diff --git a/build.sbt b/build.sbt
index 805f60463..f8b8f5957 100644
--- a/build.sbt
+++ b/build.sbt
@@ -43,7 +43,7 @@ ThisBuild / version := {
   nightlyVersion match {
     case Some(v) => v
     case _ =>
-      if ((ThisBuild / isSnapshot).value) "2.0.0-alpha12-SNAPSHOT"
+      if ((ThisBuild / isSnapshot).value) "2.0.0-alpha15-SNAPSHOT"
       else old
   }
 }
diff --git a/internal/zinc-classfile/src/main/scala/sbt/internal/inc/JarUtils.scala b/internal/zinc-classfile/src/main/scala/sbt/internal/inc/JarUtils.scala
index be7cacb79..9072b75bb 100644
--- a/internal/zinc-classfile/src/main/scala/sbt/internal/inc/JarUtils.scala
+++ b/internal/zinc-classfile/src/main/scala/sbt/internal/inc/JarUtils.scala
@@ -113,9 +113,9 @@ object JarUtils {
      */
     def fromURL(url: URL, jar: Path): ClassInJar = {
       val path = url.getPath
-      if (!path.contains("!")) sys.error(s"unexpected URL $url that does not include '!'")
+      if (!path.contains("!/")) sys.error(s"unexpected URL $url that does not include '!/'")
       else {
-        val Array(_, cls) = url.getPath.split("!")
+        val Array(_, cls) = url.getPath.split("!/")
         apply(jar, cls)
       }
     }
diff --git a/internal/zinc-core/src/main/scala/sbt/internal/inc/Incremental.scala b/internal/zinc-core/src/main/scala/sbt/internal/inc/Incremental.scala
index 8e8f2b39c..37e93decb 100644
--- a/internal/zinc-core/src/main/scala/sbt/internal/inc/Incremental.scala
+++ b/internal/zinc-core/src/main/scala/sbt/internal/inc/Incremental.scala
@@ -635,8 +635,8 @@ private final class AnalysisCallback(
   private[this] val localClasses = new TrieMap[VirtualFileRef, ConcurrentSet[VirtualFileRef]]
   // mapping between src class name and binary (flat) class name for classes generated from src file
   private[this] val classNames = new TrieMap[VirtualFileRef, ConcurrentSet[(String, String)]]
-  // generated class file to its source class name
-  private[this] val classToSource = new TrieMap[VirtualFileRef, String]
+  // generated class name to its source class name
+  private[this] val binaryNameToSourceName = new TrieMap[String, String]
   // internal source dependencies
   private[this] val intSrcDeps = new TrieMap[String, ConcurrentSet[InternalDependency]]
   // external source dependencies
@@ -779,8 +779,7 @@ private final class AnalysisCallback(
         // dependency is a product of a source not included in this compilation
         classDependency(dependsOn, fromClassName, context)
       case None =>
-        val vf = converter.toVirtualFile(classFile)
-        classToSource.get(vf) match {
+        binaryNameToSourceName.get(onBinaryClassName) match {
           case Some(dependsOn) =>
             // dependency is a product of a source in this compilation step,
             //  but not in the same compiler run (as in javac v. scalac)
@@ -842,7 +841,7 @@ private final class AnalysisCallback(
     val vf = converter.toVirtualFile(classFile)
     add(nonLocalClasses, source, (vf, binaryClassName))
     add(classNames, source, (srcClassName, binaryClassName))
-    classToSource.put(vf, srcClassName)
+    binaryNameToSourceName.put(binaryClassName, srcClassName)
     ()
   }
 
diff --git a/zinc/src/main/scala/sbt/internal/inc/MixedAnalyzingCompiler.scala b/zinc/src/main/scala/sbt/internal/inc/MixedAnalyzingCompiler.scala
index 390656bb9..81ed0f88f 100644
--- a/zinc/src/main/scala/sbt/internal/inc/MixedAnalyzingCompiler.scala
+++ b/zinc/src/main/scala/sbt/internal/inc/MixedAnalyzingCompiler.scala
@@ -70,7 +70,8 @@ final class MixedAnalyzingCompiler(
 
         def toVirtualFile(p: Path) = config.converter.toVirtualFile(p.toAbsolutePath)
 
-        JarUtils.getOutputJar(output) match {
+        val outputJarOpt = JarUtils.getOutputJar(output)
+        outputJarOpt match {
           case Some(outputJar) if !javac.supportsDirectToJar =>
             val outputDir = JarUtils.javacTempOutput(outputJar)
             Files.createDirectories(outputDir)
@@ -80,7 +81,7 @@ final class MixedAnalyzingCompiler(
               config.converter,
               joptions,
               CompileOutput(outputDir),
-              Some(outputJar),
+              outputJarOpt,
               callback,
               incToolOptions,
               config.reporter,
@@ -96,7 +97,7 @@ final class MixedAnalyzingCompiler(
                 config.converter,
                 joptions,
                 output,
-                None,
+                outputJarOpt,
                 callback,
                 incToolOptions,
                 config.reporter,