Missing error messages for usage of PNimrodNode in non-compiletime code

[ddlsmurf]

This compiles:
import macros
proc makeMacro: PObject =
result = nil
var p = makeMacro
This doesn't:
import macros
proc makeMacro: PNimrodNode =
result = nil
var p = makeMacro

Dump:
Hint: used config file '/Users/eric/Documents/Private/Code/nimrod/Compiler/Nimrod/config/nimrod.cfg' [Conf]
Hint: system [Processing]
Hint: test [Processing]
Hint: macros [Processing]
Hint: strutils [Processing]
Hint: parseutils [Processing]
Error: internal error: mapType
Traceback (most recent call last)
nimrod.nim(85)(?): nimrod
nimrod.nim(69)(?): HandleCmdLine
main.nim(194)(?): MainCommand
main.nim(120)(?): CommandCompileToC
main.nim(95)(?): CompileProject
main.nim(90)(?): CompileModule
passes.nim(134)(?): processModule
passes.nim(98)(?): processTopLevelStmt
cgen.nim(917)(?): myProcess
ccgstmts.nim(719)(?): genStmts
cgen.nim(677)(?): genProc
cgen.nim(659)(?): genProcNoForward
cgen.nim(654)(?): genProcPrototype
ccgtypes.nim(523)(?): genProcHeader
ccgtypes.nim(181)(?): genProcParams
ccgtypes.nim(122)(?): isInvalidReturnType
ccgtypes.nim(105)(?): mapType
msgs.nim(487)(?): InternalError
msgs.nim(457)(?): rawMessage
msgs.nim(454)(?): rawMessage
msgs.nim(410)(?): handleError
Error: unhandled exception: [Assertion failure] file: rod/msgs.nim line: 410
[EAssertionFailed]