# @generated function not picking up all the methods
**URL:** https://discourse.julialang.org/t/generated-function-not-picking-up-all-the-methods/32318
**Category:** General Usage
**Created:** [December 16, 2019, 5:05am UTC](https://discourse.julialang.org/t/generated-function-not-picking-up-all-the-methods/32318 "2019-12-16T05:05:15Z")
**Posts on this page:** 3
**Page:** 1
### Author:  [@fjarri](https://discourse.julialang.org/u/fjarri)
#### Post date: [December 16, 2019, 5:05am UTC](https://discourse.julialang.org/t/generated-function-not-picking-up-all-the-methods/32318/1 "2019-12-16T05:05:15Z")
The code:
```julia
module Test
func(x) = false
@generated function test(x::T) where T
if Base.invokelatest(func, T)
:( 1 )
else
:( 0 )
end
end
function test2(x::T) where T
if func(T)
1
else
0
end
end
end
Test.func(::Type{UInt64}) = true
println(Test.test(UInt64(1))) # outputs 0
println(Test.test2(UInt64(1))) # outputs 1
```
Basically, the underlying problem is that there’s a function `test` that needs to do a heavy computation, but only once for type `T`. In the process it calls `func` for type `T`, which also needs to do a heavy computation, but for some types `T` the user can provide a precomputed result.
As seen from the code, the `@generated` function does not pick up the user-defined method of `func` even with `invokelatest()`, while a non-generated `test2()` has no problem with it. Moreover, if one prints `methods(func)` in `test()`, it shows the user-defined method, but it still does not get called. Is it a bug or an intended behavior?
---
### Author:  [@Keno](https://discourse.julialang.org/u/Keno)
#### Post date: [December 16, 2019, 6:51am UTC](https://discourse.julialang.org/t/generated-function-not-picking-up-all-the-methods/32318/2 "2019-12-16T06:51:41Z")
It’s intended - generated functions always execute in the world age that they are defined in. The reason behind this is that we don’t track backedges to generated functions, so we wouldn’t know when changes to the global state would affect the output of the generated function and without being guaranteed that the output of the generated function doesn’t change the system would be unsound and could potentially cause crashes. Imagine one version of the function returns a pointer and the next an integer - if we didn’t guarantee that the output doesn’t change, we’d now interpret the integer as a pointer and bad things would happen.
---
### Author:  [@fjarri](https://discourse.julialang.org/u/fjarri)
#### Post date: [December 16, 2019, 6:56am UTC](https://discourse.julialang.org/t/generated-function-not-picking-up-all-the-methods/32318/3 "2019-12-16T06:56:13Z")
I see, thanks. I guess I’ll have to work around that.