Fix: nested without calls in generic code

questionable/private/binderror.nim

@@ -1,15 +1,15 @@
 import std/options
 
-var captureEnabled {.global, compileTime.}: bool
+var captures {.global, compileTime.}: int
 var errorVariable: ptr ref CatchableError
 
 template captureBindError*(error: var ref CatchableError, expression): auto =
   let previousErrorVariable = errorVariable
   errorVariable = addr error
 
-  static: captureEnabled = true
+  static: inc captures
   let evaluated = expression
-  static: captureEnabled = false
+  static: dec captures
 
   errorVariable = previousErrorVariable
 
@@ -19,6 +19,6 @@ func error[T](option: Option[T]): ref CatchableError =
   newException(ValueError, "Option is set to `none`")
 
 template bindFailed*(expression) =
-  when captureEnabled:
+  when captures > 0:
     mixin error
     errorVariable[] = expression.error

testmodules/result/test.nim

@@ -294,6 +294,22 @@ suite "result":
 
     foo()
 
+  test "without statement with error works in nested generic calls":
+    proc works(_: type int): ?!int =
+      without _ =? int.failure "error1", err:
+        return success 42
+
+    proc fails(_: type int): ?!int =
+      return failure "error2"
+
+    proc foo =
+      without a =? int.works() and b =? int.fails(), error:
+        check error.msg == "error2"
+        return
+      fail()
+
+    foo()
+
   test "catch can be used to convert exceptions to results":
     check parseInt("42").catch == 42.success
     check parseInt("foo").catch.error of ValueError