variant coercion for bigint

Author: mununki

jscomp/ml/variant_coercion.ml

@@ -5,6 +5,7 @@ let can_coerce_primitive (path : Path.t) =
   Path.same path Predef.path_string
   || Path.same path Predef.path_int
   || Path.same path Predef.path_float
+  || Path.same path Predef.path_bigint
 
 let check_paths_same p1 p2 target_path =
   Path.same p1 target_path && Path.same p2 target_path
@@ -38,6 +39,8 @@ let variant_has_same_runtime_representation_as_target ~(targetPath : Path.t)
       path_same Predef.path_string
       || (* unboxed Number(float) :> float *)
       path_same Predef.path_float
+      || (* unboxed Bigint(bigint) :> bigint *)
+      path_same Predef.path_bigint
     | Cstr_tuple [] -> (
       (* Check that @as payloads match with the target path to coerce to.
            No @as means the default encoding, which is string *)

jscomp/test/VariantCoercion.js

@@ -80,3 +80,15 @@ module CoerceFromFloatToVariant = {
   let c = 120.
   let cc: mixed = (c :> mixed)
 }
+
+module CoerceFromBigintToVariant = {
+  @unboxed type bigints = Bigint(bigint) | @as(1n) First | @as(2n) Second | @as(3n) Third
+  let a = 100n
+  let aa = 1n
+  let b: bigints = (a :> bigints)
+  let bb: bigints = (aa :> bigints)
+
+  @unboxed type mixed = Bigint(bigint) | @as(1n) One | @as(null) Null | Two
+  let c = 120n
+  let cc: mixed = (c :> mixed)
+}