assertion failure on uncertain ccall return type

[vtjnash]

julia> h{T}(::Type{T}) = ccall(:time, Ptr{T.parameters[1]}, (Int,), 0)+1
h (generic function with 1 method)

julia> h(Vector{Int})
Assertion failed: ("Don't know how to box this type" && false), function boxed, file ./cgutils.cpp, line 1522.

This happens because ccall returns an unboxed Ptr{Int}, but codegen doesn't quite know what to expect when it goes to box it (inference told it to expect Ptr{T})

[JeffBezanson]

Type inference can be made to handle this case, but we also need better (error) handling of cases like

h{T}(::Type{T}) = ccall(:time, Ptr{randbool()?Int8:Int16}, (Int,), 0)+1

[JeffBezanson]

I consider this fixed since the code now works; improving type inference here is a separate matter.