fix vararg type prediction prior v1.7

Author: KDr2

src/tapedfunction.jl

@@ -141,7 +141,14 @@ function run_and_record!(tape::Tape, f, args...)
         # detect if there is an vararg for f
         if length(v_args) == 1
             m = which(f, typeof(real_args))
-            if !isa(m.sig.types[end], Core.TypeofVararg)
+            no_vararg = @static if VERSION >= v"1.7"
+                (m.sig <: Tuple) && hasproperty(m.sig, :types) &&
+                    !isa(m.sig.types[end], Core.TypeofVararg)
+            else
+                (m.sig <: Tuple) && hasproperty(m.sig, :types) &&
+                    !(m.sig.types[end] <: Vararg{Any})
+            end
+            if no_vararg
                 v_args = v_args[1]
             end
         end