diff --git a/akka-http-tests/src/test/scala/akka/http/server/directives/PathDirectivesSpec.scala b/akka-http-tests/src/test/scala/akka/http/server/directives/PathDirectivesSpec.scala
index 517f872840..958eac5a88 100644
--- a/akka-http-tests/src/test/scala/akka/http/server/directives/PathDirectivesSpec.scala
+++ b/akka-http-tests/src/test/scala/akka/http/server/directives/PathDirectivesSpec.scala
@@ -80,6 +80,19 @@ class PathDirectivesSpec extends RoutingSpec with Inside {
     "reject [/2147483648]" in test() // > Int.MaxValue
   }
 
+  "pathPrefix(CustomShortNumber)" should {
+    object CustomShortNumber extends NumberMatcher[Short](Short.MaxValue, 10) {
+      def fromChar(c: Char) = fromDecimalChar(c)
+    }
+
+    val test = testFor(pathPrefix(CustomShortNumber) { echoCaptureAndUnmatchedPath })
+    "accept [/23]" in test("23:")
+    "accept [/12345yes]" in test("12345:yes")
+    "reject [/]" in test()
+    "reject [/abc]" in test()
+    "reject [/33000]" in test() // > Short.MaxValue
+  }
+
   "pathPrefix(JavaUUID)" should {
     val test = testFor(pathPrefix(JavaUUID) { echoCaptureAndUnmatchedPath })
     "accept [/bdea8652-f26c-40ca-8157-0b96a2a8389d]" in test("bdea8652-f26c-40ca-8157-0b96a2a8389d:")
diff --git a/akka-http/src/main/scala/akka/http/server/PathMatcher.scala b/akka-http/src/main/scala/akka/http/server/PathMatcher.scala
index a896a63cba..94ce18684d 100644
--- a/akka-http/src/main/scala/akka/http/server/PathMatcher.scala
+++ b/akka-http/src/main/scala/akka/http/server/PathMatcher.scala
@@ -397,13 +397,12 @@ trait PathMatchers {
 
     def fromChar(c: Char): T
 
-    def fromDecimalChar(c: Char): T = if ('0' <= c && c <= '9') (c - '0').asInstanceOf[T] else minusOne
+    def fromDecimalChar(c: Char): T = if ('0' <= c && c <= '9') x.fromInt(c - '0') else minusOne
 
     def fromHexChar(c: Char): T =
-      if ('0' <= c && c <= '9') (c - '0').asInstanceOf[T] else {
+      if ('0' <= c && c <= '9') x.fromInt(c - '0') else {
         val cn = c | 0x20 // normalize to lowercase
-        if ('a' <= cn && cn <= 'f') (cn - 'a' + 10).asInstanceOf[T] else
-          minusOne
+        if ('a' <= cn && cn <= 'f') x.fromInt(cn - 'a' + 10) else minusOne
       }
   }