fix: fix variable discovery in arrays of Num passed to callable params

Author: AayushSabharwal

src/utils.jl

@@ -387,15 +387,21 @@ function vars!(vars, O; op = Differential)
             f = getcalledparameter(O)
             push!(vars, f)
             for arg in arguments(O)
-                vars!(vars, arg; op)
+                if symbolic_type(arg) == NotSymbolic() && arg isa AbstractArray
+                    for el in arg
+                        vars!(vars, unwrap(el); op)
+                    end
+                else
+                    vars!(vars, arg; op)
+                end
             end
             return vars
         end
         return push!(vars, O)
     end
     if symbolic_type(O) == NotSymbolic() && O isa AbstractArray
         for arg in O
-            vars!(vars, arg; op)
+            vars!(vars, unwrap(arg); op)
         end
         return vars
     end

test/odesystem.jl

@@ -1442,3 +1442,11 @@ end
         end
     end
 end
+
+@testset "Variable discovery in arrays of `Num` inside callable symbolic" begin
+    @variables x(t) y(t)
+    @parameters foo(::AbstractVector)
+    sys = @test_nowarn ODESystem(D(x) ~ foo([x, 2y]), t; name = :sys)
+    @test length(unknowns(sys)) == 2
+    @test any(isequal(y), unknowns(sys))
+end