Add PathString+string operator to prevent too much string<->PathString implicit conversion.

src/Microsoft.AspNet.Http.Core/PathString.cs

@@ -227,6 +227,18 @@ namespace Microsoft.AspNet.Http
             return string.Concat(left, right.ToString());
         }
 
+        /// <summary>
+        /// </summary>
+        /// <param name="left">The left parameter</param>
+        /// <param name="right">The right parameter</param>
+        /// <returns>The ToString combination of both values</returns>
+        public static string operator +(PathString left, string right)
+        {
+            // This overload exists to prevent the implicit string<->PathString converter from
+            // trying to call the PathString+PathString operator for things that are not path strings.
+            return string.Concat(left.ToString(), right);
+        }
+
         /// <summary>
         /// Operator call through to Add
         /// </summary>

test/Microsoft.AspNet.Http.Core.Tests/PathStringTests.cs

@@ -63,6 +63,12 @@ namespace Microsoft.AspNet.Http
 
             var result = scheme + "://" + host + pathBase + path + query + fragment;
             Assert.Equal("http://localhost:80/base/path?query#frag", result);
+
+            result = pathBase + path + query + fragment;
+            Assert.Equal("/base/path?query#frag", result);
+
+            result = path + "text";
+            Assert.Equal("/pathtext", result);
         }
     }
 }