Fix #16437 (#17277)

* Fix #16437

* Fix

* Small cleanup

tests/arc/tcursor_on_localvar.nim

@@ -4,7 +4,10 @@ discard """
 Section: local
   Param: Str
   Param: Bool
-  Param: Floats2'''
+  Param: Floats2
+destroy Foo
+destroy Foo
+'''
   cmd: '''nim c --gc:arc $file'''
 """
 
@@ -123,4 +126,36 @@ when isMainModule:
         for p in cfg.params(s):
             echo "  Param: " & p
 
+# bug #16437
+
+type
+  Foo = object
+  FooRef = ref Foo
+
+  Bar = ref object
+    f: FooRef
+
+proc `=destroy`(o: var Foo) =
+  echo "destroy Foo"
+
+proc testMe(x: Bar) =
+  var c = (if x != nil: x.f else: nil)
+  assert c != nil
+
+proc main =
+  var b = Bar(f: FooRef())
+  testMe(b)
+
+main()
+
+proc testMe2(x: Bar) =
+  var c: FooRef
+  c = (if x != nil: x.f else: nil)
+  assert c != nil
+
+proc main2 =
+  var b = Bar(f: FooRef())
+  testMe2(b)
+
+main2()
 

tests/arc/topt_cursor.nim

@@ -4,21 +4,18 @@ discard """
   nimout: '''--expandArc: main
 
 var
+  x_cursor
   :tmpD
-  :tmpD_1
-  :tmpD_2
 try:
-  var x_cursor = ("hi", 5)
-  x_cursor = if cond:
-    :tmpD = ("different", 54)
-    :tmpD else:
-    :tmpD_1 = ("string here", 80)
-    :tmpD_1
+  x_cursor = ("hi", 5)
+  if cond:
+    x_cursor = ("different", 54) else:
+    x_cursor = ("string here", 80)
   echo [
-    :tmpD_2 = `$`(x_cursor)
-    :tmpD_2]
+    :tmpD = `$`(x_cursor)
+    :tmpD]
 finally:
-  `=destroy`(:tmpD_2)
+  `=destroy`(:tmpD)
 -- end of expandArc ------------------------
 --expandArc: sio
 

tests/arc/topt_no_cursor.nim

@@ -63,12 +63,13 @@ result.value = move lvalue
 --expandArc: tt
 
 var
+  it_cursor
   a
   :tmpD
   :tmpD_1
   :tmpD_2
 try:
-  var it_cursor = x
+  it_cursor = x
   a = (
     wasMoved(:tmpD)
     `=copy`(:tmpD, it_cursor.key)

tests/arc/topt_refcursors.nim

@@ -3,17 +3,21 @@ discard """
   cmd: '''nim c --gc:arc --expandArc:traverse --hint:Performance:off $file'''
   nimout: '''--expandArc: traverse
 
-var it_cursor = root
+var
+  it_cursor
+  jt_cursor
+it_cursor = root
 block :tmp:
   while (
     not (it_cursor == nil)):
     echo [it_cursor.s]
     it_cursor = it_cursor.ri
-var jt_cursor = root
+jt_cursor = root
 block :tmp_1:
   while (
     not (jt_cursor == nil)):
-    let ri_1_cursor = jt_cursor.ri
+    var ri_1_cursor
+    ri_1_cursor = jt_cursor.ri
     echo [jt_cursor.s]
     jt_cursor = ri_1_cursor
 -- end of expandArc ------------------------'''