Refine @compileTimeOnly

 - Don't default the message, and show it exclusively.
 - Fix cut-and-pasto in the @since tag
 - Be tolerant if the annotaion class is missing, as seems to
   have been the case compiling the continuations plugin.
 - s/\t/  / in the test file to show the errors are positioned
   correctly.
 - Use defensive getOrElse

2 files changed, 3 insertions, 3 deletions

diff --git a/src/reflect/scala/reflect/internal/Definitions.scala b/src/reflect/scala/reflect/internal/Definitions.scala
index 4c7694c319..2a7b55cb5a 100644
--- a/src/reflect/scala/reflect/internal/Definitions.scala
+++ b/src/reflect/scala/reflect/internal/Definitions.scala
@@ -944,7 +944,7 @@ trait Definitions extends api.StandardDefinitions {
     lazy val BeanPropertyAttr           = requiredClass[scala.beans.BeanProperty]
     lazy val BooleanBeanPropertyAttr    = requiredClass[scala.beans.BooleanBeanProperty]
     lazy val CloneableAttr              = requiredClass[scala.annotation.cloneable]
-    lazy val CompileTimeOnlyAttr        = requiredClass[scala.reflect.macros.compileTimeOnly]
+    lazy val CompileTimeOnlyAttr        = getClassIfDefined("scala.reflect.macros.compileTimeOnly")
     lazy val DeprecatedAttr             = requiredClass[scala.deprecated]
     lazy val DeprecatedNameAttr         = requiredClass[scala.deprecatedName]
     lazy val DeprecatedInheritanceAttr  = requiredClass[scala.deprecatedInheritance]
diff --git a/src/reflect/scala/reflect/macros/compileTimeOnly.scala b/src/reflect/scala/reflect/macros/compileTimeOnly.scala
index 4018e7db71..5a3a352a53 100644
--- a/src/reflect/scala/reflect/macros/compileTimeOnly.scala
+++ b/src/reflect/scala/reflect/macros/compileTimeOnly.scala
@@ -10,7 +10,7 @@ import scala.annotation.meta._
  *
  * @param  message the error message to print during compilation if a reference remains
  *                 after type checking
- * @since  2.10.0
+ * @since  2.10.1
  */
 @getter @setter @beanGetter @beanSetter
-final class compileTimeOnly(message: String = "") extends scala.annotation.StaticAnnotation
+final class compileTimeOnly(message: String) extends scala.annotation.StaticAnnotation