Revert "fix tforwardgeneric"

This reverts commit d82a032566.

compiler/ast.nim

@@ -1285,9 +1285,9 @@ proc getStrOrChar*(a: PNode): string =
 proc isGenericRoutine*(s: PSym): bool = 
   case s.kind
   of skProc, skTemplate, skMacro, skIterator, skMethod, skConverter:
-    result = sfFromGeneric in s.flags
+    result = s.ast != nil and s.ast[genericParamsPos].kind != nkEmpty
   else: nil
-
+  
 proc isRoutine*(s: PSym): bool {.inline.} =
   result = s.kind in {skProc, skTemplate, skMacro, skIterator, skMethod,
                       skConverter}

compiler/lambdalifting.nim

@@ -288,9 +288,6 @@ proc interestingVar(s: PSym): bool {.inline.} =
 proc semCaptureSym*(s, owner: PSym) =
   if interestingVar(s) and owner.id != s.owner.id and s.kind != skResult:
     if owner.typ != nil and not isGenericRoutine(owner):
-      # XXX: is this really safe?
-      # if we capture a var from another generic routine,
-      # it won't be consider captured.
       owner.typ.callConv = ccClosure
     #echo "semCaptureSym ", owner.name.s, owner.id, " ", s.name.s, s.id
     # since the analysis is not entirely correct, we don't set 'tfCapturesEnv'

compiler/seminst.nim

@@ -125,6 +125,8 @@ proc fixupInstantiatedSymbols(c: PContext, s: PSym) =
       openScope(c)
       var n = oldPrc.ast
       n.sons[bodyPos] = copyTree(s.getBody)
+      if n.sons[paramsPos].kind != nkEmpty: 
+        addParams(c, oldPrc.typ.n, oldPrc.kind)
       instantiateBody(c, n, oldPrc)
       closeScope(c)
       popInfoContext()