diff --git a/compiler/GHC/Builtin/Names.hs b/compiler/GHC/Builtin/Names.hs
index 3b91196d7afa9d9df2f2fe874c683b4bfa974d57..b45ae319cfce3c9cb97b43b1f7e7741e200c1983 100644
--- a/compiler/GHC/Builtin/Names.hs
+++ b/compiler/GHC/Builtin/Names.hs
@@ -358,6 +358,7 @@ basicKnownKeyNames
         stablePtrTyConName, ptrTyConName, funPtrTyConName, constPtrConName,
         int8TyConName, int16TyConName, int32TyConName, int64TyConName,
         word8TyConName, word16TyConName, word32TyConName, word64TyConName,
+        jsvalTyConName,
 
         -- Others
         otherwiseIdName, inlineIdName,
@@ -1659,6 +1660,9 @@ constPtrConName :: Name
 constPtrConName =
     tcQual fOREIGN_C_CONSTPTR (fsLit "ConstPtr") constPtrTyConKey
 
+jsvalTyConName :: Name
+jsvalTyConName = tcQual (mkGhcInternalModule (fsLit "GHC.Wasm.Prim.Types")) (fsLit "JSVal") jsvalTyConKey
+
 {-
 ************************************************************************
 *                                                                      *
@@ -1863,7 +1867,7 @@ statePrimTyConKey, stableNamePrimTyConKey, stableNameTyConKey,
     funPtrTyConKey, tVarPrimTyConKey, eqPrimTyConKey,
     eqReprPrimTyConKey, eqPhantPrimTyConKey,
     compactPrimTyConKey, stackSnapshotPrimTyConKey,
-    promptTagPrimTyConKey, constPtrTyConKey :: Unique
+    promptTagPrimTyConKey, constPtrTyConKey, jsvalTyConKey :: Unique
 statePrimTyConKey                       = mkPreludeTyConUnique 50
 stableNamePrimTyConKey                  = mkPreludeTyConUnique 51
 stableNameTyConKey                      = mkPreludeTyConUnique 52
@@ -2080,6 +2084,8 @@ typeCharToNatTyFamNameKey = mkPreludeTyConUnique 415
 typeNatToCharTyFamNameKey = mkPreludeTyConUnique 416
 constPtrTyConKey = mkPreludeTyConUnique 417
 
+jsvalTyConKey = mkPreludeTyConUnique 418
+
 {-
 ************************************************************************
 *                                                                      *
diff --git a/compiler/GHC/Tc/Gen/Foreign.hs b/compiler/GHC/Tc/Gen/Foreign.hs
index 84b48b4d2d7ccabcb76a18960b5b04e66d032d66..3d41a5af4592ff9bbf4c9308c817ff4997979067 100644
--- a/compiler/GHC/Tc/Gen/Foreign.hs
+++ b/compiler/GHC/Tc/Gen/Foreign.hs
@@ -753,6 +753,7 @@ boxedMarshalableTyCon tc
                     , charTyConKey
                     , stablePtrTyConKey
                     , boolTyConKey
+                    , jsvalTyConKey
                     ]
   = IsValid
 
@@ -794,4 +795,4 @@ In turn that means you can't write
 
 Reason: the back end falls over with panic "primRepHint:VoidRep";
         and there is no compelling reason to permit it
--}
\ No newline at end of file
+-}