tuple unpacking is not enforced in for loops anymore

tests/accept/compile/tgenericmatcher2.nim

@@ -0,0 +1,18 @@
+
+type
+  TMatcherKind = enum
+    mkTerminal, mkSequence, mkAlternation, mkRepeat
+  TMatcher[T] = object
+    case kind: TMatcherKind
+    of mkTerminal:
+      value: T
+    of mkSequence, mkAlternation:
+      matchers: seq[TMatcher[T]]
+    of mkRepeat:
+      matcher: ref TMatcher[T]
+      min, max: int
+
+var 
+  m: ref TMatcher[int]
+
+

tests/accept/compile/titer_no_tuple_unpack.nim

@@ -0,0 +1,13 @@
+
+iterator xrange(fromm, to: int, step = 1): tuple[x, y: int] =
+  var a = fromm
+  while a <= to:
+    yield (a, a+1)
+    inc(a, step)
+
+for a, b in xrange(3, 7):
+  echo a, " ", b
+  
+for tup in xrange(3, 7):
+  echo tup
+