .panic
 
 /- [no_nested_borrows::list_rev_aux]: forward function
-   Source: 'src/no_nested_borrows.rs', lines 370:0-370:63 -/
+   Source: 'src/no_nested_borrows.rs', lines 379:0-379:63 -/
 divergent def list_rev_aux
   (T : Type) (li : List T) (lo : List T) : Result (List T) :=
   match li with
@@ -430,13 +440,13 @@ divergent def list_rev_aux
 
 /- [no_nested_borrows::list_rev]: merged forward/backward function
    (there is a single backward function, and the forward function returns ())
-   Source: 'src/no_nested_borrows.rs', lines 384:0-384:42 -/
+   Source: 'src/no_nested_borrows.rs', lines 393:0-393:42 -/
 def list_rev (T : Type) (l : List T) : Result (List T) :=
   let li := core.mem.replace (List T) l List.Nil
   list_rev_aux T li List.Nil
 
 /- [no_nested_borrows::test_list_functions]: forward function
-   Source: 'src/no_nested_borrows.rs', lines 389:0-389:28 -/
+   Source: 'src/no_nested_borrows.rs', lines 398:0-398:28 -/
 def test_list_functions : Result Unit :=
   do
     let l := List.Nil
@@ -483,97 +493,97 @@ def test_list_functions : Result Unit :=
 #assert (test_list_functions == Result.ret ())
 
 /- [no_nested_borrows::id_mut_pair1]: forward function
-   Source: 'src/no_nested_borrows.rs', lines 405:0-405:89 -/
+   Source: 'src/no_nested_borrows.rs', lines 414:0-414:89 -/
 def id_mut_pair1 (T1 T2 : Type) (x : T1) (y : T2) : Result (T1 × T2) :=
   Result.ret (x, y)
 
 /- [no_nested_borrows::id_mut_pair1]: backward function 0
-   Source: 'src/no_nested_borrows.rs', lines 405:0-405:89 -/
+   Source: 'src/no_nested_borrows.rs', lines 414:0-414:89 -/
 def id_mut_pair1_back
   (T1 T2 : Type) (x : T1) (y : T2) (ret : (T1 × T2)) : Result (T1 × T2) :=
   let (t, t0) := ret
   Result.ret (t, t0)
 
 /- [no_nested_borrows::id_mut_pair2]: forward function
-   Source: 'src/no_nested_borrows.rs', lines 409:0-409:88 -/
+   Source: 'src/no_nested_borrows.rs', lines 418:0-418:88 -/
 def id_mut_pair2 (T1 T2 : Type) (p : (T1 × T2)) : Result (T1 × T2) :=
   let (t, t0) := p
   Result.ret (t, t0)
 
 /- [no_nested_borrows::id_mut_pair2]: backward function 0
-   Source: 'src/no_nested_borrows.rs', lines 409:0-409:88 -/
+   Source: 'src/no_nested_borrows.rs', lines 418:0-418:88 -/
 def id_mut_pair2_back
   (T1 T2 : Type) (p : (T1 × T2)) (ret : (T1 × T2)) : Result (T1 × T2) :=
   let (t, t0) := ret
   Result.ret (t, t0)
 
 /- [no_nested_borrows::id_mut_pair3]: forward function
-   Source: 'src/no_nested_borrows.rs', lines 413:0-413:93 -/
+   Source: 'src/no_nested_borrows.rs', lines 422:0-422:93 -/
 def id_mut_pair3 (T1 T2 : Type) (x : T1) (y : T2) : Result (T1 × T2) :=
   Result.ret (x, y)
 
 /- [no_nested_borrows::id_mut_pair3]: backward function 0
-   Source: 'src/no_nested_borrows.rs', lines 413:0-413:93 -/
+   Source: 'src/no_nested_borrows.rs', lines 422:0-422:93 -/
 def id_mut_pair3_back'a
   (T1 T2 : Type) (x : T1) (y : T2) (ret : T1) : Result T1 :=
   Result.ret ret
 
 /- [no_nested_borrows::id_mut_pair3]: backward function 1
-   Source: 'src/no_nested_borrows.rs', lines 413:0-413:93 -/
+   Source: 'src/no_nested_borrows.rs', lines 422:0-422:93 -/
 def id_mut_pair3_back'b
   (T1 T2 : Type) (x : T1) (y : T2) (ret : T2) : Result T2 :=
   Result.ret ret
 
 /- [no_nested_borrows::id_mut_pair4]: forward function
-   Source: 'src/no_nested_borrows.rs', lines 417:0-417:92 -/
+   Source: 'src/no_nested_borrows.rs', lines 426:0-426:92 -/
 def id_mut_pair4 (T1 T2 : Type) (p : (T1 × T2)) : Result (T1 × T2) :=
   let (t, t0) := p
   Result.ret (t, t0)
 
 /- [no_nested_borrows::id_mut_pair4]: backward function 0
-   Source: 'src/no_nested_borrows.rs', lines 417:0-417:92 -/
+   Source: 'src/no_nested_borrows.rs', lines 426:0-426:92 -/
 def id_mut_pair4_back'a
   (T1 T2 : Type) (p : (T1 × T2)) (ret : T1) : Result T1 :=
   Result.ret ret
 
 /- [no_nested_borrows::id_mut_pair4]: backward function 1
-   Source: 'src/no_nested_borrows.rs', lines 417:0-417:92 -/
+   Source: 'src/no_nested_borrows.rs', lines 426:0-426:92 -/
 def id_mut_pair4_back'b
   (T1 T2 : Type) (p : (T1 × T2)) (ret : T2) : Result T2 :=
   Result.ret ret
 
 /- [no_nested_borrows::StructWithTuple]
-   Source: 'src/no_nested_borrows.rs', lines 424:0-424:34 -/
+   Source: 'src/no_nested_borrows.rs', lines 433:0-433:34 -/
 structure StructWithTuple (T1 T2 : Type) where
   p : (T1 × T2)
 
 /- [no_nested_borrows::new_tuple1]: forward function
-   Source: 'src/no_nested_borrows.rs', lines 428:0-428:48 -/
+   Source: 'src/no_nested_borrows.rs', lines 437:0-437:48 -/
 def new_tuple1 : Result (StructWithTuple U32 U32) :=
   Result.ret { p := (1#u32, 2#u32) }
 
 /- [no_nested_borrows::new_tuple2]: forward function
-   Source: 'src/no_nested_borrows.rs', lines 432:0-432:48 -/
+   Source: 'src/no_nested_borrows.rs', lines 441:0-441:48 -/
 def new_tuple2 : Result (StructWithTuple I16 I16) :=
   Result.ret { p := (1#i16, 2#i16) }
 
 /- [no_nested_borrows::new_tuple3]: forward function
-   Source: 'src/no_nested_borrows.rs', lines 436:0-436:48 -/
+   Source: 'src/no_nested_borrows.rs', lines 445:0-445:48 -/
 def new_tuple3 : Result (StructWithTuple U64 I64) :=
   Result.ret { p := (1#u64, 2#i64) }
 
 /- [no_nested_borrows::StructWithPair]
-   Source: 'src/no_nested_borrows.rs', lines 441:0-441:33 -/
+   Source: 'src/no_nested_borrows.rs', lines 450:0-450:33 -/
 structure StructWithPair (T1 T2 : Type) where
   p : Pair T1 T2
 
 /- [no_nested_borrows::new_pair1]: forward function
-   Source: 'src/no_nested_borrows.rs', lines 445:0-445:46 -/
+   Source: 'src/no_nested_borrows.rs', lines 454:0-454:46 -/
 def new_pair1 : Result (StructWithPair U32 U32) :=
   Result.ret { p := { x := 1#u32, y := 2#u32 } }
 
 /- [no_nested_borrows::test_constants]: forward function
-   Source: 'src/no_nested_borrows.rs', lines 453:0-453:23 -/
+   Source: 'src/no_nested_borrows.rs', lines 462:0-462:23 -/
 def test_constants : Result Unit :=
   do
     let swt ← new_tuple1
@@ -603,7 +613,7 @@ def test_constants : Result Unit :=
 #assert (test_constants == Result.ret ())
 
 /- [no_nested_borrows::test_weird_borrows1]: forward function
-   Source: 'src/no_nested_borrows.rs', lines 462:0-462:28 -/
+   Source: 'src/no_nested_borrows.rs', lines 471:0-471:28 -/
 def test_weird_borrows1 : Result Unit :=
   Result.ret ()
 
@@ -612,7 +622,7 @@ def test_weird_borrows1 : Result Unit :=
 
 /- [no_nested_borrows::test_mem_replace]: merged forward/backward function
    (there is a single backward function, and the forward function returns ())
-   Source: 'src/no_nested_borrows.rs', lines 472:0-472:37 -/
+   Source: 'src/no_nested_borrows.rs', lines 481:0-481:37 -/
 def test_mem_replace (px : U32) : Result U32 :=
   let y := core.mem.replace U32 px 1#u32
   if not (y = 0#u32)
@@ -620,55 +630,55 @@ def test_mem_replace (px : U32) : Result U32 :=
   else Result.ret 2#u32
 
 /- [no_nested_borrows::test_shared_borrow_bool1]: forward function
-   Source: 'src/no_nested_borrows.rs', lines 479:0-479:47 -/
+   Source: 'src/no_nested_borrows.rs', lines 488:0-488:47 -/
 def test_shared_borrow_bool1 (b : Bool) : Result U32 :=
   if b
   then Result.ret 0#u32
   else Result.ret 1#u32
 
 /- [no_nested_borrows::test_shared_borrow_bool2]: forward function
-   Source: 'src/no_nested_borrows.rs', lines 492:0-492:40 -/
+   Source: 'src/no_nested_borrows.rs', lines 501:0-501:40 -/
 def test_shared_borrow_bool2 : Result U32 :=
   Result.ret 0#u32
 
 /- [no_nested_borrows::test_shared_borrow_enum1]: forward function
-   Source: 'src/no_nested_borrows.rs', lines 507:0-507:52 -/
+   Source: 'src/no_nested_borrows.rs', lines 516:0-516:52 -/
 def test_shared_borrow_enum1 (l : List U32) : Result U32 :=
   match l with
   | List.Cons i l0 => Result.ret 1#u32
   | List.Nil => Result.ret 0#u32
 
 /- [no_nested_borrows::test_shared_borrow_enum2]: forward function
-   Source: 'src/no_nested_borrows.rs', lines 519:0-519:40 -/
+   Source: 'src/no_nested_borrows.rs', lines 528:0-528:40 -/
 def test_shared_borrow_enum2 : Result U32 :=
   Result.ret 0#u32
 
 /- [no_nested_borrows::Tuple]
-   Source: 'src/no_nested_borrows.rs', lines 530:0-530:24 -/
+   Source: 'src/no_nested_borrows.rs', lines 539:0-539:24 -/
 def Tuple (T1 T2 : Type) := T1 × T2
 
 /- [no_nested_borrows::use_tuple_struct]: merged forward/backward function
    (there is a single backward function, and the forward function returns ())
-   Source: 'src/no_nested_borrows.rs', lines 532:0-532:48 -/
+   Source: 'src/no_nested_borrows.rs', lines 541:0-541:48 -/
 def use_tuple_struct (x : Tuple U32 U32) : Result (Tuple U32 U32) :=
   Result.ret (1#u32, x.1)
 
 /- [no_nested_borrows::create_tuple_struct]: forward function
-   Source: 'src/no_nested_borrows.rs', lines 536:0-536:61 -/
+   Source: 'src/no_nested_borrows.rs', lines 545:0-545:61 -/
 def create_tuple_struct (x : U32) (y : U64) : Result (Tuple U32 U64) :=
   Result.ret (x, y)
 
 /- [no_nested_borrows::IdType]
-   Source: 'src/no_nested_borrows.rs', lines 541:0-541:20 -/
+   Source: 'src/no_nested_borrows.rs', lines 550:0-550:20 -/
 @[reducible] def IdType (T : Type) := T
 
 /- [no_nested_borrows::use_id_type]: forward function
-   Source: 'src/no_nested_borrows.rs', lines 543:0-543:40 -/
+   Source: 'src/no_nested_borrows.rs', lines 552:0-552:40 -/
 def use_id_type (T : Type) (x : IdType T) : Result T :=
   Result.ret x
 
 /- [no_nested_borrows::create_id_type]: forward function
-   Source: 'src/no_nested_borrows.rs', lines 547:0-547:43 -/
+   Source: 'src/no_nested_borrows.rs', lines 556:0-556:43 -/
 def create_id_type (T : Type) (x : T) : Result (IdType T) :=
   Result.ret x