Fix is_rational (#1161)

thofma · Jul 8, 2023 · c7ab8cd · c7ab8cd · thofma · Jul 8, 2023
1 parent 6d5e988
commit c7ab8cd
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Showing 3 changed files with 9 additions and 2 deletions.
diff --git a/Project.toml b/Project.toml
@@ -1,6 +1,6 @@
 name = "Hecke"
 uuid = "3e1990a7-5d81-5526-99ce-9ba3ff248f21"
-version = "0.19.4"
+version = "0.19.5"
 
 [deps]
 AbstractAlgebra = "c3fe647b-3220-5bb0-a1ea-a7954cac585d"

diff --git a/src/NumField/NfRel/NfRel.jl b/src/NumField/NfRel/NfRel.jl
@@ -496,7 +496,7 @@ function is_rational(a::NfRelElem)
       return false
     end
   end
-  return true
+  return is_rational(coeff(a, 0))
 end
 
 ################################################################################

diff --git a/test/NfRel/NfRel.jl b/test/NfRel/NfRel.jl
@@ -123,5 +123,12 @@
     @test is_rational(2*b^0)
     @test is_rational(2*o^0)
     @test !is_rational(o)
+
+    Qx, x = QQ["x"]
+    K, r = number_field(x^3 - 3x^2 - 4x + 8, "r")
+    Ky, y = K["y"]
+    L, = number_field(y^2 - (2-r^2)//2, "q")
+    @test !(@inferred is_rational(L(r)))
+    @test_throws ErrorException QQ(L(r))
   end
 end