Problem with residue_field

[mkirschm]

The following example

P, x = polynomial_ring(ZZ)
K, a = number_field(x^5 + x^3 - x^2 - x - 1)
M = Order(K, [1, 121*a, a^2 - 17*a, a^3 - 72*a, a^4 - 76*a])
P = prime_ideals_over(M, 11)

for i in 1:1000
  for p in P
    k, h = residue_field(M, p, false)
    tmp = preimage(h, Hecke.primitive_element(k))
  end
end

fails with

ERROR: Not a valid order element
Stacktrace:
 [1] error(s::String)
   @ Base ./error.jl:35
 [2] assure_has_coord
   @ ~/.julia/dev/Hecke/src/NumFieldOrd/NfOrd/Elem.jl:186 [inlined]
 [3] coordinates(a::NfOrdElem; copy::Bool)
   @ Hecke ~/.julia/dev/Hecke/src/NumFieldOrd/NfOrd/Elem.jl:205
 [4] coordinates
   @ ~/.julia/dev/Hecke/src/NumFieldOrd/NfOrd/Elem.jl:204 [inlined]
 [5] (::Hecke.var"#_image#316"{FqFieldElem, Vector{FqFieldElem}, Int64, FqField})(x::NfOrdElem)
   @ Hecke ~/.julia/dev/Hecke/src/Map/NfOrd.jl:590
 [6] (::Hecke.var"#_preimage#317"{NfOrd, Hecke.var"#_image#316"{FqFieldElem, Vector{FqFieldElem}, Int64, FqField}, Vector{nf_elem}, Int64, ZZRingElem})(y::FqFieldElem)
   @ Hecke ~/.julia/dev/Hecke/src/Map/NfOrd.jl:608
 [7] preimage(f::Hecke.NfOrdToFqFieldMor, x::FqFieldElem)
   @ Hecke ~/.julia/dev/Hecke/src/Map/NfOrd.jl:654
 [8] top-level scope
   @ ./REPL[6]:4

[thofma]

Thanks. I will open a PR with a fix soonish.