[nomerge] Scala classes ending in $ get a signature

Classes ending in `$` did not get a ScalaSignature by mistake.
They were filtered out by the name-based test that is supposed
to identify module classes.

This fix is already in 2.13.x, part of 3aea776.

Author: lrytz

src/compiler/scala/tools/nsc/backend/jvm/BCodeHelpers.scala

@@ -501,7 +501,7 @@ abstract class BCodeHelpers extends BCodeIdiomatic with BytecodeWriters {
      */
     def getAnnotPickle(jclassName: String, sym: Symbol): Option[AnnotationInfo] = {
       currentRun.symData get sym match {
-        case Some(pickle) if !nme.isModuleName(newTermName(jclassName)) =>
+        case Some(pickle) if !sym.isModuleClass =>
           val scalaAnnot = {
             val sigBytes = ScalaSigBytes(pickle.bytes.take(pickle.writeIndex))
             AnnotationInfo(sigBytes.sigAnnot, Nil, (nme.bytes, sigBytes) :: Nil)

test/junit/scala/tools/nsc/backend/jvm/BytecodeTest.scala

@@ -9,6 +9,7 @@ import scala.tools.asm.Opcodes._
 import scala.tools.partest.ASMConverters._
 import scala.tools.testing.BytecodeTesting
 import scala.tools.testing.BytecodeTesting._
+import scala.collection.JavaConverters._
 
 @RunWith(classOf[JUnit4])
 class BytecodeTest extends BytecodeTesting {
@@ -195,4 +196,12 @@ class BytecodeTest extends BytecodeTesting {
     val List(ExceptionHandler(_, _, _, desc)) = m.handlers
     assert(desc == None, desc)
   }
+
+  @Test
+  def classesEndingInDollarHaveSignature(): Unit = {
+    // A name-based test in the backend prevented classes ending in $ from getting a Scala signature
+    val code = "class C$"
+    val c = compileClass(code)
+    assertEquals(c.attrs.asScala.toList.map(_.`type`).sorted, List("ScalaInlineInfo", "ScalaSig"))
+  }
 }