concat accept an array; tests update

Author: butterunderflow

src/res_core.ml

@@ -3753,7 +3753,7 @@ and parseListExpr ~startPos p =
      Ast_helper.Exp.(apply ~loc
                        (Ast_helper.Exp.ident ~loc
                           (Location.mkloc (Longident.(Ldot (Ldot (Lident "Belt", "List"), "concatMany"))) loc))
-                       [Asttypes.Nolabel, makeListExpression loc listExprs None])
+                       [Asttypes.Nolabel, Ast_helper.Exp.array ~loc listExprs])
   (* | (true (\* spread expression *\), expr, _) :: exprs ->
    *   let exprs = check_all_non_spread_exp exprs in
    *   makeListExpression loc exprs (Some expr)

tests/parsing/errors/other/expected/spread.res.txt

@@ -49,20 +49,6 @@ Explanation: you can't collect a subset of a record's field into its own record,
 Solution: you need to pull out each field you want explicitly.
 
 
-  Syntax error!
-  tests/parsing/errors/other/spread.res:8:1-3
-
-   6 │ 
-   7 │ let myList = list{...x, ...y}
-   8 │ let list{...x, ...y} = myList
-   9 │ 
-  10 │ type t = {...a}
-
-  Lists can only have one `...` spread, and at the end.
-Explanation: lists are singly-linked list, where a node contains a value and points to the next node. `list{a, ...bc}` efficiently creates a new item and links `bc` as its next nodes. `list{...bc, a}` would be expensive, as it'd need to traverse `bc` and prepend each item to `a` one by one. We therefore disallow such syntax sugar.
-Solution: directly use `concat`.
-
-
   Syntax error!
   tests/parsing/errors/other/spread.res:8:13-22
 
@@ -114,7 +100,7 @@ let arr = [|x;y|]
 let [|arr;_|] = [|1;2;3|]
 let record = { x with y }
 let { x; y } = myRecord
-let myList = x :: y
+let myList = Belt.List.concatMany [|x;y|]
 let x::y = myList
 type nonrec t = < a  > 
 type nonrec t =

tests/parsing/grammar/expressions/expected/list.res.txt

@@ -3,4 +3,5 @@ let x = [1; 2; 3]
 let x = [1; 2; 3]
 let x = [(1 : int); (2 : int); (3 : int)]
 let x = 4 :: 5 :: y
+let x = Belt.List.concatMany [|(1 :: x);(2 :: 3 :: x)|]
 let x = 1 :: 2 :: (y : int list)

tests/parsing/grammar/expressions/list.res

@@ -12,5 +12,8 @@ let x = list{1: int, (2: int), 3: int}
 // spread
 let x = list{4, 5, ...y}
 
+// spread anywhere
+let x = list{1, ...x, 2, 3, ...x}
+
 // spread constrained expression
 let x = list{1, 2, ...y: list<int>}