diff --git a/compile/interface/src/test/scala/xsbt/ExtractAPISpecification.scala b/compile/interface/src/test/scala/xsbt/ExtractAPISpecification.scala
index 839955689..3d58699e9 100644
--- a/compile/interface/src/test/scala/xsbt/ExtractAPISpecification.scala
+++ b/compile/interface/src/test/scala/xsbt/ExtractAPISpecification.scala
@@ -15,7 +15,7 @@ class ExtractAPISpecification extends Specification {
 
   def stableExistentialNames: Boolean = {
     def compileAndGetFooMethodApi(src: String): Def = {
-      val compilerForTesting = new ScalaCompilerForUnitTesting
+      val compilerForTesting = new ScalaCompilerForUnitTesting(nameHashing = false)
       val sourceApi = compilerForTesting.extractApiFromSrc(src)
       val FooApi = sourceApi.definitions().find(_.name() == "Foo").get.asInstanceOf[ClassLike]
       val fooMethodApi = FooApi.structure().declared().find(_.name == "foo").get
@@ -66,7 +66,7 @@ class ExtractAPISpecification extends Specification {
          |  class Foo extends Namers
          |}
          |""".stripMargin
-    val compilerForTesting = new ScalaCompilerForUnitTesting
+    val compilerForTesting = new ScalaCompilerForUnitTesting(nameHashing = false)
     val apis = compilerForTesting.extractApisFromSrcs(reuseCompilerInstance = false)(List(src1, src2), List(src2))
     val _ :: src2Api1 :: src2Api2 :: Nil = apis.toList
     val namerApi1 = selectNamer(src2Api1)
@@ -92,7 +92,7 @@ class ExtractAPISpecification extends Specification {
     val srcC6 = "class C6 extends AnyRef with X { self: X with Y => }"
     val srcC7 = "class C7 { _ => }"
     val srcC8 = "class C8 { self => }"
-    val compilerForTesting = new ScalaCompilerForUnitTesting
+    val compilerForTesting = new ScalaCompilerForUnitTesting(nameHashing = false)
     val apis = compilerForTesting.extractApisFromSrcs(reuseCompilerInstance = true)(
       List(srcX, srcY, srcC1, srcC2, srcC3, srcC4, srcC5, srcC6, srcC7, srcC8)
     ).map(x => collectFirstClass(x.definitions))
diff --git a/compile/interface/src/test/scala/xsbt/ScalaCompilerForUnitTesting.scala b/compile/interface/src/test/scala/xsbt/ScalaCompilerForUnitTesting.scala
index 95a27a30d..31faf2a24 100644
--- a/compile/interface/src/test/scala/xsbt/ScalaCompilerForUnitTesting.scala
+++ b/compile/interface/src/test/scala/xsbt/ScalaCompilerForUnitTesting.scala
@@ -20,7 +20,7 @@ import ScalaCompilerForUnitTesting.ExtractedSourceDependencies
  * Provides common functionality needed for unit tests that require compiling
  * source code using Scala compiler.
  */
-class ScalaCompilerForUnitTesting(nameHashing: Boolean = false) {
+class ScalaCompilerForUnitTesting(nameHashing: Boolean, includeSynthToNameHashing: Boolean = false) {
 
   /**
    * Compiles given source code using Scala compiler and returns API representation
@@ -127,7 +127,7 @@ class ScalaCompilerForUnitTesting(nameHashing: Boolean = false) {
   private def compileSrcs(groupedSrcs: List[List[String]],
     reuseCompilerInstance: Boolean): (Seq[File], TestCallback) = {
     withTemporaryDirectory { temp =>
-      val analysisCallback = new TestCallback(nameHashing)
+      val analysisCallback = new TestCallback(nameHashing, includeSynthToNameHashing)
       val classesDir = new File(temp, "classes")
       classesDir.mkdir()
 
diff --git a/interface/src/test/scala/xsbti/TestCallback.scala b/interface/src/test/scala/xsbti/TestCallback.scala
index f0658597b..04c9b5756 100644
--- a/interface/src/test/scala/xsbti/TestCallback.scala
+++ b/interface/src/test/scala/xsbti/TestCallback.scala
@@ -5,7 +5,7 @@ import scala.collection.mutable.ArrayBuffer
 import xsbti.api.SourceAPI
 import xsbti.DependencyContext._
 
-class TestCallback(override val nameHashing: Boolean = false) extends AnalysisCallback
+class TestCallback(override val nameHashing: Boolean, override val includeSynthToNameHashing: Boolean) extends AnalysisCallback
 {
 	val sourceDependencies = new ArrayBuffer[(File, File, DependencyContext)]
 	val binaryDependencies = new ArrayBuffer[(File, String, File, DependencyContext)]