Fix for old julias

Author: lgoettgens

src/utils.jl

@@ -67,6 +67,10 @@ else
     type_parameter(@nospecialize t) = only(t.parameters)
 end
 
+@static if !isdefined(Base, :only)
+    only(iter) = first(iter)
+end
+
 function is_kwcall(signature::Type)
     @static if VERSION < v"1.9"
         signature = Base.unwrap_unionall(signature)::DataType

test/test_exclude.jl

@@ -11,7 +11,7 @@ using Aqua: getexclude, normalize_exclude, normalize_exclude_obj, normalize_and_
 @assert rootmodule(Broadcast.Broadcasted) === Base
 
 @testset "roundtrip" begin
-    @testset for x in Any[
+    for x in Any[
         foldl
         Some
         Tuple