Disables typechecking that precedes reflective compilation

Previously toolboxes used to typecheck their inputs before compiling.
Actually, the initial demo by Martin first typechecked the reified tree,
then ran it, which typechecked it again, and only then launched the
reflective compiler.

However, as observed in https://issues.scala-lang.org/browse/SI-5464
current implementation of typechecking is not always idempotent.
That's why we cannot allow inputs of toolboxes to be typechecked,
at least not until the aforementioned issue is closed.

This is not only a convention but also a check inside compileExpr.

1 files changed, 106 insertions, 0 deletions

diff --git a/test/files/run/reify_fors.scala b/test/files/run/reify_fors.scala
new file mode 100644
index 0000000000..27ee85d18b
--- /dev/null
+++ b/test/files/run/reify_fors.scala
@@ -0,0 +1,106 @@
+import scala.tools.nsc.reporters._
+import scala.tools.nsc.Settings
+import reflect.runtime.Mirror.ToolBox
+
+object Test extends App {
+  val code = scala.reflect.Code.lift{
+    object Persons {
+      /** A list of persons. To create a list, we use Predef.List
+       *  which takes a variable number of arguments and constructs
+       *  a list out of them.
+       */
+      val persons = List(
+        new Person("Bob", 17),
+        new Person("John", 40),
+        new Person("Richard", 68)
+      )
+
+      /** A Person class. 'val' constructor parameters become
+       *  public members of the class.
+       */
+      class Person(val name: String, val age: Int)
+
+      /** Return an iterator over persons that are older than 20.
+       */
+      def olderThan20(xs: Seq[Person]): Iterator[String] =
+        olderThan20(xs.iterator)
+
+      /** Return an iterator over persons older than 20, given
+       *  an iterator over persons.
+       */
+      def olderThan20(xs: Iterator[Person]): Iterator[String] = {
+
+        // The first expression is called a 'generator' and makes
+        // 'p' take values from 'xs'. The second expression is
+        // called a 'filter' and it is a boolean expression which
+        // selects only persons older than 20. There can be more than
+        // one generator and filter. The 'yield' expression is evaluated
+        // for each 'p' which satisfies the filters and used to assemble
+        // the resulting iterator
+        for (p <- xs if p.age > 20) yield p.name
+      }
+    }
+
+    /** Some functions over lists of numbers which demonstrate
+     *  the use of for comprehensions.
+     */
+    object Numeric {
+
+      /** Return the divisors of n. */
+      def divisors(n: Int): List[Int] =
+        for (i <- List.range(1, n+1) if n % i == 0) yield i
+
+      /** Is 'n' a prime number? */
+      def isPrime(n: Int) = divisors(n).length == 2
+
+      /** Return pairs of numbers whose sum is prime. */
+      def findNums(n: Int): Iterable[(Int, Int)] = {
+
+        // a for comprehension using two generators
+        for (i <- 1 until n;
+             j <- 1 until (i-1);
+             if isPrime(i + j)) yield (i, j)
+      }
+
+      /** Return the sum of the elements of 'xs'. */
+      def sum(xs: List[Double]): Double =
+        xs.foldLeft(0.0) { (x, y) => x + y }
+
+      /** Return the sum of pairwise product of the two lists. */
+      def scalProd(xs: List[Double], ys: List[Double]) =
+        sum(for((x, y) <- xs zip ys) yield x * y);
+
+      /** Remove duplicate elements in 'xs'. */
+      def removeDuplicates[A](xs: List[A]): List[A] =
+        if (xs.isEmpty)
+          xs
+        else
+          xs.head :: removeDuplicates(for (x <- xs.tail if x != xs.head) yield x)
+    }
+
+    // import all members of object 'persons' in the current scope
+    import Persons._
+
+    print("Persons over 20:")
+    olderThan20(persons) foreach { x => print(" " + x) }
+    println
+
+    import Numeric._
+
+    println("divisors(34) = " + divisors(34))
+
+    print("findNums(15) =")
+    findNums(15) foreach { x => print(" " + x) }
+    println
+
+    val xs = List(3.5, 5.0, 4.5)
+    println("average(" + xs + ") = " + sum(xs) / xs.length)
+
+    val ys = List(2.0, 1.0, 3.0)
+    println("scalProd(" + xs + ", " + ys +") = " + scalProd(xs, ys))
+  };
+
+  val reporter = new ConsoleReporter(new Settings)
+  val toolbox = new ToolBox(reporter)
+  toolbox.runExpr(code.tree)
+}