diff --git a/src/api/dotnet/Context.cs b/src/api/dotnet/Context.cs
index 30e5ece4f..3e438d69d 100644
--- a/src/api/dotnet/Context.cs
+++ b/src/api/dotnet/Context.cs
@@ -388,7 +388,7 @@ namespace Microsoft.Z3
             IntPtr[] n_constr = new IntPtr[n];
             for (uint i = 0; i < n; i++)
             {
-                var constructor = c[i];
+                Constructor[] constructor = c[i];
                 Contract.Assume(Contract.ForAll(constructor, arr => arr != null), "Clousot does not support yet quantified formula on multidimensional arrays");
                 CheckContextMatch(constructor);
                 cla[i] = new ConstructorList(this, constructor);
diff --git a/src/api/dotnet/Expr.cs b/src/api/dotnet/Expr.cs
index 22a506c71..6c2ebb3ad 100644
--- a/src/api/dotnet/Expr.cs
+++ b/src/api/dotnet/Expr.cs
@@ -433,7 +433,8 @@ namespace Microsoft.Z3
             get
             {
                 return (Native.Z3_is_app(Context.nCtx, NativeObject) != 0 &&
-                        (Z3_sort_kind)Native.Z3_get_sort_kind(Context.nCtx, Native.Z3_get_sort(Context.nCtx, NativeObject)) == Z3_sort_kind.Z3_ARRAY_SORT);
+                        (Z3_sort_kind)Native.Z3_get_sort_kind(Context.nCtx, Native.Z3_get_sort(Context.nCtx, NativeObject)) 
+                        == Z3_sort_kind.Z3_ARRAY_SORT);
             }
         }
 
@@ -1308,7 +1309,8 @@ namespace Microsoft.Z3
             get
             {
                 return (Native.Z3_is_app(Context.nCtx, NativeObject) != 0 &&
-                        (Z3_sort_kind)Native.Z3_get_sort_kind(Context.nCtx, Native.Z3_get_sort(Context.nCtx, NativeObject)) == Z3_sort_kind.Z3_RELATION_SORT);
+                        Native.Z3_get_sort_kind(Context.nCtx, Native.Z3_get_sort(Context.nCtx, NativeObject)) 
+                        == (uint)Z3_sort_kind.Z3_RELATION_SORT);
             }
         }
 
@@ -1429,7 +1431,7 @@ namespace Microsoft.Z3
             get
             {
                 return (Native.Z3_is_app(Context.nCtx, NativeObject) != 0 &&
-                        (Z3_sort_kind)Native.Z3_get_sort_kind(Context.nCtx, Native.Z3_get_sort(Context.nCtx, NativeObject)) == Z3_sort_kind.Z3_FINITE_DOMAIN_SORT);
+                        Native.Z3_get_sort_kind(Context.nCtx, Native.Z3_get_sort(Context.nCtx, NativeObject)) == (uint)Z3_sort_kind.Z3_FINITE_DOMAIN_SORT);
             }
         }
 
@@ -1489,8 +1491,8 @@ namespace Microsoft.Z3
         internal override void CheckNativeObject(IntPtr obj)
         {
             if (Native.Z3_is_app(Context.nCtx, obj) == 0 &&
-                (Z3_ast_kind)Native.Z3_get_ast_kind(Context.nCtx, obj) != Z3_ast_kind.Z3_VAR_AST &&
-                (Z3_ast_kind)Native.Z3_get_ast_kind(Context.nCtx, obj) != Z3_ast_kind.Z3_QUANTIFIER_AST)
+                Native.Z3_get_ast_kind(Context.nCtx, obj) != (uint)Z3_ast_kind.Z3_VAR_AST &&
+                Native.Z3_get_ast_kind(Context.nCtx, obj) != (uint)Z3_ast_kind.Z3_QUANTIFIER_AST)
                 throw new Z3Exception("Underlying object is not a term");
             base.CheckNativeObject(obj);
         }