fixes #267

compiler/ast.nim

@@ -365,12 +365,8 @@ type
     tfFromGeneric,    # type is an instantiation of a generic; this is needed
                       # because for instantiations of objects, structural
                       # type equality has to be used
-    tfInstantiated,   # XXX: used to mark generic params after instantiation.
+    tfUnresolved,     # marks unresolved typedesc params: e.g.
-                      # if the concrete type happens to be an implicit generic
+                      # proc foo(T: typedesc, list: seq[T]): var T
-                      # this can lead to invalid proc signatures in the second
-                      # pass of semProcTypeNode performed after instantiation.
-                      # this won't be needed if we don't perform this redundant
-                      # second pass (stay tuned).
     tfRetType,        # marks return types in proc (used to detect type classes 
                       # used as return types for return type inference)
     tfAll,            # type class requires all constraints to be met (default)
@@ -1045,7 +1041,6 @@ proc copyType(t: PType, owner: PSym, keepId: bool): PType =
   if keepId: 
     result.id = t.id
   else: 
-    result.id = getID()
     when debugIds: RegisterId(result)
   result.sym = t.sym          # backend-info should not be copied
   

compiler/semdata.nim

@@ -207,6 +207,11 @@ proc makeTypeDesc*(c: PContext, typ: PType): PType =
 proc newTypeS(kind: TTypeKind, c: PContext): PType = 
   result = newType(kind, getCurrOwner())
 
+proc newTypeWithSons*(c: PContext, kind: TTypeKind,
+                      sons: seq[PType]): PType =
+  result = newType(kind, getCurrOwner())
+  result.sons = sons
+
 proc errorType*(c: PContext): PType =
   ## creates a type representing an error state
   result = newTypeS(tyError, c)

compiler/seminst.nim

@@ -38,7 +38,6 @@ proc instantiateGenericParamList(c: PContext, n: PNode, pt: TIdTable,
       #t = instGenericContainer(c, a, t)
       t = generateTypeInstance(c, pt, a, t)
       #t = ReplaceTypeVarsT(cl, t)
-    t.flags.incl tfInstantiated
     s.typ = t
     addDecl(c, s)
     entry.concreteTypes[i] = t
@@ -84,11 +83,28 @@ proc freshGenSyms(n: PNode, owner: PSym, symMap: var TIdTable) =
   else:
     for i in 0 .. <safeLen(n): freshGenSyms(n.sons[i], owner, symMap)
 
+proc addParamOrResult(c: PContext, param: PSym, kind: TSymKind)
+
 proc instantiateBody(c: PContext, n: PNode, result: PSym) =
   if n.sons[bodyPos].kind != nkEmpty:
     # add it here, so that recursive generic procs are possible:
     addDecl(c, result)
     pushProcCon(c, result)
+    # add params to scope
+    let origFormalParams = result.typ.n
+    result.typ.n = newNodeI(nkFormalParams,
+                            origFormalParams.info,
+                            origFormalParams.len)
+    result.typ.n.sons[0] = copyNode(origFormalParams.sons[0])
+    for i in 1 .. <result.typ.len:
+      let origParam = origFormalParams[i].sym
+      var param = copySym(origParam)
+      result.typ.n.sons[i] = newSymNode(param)
+      param.typ = result.typ.sons[i]
+      param.ast = origParam.ast
+      param.owner = result
+      addParamOrResult(c, param, result.kind)
+    # debug result.typ.n
     maybeAddResult(c, result, n)
     var b = n.sons[bodyPos]
     var symMap: TIdTable
@@ -123,6 +139,70 @@ proc sideEffectsCheck(c: PContext, s: PSym) =
       s.ast.sons[genericParamsPos].kind == nkEmpty:
     c.threadEntries.add(s)
 
+proc instGenericContainer(c: PContext, info: TLineInfo, header: PType): PType =
+  var cl: TReplTypeVars
+  InitIdTable(cl.symMap)
+  InitIdTable(cl.typeMap)
+  cl.info = info
+  cl.c = c
+  result = ReplaceTypeVarsT(cl, header)
+
+proc instGenericContainer(c: PContext, n: PNode, header: PType): PType =
+  result = instGenericContainer(c, n.info, header)
+
+proc fixupProcTypeR(c: PContext, genericType: PType,
+                    inst: TInstantiation): PType =
+  result = genericType
+  if result == nil: return
+
+  case genericType.kind
+  of tyGenericParam, tyTypeClass:
+    result = inst.concreteTypes[genericType.sym.position]
+  of tyTypeDesc:
+    result = inst.concreteTypes[genericType.sym.position]
+    if tfUnresolved in genericType.flags:
+      result = result.sons[0]
+  of tyExpr:
+    result = inst.concreteTypes[genericType.sym.position]
+  of tyOpenArray, tyArray, tySet, tySequence, tyTuple, tyProc,
+     tyPtr, tyVar, tyRef, tyOrdinal, tyRange, tyVarargs:
+    if genericType.sons == nil: return
+    for i in 0 .. <genericType.sons.len:
+      let changed = fixupProcTypeR(c, genericType.sons[i], inst)
+      if changed != genericType.sons[i]:
+        if result == genericType:
+          # the first detected change initializes the result
+          result = copyType(genericType, genericType.owner, true)
+          if genericType.n != nil:
+            result.n = copyTree(genericType.n)
+        result.sons[i] = changed
+        if result.n != nil:
+          if result.n.kind == nkRecList:
+            result.n.sons[i].typ = changed
+          if result.n.kind == nkFormalParams:
+            if i == 0:
+              nil
+            else:
+              let origParam = result.n.sons[i].sym
+              var param = copySym(origParam)
+              param.typ = changed
+              param.ast = origParam.ast
+              result.n.sons[i] = newSymNode(param)
+              
+  of tyGenericInvokation:
+    result = newTypeWithSons(c, tyGenericInvokation, genericType.sons)
+    for i in 1 .. <genericType.sons.len:
+      result.sons[i] = fixupProcTypeR(c, result.sons[i], inst)
+    result = instGenericContainer(c, getInfoContext(-1), result)
+  else:
+    nil
+
+proc fixupProcType(c: PContext, genericType: PType,
+                   inst: TInstantiation): PType =
+  result = copyType(genericType, genericType.owner, false)
+  for i in 0 .. <result.sons.len:
+    result.sons[i] = fixupProcTypeR(c, result.sons[i], inst)
+  
 proc generateInstance(c: PContext, fn: PSym, pt: TIdTable,
                       info: TLineInfo): PSym =
   # no need to instantiate generic templates/macros:
@@ -152,16 +232,8 @@ proc generateInstance(c: PContext, fn: PSym, pt: TIdTable,
   var entry = TInstantiation.new
   entry.sym = result
   instantiateGenericParamList(c, n.sons[genericParamsPos], pt, entry[])
+  result.typ = fixupProcType(c, fn.typ, entry[])
   n.sons[genericParamsPos] = ast.emptyNode
-  # semantic checking for the parameters:
-  if n.sons[paramsPos].kind != nkEmpty:
-    removeDefaultParamValues(n.sons[ParamsPos])
-    semParamList(c, n.sons[ParamsPos], nil, result)
-  else:
-    result.typ = newTypeS(tyProc, c)
-    rawAddSon(result.typ, nil)
-  result.typ.callConv = fn.typ.callConv
-  if result.kind == skIterator: result.typ.flags.incl(tfIterator)
   var oldPrc = GenericCacheGet(fn, entry[])
   if oldPrc == nil:
     fn.procInstCache.safeAdd(entry)
@@ -183,11 +255,4 @@ proc generateInstance(c: PContext, fn: PSym, pt: TIdTable,
   dec(c.InstCounter)
   if result.kind == skMethod: finishMethod(c, result)
 
-proc instGenericContainer(c: PContext, n: PNode, header: PType): PType = 
-  var cl: TReplTypeVars
-  InitIdTable(cl.symMap)
-  InitIdTable(cl.typeMap)
-  cl.info = n.info
-  cl.c = c
-  result = ReplaceTypeVarsT(cl, header)
 

compiler/semtypes.nim

@@ -235,7 +235,9 @@ proc semTypeIdent(c: PContext, n: PNode): PSym =
         if result.typ.sym == nil:
           LocalError(n.info, errTypeExpected)
           return errorSym(c, n)
-        return result.typ.sym
+        result = result.typ.sym.copySym
+        result.typ = copyType(result.typ, result.typ.owner, true)
+        result.typ.flags.incl tfUnresolved
       if result.kind != skType: 
         # this implements the wanted ``var v: V, x: V`` feature ...
         var ov: TOverloadIter
@@ -573,82 +575,96 @@ proc addParamOrResult(c: PContext, param: PSym, kind: TSymKind) =
   else:
     if sfGenSym notin param.flags: addDecl(c, param)
 
-proc paramTypeClass(c: PContext, paramType: PType, procKind: TSymKind):
-  tuple[typ: PType, id: PIdent] =
-  # if typ is not-nil, the param should be turned into a generic param
-  # if id is not nil, the generic param will bind just once (see below)
-  case paramType.kind:
-  of tyExpr:
-    if paramType.sonsLen == 0:
-      # proc(a, b: expr)
-      # no constraints, treat like generic param
-      result.typ = newTypeS(tyGenericParam, c)
-    else:
-      # proc(a: expr{string}, b: expr{nkLambda})
-      # overload on compile time values and AST trees
-      result.typ = newTypeS(tyExpr, c)
-      result.typ.sons = paramType.sons
-  of tyTypeDesc:
-     if tfInstantiated notin paramType.flags:
-      result.typ = newTypeS(tyTypeDesc, c)
-      result.typ.sons = paramType.sons
-  of tyDistinct:
-    result = paramTypeClass(c, paramType.lastSon, procKind)
-    # disable the bindOnce behavior for the type class
-    result.id = nil
-    return
-  of tyGenericBody:
-    # type Foo[T] = object
-    # proc x(a: Foo, b: Foo) 
-    result.typ = newTypeS(tyTypeClass, c)
-    result.typ.addSonSkipIntLit(paramType)
-  of tyTypeClass:
-    result.typ = copyType(paramType, getCurrOwner(), false)
-  else: nil
-  # bindOnce by default
-  if paramType.sym != nil: result.id = paramType.sym.name
-
 proc liftParamType(c: PContext, procKind: TSymKind, genericParams: PNode,
                    paramType: PType, paramName: string,
-                   info: TLineInfo): PType =
+                   info: TLineInfo, anon = false): PType =
-  result = paramType
   if procKind in {skMacro, skTemplate}:
     # generic param types in macros and templates affect overload
     # resolution, but don't work as generic params when it comes
     # to proc instantiation. We don't need to lift such params here.  
     return
-  ## Params having implicit generic types or pseudo types such as 'expr'
+
-  ## need to be added to the generic params lists. 
+  proc addImplicitGenericImpl(typeClass: PType, typId: PIdent): PType =
-  ## 'expr' is different from 'expr{string}' so we must first call 
+    let finalTypId = if typId != nil: typId
-  ## paramTypeClass to get the actual type we are going to use.
+                     else: getIdent(paramName & ":type")
-  var (typeClass, paramTypId) = paramTypeClass(c, paramType, procKind)
-  let isAnon = paramTypId == nil
-  if typeClass != nil:
-    if isAnon: paramTypId = getIdent(paramName & ":type")
-    if genericParams == nil:
-      # genericParams is nil when the proc is being instantiated
-      # the resolved type will be in scope then
-      let s = searchInScopes(c, paramTypId)
-      # tests/run/tinterf triggers this:
-      if s != nil: result = s.typ
-      else:
-        LocalError(info, errCannotInstantiateX, paramName)
-        result = errorType(c)
-    else:
-      block addImplicitGeneric:
     # is this a bindOnce type class already present in the param list?
     for i in countup(0, genericParams.len - 1):
-          if genericParams.sons[i].sym.name.id == paramTypId.id:
+      if genericParams.sons[i].sym.name.id == finalTypId.id:
-            result = genericParams.sons[i].typ
+        return genericParams.sons[i].typ
-            break addImplicitGeneric
 
-        var s = newSym(skType, paramTypId, getCurrOwner(), info)
+    var s = newSym(skType, finalTypId, getCurrOwner(), info)
-        if isAnon: s.flags.incl(sfAnon)
+    if typId == nil: s.flags.incl(sfAnon)
     s.linkTo(typeClass)
     s.position = genericParams.len
     genericParams.addSon(newSymNode(s))
     result = typeClass
 
+  # XXX: There are codegen errors if this is turned into a nested proc
+  template liftingWalk(typ: PType, anonFlag = false): expr =
+    liftParamType(c, procKind, genericParams, typ, paramName, info, anonFlag)
+  #proc liftingWalk(paramType: PType, anon = false): PType =
+
+  var paramTypId = if not anon and paramType.sym != nil: paramType.sym.name
+                   else: nil
+
+  template addImplicitGeneric(e: expr): expr =
+    addImplicitGenericImpl(e, paramTypId)
+
+  case paramType.kind:
+  of tyExpr:
+    if paramType.sonsLen == 0:
+      # proc(a, b: expr)
+      # no constraints, treat like generic param
+      result = addImplicitGeneric(newTypeS(tyGenericParam, c))
+    else:
+      # proc(a: expr{string}, b: expr{nkLambda})
+      # overload on compile time values and AST trees
+      result = addImplicitGeneric(c.newTypeWithSons(tyExpr, paramType.sons))
+  of tyTypeDesc:
+    if tfUnresolved notin paramType.flags:
+      result = addImplicitGeneric(c.newTypeWithSons(tyTypeDesc, paramType.sons))
+  of tyDistinct:
+    if paramType.sonsLen == 1:
+      # disable the bindOnce behavior for the type class
+      result = liftingWalk(paramType.sons[0], true)
+  of tySequence, tySet, tyArray, tyOpenArray:
+    # XXX: this is a bit strange, but proc(s: seq)
+    # produces tySequence(tyGenericParam, null).
+    # This also seems to be true when creating aliases
+    # like: type myseq = distinct seq.
+    # Maybe there is another better place to associate
+    # the seq type class with the seq identifier.
+    if paramType.lastSon == nil:
+      let typ = c.newTypeWithSons(tyTypeClass, @[newTypeS(paramType.kind, c)])
+      result = addImplicitGeneric(typ)
+    else:
+      for i in 0 .. <paramType.sons.len:
+        var lifted = liftingWalk(paramType.sons[i])
+        if lifted != nil:
+          paramType.sons[i] = lifted
+          result = paramType
+  of tyGenericBody:
+    # type Foo[T] = object
+    # proc x(a: Foo, b: Foo) 
+    var typ = newTypeS(tyTypeClass, c)
+    typ.addSonSkipIntLit(paramType)
+    result = addImplicitGeneric(typ)
+  of tyGenericInst:
+    for i in 1 .. (paramType.sons.len - 2):
+      var lifted = liftingWalk(paramType.sons[i])
+      if lifted != nil:
+        paramType.sons[i] = lifted
+        result = paramType
+    
+    if result != nil:
+      result.kind = tyGenericInvokation
+      result.sons.setLen(result.sons.len - 1)
+  of tyTypeClass:
+    result = addImplicitGeneric(copyType(paramType, getCurrOwner(), false))
+  else: nil
+
+  # result = liftingWalk(paramType)
+
 proc semParamType(c: PContext, n: PNode, constraint: var PNode): PType =
   if n.kind == nkCurlyExpr:
     result = semTypeNode(c, n.sons[0], nil)
@@ -686,7 +702,6 @@ proc semProcTypeNode(c: PContext, n, genericParams: PNode,
       length = sonsLen(a)
       hasType = a.sons[length-2].kind != nkEmpty
       hasDefault = a.sons[length-1].kind != nkEmpty
-
     if hasType:
       typ = semParamType(c, a.sons[length-2], constraint)
 
@@ -707,8 +722,9 @@ proc semProcTypeNode(c: PContext, n, genericParams: PNode,
     if skipTypes(typ, {tyGenericInst}).kind == tyEmpty: continue
     for j in countup(0, length-3): 
       var arg = newSymG(skParam, a.sons[j], c)
-      var finalType = liftParamType(c, kind, genericParams, typ,
+      let lifted = liftParamType(c, kind, genericParams, typ,
-                                    arg.name.s, arg.info).skipIntLit
+                                 arg.name.s, arg.info)
+      let finalType = if lifted != nil: lifted else: typ.skipIntLit
       arg.typ = finalType
       arg.position = counter
       arg.constraint = constraint
@@ -726,7 +742,9 @@ proc semProcTypeNode(c: PContext, n, genericParams: PNode,
     # compiler only checks for 'nil':
     if skipTypes(r, {tyGenericInst}).kind != tyEmpty:
       if r.sym == nil or sfAnon notin r.sym.flags:
-        r = liftParamType(c, kind, genericParams, r, "result", n.sons[0].info)
+        let lifted = liftParamType(c, kind, genericParams, r, "result",
+                                   n.sons[0].info)
+        if lifted != nil: r = lifted
         r.flags.incl tfRetType
       result.sons[0] = skipIntLit(r)
       res.typ = result.sons[0]
@@ -1012,6 +1030,7 @@ proc semGenericParamList(c: PContext, n: PNode, father: PType = nil): PNode =
   if n.kind != nkGenericParams: 
     illFormedAst(n)
     return
+  var position = 0
   for i in countup(0, sonsLen(n)-1): 
     var a = n.sons[i]
     if a.kind != nkIdentDefs: illFormedAst(n)
@@ -1049,6 +1068,7 @@ proc semGenericParamList(c: PContext, n: PNode, father: PType = nil): PNode =
       if def.kind != nkEmpty: s.ast = def
       s.typ.sym = s
       if father != nil: addSonSkipIntLit(father, s.typ)
-      s.position = i
+      s.position = position
+      inc position
       addSon(result, newSymNode(s))
       if sfGenSym notin s.flags: addDecl(c, s)

compiler/types.nim

@@ -982,6 +982,8 @@ proc matchTypeClass*(bindings: var TIdTable, typeClass, t: PType): bool =
   # if the loop finished without returning, either all constraints matched
   # or none of them matched.
   result = if tfAny in typeClass.flags: false else: true
+  if result == true:
+    IdTablePut(bindings, typeClass, t)
 
 proc matchTypeClass*(typeClass, typ: PType): bool =
   var bindings: TIdTable