fix the filtering of void params in procs' signatures

compiler/semtypinst.nim

@@ -189,7 +189,6 @@ proc handleGenericInvokation(cl: var TReplTypeVars, t: PType): PType =
   newbody.flags = newbody.flags + t.flags + body.flags
   result.flags = result.flags + newbody.flags
   newbody.callConv = body.callConv
-  newbody.n = replaceTypeVarsN(cl, lastSon(body).n)
   # This type may be a generic alias and we want to resolve it here.
   # One step is enough, because the recursive nature of
   # handleGenericInvokation will handle the alias-to-alias-to-alias case
@@ -197,6 +196,25 @@ proc handleGenericInvokation(cl: var TReplTypeVars, t: PType): PType =
   rawAddSon(result, newbody)
   checkPartialConstructedType(cl.info, newbody)
 
+proc normalizeProcType(t: PType) =
+  if t.sons[0] != nil and t.sons[0].kind == tyEmpty:
+    t.sons[0] = nil
+  
+  for i in 1 .. <t.sonsLen:
+    if t.sons[i].kind == tyEmpty:
+      # the nested loops are here in order to avoid
+      # touching any memory and callign setLen unless
+      # it's really necessary
+      var pos = i
+      for j in i+1 .. <t.sonsLen:
+        if t.sons[j].kind != tyEmpty:
+          t.sons[pos] = t.sons[j]
+          t.n.sons[pos] = t.n.sons[j]
+          inc pos
+      setLen t.sons, pos
+      setLen t.n.sons, pos
+      return
+
 proc replaceTypeVarsT*(cl: var TReplTypeVars, t: PType): PType = 
   result = t
   if t == nil: return
@@ -244,9 +262,7 @@ proc replaceTypeVarsT*(cl: var TReplTypeVars, t: PType): PType =
       result.n = replaceTypeVarsN(cl, result.n)
       if result.kind in GenericTypes:
         localError(cl.info, errCannotInstantiateX, typeToString(t, preferName))
-      if result.kind == tyProc and result.sons[0] != nil:
+      if result.kind == tyProc: normalizeProcType(result)
-        if result.sons[0].kind == tyEmpty:
-          result.sons[0] = nil
 
 proc generateTypeInstance*(p: PContext, pt: TIdTable, info: TLineInfo,
                            t: PType): PType =

tests/reject/mbind4.nim

@@ -1,9 +0,0 @@
-# Module A
-var 
-  lastId = 0
-
-template genId*: expr =
-  inc(lastId)
-  lastId
-
-

tests/reject/tbind4.nim

@@ -1,13 +0,0 @@
-discard """
-  file: "mbind4.nim"
-  line: 6
-  errormsg: "undeclared identifier: \'lastId\'"
-"""
-# Module B
-import mbind4
-
-echo genId()
-
-
-
-

tests/reject/teffects1.nim

@@ -1,5 +1,5 @@
 discard """
-  line: 1840
+  line: 1847
   file: "system.nim"
   errormsg: "can raise an unlisted exception: ref EIO"
 """