destructors: lift type bound operations for case and distinct objects (#10238)

compiler/semasgn.nim

@@ -49,6 +49,14 @@ proc liftBodyObj(c: var TLiftCtx; n, body, x, y: PNode) =
     liftBodyAux(c, f.typ, body, x.dotField(f), y.dotField(f))
   of nkNilLit: discard
   of nkRecCase:
+    if c.kind in {attachedSink, attachedAsgn, attachedDeepCopy}:
+      ## the value needs to be destroyed before we assign the selector
+      ## or the value is lost
+      let prevKind = c.kind
+      c.kind = attachedDestructor
+      liftBodyObj(c, n, body, x, y)
+      c.kind = prevKind
+
     # copy the selector:
     liftBodyObj(c, n[0], body, x, y)
     # we need to generate a case statement:
@@ -66,7 +74,6 @@ proc liftBodyObj(c: var TLiftCtx; n, body, x, y: PNode) =
       liftBodyObj(c, n[i].lastSon, branch.sons[L-1], x, y)
       caseStmt.add(branch)
     body.add(caseStmt)
-    localError(c.c.config, c.info, "cannot lift assignment operator to 'case' object")
   of nkRecList:
     for t in items(n): liftBodyObj(c, t, body, x, y)
   else:
@@ -235,11 +242,12 @@ proc liftBodyAux(c: var TLiftCtx; t: PType; body, x, y: PNode) =
       discard considerOverloadedOp(c, t, body, x, y)
     else:
       defaultOp(c, t, body, x, y)
-  of tyObject, tyDistinct:
+  of tyObject:
     if not considerOverloadedOp(c, t, body, x, y):
-      if t.sons[0] != nil:
-        liftBodyAux(c, t.sons[0].skipTypes(skipPtrs), body, x, y)
-      if t.kind == tyObject: liftBodyObj(c, t.n, body, x, y)
+      liftBodyObj(c, t.n, body, x, y)
+  of tyDistinct:
+    if not considerOverloadedOp(c, t, body, x, y):
+      liftBodyAux(c, t.sons[0].skipTypes(skipPtrs), body, x, y)
   of tyTuple:
     liftBodyTup(c, t, body, x, y)
   of tyProc:
@@ -279,8 +287,36 @@ proc addParam(procType: PType; param: PSym) =
   addSon(procType.n, newSymNode(param))
   rawAddSon(procType, param.typ)
 
+proc liftBodyDistinctType(c: PContext; typ: PType; kind: TTypeAttachedOp; info: TLineInfo): PSym =
+  assert typ.kind == tyDistinct
+  let baseType = typ[0]
+  case kind
+    of attachedAsgn:
+      if baseType.assignment == nil:
+        discard liftBody(c, baseType, kind, info)
+      typ.assignment = baseType.assignment
+      result = typ.assignment
+    of attachedSink:
+      if baseType.sink == nil:
+        discard liftBody(c, baseType, kind, info)
+      typ.sink = baseType.sink
+      result = typ.sink
+    of attachedDeepCopy:
+      if baseType.deepCopy == nil:
+        discard liftBody(c, baseType, kind, info)
+      typ.deepCopy = baseType.deepCopy
+      result = typ.deepCopy
+    of attachedDestructor:
+      if baseType.destructor == nil:
+        discard liftBody(c, baseType, kind, info)
+      typ.destructor = baseType.destructor
+      result = typ.destructor
+
 proc liftBody(c: PContext; typ: PType; kind: TTypeAttachedOp;
               info: TLineInfo): PSym =
+  if typ.kind == tyDistinct:
+    return liftBodyDistinctType(c, typ, kind, info)
+
   var a: TLiftCtx
   a.info = info
   a.c = c

tests/destructor/tdestructor.nim

@@ -7,21 +7,28 @@ mygeneric1 constructed
 mygeneric1 destroyed
 ----
 mygeneric2 constructed
-mygeneric2 destroyed
 myobj destroyed
+mygeneric2 destroyed
 ----
 mygeneric3 constructed
 mygeneric1 destroyed
 ----
-mygeneric1 destroyed
+mydistinctObj constructed
+myobj destroyed
+mygeneric2 destroyed
+------------------
+----
 ----
 myobj destroyed
-----
-----
+mygeneric1 destroyed
+myobj destroyed
+myobj destroyed
+myobj destroyed
+---
+myobj destroyed
+myobj destroyed
 myobj destroyed
 '''
-  cmd: '''nim c --newruntime $file'''
-  disabled: "true"
 """
 
 type
@@ -29,6 +36,11 @@ type
     x, y: int
     p: pointer
 
+proc `=destroy`(o: var TMyObj) =
+  if o.p != nil: dealloc o.p
+  echo "myobj destroyed"
+
+type
   TMyGeneric1[T] = object
     x: T
 
@@ -36,37 +48,40 @@ type
     x: A
     y: B
 
+proc `=destroy`(o: var TMyGeneric1[int]) =
+  echo "mygeneric1 destroyed"
+
+proc `=destroy`[A, B](o: var TMyGeneric2[A, B]) =
+  echo "mygeneric2 destroyed"
+
+type
   TMyGeneric3[A, B, C] = object
     x: A
     y: B
     z: C
 
-  TObjKind = enum A, B, C, D
+  TDistinctObjX = distinct TMyGeneric3[TMyObj, TMyGeneric2[int, int], int]
+  TDistinctObj = TDistinctObjX
+
+  TObjKind = enum Z, A, B, C, D
 
   TCaseObj = object
+    z: TMyGeneric3[TMyObj, float, int]
     case kind: TObjKind
+    of Z: discard
     of A:
       x: TMyGeneric1[int]
     of B, C:
       y: TMyObj
     else:
       case innerKind: TObjKind
+      of Z: discard
       of A, B, C:
         p: TMyGeneric3[int, float, string]
       of D:
         q: TMyGeneric3[TMyObj, int, int]
       r: string
 
-proc `=destroy`(o: var TMyObj) =
-  if o.p != nil: dealloc o.p
-  echo "myobj destroyed"
-
-proc `=destroy`(o: var TMyGeneric1[int]) =
-  echo "mygeneric1 destroyed"
-
-proc `=destroy`[A, B](o: var TMyGeneric2[A, B]) =
-  echo "mygeneric2 destroyed"
-
 proc open: TMyObj =
   # allow for superfluous ()
   result = (TMyObj(x: 1, y: 2, p: alloc(3)))
@@ -95,6 +110,12 @@ proc mygeneric3 =
 
   echo "mygeneric3 constructed"
 
+proc mydistinctObj =
+  var x = TMyGeneric3[TMyObj, TMyGeneric2[int, int], int](
+    x: open(), y: TMyGeneric2[int, int](x: 5, y: 15), z: 20)
+
+  echo "mydistinctObj constructed"
+
 echo "----"
 myobj()
 
@@ -107,9 +128,11 @@ mygeneric2[int](10)
 echo "----"
 mygeneric3()
 
+echo "----"
+mydistinctObj()
+
 proc caseobj =
   block:
-    echo "----"
     var o1 = TCaseObj(kind: A, x: TMyGeneric1[int](x: 10))
 
   block:
@@ -121,10 +144,16 @@ proc caseobj =
     var o3 = TCaseObj(kind: D, innerKind: B, r: "test",
                       p: TMyGeneric3[int, float, string](x: 10, y: 1.0, z: "test"))
 
-  block:
-    echo "----"
-    var o4 = TCaseObj(kind: D, innerKind: D, r: "test",
-                      q: TMyGeneric3[TMyObj, int, int](x: open(), y: 1, z: 0))
 
+echo "------------------"
 caseobj()
 
+proc caseobj_test_sink: TCaseObj =
+  # check that lifted sink can destroy case val correctly
+  result = TCaseObj(kind: D, innerKind: D, r: "test",
+                      q: TMyGeneric3[TMyObj, int, int](x: open(), y: 1, z: 0))
+  result = TCaseObj(kind: B, y: open())
+
+
+echo "---"
+discard caseobj_test_sink()