fixes #11205

tests/destructor/tcaseobj_transitions.nim

@@ -0,0 +1,33 @@
+discard """
+  cmd: '''nim c --newruntime $file'''
+  output: '''no crash'''
+"""
+
+# bug #11205
+
+type
+  MyEnum = enum
+    A, B, C
+  MyCaseObject = object
+    case kind: MyEnum
+    of A: iseq: seq[int]
+    of B: fseq: seq[float]
+    of C: str: string
+
+
+  MyCaseObjectB = object # carefully constructed to use the same enum,
+                         # but a different object type!
+    case kind: MyEnum
+    of A, C: x: int
+    of B: fseq: seq[float]
+
+
+var x = MyCaseObject(kind: A)
+x.iseq.add 1
+#x.kind = B
+#x.fseq.add -3.0
+
+var y = MyCaseObjectB(kind: A)
+y.x = 1
+y.kind = C
+echo "no crash"