Merge pull request #4164 from retronym/ticket/9003

SI-9003 Eagerly capture more potentially mutable binders

2 files changed, 72 insertions, 0 deletions

diff --git a/test/files/run/t9003.flags b/test/files/run/t9003.flags
new file mode 100644
index 0000000000..49d036a887
--- /dev/null
+++ b/test/files/run/t9003.flags
@@ -0,0 +1 @@
+-optimize
diff --git a/test/files/run/t9003.scala b/test/files/run/t9003.scala
new file mode 100644
index 0000000000..4f24712201
--- /dev/null
+++ b/test/files/run/t9003.scala
@@ -0,0 +1,71 @@
+object Single {
+  var i = 0
+  def isEmpty = false
+  def get = i
+  def unapply(a: Single.type) = this
+}
+
+object Product {
+  var i = 0
+  def _1: Int = i
+  def _2: String = ???
+  def productArity = 2
+  def unapply(a: Product.type) = this
+  def isEmpty = false
+  def get: this.type = this
+}
+
+object Sequence {
+  var i = 0
+  def apply(n: Int): Int = i
+  def length = 2
+  def unapplySeq(a: Sequence.type) = this
+  def isEmpty = false
+  def get = this
+}
+
+object Test {
+  def main(args: Array[String]): Unit = {
+    def assertZero(i: Int) = assert(i == 0)
+
+    Single match {
+      case Single(i) =>
+        Single.i = 1
+        assertZero(i) // fails under -optimize
+    }
+
+    Product match {
+      case Product(i, _) =>
+        Product.i = 1
+        assertZero(i) // fails under -optimize
+    }
+
+    Sequence match {
+      case Sequence(i, _ @ _*) =>
+        Sequence.i = 1
+        assertZero(i) // okay
+    }
+
+    Sequence.i = 0
+    Sequence match {
+      case Sequence(_, i) =>
+        Sequence.i = 1
+        assertZero(i) // okay
+    }
+
+    val buffer = collection.mutable.Buffer(0, 0)
+    buffer match {
+      case Seq(_, i) =>
+        buffer(1) = 1
+        assertZero(i) // failed
+    }
+
+    case class CaseSequence(as: Int*)
+    val buffer1 = collection.mutable.Buffer(0, 0)
+    CaseSequence(buffer1: _*) match {
+      case CaseSequence(_, i) =>
+        buffer1(1) = 1
+        assertZero(i) // failed
+    }
+  }
+}