diff --git a/src/Microsoft.AspNetCore.Routing.Abstractions/EndpointMetadataCollection.cs b/src/Microsoft.AspNetCore.Routing.Abstractions/EndpointMetadataCollection.cs
index ee12d0b8e7..4ca653a8fa 100644
--- a/src/Microsoft.AspNetCore.Routing.Abstractions/EndpointMetadataCollection.cs
+++ b/src/Microsoft.AspNetCore.Routing.Abstractions/EndpointMetadataCollection.cs
@@ -112,8 +112,7 @@ namespace Microsoft.AspNetCore.Routing
             var items = new List<T>();
             for (var i = 0; i < _items.Length; i++)
             {
-                var item = _items[i] as T;
-                if (item != null)
+                if (_items[i] is T item)
                 {
                     items.Add(item);
                 }
@@ -150,19 +149,18 @@ namespace Microsoft.AspNetCore.Routing
             // Intentionally not readonly to prevent defensive struct copies
             private object[] _items;
             private int _index;
-            private object _current;
 
             internal Enumerator(EndpointMetadataCollection collection)
             {
                 _items = collection._items;
                 _index = 0;
-                _current = null;
+                Current = null;
             }
 
             /// <summary>
             /// Gets the element at the current position of the enumerator
             /// </summary>
-            public object Current => _current;
+            public object Current { get; private set; }
 
             /// <summary>
             /// Releases all resources used by the <see cref="Enumerator"/>.
@@ -182,11 +180,11 @@ namespace Microsoft.AspNetCore.Routing
             {
                 if (_index < _items.Length)
                 {
-                    _current = _items[_index++];
+                    Current = _items[_index++];
                     return true;
                 }
 
-                _current = null;
+                Current = null;
                 return false;
             }
 
@@ -196,7 +194,7 @@ namespace Microsoft.AspNetCore.Routing
             public void Reset()
             {
                 _index = 0;
-                _current = null;
+                Current = null;
             }
         }
     }
diff --git a/src/Microsoft.AspNetCore.Routing.Abstractions/RouteValueDictionary.cs b/src/Microsoft.AspNetCore.Routing.Abstractions/RouteValueDictionary.cs
index 182147b9af..2d30f6f25f 100644
--- a/src/Microsoft.AspNetCore.Routing.Abstractions/RouteValueDictionary.cs
+++ b/src/Microsoft.AspNetCore.Routing.Abstractions/RouteValueDictionary.cs
@@ -222,13 +222,7 @@ namespace Microsoft.AspNetCore.Routing
             }
         }
 
-        IEnumerable<string> IReadOnlyDictionary<string, object>.Keys
-        {
-            get
-            {
-                return Keys;
-            }
-        }
+        IEnumerable<string> IReadOnlyDictionary<string, object>.Keys => Keys;
 
         /// <inheritdoc />
         public ICollection<object> Values
@@ -248,13 +242,7 @@ namespace Microsoft.AspNetCore.Routing
             }
         }
 
-        IEnumerable<object> IReadOnlyDictionary<string, object>.Values
-        {
-            get
-            {
-                return Values;
-            }
-        }
+        IEnumerable<object> IReadOnlyDictionary<string, object>.Values => Values;
 
         /// <inheritdoc />
         void ICollection<KeyValuePair<string, object>>.Add(KeyValuePair<string, object> item)
@@ -565,7 +553,7 @@ namespace Microsoft.AspNetCore.Routing
 
         internal class PropertyStorage
         {
-            private static readonly PropertyCache _propertyCache = new PropertyCache();
+            private static readonly ConcurrentDictionary<Type, PropertyHelper[]> _propertyCache = new ConcurrentDictionary<Type, PropertyHelper[]>();
 
             public readonly object Value;
             public readonly PropertyHelper[] Properties;
@@ -606,9 +594,5 @@ namespace Microsoft.AspNetCore.Routing
                 }
             }
         }
-
-        private class PropertyCache : ConcurrentDictionary<Type, PropertyHelper[]>
-        {
-        }
     }
 }
diff --git a/src/Microsoft.AspNetCore.Routing/Patterns/RoutePattern.cs b/src/Microsoft.AspNetCore.Routing/Patterns/RoutePattern.cs
index c6d80b0a06..80c2dfd801 100644
--- a/src/Microsoft.AspNetCore.Routing/Patterns/RoutePattern.cs
+++ b/src/Microsoft.AspNetCore.Routing/Patterns/RoutePattern.cs
@@ -21,10 +21,10 @@ namespace Microsoft.AspNetCore.Routing.Patterns
 
         internal RoutePattern(
             string rawText,
-            Dictionary<string, object> defaults,
-            Dictionary<string, IReadOnlyList<RoutePatternConstraintReference>> constraints,
-            RoutePatternParameterPart[] parameters,
-            RoutePatternPathSegment[] pathSegments)
+            IReadOnlyDictionary<string, object> defaults,
+            IReadOnlyDictionary<string, IReadOnlyList<RoutePatternConstraintReference>> constraints,
+            IReadOnlyList<RoutePatternParameterPart> parameters,
+            IReadOnlyList<RoutePatternPathSegment> pathSegments)
         {
             Debug.Assert(defaults != null);
             Debug.Assert(constraints != null);
diff --git a/src/Microsoft.AspNetCore.Routing/Patterns/RoutePatternFactory.cs b/src/Microsoft.AspNetCore.Routing/Patterns/RoutePatternFactory.cs
index 44dd675543..f34007481e 100644
--- a/src/Microsoft.AspNetCore.Routing/Patterns/RoutePatternFactory.cs
+++ b/src/Microsoft.AspNetCore.Routing/Patterns/RoutePatternFactory.cs
@@ -298,19 +298,35 @@ namespace Microsoft.AspNetCore.Routing.Patterns
                 rawText,
                 updatedDefaults,
                 updatedConstraints.ToDictionary(kvp => kvp.Key, kvp => (IReadOnlyList<RoutePatternConstraintReference>)kvp.Value.ToArray()),
-                parameters.ToArray(),
-                updatedSegments.ToArray());
+                parameters,
+                updatedSegments);
 
             RoutePatternPathSegment VisitSegment(RoutePatternPathSegment segment)
             {
-                var updatedParts = new RoutePatternPart[segment.Parts.Count];
+                RoutePatternPart[] updatedParts = null;
                 for (var i = 0; i < segment.Parts.Count; i++)
                 {
                     var part = segment.Parts[i];
-                    updatedParts[i] = VisitPart(part);
+                    var updatedPart = VisitPart(part);
+
+                    if (part != updatedPart)
+                    {
+                        if (updatedParts == null)
+                        {
+                            updatedParts = segment.Parts.ToArray();
+                        }
+
+                        updatedParts[i] = updatedPart;
+                    }
                 }
 
-                return SegmentCore(updatedParts);
+                if (updatedParts == null)
+                {
+                    // Segment has not changed
+                    return segment;
+                }
+
+                return new RoutePatternPathSegment(updatedParts);
             }
 
             RoutePatternPart VisitPart(RoutePatternPart part)
@@ -357,6 +373,14 @@ namespace Microsoft.AspNetCore.Routing.Patterns
                     parameterConstraints.AddRange(parameter.Constraints);
                 }
 
+                if (Equals(parameter.Default, @default)
+                    && parameter.Constraints.Count == 0
+                    && (parameterConstraints?.Count ?? 0) == 0)
+                {
+                    // Part has not changed
+                    return part;
+                }
+
                 return ParameterPartCore(
                     parameter.Name,
                     @default,
diff --git a/src/Microsoft.AspNetCore.Routing/Patterns/RoutePatternParser.cs b/src/Microsoft.AspNetCore.Routing/Patterns/RoutePatternParser.cs
index 0af65b286c..990d1854fc 100644
--- a/src/Microsoft.AspNetCore.Routing/Patterns/RoutePatternParser.cs
+++ b/src/Microsoft.AspNetCore.Routing/Patterns/RoutePatternParser.cs
@@ -138,7 +138,7 @@ namespace Microsoft.AspNetCore.Routing.Patterns
 
             if (IsSegmentValid(context, parts))
             {
-                segments.Add(new RoutePatternPathSegment(parts.ToArray()));
+                segments.Add(new RoutePatternPathSegment(parts));
                 return true;
             }
             else
diff --git a/src/Microsoft.AspNetCore.Routing/Patterns/RoutePatternPathSegment.cs b/src/Microsoft.AspNetCore.Routing/Patterns/RoutePatternPathSegment.cs
index 1fd65f45d7..4e7b010518 100644
--- a/src/Microsoft.AspNetCore.Routing/Patterns/RoutePatternPathSegment.cs
+++ b/src/Microsoft.AspNetCore.Routing/Patterns/RoutePatternPathSegment.cs
@@ -20,7 +20,7 @@ namespace Microsoft.AspNetCore.Routing.Patterns
     [DebuggerDisplay("{DebuggerToString()}")]
     public sealed class RoutePatternPathSegment
     {
-        internal RoutePatternPathSegment(RoutePatternPart[] parts)
+        internal RoutePatternPathSegment(IReadOnlyList<RoutePatternPart> parts)
         {
             Parts = parts;
         }