Address PR feedback

csharp/PhoneNumbers/PhoneNumberUtil.cs

@@ -16,6 +16,7 @@
 
 using System;
 using System.Collections.Generic;
+using System.ComponentModel;
 using System.Globalization;
 using System.IO;
 using System.Linq;
@@ -178,6 +179,9 @@ private static char MapAllPlusNumberGroupingSymbols(char c)
         private static Regex SeparatorPattern() => _separatorPattern;
 #endif
 
+        [Obsolete("This is an internal implementation detail not meant for public use", error: true), EditorBrowsable(EditorBrowsableState.Never)]
+        public static readonly Regex ValidStartCharPattern;
+
         // We use this pattern to check if the phone number has at least three letters in it - if so, then
         // we treat it as a number where some phone-number digits are represented by letters.
         private static bool IsValidAlphaPhone(StringBuilder number)

csharp/PhoneNumbers/PhoneRegex.cs

@@ -16,10 +16,12 @@
 
 using System;
 using System.Collections.Concurrent;
+using System.ComponentModel;
 using System.Text.RegularExpressions;
 
 namespace PhoneNumbers
 {
+    [EditorBrowsable(EditorBrowsableState.Never)]
     public sealed class PhoneRegex
     {
         private readonly string pattern;
@@ -29,9 +31,9 @@ public sealed class PhoneRegex
 
         private static readonly ConcurrentDictionary<string, PhoneRegex> cache = new();
 
-        public static PhoneRegex Get(string regex) => cache.GetOrAdd(regex, k => new PhoneRegex(k));
+        internal static PhoneRegex Get(string regex) => cache.GetOrAdd(regex, k => new PhoneRegex(k));
 
-        private PhoneRegex(string pattern)
+        public PhoneRegex(string pattern)
         {
             this.pattern = pattern;
 
@@ -40,6 +42,16 @@ private PhoneRegex(string pattern)
             beginRegex = new Lazy<Regex>(() => new Regex($"^(?:{this.pattern})", RegexOptions.CultureInvariant), true);
         }
 
+        [Obsolete("This is an internal implementation detail not meant for public use")]
+        public PhoneRegex(string pattern, RegexOptions options)
+        {
+            this.pattern = pattern;
+
+            regex = new Lazy<Regex>(() => new Regex(pattern, options), true);
+            allRegex = new Lazy<Regex>(() => new Regex($"^(?:{pattern})$", options), true);
+            beginRegex = new Lazy<Regex>(() => new Regex($"^(?:{pattern})", options), true);
+        }
+
         public bool IsMatch(string value) => regex.Value.IsMatch(value);
         public Match Match(string value) => regex.Value.Match(value);
         public string Replace(string value, string replacement) => regex.Value.Replace(value, replacement);

csharp/PhoneNumbers/RegexCache.cs

@@ -0,0 +1,29 @@
+/*
+ * Copyright (C) 2009 Google Inc.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+using System;
+using System.ComponentModel;
+
+namespace PhoneNumbers
+{
+    [Obsolete("This is an internal implementation detail not meant for public use"), EditorBrowsable(EditorBrowsableState.Never)]
+    public class RegexCache
+    {
+        public RegexCache(int size) { }
+        public PhoneRegex GetPatternForRegex(string regex) => PhoneRegex.Get(regex);
+        public bool ContainsRegex(string regex) => false;
+    }
+}