1 files changed, 89 insertions, 0 deletions
diff --git a/test/junit/scala/tools/nsc/symtab/FlagsTest.scala b/test/junit/scala/tools/nsc/symtab/FlagsTest.scala
new file mode 100644
index 0000000000..fc0e8b0f6b
--- /dev/null
+++ b/test/junit/scala/tools/nsc/symtab/FlagsTest.scala
@@ -0,0 +1,89 @@
+package scala.tools.nsc
+package symtab
+
+import org.junit.Assert._
+import scala.tools.testing.AssertUtil._
+import org.junit.Test
+import org.junit.runner.RunWith
+import org.junit.runners.JUnit4
+
+@RunWith(classOf[JUnit4])
+class FlagsTest {
+  object symbolTable extends SymbolTableForUnitTesting
+  import symbolTable._
+  import Flags._
+
+  def sym = NoSymbol.newTermSymbol(nme.EMPTY)
+
+  def withFlagMask[A](mask: Long)(body: => A): A = enteringPhase(new Phase(NoPhase) {
+    override def flagMask = mask
+    def name = ""
+    def run() = ()
+  })(body)
+
+  def testTimedFlag(flag: Long, test: Symbol => Boolean, enabling: Boolean) = {
+    assertEquals(withFlagMask(InitialFlags)(test(sym.setFlag(flag))), !enabling)
+    assertEquals(withFlagMask(InitialFlags | flag)(test(sym.setFlag(flag))), enabling)
+  }
+
+  def testLate(flag: Long, test: Symbol => Boolean) = testTimedFlag(flag, test, enabling = true)
+  def testNot(flag: Long, test: Symbol => Boolean) = testTimedFlag(flag, test, enabling = false)
+
+  @Test
+  def testTimedFlags(): Unit = {
+    testLate(lateDEFERRED, _.isDeferred)
+    testLate(lateFINAL, _.isFinal)
+    testLate(lateINTERFACE, _.isInterface)
+    testLate(lateMETHOD, _.isMethod)
+    testLate(lateMODULE, _.isModule)
+    testNot(PROTECTED | notPROTECTED, _.isProtected)
+    testNot(OVERRIDE | notOVERRIDE, _.isOverride)
+    testNot(PRIVATE | notPRIVATE, _.isPrivate)
+
+    assertFalse(withFlagMask(AllFlags)(sym.setFlag(PRIVATE | notPRIVATE).isPrivate))
+
+    assertEquals(withFlagMask(InitialFlags)(sym.setFlag(PRIVATE | notPRIVATE).flags & PRIVATE), PRIVATE)
+    assertEquals(withFlagMask(AllFlags)(sym.setFlag(PRIVATE | notPRIVATE).flags & PRIVATE), 0)
+  }
+
+  @Test
+  def normalLateOverlap(): Unit = {
+    // late flags are shifted by LateShift == 47.
+    // however, the first late flag is lateDEFERRED, which is DEFERRED << 47 == (1 << 4) << 47 == 1 << 51
+    // the flags from 1 << 47 to 1 << 50 are not late flags. this is ensured by the LateFlags mask.
+
+    for (i <- 0 to 3) {
+      val f = 1L << i
+      assertEquals(withFlagMask(AllFlags)(sym.setFlag(f << LateShift).flags & f), 0) // not treated as late flag
+    }
+    for (i <- 4 to 8) {
+      val f = 1L << i
+      assertEquals(withFlagMask(AllFlags)(sym.setFlag(f << LateShift).flags & f), f) // treated as late flag
+    }
+  }
+
+  @Test
+  def normalAnti(): Unit = {
+    for (i <- 0 to 2) {
+      val f = 1L << i
+      assertEquals(withFlagMask(AllFlags)(sym.setFlag(f | (f << AntiShift)).flags & f), 0) // negated flags
+    }
+    for (i <- 3 to 7) {
+      val f = 1L << i
+      assertEquals(withFlagMask(AllFlags)(sym.setFlag(f | (f << AntiShift)).flags & f), f) // not negated
+    }
+  }
+
+  @Test
+  def lateAntiCrossCheck(): Unit = {
+    val allButNegatable = AllFlags & ~(PROTECTED | OVERRIDE | PRIVATE)
+    val lateable        = 0L | DEFERRED | FINAL | INTERFACE | METHOD | MODULE
+    val lateFlags       = lateable << LateShift
+    val allButLateable  = AllFlags & ~lateable
+
+    assertEquals(withFlagMask(AllFlags)(sym.setFlag(AllFlags).flags), allButNegatable)
+    assertEquals(withFlagMask(AllFlags)(sym.setFlag(allButLateable).flags), allButNegatable)
+
+    assertEquals(withFlagMask(AllFlags)(sym.setFlag(lateFlags).flags), lateFlags | lateable)
+  }
+}