Expose seq field for variable arity definitions

In 2.11 we've changed TupleClass, ProductClass and FunctionClass
endpoints to be exposed as (Int => Symbol) functions that never throw
exceptions but rather return NoSymbol instead of previous error-prone
indexed access on array that could explode.

While simplifying one use case (indexed access) it complicated
ability to check if symbol at hand is in fact a tuple, product or
function:

  (1 to 22).map(TupleClass).toList.contains(symbol)

To cover this extra use case we add a seq method to the variable arity
class definitions that exposes a corresponding sequence of class symbols:

  TupleClass.seq.contains(symbol)

1 files changed, 19 insertions, 0 deletions

diff --git a/test/files/run/var-arity-class-symbol.scala b/test/files/run/var-arity-class-symbol.scala
new file mode 100644
index 0000000000..29fe960eb3
--- /dev/null
+++ b/test/files/run/var-arity-class-symbol.scala
@@ -0,0 +1,19 @@
+import scala.reflect.runtime.universe._, definitions._
+object Test extends App {
+  // Tuples
+  assert(TupleClass.seq.size == 22)
+  assert(TupleClass(0) == NoSymbol)
+  assert(TupleClass(23) == NoSymbol)
+  assert((1 to 22).forall { i => TupleClass(i).name.toString == s"Tuple$i" })
+  // Functions
+  assert(FunctionClass.seq.size == 23)
+  assert(FunctionClass(-1) == NoSymbol)
+  assert(FunctionClass(23) == NoSymbol)
+  assert((0 to 22).forall { i => FunctionClass(i).name.toString == s"Function$i" })
+  // Products
+  assert(ProductClass.seq.size == 23)
+  assert(ProductClass(-1) == NoSymbol)
+  assert(ProductClass(0) == UnitClass)
+  assert(ProductClass(23) == NoSymbol)
+  assert((1 to 22).forall { i => ProductClass(i).name.toString == s"Product$i" })
+}