tests for idempotency issues in the typechecker

For more details see https://issues.scala-lang.org/browse/SI-5464.

Check files are intentionally very precise, so that we can monitor
how the situation changes over time.

12 files changed, 241 insertions, 0 deletions

diff --git a/test/files/run/idempotency-case-classes.check b/test/files/run/idempotency-case-classes.check
new file mode 100644
index 0000000000..d2fb8169cb
--- /dev/null
+++ b/test/files/run/idempotency-case-classes.check
@@ -0,0 +1,52 @@
+C(2,3)
+()
+{
+  case class C extends AnyRef with Product with Serializable {
+    <caseaccessor> <paramaccessor> private[this] val x: Int = _;
+    <stable> <caseaccessor> <accessor> <paramaccessor> def x: Int = C.this.x;
+    <caseaccessor> <paramaccessor> private[this] val y: Int = _;
+    <stable> <caseaccessor> <accessor> <paramaccessor> def y: Int = C.this.y;
+    def <init>(x: Int, y: Int): C = {
+      C.super.<init>();
+      ()
+    };
+    <synthetic> def copy(x: Int = x, y: Int = y): C = new C(x, y);
+    <synthetic> def copy$default$1: Int = C.this.x;
+    <synthetic> def copy$default$2: Int = C.this.y;
+    override <synthetic> def productPrefix: String = "C";
+    <synthetic> def productArity: Int = 2;
+    <synthetic> def productElement(x$1: Int): Any = x$1 match {
+      case 0 => C.this.x
+      case 1 => C.this.y
+      case _ => throw new IndexOutOfBoundsException(x$1.toString())
+    };
+    override <synthetic> def productIterator: Iterator[Any] = runtime.this.ScalaRunTime.typedProductIterator[Any](C.this);
+    <synthetic> def canEqual(x$1: Any): Boolean = x$1.$isInstanceOf[C]();
+    override <synthetic> def hashCode(): Int = {
+      <synthetic> var acc: Int = -889275714;
+      acc = Statics.this.mix(acc, x);
+      acc = Statics.this.mix(acc, y);
+      Statics.this.finalizeHash(acc, 2)
+    };
+    override <synthetic> def toString(): String = ScalaRunTime.this._toString(C.this);
+    override <synthetic> def equals(x$1: Any): Boolean = C.this.eq(x$1.asInstanceOf[Object]).||(x$1.isInstanceOf[C].&&({
+      <synthetic> val C$1: C = x$1.asInstanceOf[C];
+      C.this.x.==(C$1.x).&&(C.this.y.==(C$1.y)).&&(C$1.canEqual(C.this))
+    }))
+  };
+  <synthetic> object C extends scala.runtime.AbstractFunction2[Int,Int,C] with Serializable {
+    def <init>(): C.type = {
+      C.super.<init>();
+      ()
+    };
+    final override def toString(): String = "C";
+    case <synthetic> def apply(x: Int, y: Int): C = new C(x, y);
+    case <synthetic> def unapply(x$0: C): Option[(Int, Int)] = if (x$0.==(null))
+      scala.this.None
+    else
+      Some.apply[(Int, Int)](Tuple2.apply[Int, Int](x$0.x, x$0.y));
+    <synthetic> private def readResolve(): Object = C
+  };
+  scala.this.Predef.println(C.apply(2, 3))
+}
+error!
diff --git a/test/files/run/idempotency-case-classes.scala b/test/files/run/idempotency-case-classes.scala
new file mode 100644
index 0000000000..4da8393cb6
--- /dev/null
+++ b/test/files/run/idempotency-case-classes.scala
@@ -0,0 +1,22 @@
+import scala.reflect.runtime.universe._
+import scala.reflect.runtime.{currentMirror => cm}
+import scala.tools.reflect.{ToolBox, ToolBoxError}
+import scala.tools.reflect.Eval
+
+object Test extends App {
+  val casee = reify {
+    case class C(x: Int, y: Int)
+    println(C(2, 3))
+  }
+  println(casee.eval)
+  val tb = cm.mkToolBox()
+  val tcasee = tb.typeCheck(casee.tree)
+  println(tcasee)
+  val rtcasee = tb.resetAllAttrs(tcasee)
+  try {
+    println(tb.eval(rtcasee))
+  } catch {
+    // this is the current behaviour, rather than the desired behavior; see SI-5467
+    case _: ToolBoxError => println("error!")
+  }
+}
\ No newline at end of file
diff --git a/test/files/run/idempotency-extractors.check b/test/files/run/idempotency-extractors.check
new file mode 100644
index 0000000000..fcd50faa79
--- /dev/null
+++ b/test/files/run/idempotency-extractors.check
@@ -0,0 +1,5 @@
+2
+2 match {
+  case Test.this.Extractor.unapply(<unapply-selector>) <unapply> ((x @ _)) => x
+}
+error!
diff --git a/test/files/run/idempotency-extractors.scala b/test/files/run/idempotency-extractors.scala
new file mode 100644
index 0000000000..fe033295f5
--- /dev/null
+++ b/test/files/run/idempotency-extractors.scala
@@ -0,0 +1,22 @@
+import scala.reflect.runtime.universe._
+import scala.reflect.runtime.{currentMirror => cm}
+import scala.tools.reflect.{ToolBox, ToolBoxError}
+import scala.tools.reflect.Eval
+
+object Test extends App {
+  object Extractor { def unapply(x: Int): Option[Int] = Some(x) }
+  val extractor = reify {
+    2 match { case Extractor(x) => x }
+  }
+  println(extractor.eval)
+  val tb = cm.mkToolBox()
+  val textractor = tb.typeCheck(extractor.tree)
+  println(textractor)
+  val rtextractor = tb.resetAllAttrs(textractor)
+  try {
+    println(tb.eval(rtextractor))
+  } catch {
+    // this is the current behaviour, rather than the desired behavior; see SI-5465
+    case _: ToolBoxError => println("error!")
+  }
+}
\ No newline at end of file
diff --git a/test/files/run/idempotency-labels.check b/test/files/run/idempotency-labels.check
new file mode 100644
index 0000000000..8709efeb43
--- /dev/null
+++ b/test/files/run/idempotency-labels.check
@@ -0,0 +1,15 @@
+2
+{
+  var x: Int = 0;
+  while$1(){
+    if (x.<(2))
+      {
+        x = x.+(1);
+        while$1()
+      }
+    else
+      ()
+  };
+  x
+}
+2
diff --git a/test/files/run/idempotency-labels.scala b/test/files/run/idempotency-labels.scala
new file mode 100644
index 0000000000..82d009751a
--- /dev/null
+++ b/test/files/run/idempotency-labels.scala
@@ -0,0 +1,22 @@
+import scala.reflect.runtime.universe._
+import scala.reflect.runtime.{currentMirror => cm}
+import scala.tools.reflect.{ToolBox, ToolBoxError}
+import scala.tools.reflect.Eval
+
+object Test extends App {
+  val label = reify {
+    var x = 0
+    while (x < 2) { x += 1 }
+    x
+  }
+  println(label.eval)
+  val tb = cm.mkToolBox()
+  val tlabel = tb.typeCheck(label.tree)
+  println(tlabel)
+  val rtlabel = tb.resetAllAttrs(tlabel)
+  try {
+    println(tb.eval(rtlabel))
+  } catch {
+    case _: ToolBoxError => println("error!")
+  }
+}
\ No newline at end of file
diff --git a/test/files/run/idempotency-lazy-vals.check b/test/files/run/idempotency-lazy-vals.check
new file mode 100644
index 0000000000..4dcbf96184
--- /dev/null
+++ b/test/files/run/idempotency-lazy-vals.check
@@ -0,0 +1,23 @@
+6
+{
+  class C extends AnyRef {
+    def <init>(): C = {
+      C.super.<init>();
+      ()
+    };
+    lazy private[this] val x: Int = _;
+    <stable> <accessor> lazy def x: Int = {
+      C.this.x = 2;
+      C.this.x
+    };
+    lazy private[this] val y: Int = _;
+    implicit <stable> <accessor> lazy def y: Int = {
+      C.this.y = 3;
+      C.this.y
+    }
+  };
+  val c: C = new C();
+  import c._;
+  c.x.*(scala.this.Predef.implicitly[Int](c.y))
+}
+error!
diff --git a/test/files/run/idempotency-lazy-vals.scala b/test/files/run/idempotency-lazy-vals.scala
new file mode 100644
index 0000000000..3531f9ff4b
--- /dev/null
+++ b/test/files/run/idempotency-lazy-vals.scala
@@ -0,0 +1,27 @@
+import scala.reflect.runtime.universe._
+import scala.reflect.runtime.{currentMirror => cm}
+import scala.tools.reflect.{ToolBox, ToolBoxError}
+import scala.tools.reflect.Eval
+
+object Test extends App {
+  val lazee = reify {
+    class C {
+      lazy val x = 2
+      implicit lazy val y = 3
+    }
+    val c = new C()
+    import c._
+    x * implicitly[Int]
+  }
+  println(lazee.eval)
+  val tb = cm.mkToolBox()
+  val tlazee = tb.typeCheck(lazee.tree)
+  println(tlazee)
+  val rtlazee = tb.resetAllAttrs(tlazee)
+  try {
+    println(tb.eval(rtlazee))
+  } catch {
+    // this is the current behaviour, rather than the desired behavior; see SI-5466
+    case _: ToolBoxError => println("error!")
+  }
+}
\ No newline at end of file
diff --git a/test/files/run/idempotency-partial-functions.check b/test/files/run/idempotency-partial-functions.check
new file mode 100644
index 0000000000..5c8a411655
--- /dev/null
+++ b/test/files/run/idempotency-partial-functions.check
@@ -0,0 +1,2 @@
+error!!
+error!
diff --git a/test/files/run/idempotency-partial-functions.scala b/test/files/run/idempotency-partial-functions.scala
new file mode 100644
index 0000000000..dd5f1167f1
--- /dev/null
+++ b/test/files/run/idempotency-partial-functions.scala
@@ -0,0 +1,25 @@
+import scala.reflect.runtime.universe._
+import scala.reflect.runtime.{currentMirror => cm}
+import scala.tools.reflect.{ToolBox, ToolBoxError}
+import scala.tools.reflect.Eval
+
+object Test extends App {
+  val partials = reify {
+    List((false,true)) collect { case (x,true) => x }
+  }
+  try {
+    println(partials.eval)
+  } catch {
+    case _: ToolBoxError => println("error!!")
+  }
+  try {
+    val tb = cm.mkToolBox()
+    val tpartials = tb.typeCheck(partials.tree)
+    println(tpartials)
+    val rtpartials = tb.resetAllAttrs(tpartials)
+    println(tb.eval(rtpartials))
+  } catch {
+    // this is the current behaviour, rather than the desired behavior; see SI-6187
+    case _: ToolBoxError => println("error!")
+  }
+}
\ No newline at end of file
diff --git a/test/files/run/idempotency-this.check b/test/files/run/idempotency-this.check
new file mode 100644
index 0000000000..08738c4565
--- /dev/null
+++ b/test/files/run/idempotency-this.check
@@ -0,0 +1,4 @@
+List()
+immutable.this.List.apply[String]("")
+Apply(TypeApply(Select(Select(This(newTypeName("immutable")), scala.collection.immutable.List), newTermName("apply")), List(TypeTree().setOriginal(Ident(newTypeName("String"))))), List(Literal(Constant(""))))
+error!
diff --git a/test/files/run/idempotency-this.scala b/test/files/run/idempotency-this.scala
new file mode 100644
index 0000000000..5cd4226326
--- /dev/null
+++ b/test/files/run/idempotency-this.scala
@@ -0,0 +1,22 @@
+import scala.reflect.runtime.universe._
+import scala.reflect.runtime.{currentMirror => cm}
+import scala.tools.reflect.{ToolBox, ToolBoxError}
+import scala.tools.reflect.Eval
+
+object Test extends App {
+  val thiss = reify {
+    List[String]("")
+  }
+  println(thiss.eval)
+  val tb = cm.mkToolBox()
+  val tthiss = tb.typeCheck(thiss.tree)
+  println(tthiss)
+  println(showRaw(tthiss))
+  val rtthiss = tb.resetAllAttrs(tthiss)
+  try {
+    println(tb.eval(rtthiss))
+  } catch {
+    // this is the current behaviour, rather than the desired behavior; see SI-5705
+    case _: ToolBoxError => println("error!")
+  }
+}
\ No newline at end of file