importcpp generates @ literally

[vegansk]

This was a working example of FFI with Qt. And now it is broken on devel. config.nims:

mode = ScriptMode.Verbose

task build, "Build the app":
  let cflags = staticExec"pkg-config --cflags Qt5Core" & "-fPIC"
  let libs = staticExec"pkg-config --libs Qt5Core"
  switch "passC", cflags
  switch "passL", libs
  setCommand "cpp", "qtapp"

qtapp.nim

import unittest

type
  QByteArray {.importcpp: "QByteArray", header: "QByteArray".} = object
  QString {.importcpp: "QString", header: "QString".} = object

####################################################################################################
# QByteArray
proc initQByteArray(): QByteArray {.importcpp: "QByteArray(@)", constructor.}
proc initQByteArray(data: cstring, size: cint = -1): QByteArray {.importcpp: "QByteArray(@)", constructor.}
proc constData(this: QByteArray): cstring {.importcpp: "constData".}

####################################################################################################
# QString
proc initQString(): QString {.importcpp: "QString(@)", constructor.}
proc initQString(s: cstring = ""): QString {.importcpp: "QString(@)", constructor.}
proc initQString(ba: QByteArray): QString {.importcpp: "QString(@)", constructor.}
proc toUtf8(this: QString): QByteArray {.importcpp: "toUtf8".}
proc fromUtf8(s: cstring): QString {.importcpp: "QString::fromUtf8(@)".}
proc `$`(s: QString): string = $s.toUtf8.constData

suite "Qt tests":

  test "QString":
    let s = "Hello, world!".initQString
    echo s
    check: $s == "Hello, world!"

The error is:

Error: execution of an external compiler program 'g++ -c  -I/usr/include/qt5/QtCore -I/usr/include/qt5  -fPIC -w -w -fpermissive  -I/home/vega/work/nim/Nim/lib -o /home/vega/work/nim/nimtests/ffi/qt/nimcache/nimtests_qtapp.o /home/vega/work/nim/nimtests/ffi/qt/nimcache/nimtests_qtapp.cpp' failed with exit code: 256

In file included from /home/vega/work/nim/nimtests/ffi/qt/nimcache/nimtests_qtapp.cpp:9:0:
/home/vega/work/nim/nimtests/ffi/qt/nimcache/nimtests_qtapp.cpp:200:28: error: stray ‘@’ in program
 N_NIMCALL(QString, QString(@))(NCSTRING s);
                            ^
/home/vega/work/nim/Nim/lib/nimbase.h:215:44: note: in definition of macro ‘N_NIMCALL’
 #  define N_NIMCALL(rettype, name) rettype name /* no modifier */
                                            ^
/home/vega/work/nim/nimtests/ffi/qt/nimcache/nimtests_qtapp.cpp:200:42: error: ‘QString’ declared as function returning a function
 N_NIMCALL(QString, QString(@))(NCSTRING s);
                                          ^

[vegansk]

The problem disappears if I add nodecl or header pragma