Fix SI-4954.

Override inner classes in `LinkedHashMap` that correspond
to `filterKeys`, `mapValues` and `keys` to retain a proper
ordering of elements when they are transformed.

1 files changed, 45 insertions, 0 deletions

diff --git a/test/files/run/t4954.scala b/test/files/run/t4954.scala
new file mode 100644
index 0000000000..b4916e651d
--- /dev/null
+++ b/test/files/run/t4954.scala
@@ -0,0 +1,45 @@
+
+
+import collection._
+
+
+object Test {
+  
+  def main(args: Array[String]) {
+    val m = scala.collection.mutable.LinkedHashMap("one" -> 1, "two" -> 2, "three" -> 3, "four" -> 4, "five" -> 5)
+    val expected = List("one", "two", "three", "four", "five")
+    assert(m.keys.iterator.toList == expected)
+    assert(m.keys.drop(0).iterator.toList == expected)
+    assert(m.keys.drop(1).iterator.toList == expected.drop(1))
+    assert(m.keys.drop(2).iterator.toList == expected.drop(2))
+    assert(m.keys.drop(3).iterator.toList == expected.drop(3))
+    assert(m.keys.drop(4).iterator.toList == expected.drop(4))
+    assert(m.keys.drop(5).iterator.toList == expected.drop(5))
+    
+    val expvals = List(1, 2, 3, 4, 5)
+    assert(m.values.iterator.toList == expvals)
+    assert(m.values.drop(0).iterator.toList == expvals)
+    assert(m.values.drop(1).iterator.toList == expvals.drop(1))
+    assert(m.values.drop(2).iterator.toList == expvals.drop(2))
+    assert(m.values.drop(3).iterator.toList == expvals.drop(3))
+    assert(m.values.drop(4).iterator.toList == expvals.drop(4))
+    assert(m.values.drop(5).iterator.toList == expvals.drop(5))
+    
+    val pred = (x: String) => x.length < 6
+    val filtered = m.filterKeys(pred)
+    assert(filtered.drop(0).keys.toList == expected.filter(pred))
+    assert(filtered.drop(1).keys.toList == expected.filter(pred).drop(1))
+    assert(filtered.drop(2).keys.toList == expected.filter(pred).drop(2))
+    assert(filtered.drop(3).keys.toList == expected.filter(pred).drop(3))
+    assert(filtered.drop(4).keys.toList == expected.filter(pred).drop(4))
+    
+    val mapped = m.mapValues(-_)
+    assert(mapped.drop(0).keys.toList == expected)
+    assert(mapped.drop(1).keys.toList == expected.drop(1))
+    assert(mapped.drop(2).keys.toList == expected.drop(2))
+    assert(mapped.drop(3).keys.toList == expected.drop(3))
+    assert(mapped.drop(4).keys.toList == expected.drop(4))
+    assert(mapped.drop(5).keys.toList == expected.drop(5))
+  }
+  
+}