injectdestructors fixes and refactor (#14964)

* injectdestructors fixes and refactor

* Tiny cleanup

* Refactor and expand testcase

* Closes #14902 by adding testcase

* Better naming

* Fix test failures

* Misc cleanup

* Add testcase for #14968

* Better approach; expand testcases

* Optimizations and fixes

* Add testcase

* typo

* Tiny cleanup

tests/arc/tarcmisc.nim

@@ -3,6 +3,11 @@ discard """
 123xyzabc
 destroyed: false
 destroyed: false
+destroyed2: false
+destroyed2: false
+destroying variable: 2
+destroying variable: 1
+whiley ends :(
 1
 (x: "0")
 (x: "1")
@@ -17,7 +22,8 @@ destroyed: false
 (x: "10")
 0
 closed
-destroying variable
+destroying variable: 20
+destroying variable: 10
 '''
   cmd: "nim c --gc:arc $file"
 """
@@ -40,11 +46,12 @@ type Variable = ref object
   value: int
 
 proc `=destroy`(self: var typeof(Variable()[])) =
-  echo "destroying variable"
+  echo "destroying variable: ",self.value
 
 proc newVariable(value: int): Variable =
   result = Variable()
   result.value = value
+  #echo "creating variable: ",result.value
 
 proc test(count: int) =
   var v {.global.} = newVariable(10)
@@ -57,6 +64,28 @@ proc test(count: int) =
 
 test(3)
 
+proc test2(count: int) =
+  #block: #XXX: Fails with block currently
+    var v {.global.} = newVariable(20)
+
+    var count = count - 1
+    if count == 0: return
+
+    test2(count)
+    echo "destroyed2: ", v.isNil
+
+test2(3)
+
+proc whiley =
+  var a = newVariable(1)
+  while true:
+    var b = newVariable(2)
+    if true: raise newException(CatchableError, "test")
+
+try:
+  whiley()
+except CatchableError:
+  echo "whiley ends :("
 
 #------------------------------------------------------------------------------
 # issue #13810
@@ -209,3 +238,8 @@ proc setParent(self: SimpleLoopB, parent: SimpleLoopB) =
 
 var l = SimpleLoopB()
 l.setParent(l)
+
+
+# bug #14968
+import times
+let currentTime = now().utc