Improve the error message thrown when a companion object cannot be found

Instead of letting the compiler fail with a NoSymbol error, try to catch
it during compilation and offer up a more informative error message.

enumeratum-core/src/test/scala/enumeratum/EnumSpec.scala

@@ -414,15 +414,19 @@ class EnumSpec extends FunSpec with Matchers {
 
   describe("materializeEnum") {
     import DummyEnum._
+    def findEnum[A <: EnumEntry: Enum](v: A) = implicitly[Enum[A]]
 
     it("should return the proper Enum object") {
-      def findEnum[A <: EnumEntry: Enum](v: A) = implicitly[Enum[A]]
-
       val hello: DummyEnum = Hello
       val companion        = findEnum(hello)
       companion shouldBe DummyEnum
       companion.values should contain(Hello)
+    }
 
+    it("should fail to compile when passed a singleton object") {
+      """
+        | findEnum(Hello)
+      """ shouldNot compile
     }
   }
 }

macros/src/main/scala/enumeratum/EnumMacros.scala

@@ -1,6 +1,7 @@
 package enumeratum
 
 import ContextUtils.Context
+
 import scala.collection.immutable._
 import scala.util.control.NonFatal
 
@@ -22,8 +23,24 @@ object EnumMacros {
     */
   def materializeEnumImpl[A: c.WeakTypeTag](c: Context) = {
     import c.universe._
-    val symbol = weakTypeOf[A].typeSymbol
-    c.Expr[A](Ident(ContextUtils.companion(c)(symbol)))
+    val symbol          = weakTypeOf[A].typeSymbol
+    val companionSymbol = ContextUtils.companion(c)(symbol)
+    if (companionSymbol == NoSymbol) {
+      c.abort(c.enclosingPosition,
+              s"""
+           |
+           |  Could not find the companion object for type $symbol.
+           |
+           |  If you're sure the companion object exists, you might be able to fix this error by annotating the
+           |  value you're trying to find the companion object for with a parent type (e.g. Light.Red: Light).
+           |
+           |  This error usually happens when trying to find the companion object of a hard-coded enum member, and
+           |  is caused by Scala inferring the type to be the member's single type (e.g. Light.Red.type instead of
+           |  Light).
+         """.stripMargin)
+    } else {
+      c.Expr[A](Ident(companionSymbol))
+    }
   }
 
   /**