6 files changed, 71 insertions, 0 deletions
diff --git a/test/files/neg/double-def-top-level.check b/test/files/neg/double-def-top-level.check
new file mode 100644
index 0000000000..85b16e81e5
--- /dev/null
+++ b/test/files/neg/double-def-top-level.check
@@ -0,0 +1,7 @@
+D_3.scala:1: error: C is already defined as class C
+class C
+      ^
+D_3.scala:2: error: O is already defined as object O
+object O
+       ^
+two errors found
diff --git a/test/files/neg/double-def-top-level/A_1.scala b/test/files/neg/double-def-top-level/A_1.scala
new file mode 100644
index 0000000000..c3d68d9d05
--- /dev/null
+++ b/test/files/neg/double-def-top-level/A_1.scala
@@ -0,0 +1,4 @@
+package p
+
+class C
+object O
diff --git a/test/files/neg/double-def-top-level/B_2.scala b/test/files/neg/double-def-top-level/B_2.scala
new file mode 100644
index 0000000000..c328e8c964
--- /dev/null
+++ b/test/files/neg/double-def-top-level/B_2.scala
@@ -0,0 +1,2 @@
+class C /* noerror */
+object O /* noerror */
+\ No newline at end of file
diff --git a/test/files/neg/double-def-top-level/C_3.scala b/test/files/neg/double-def-top-level/C_3.scala
new file mode 100644
index 0000000000..e1c327c15a
--- /dev/null
+++ b/test/files/neg/double-def-top-level/C_3.scala
@@ -0,0 +1,2 @@
+class C
+object O
+\ No newline at end of file
diff --git a/test/files/neg/double-def-top-level/D_3.scala b/test/files/neg/double-def-top-level/D_3.scala
new file mode 100644
index 0000000000..518e0d1c54
--- /dev/null
+++ b/test/files/neg/double-def-top-level/D_3.scala
@@ -0,0 +1,2 @@
+class C
+object O
diff --git a/test/junit/scala/reflect/internal/ScopeTest.scala b/test/junit/scala/reflect/internal/ScopeTest.scala
new file mode 100644
index 0000000000..5166620189
--- /dev/null
+++ b/test/junit/scala/reflect/internal/ScopeTest.scala
@@ -0,0 +1,54 @@
+package symtab
+
+import scala.tools.nsc.symtab
+
+import org.junit.Assert._
+import org.junit.Test
+import org.junit.runner.RunWith
+import org.junit.runners.JUnit4
+
+import scala.tools.testing.AssertUtil.assertThrows
+import scala.tools.nsc.symtab.SymbolTableForUnitTesting
+
+@RunWith(classOf[JUnit4])
+class ScopeTest {
+  object symbolTable extends SymbolTableForUnitTesting
+
+  import symbolTable._
+
+  @Test
+  def testNestedScopeSmall(): Unit = testNestedScope(0)
+  @Test
+  def testNestedScopeLarge(): Unit = testNestedScope(64) // exceeding MIN_HASH
+
+  private def testNestedScope(initSize: Int) {
+    def sym(termName: String): Symbol = NoSymbol.newValue(TermName(termName))
+    val foo = sym("foo")
+    val bar = sym("bar")
+
+    val outerElems = List.tabulate(initSize)(i => sym(i.toString))
+    val outer = newScopeWith(outerElems ++ List(foo, bar) : _*)
+    assertTrue(outer.containsName(foo.name))
+    assertTrue(outer.containsName(bar.name))
+
+    val baz = sym("baz")
+    val nested = newNestedScope(outer)
+
+    // Entries from the outer scope are entered in the nested.
+    assertTrue(outer.containsName(foo.name))
+    assertTrue(outer.containsName(bar.name))
+
+    // Nested scopes structurally share ScopeEntry-s with the outer.
+    assertSame(outer.lookupEntry(foo.name), nested.lookupEntry(foo.name))
+    nested.enter(baz)
+
+    // Symbols entered in the nested scope aren't visible in the outer.
+    assertTrue(nested.containsName(baz.name))
+    assertTrue(!outer.containsName(baz.name))
+
+    // Unlinking a symbol in the inner scope doesn't modify the outer
+    nested.unlink(bar)
+    assert(!nested.containsName(bar.name))
+    assert(outer.containsName(bar.name))
+  }
+}