destructors: supportsCopyMem finally works for recursive types

compiler/semasgn.nim

@@ -319,6 +319,8 @@ proc liftTypeBoundOps*(c: PContext; typ: PType; info: TLineInfo) =
   ## to ensure we lift assignment, destructors and moves properly.
   ## The later 'destroyer' pass depends on it.
   if not newDestructors or not hasDestructor(typ): return
+  # do not produce wrong liftings while we're still instantiating generics:
+  if c.typesWithOps.len > 0: return
   let typ = typ.skipTypes({tyGenericInst, tyAlias})
   # we generate the destructor first so that other operators can depend on it:
   if typ.destructor == nil:

compiler/semdata.nim

@@ -132,6 +132,11 @@ type
     recursiveDep*: string
     suggestionsMade*: bool
     inTypeContext*: int
+    typesWithOps*: seq[(PType, PType)] #\
+      # We need to instantiate the type bound ops lazily after
+      # the generic type has been constructed completely. See
+      # tests/destructor/topttree.nim for an example that
+      # would otherwise fail.
 
 proc makeInstPair*(s: PSym, inst: PInstantiation): TInstantiationPair =
   result.genericSym = s
@@ -219,6 +224,7 @@ proc newContext*(graph: ModuleGraph; module: PSym; cache: IdentCache): PContext
   result.cache = cache
   result.graph = graph
   initStrTable(result.signatures)
+  result.typesWithOps = @[]
 
 
 proc inclSym(sq: var TSymSeq, s: PSym) =

compiler/semtypes.nim

@@ -1295,8 +1295,7 @@ proc symFromExpectedTypeNode(c: PContext, n: PNode): PSym =
 
 proc semTypeNode(c: PContext, n: PNode, prev: PType): PType =
   result = nil
-  when defined(nimsuggest):
+  inc c.inTypeContext
-    inc c.inTypeContext
 
   if gCmd == cmdIdeTools: suggestExpr(c, n)
   case n.kind
@@ -1511,8 +1510,13 @@ proc semTypeNode(c: PContext, n: PNode, prev: PType): PType =
     localError(n.info, errTypeExpected)
     result = newOrPrevType(tyError, prev, c)
   n.typ = result
-  when defined(nimsuggest):
+  dec c.inTypeContext
-    dec c.inTypeContext
+  if c.inTypeContext == 0: instAllTypeBoundOp(c, n.info)
+
+when false:
+  proc semTypeNode(c: PContext, n: PNode, prev: PType): PType =
+    result = semTypeNodeInner(c, n, prev)
+    instAllTypeBoundOp(c, n.info)
 
 proc setMagicType(m: PSym, kind: TTypeKind, size: int) =
   # source : https://en.wikipedia.org/wiki/Data_structure_alignment#x86

compiler/semtypinst.nim

@@ -77,7 +77,7 @@ type
     topLayer*: TIdTable
     nextLayer*: ptr LayeredIdTable
 
-  TReplTypeVars* {.final.} = object
+  TReplTypeVars* = object
     c*: PContext
     typeMap*: ptr LayeredIdTable # map PType to PType
     symMap*: TIdTable         # map PSym to PSym
@@ -261,6 +261,17 @@ proc instCopyType*(cl: var TReplTypeVars, t: PType): PType =
   if not (t.kind in tyMetaTypes or
          (t.kind == tyStatic and t.n == nil)):
     result.flags.excl tfInstClearedFlags
+  when false:
+    if newDestructors:
+      result.assignment = nil
+      #result.destructor = nil
+      result.sink = nil
+
+template typeBound(c, newty, oldty, field, info) =
+  let opr = newty.field
+  if opr != nil and sfFromGeneric notin opr.flags:
+    # '=' needs to be instantiated for generics when the type is constructed:
+    newty.field = c.instTypeBoundOp(c, opr, oldty, info, attachedAsgn, 1)
 
 proc handleGenericInvocation(cl: var TReplTypeVars, t: PType): PType =
   # tyGenericInvocation[A, tyGenericInvocation[A, B]]
@@ -357,16 +368,10 @@ proc handleGenericInvocation(cl: var TReplTypeVars, t: PType): PType =
         assert newbody.kind in {tyRef, tyPtr}
         assert newbody.lastSon.typeInst == nil
         newbody.lastSon.typeInst = result
-    template typeBound(field) =
-      let opr = newbody.field
-      if opr != nil and sfFromGeneric notin opr.flags:
-        # '=' needs to be instantiated for generics when the type is constructed:
-        newbody.field = cl.c.instTypeBoundOp(cl.c, opr, result, cl.info,
-                                             attachedAsgn, 1)
     if newDestructors:
-      typeBound(destructor)
+      cl.c.typesWithOps.add((newbody, result))
-      typeBound(sink)
+    else:
-    typeBound(assignment)
+      typeBound(cl.c, newbody, result, assignment, cl.info)
     let methods = skipTypes(bbody, abstractPtrs).methods
     for col, meth in items(methods):
       # we instantiate the known methods belonging to that type, this causes
@@ -534,6 +539,17 @@ proc replaceTypeVarsTAux(cl: var TReplTypeVars, t: PType): PType =
 
       else: discard
 
+proc instAllTypeBoundOp*(c: PContext, info: TLineInfo) =
+  if not newDestructors: return
+  var i = 0
+  while i < c.typesWithOps.len:
+    let (newty, oldty) = c.typesWithOps[i]
+    typeBound(c, newty, oldty, destructor, info)
+    typeBound(c, newty, oldty, sink, info)
+    typeBound(c, newty, oldty, assignment, info)
+    inc i
+  setLen(c.typesWithOps, 0)
+
 proc initTypeVars*(p: PContext, typeMap: ptr LayeredIdTable, info: TLineInfo;
                    owner: PSym): TReplTypeVars =
   initIdTable(result.symMap)

compiler/sigmatch.nim

@@ -2299,7 +2299,8 @@ proc instTypeBoundOp*(c: PContext; dc: PSym; t: PType; info: TLineInfo;
     localError(info, errGenerated, "cannot instantiate '" & dc.name.s & "'")
   else:
     result = c.semGenerateInstance(c, dc, m.bindings, info)
-    assert sfFromGeneric in result.flags
+    if op == attachedDeepCopy:
+      assert sfFromGeneric in result.flags
 
 include suggest
 

tests/destructor/topttree.nim

@@ -3,7 +3,11 @@ discard """
 60.0
 90.0
 120.0
-4 4'''
+10.0
+60.0
+90.0
+120.0
+8 8'''
   cmd: '''nim c --newruntime $file'''
 """
 
@@ -18,8 +22,8 @@ var
 
 proc `=destroy`*[T](x: var opt[T]) =
   if x.data != nil:
-    #when not supportsCopyMem(T):
+    when not supportsCopyMem(T):
-    `=destroy`(x.data[])
+      `=destroy`(x.data[])
     dealloc(x.data)
     inc deallocCount
     x.data = nil
@@ -93,6 +97,8 @@ proc main =
   insert t, 10.0
   insert t, 120.0
   write t
+  let copy = t
+  write copy
 
 main()
 echo allocCount, " ", deallocCount