diff --git a/src/fsharp/ast.fs b/src/fsharp/ast.fs
index e7b31992413aff290efef535e3e1f1f4299f5f21..0e0f7ca0d97c4a1db9fa2a22e370e07abf10e59d 100644
--- a/src/fsharp/ast.fs
+++ b/src/fsharp/ast.fs
@@ -1147,7 +1147,7 @@ and
 and
     [<NoEquality; NoComparison>]
     SynMatchClause =
-    | Clause of SynPat * SynExpr option *  SynExpr * range:range * SequencePointInfoForTarget
+    | Clause of SynPat * whenExpr: SynExpr option * SynExpr * range:range * SequencePointInfoForTarget
 
     member this.RangeOfGuardAndRhs =
         match this with
@@ -1395,7 +1395,7 @@ and
     [<NoEquality; NoComparison>]
     /// The untyped, unchecked syntax tree for a field declaration in a record or class
     SynField =
-    | Field of attrs:SynAttributes * isStatic:bool * Ident option * SynType * bool * xmlDoc:PreXmlDoc * accessibility:SynAccess option * range:range
+    | Field of attrs:SynAttributes * isStatic:bool * Ident option * SynType * isMutable: bool * xmlDoc:PreXmlDoc * accessibility:SynAccess option * range:range
 
 and
     [<NoEquality; NoComparison>]