Resolve some JET warnings (#2812)

... about captured variables and runtime dispatch

experimental/GModule/Cohomology.jl

@@ -2179,36 +2179,35 @@ function compatible_pairs(C::GModule)
   autG = automorphism_group(G)
   autM = automorphism_group(M)
 
-  T, emb, pro = direct_product(autM, autG, morphisms = true)
+  D, emb, pro = direct_product(autM, autG, morphisms = true)
 
   function action_on_chain(g::GAPGroupElem, c::CoChain{2, S, T}) where {S, T}
-    al = pro[1](C[2](g))
-    ga = pro[2](C[2](g))
-    d = Dict(ab=> al(c((inv(ga)(ab[1]), inv(ga)(ab[2])))) for ab = keys(c.d))
-    return CoChain{2, S, T}(c.C, d)
+    al = pro[1](func(g)::elem_type(D))::elem_type(autM)
+    ga = pro[2](func(g)::elem_type(D))::elem_type(autG)
+    d = Dict{Tuple{S, S}, T}(ab=> al(c((inv(ga)(ab[1]), inv(ga)(ab[2])))) for ab = keys(c.d))
+    return CoChain{2, S, T}(C, d)
   end
 
   h = hom(G, autM, [autM(x) for x = C.ac])
   im = image(h)[1]
   ke = kernel(h)[1]
 
   if order(im) == 1
-    C = (T, x->x)
-    return T, action_on_chain
+    func = Base.identity
+    return D, action_on_chain
   end
 
   N, mN = normalizer(autM, im)
   S, mS = stabilizer(autG, ke, (x,y)->image(hom(y), x)[1])
 
   NS, em, pr = direct_product(N, S, morphisms = true)
   #from Holt/ Eick, ... Handbook of Computational Group Theory, P319
-  C = stabilizer(NS, h, (x, y) -> hom(G, autM,
+  S, func = stabilizer(NS, h, (x, y) -> hom(G, autM,
             [inv(pr[1](y))*x(inv(pr[2](y))(g))*pr[1](y) for g = gens(G)]))
-
   #the more direct naive (and slow) approach...
-  #C = sub(T, [t for t in preimage(pro[1], N)[1] if all(ag -> action(C, pro[2](t)(ag[2]), ag[1]) == pro[1](t)(action(C, ag[2], inv(pro[1](t))(ag[1]))), Iterators.product(gens(M), gens(G)))])
+  #C = sub(D, [t for t in preimage(pro[1], N)[1] if all(ag -> action(C, pro[2](t)(ag[2]), ag[1]) == pro[1](t)(action(C, ag[2], inv(pro[1](t))(ag[1]))), Iterators.product(gens(M), gens(G)))])
 
-  return C[1], action_on_chain
+  return S, action_on_chain
 end
 
 function split_extension(C::GModule)

experimental/QuadFormAndIsom/src/enumeration.jl

@@ -624,7 +624,10 @@ function splitting_of_prime_power(Lf::ZZLatWithIsom, p::Int, b::Int = 0)
   @req is_prime(p) "p must be a prime number"
   @req b in [0, 1] "b must be an integer equal to 0 or 1"
 
-  ok, e, q = is_prime_power_with_data(order_of_isometry(Lf))
+  ord = order_of_isometry(Lf)
+  @req ord isa Int "Order of isometry must be finite"
+
+  ok, e, q = is_prime_power_with_data(ord)
 
   @req ok || e == 0 "Order of isometry must be a prime power"
   @req p != q "Prime numbers must be distinct"

src/Groups/homomorphisms.jl

@@ -567,12 +567,11 @@ function isomorphism(::Type{T}, A::GrpAbFinGen) where T <: GAPGroup
        exponents = diagonal(rels(A))
        A2 = A
        A2_to_A = identity_map(A)
-       A_to_A2 = identity_map(A)
      else
        exponents = elementary_divisors(A)
        A2, A2_to_A = snf(A)
-       A_to_A2 = inv(A2_to_A)
      end
+     A_to_A2 = inv(A2_to_A)
      # the isomorphic gap group
      G = abelian_group(T, exponents)
      # `GAPWrap.GeneratorsOfGroup(G.X)` consists of independent elements
@@ -590,7 +589,7 @@ function isomorphism(::Type{T}, A::GrpAbFinGen) where T <: GAPGroup
        @assert length(Ggens) + length(filter(x -> x == 1, exponents)) ==
                length(exponents)
        o = one(G).X
-       newGgens = []
+       newGgens = Vector{GapObj}()
        pos = 1
        for i in 1:length(exponents)
          if exponents[i] == 1

src/Groups/matrices/FiniteFormOrthogonalGroup.jl

@@ -25,7 +25,6 @@
 function _mod_p_to_a_kernel(G::Union{zzModMatrix, ZZModMatrix}, a, p)
   n = ncols(G)
   R = base_ring(G)
-  E = identity_matrix(R, n)
   ind, val = Hecke._block_indices_vals(G, p)
   # add a virtual even block at the end
   push!(ind, n+1)
@@ -57,15 +56,15 @@ function _mod_p_to_a_kernel(G::Union{zzModMatrix, ZZModMatrix}, a, p)
       end
     end
     for h in gensk
-      g = deepcopy(E)
+      g = identity_matrix(R, n)
       g[i1:i2-1, i1:i2-1] = Ek + p^a*h*Gk_inv
       push!(gens, g)
     end
   end
   # generators below the block diagonal.
   for i in 1:n
     for j in 1:i
-      g = deepcopy(E)
+      g = identity_matrix(R, n)
       g[i,j] = p^a
       flag = true
       for k in 1:(length(ind)-1)
@@ -184,15 +183,14 @@ function _orthogonal_gens_bilinear(G::Union{ZZModMatrix, zzModMatrix})
     # but we obtain several possible lifts
     gens_1 = _gens_af(G[1:end-2,1:end-2], 2)
     gens_1 = [diagonal_matrix(g, identity_matrix(R, 2)) for g in gens_1]
-    E = identity_matrix(R, r)
     for i in 1:r-2
-      g = deepcopy(E)
+      g = identity_matrix(R, r)
       g[i, r-1] = 1
       g[i, r] = 1
       g[r-1:end, 1:r-1] = transpose(g[1:r-1, r-1:end]) * G[1:r-1, 1:r-1]
       push!(gens_1, g)
     end
-    g = deepcopy(E)
+    g = identity_matrix(R, r)
     g[end-1:end, end-1:end] = matrix(R, 2, 2, [0, 1, 1, 0])
     push!(gens_1, g)
   else
@@ -443,7 +441,6 @@ end
 function _gens_mod_p(G::Union{ZZModMatrix, zzModMatrix}, p)
   n = ncols(G)
   R = base_ring(G)
-  E = identity_matrix(R, n)
   indices, valuations = Hecke._block_indices_vals(G, p)
   push!(indices, n+1)
   gens1 = typeof(G)[]
@@ -453,15 +450,15 @@ function _gens_mod_p(G::Union{ZZModMatrix, zzModMatrix}, p)
     Gi = divexact(G[i1:i2, i1:i2], R(p)^valuations[k])
     gens_homog = _orthogonal_grp_gens_odd(Gi, p)
     for f in gens_homog
-      g = deepcopy(E)
+      g = identity_matrix(R, n)
       g[i1:i2, i1:i2] = f
       push!(gens1, g)
     end
   end
   # generators below the block diagonal.
   for i in 1:n
     for j in 1:i-1
-      g = deepcopy(E)
+      g = identity_matrix(R, n)
       g[i,j] = 1
       flag = true
       for k in 1:(length(indices)-1)
@@ -494,7 +491,6 @@ end
 function _gens_mod_2(G::Union{ZZModMatrix, zzModMatrix})
     n = ncols(G)
     R = base_ring(G)
-    E = identity_matrix(R, n)
     p = ZZ(2)
     ind0, val0 = Hecke._block_indices_vals(G, 2)
     par0 = Int[]
@@ -548,13 +544,13 @@ function _gens_mod_2(G::Union{ZZModMatrix, zzModMatrix})
         end
 
         for h in gens_k
-            g = deepcopy(E)
+            g = identity_matrix(R, n)
             g[i1:i3,i1:i3] = h
             push!(gens, g)
         end
     end
     # a change in convention
-    trafo = deepcopy(E)
+    trafo = identity_matrix(R, n)
     for k in 2:length(ind)-1
         if par[k] == 1 && mod(ind[k][2]-ind[k][1],2) == 1
            i = ind[k][2]
@@ -585,19 +581,18 @@ function _gens_pair(G::Union{ZZModMatrix, zzModMatrix}, k, on_second)
   G1 = G[1:k,1:k]  # 2^1 - modular
   G1inv = inv(divexact(G1, 2))
   G2 = G[k+1:end,k+1:end]  # 2^0 - modular
-  E = identity_matrix(R, n)
   if on_second
     for f in _orthogonal_gens_bilinear(G2)
       a = diagonal(divexact(f*G2*transpose(f)-G2, 2))
-      g = deepcopy(E)
+      g = identity_matrix(R, n)
       g[k+1:end, k+1:end] = f
       g[k+1:end, k] = a
       push!(gen, g)
     end
   else
     for f in _orthogonal_gens_bilinear(divexact(G1, 2))
       a = [divexact(x,2) for x in diagonal(f*G1*transpose(f) - G1)]
-      g = deepcopy(E)
+      g = identity_matrix(R, n)
       g[1:k,1:k] = f
       g[1:k,end] = a
       g[k+1:end,1:k] = - G2 * transpose(divexact(g[1:k,k+1:end],2)) * transpose(inv(f)) * G1inv
@@ -614,15 +609,14 @@ end
 function _ker_gens(G::Union{ZZModMatrix, zzModMatrix}, i1, i2, parity)
   n = nrows(G)
   R = base_ring(G)
-  E = identity_matrix(R, n)
   gens = typeof(G)[]
   e = n - 1
   if parity[3]==1 && mod(n - i2, 2)==0
     e = n - 2
   end
   for i in i2+1:n
     for j in 1:i2
-      g = deepcopy(E)
+      g = identity_matrix(R, n)
       if parity == [0,0,0] || parity == [1,0,0]
         g[i,j] = 1
       elseif parity == [0,0,1]

src/Groups/spinor_norms.jl

@@ -322,7 +322,7 @@ function det_spin_homomorphism(L::ZZLat; signed=false)
   T = discriminant_group(L)
   Oq = orthogonal_group(T)
   S = prime_divisors(2 * order(domain(Oq)))
-  A, diagonal, proj,inj,det_hom = _det_spin_group(S, infinity=false)
+  A, diagonal, _, inj, det_hom = _det_spin_group(S, infinity=false)
 
   # \Sigma^\#(L)
   # This is the the image of K under `(det, spin)` where `K` is the kernel