Merge pull request sbt#484 from scalacenter/ticket/292

Remove "Modified names" assertion

Author: dwijnand

internal/zinc-core/src/main/scala/sbt/internal/inc/Changes.scala

@@ -50,9 +50,7 @@ final case class APIChangeDueToMacroDefinition(modified0: String) extends APICha
  * This class is used only when name hashing algorithm is enabled.
  */
 final case class NamesChange(modified0: String, modifiedNames: ModifiedNames)
-    extends APIChange(modified0) {
-  assert(modifiedNames.names.nonEmpty, s"Modified names for $modified0 is empty")
-}
+    extends APIChange(modified0)
 
 /**
  * ModifiedNames are determined by comparing name hashes in two versions of an API representation.

zinc/src/sbt-test/source-dependencies/empty-modified-names/T.scala

@@ -0,0 +1,3 @@
+trait T2
+trait T1 extends T2 { def foo: String }
+class C1 extends T1 { def foo = "test" }

zinc/src/sbt-test/source-dependencies/empty-modified-names/changes/T.scala

@@ -0,0 +1,3 @@
+trait T2 { def foo: String }
+trait T1 extends T2
+class C1 extends T1 { def foo = "test" }

zinc/src/sbt-test/source-dependencies/empty-modified-names/test

@@ -0,0 +1,3 @@
+> compile
+$ copy-file changes/T.scala T.scala
+> compile