fix #14312

compiler/liftdestructors.nim

@@ -62,9 +62,18 @@ proc newAsgnStmt(le, ri: PNode): PNode =
   result[0] = le
   result[1] = ri
 
+proc genBuiltin(g: ModuleGraph; magic: TMagic; name: string; i: PNode): PNode =
+  result = newNodeI(nkCall, i.info)
+  result.add createMagic(g, name, magic).newSymNode
+  result.add i
+
 proc defaultOp(c: var TLiftCtx; t: PType; body, x, y: PNode) =
   if c.kind in {attachedAsgn, attachedDeepCopy, attachedSink}:
     body.add newAsgnStmt(x, y)
+  elif c.kind == attachedDestructor and c.addMemReset:
+    let call = genBuiltin(c.g, mDefault, "default", x)
+    call.typ = t
+    body.add newAsgnStmt(x, call)
 
 proc genAddr(g: ModuleGraph; x: PNode): PNode =
   if x.kind == nkHiddenDeref:
@@ -74,12 +83,6 @@ proc genAddr(g: ModuleGraph; x: PNode): PNode =
     result = newNodeIT(nkHiddenAddr, x.info, makeVarType(x.typ.owner, x.typ))
     result.add x
 
-
-proc genBuiltin(g: ModuleGraph; magic: TMagic; name: string; i: PNode): PNode =
-  result = newNodeI(nkCall, i.info)
-  result.add createMagic(g, name, magic).newSymNode
-  result.add i
-
 proc genWhileLoop(c: var TLiftCtx; i, dest: PNode): PNode =
   result = newNodeI(nkWhileStmt, c.info, 2)
   let cmp = genBuiltin(c.g, mLtI, "<", i)

tests/arc/tcaseobj.nim

@@ -194,8 +194,6 @@ proc test_myobject =
 test_myobject()
 
 
-
-
 #------------------------------------------------
 # bug #14244
 
@@ -212,3 +210,16 @@ proc init(): RocksDBResult[string] =
   result.value = "ok"
 
 echo init()
+
+
+#------------------------------------------------
+# bug #14312
+
+type MyObj = object
+  case kind: bool
+    of false: x0: int # would work with a type like seq[int]; value would be reset
+    of true: x1: string
+
+var a = MyObj(kind: false, x0: 1234)
+a.kind = true
+doAssert(a.x1 == "")