fixes #368

compiler/evals.nim

@@ -1495,11 +1495,13 @@ proc evalMacroCall(c: PEvalContext, n, nOrig: PNode, sym: PSym): PNode =
   c.callsite = nOrig
   var s = newStackFrame()
   s.call = n
-  setlen(s.params, n.len)
+  var L = n.safeLen
+  if L == 0: L = 1
+  setlen(s.params, L)
   # return value:
   s.params[0] = newNodeIT(nkNilLit, n.info, sym.typ.sons[0])
   # setup parameters:
-  for i in 1 .. < n.len: s.params[i] = setupMacroParam(n.sons[i])
+  for i in 1 .. < L: s.params[i] = setupMacroParam(n.sons[i])
   pushStackFrame(c, s)
   discard eval(c, sym.getBody)
   result = s.params[0]

tests/compile/tmacro2.nim

@@ -0,0 +1,59 @@
+import macros,json
+
+var decls{.compileTime.}: seq[PNimrodNode] = @[]
+var impls{.compileTime.}: seq[PNimrodNode] = @[]
+
+macro importImpl_forward(name, returns): stmt {.immediate.} =
+  result = newNimNode(nnkEmpty)
+  var func_name = newNimNode(nnkAccQuoted)
+  func_name.add newIdentNode("import")
+  func_name.add name
+
+  var res = newNimNode(nnkProcDef)
+  res.add newNimNode(nnkPostfix)
+  res[0].add newIdentNode("*")
+  res[0].add func_name
+  res.add newNimNode(nnkEmpty)
+  res.add newNimNode(nnkEmpty)
+  res.add newNimNode(nnkFormalParams)
+  res[3].add returns
+  var p1 = newNimNode(nnkIdentDefs)
+  p1.add newIdentNode("dat")
+  p1.add newIdentNOde("PJsonNode")
+  p1.add newNimNode(nnkEmpty)
+  res[3].add p1
+  var p2 = newNimNode(nnkIdentDefs)
+  p2.add newIdentNode("errors")
+  p2.add newNimNode(nnkVarTy)
+  p2.add newNimNode(nnkEmpty)
+  p2[1].add newNimNOde(nnkBracketExpr)
+  p2[1][0].add newIdentNode("seq")
+  p2[1][0].add newIdentNode("string")
+  res[3].add p2
+
+  res.add newNimNode(nnkEmpty)
+  res.add newNimNode(nnkEmpty)
+  res.add newNimNode(nnkEmpty)
+
+  decls.add res
+  echo(repr(res))
+
+macro importImpl(name, returns: expr, body: stmt): stmt {.immediate.} = 
+  #var res = getAST(importImpl_forward(name, returns))
+  discard getAST(importImpl_forward(name, returns))
+  var res = copyNimTree(decls[decls.high])
+  res[6] = body
+  echo repr(res)
+  impls.add res
+
+macro okayy:stmt =
+  result = newNimNode(nnkStmtList)
+  for node in decls: result.add node
+  for node in impls: result.add node
+
+importimpl(Item, int):
+  echo 42
+importImpl(Foo, int16):
+  echo 77
+
+okayy