destructors: work in progress

compiler/semasgn.nim

@@ -268,10 +268,10 @@ proc liftBody(c: PContext; typ: PType; kind: TTypeAttachedOp;
   a.kind = kind
   let body = newNodeI(nkStmtList, info)
   let procname = case kind
-                 of attachedAsgn: getIdent":Asgn"
-                 of attachedSink: getIdent":Sink"
-                 of attachedDeepCopy: getIdent":DeepCopy"
-                 of attachedDestructor: getIdent":Destroy"
+                 of attachedAsgn: getIdent"="
+                 of attachedSink: getIdent"=sink"
+                 of attachedDeepCopy: getIdent"=deepcopy"
+                 of attachedDestructor: getIdent"=destroy"
 
   result = newSym(skProc, procname, typ.owner, info)
   a.fn = result
@@ -314,6 +314,24 @@ proc overloadedAsgn(c: PContext; dest, src: PNode): PNode =
   let a = getAsgnOrLiftBody(c, dest.typ, dest.info)
   result = newAsgnCall(c, a, dest, src)
 
+proc patchHead(n: PNode; alreadyPatched: var IntSet) =
+  when true:
+    if n.kind in nkCallKinds and n[0].kind == nkSym and n.len > 1:
+      let s = n[0].sym
+      if sfFromGeneric in s.flags:
+        if not containsOrIncl(alreadyPatched, s.id):
+          patchHead(s.getBody, alreadyPatched)
+        let t = n[1].typ.skipTypes({tyVar, tyGenericInst, tyAlias, tyInferred})
+        template patch(op, field) =
+          if s.name.s == op and field != nil and field != s:
+            n.sons[0].sym = field
+
+        patch "=sink", t.sink
+        patch "=", t.assignment
+        patch "=destroy", t.destructor
+    for x in n:
+      patchHead(x, alreadyPatched)
+
 proc liftTypeBoundOps*(c: PContext; typ: PType; info: TLineInfo) =
   ## In the semantic pass this is called in strategic places
   ## to ensure we lift assignment, destructors and moves properly.
@@ -321,6 +339,20 @@ proc liftTypeBoundOps*(c: PContext; typ: PType; info: TLineInfo) =
   if not newDestructors or not hasDestructor(typ): return
   let typ = typ.skipTypes({tyGenericInst, tyAlias})
   # we generate the destructor first so that other operators can depend on it:
-  if typ.destructor == nil: liftBody(c, typ, attachedDestructor, info)
-  if typ.assignment == nil: liftBody(c, typ, attachedAsgn, info)
-  if typ.sink == nil: liftBody(c, typ, attachedSink, info)
+  var changed = false
+  if typ.destructor != nil and typ.destructor.magic == mAsgn:
+    typ.destructor = nil
+  if typ.destructor == nil:
+    liftBody(c, typ, attachedDestructor, info)
+    changed = true
+  if typ.assignment == nil:
+    liftBody(c, typ, attachedAsgn, info)
+    changed = true
+  if typ.sink == nil:
+    liftBody(c, typ, attachedSink, info)
+    changed = true
+  if changed:
+    var alreadyPatched = initIntSet()
+    patchHead(typ.destructor.getBody, alreadyPatched)
+    patchHead(typ.assignment.getBody, alreadyPatched)
+    patchHead(typ.sink.getBody, alreadyPatched)