add changelog, var test using nim-lang#24037

changelog.md

@@ -42,6 +42,8 @@
 - Added `setLenUninit` to system, which doesn't initialize
 slots when enlarging a sequence.
 - Added `hasDefaultValue` to `std/typetraits` to check if a type has a valid default value.
+- Added `rangeBase` to `std/typetraits` to obtain the base type of a range type or
+  convert a value with a range type to its base type.
 - Added Viewport API for the JavaScript targets in the `dom` module.
 - Added `toSinglyLinkedRing` and `toDoublyLinkedRing` to `std/lists` to convert from `openArray`s.
 - ORC: To be enabled via `nimOrcStats` there is a new API called `GC_orcStats` that can be used to query how many

tests/metatype/ttypetraits.nim

@@ -162,6 +162,14 @@ block: # rangeBase
   doAssert foo(z) == "ranged(a..z of char) char(g)"
   {.pop.}
 
+  # works only with #24037:
+  var toChange: range[0..3] = 1
+  proc bar[T: int and not range](y: var T) =
+    inc y
+  doAssert not compiles(bar(toChange))
+  bar(rangeBase(toChange))
+  doAssert toChange == 2
+
 block: # tupleLen
   doAssert not compiles(tupleLen(int))