diff --git a/src/api/dotnet/Expr.cs b/src/api/dotnet/Expr.cs
index 6c2ebb3ad..dade77eb1 100644
--- a/src/api/dotnet/Expr.cs
+++ b/src/api/dotnet/Expr.cs
@@ -1533,6 +1533,7 @@ namespace Microsoft.Z3
                     case Z3_sort_kind.Z3_INT_SORT: return new IntNum(ctx, obj);
                     case Z3_sort_kind.Z3_REAL_SORT: return new RatNum(ctx, obj);
                     case Z3_sort_kind.Z3_BV_SORT: return new BitVecNum(ctx, obj);
+                    case Z3_sort_kind.Z3_UNKNOWN_SORT: throw new Z3Exception("Unknown Sort");
                 }
             }
 
@@ -1544,6 +1545,7 @@ namespace Microsoft.Z3
                 case Z3_sort_kind.Z3_BV_SORT: return new BitVecExpr(ctx, obj);
                 case Z3_sort_kind.Z3_ARRAY_SORT: return new ArrayExpr(ctx, obj);
                 case Z3_sort_kind.Z3_DATATYPE_SORT: return new DatatypeExpr(ctx, obj);
+                case Z3_sort_kind.Z3_UNKNOWN_SORT: throw new Z3Exception("Unknown Sort");
             }
 
             return new Expr(ctx, obj);
diff --git a/src/api/dotnet/Quantifier.cs b/src/api/dotnet/Quantifier.cs
index c6754e570..f59d0bda2 100644
--- a/src/api/dotnet/Quantifier.cs
+++ b/src/api/dotnet/Quantifier.cs
@@ -181,8 +181,6 @@ namespace Microsoft.Z3
             if (sorts.Length != names.Length)
                 throw new Z3Exception("Number of sorts does not match number of names");
 
-            IntPtr[] _patterns = AST.ArrayToNative(patterns);
-
             if (noPatterns == null && quantifierID == null && skolemID == null)
             {
                 NativeObject = Native.Z3_mk_quantifier(ctx.nCtx, (isForall) ? 1 : 0, weight,