# Why does the soft scope warning not appear in a nested loop?
**URL:** https://discourse.julialang.org/t/why-does-the-soft-scope-warning-not-appear-in-a-nested-loop/72646
**Category:** New to Julia
**Tags:** question
**Created:** [December 6, 2021, 11:08am UTC](https://discourse.julialang.org/t/why-does-the-soft-scope-warning-not-appear-in-a-nested-loop/72646 "2021-12-06T11:08:31Z")
**Posts on this page:** 8
**Page:** 1
### Author:  [@iago-lito](https://discourse.julialang.org/u/iago-lito)
#### Post date: [December 6, 2021, 11:08am UTC](https://discourse.julialang.org/t/why-does-the-soft-scope-warning-not-appear-in-a-nested-loop/72646/1 "2021-12-06T11:08:31Z")
Hello, I am confused because this basic loop yields a warning:
```julia
i = 5
for j in 1:5
# ...
i = "other_value"
# ...
end
```
```julia
┌ Warning: Assignment to `i` in soft scope is ambiguous because a global variable by the same name exists: `i` will be treated as a new local. Disambiguate by using `local i` to suppress this warning or `global i` to assign to the existing global variable.
└ @ main.jl:4
```
… which I understand. But the following yields no warning:
```julia
for i in 1:5
# ...
for j in 1:5
# ...
i = "other_value"
# ...
end
end
```
… and I’ve just struggle hard to find a bug because I inadvertently wrote something like this X) Is there a reason for the warning to exist in the former case, but not the latter?
---
### Author:  [@lmiq](https://discourse.julialang.org/u/lmiq)
#### Post date: [December 6, 2021, 11:17am UTC](https://discourse.julialang.org/t/why-does-the-soft-scope-warning-not-appear-in-a-nested-loop/72646/2 "2021-12-06T11:17:05Z")
In that case `i` belongs to the scope of the outer loop (thus a local scope).
The problem with the first one is that having a `global i` has a whole set of implications for type inference and performance (because `i` is global), and for that it has to be deal with differently.
---
### Author:  [@iago-lito](https://discourse.julialang.org/u/iago-lito)
#### Post date: [December 6, 2021, 11:22am UTC](https://discourse.julialang.org/t/why-does-the-soft-scope-warning-not-appear-in-a-nested-loop/72646/3 "2021-12-06T11:22:16Z")
Oh, okay, so there is something really special with the global scope, and this is what this warning is about. It is not just about “i belongs to the outer scope”. I understand now, thank you 🙂
---
### Author:  [@lmiq](https://discourse.julialang.org/u/lmiq)
#### Post date: [December 6, 2021, 11:26am UTC](https://discourse.julialang.org/t/why-does-the-soft-scope-warning-not-appear-in-a-nested-loop/72646/4 "2021-12-06T11:26:18Z")
Yes, that is why it is highly recommended to avoid the use of global variables. If you wrap everything in a function, or a `let` block, for example, which define their own scope, you won’t get those warnings either.
---
### Author:  [@iago-lito](https://discourse.julialang.org/u/iago-lito)
#### Post date: [December 6, 2021, 11:32am UTC](https://discourse.julialang.org/t/why-does-the-soft-scope-warning-not-appear-in-a-nested-loop/72646/5 "2021-12-06T11:32:16Z")
Well, in this case I would rather have had the warning instead of my error silently passing X)
---
### Author:  [@lmiq](https://discourse.julialang.org/u/lmiq)
#### Post date: [December 6, 2021, 11:49am UTC](https://discourse.julialang.org/t/why-does-the-soft-scope-warning-not-appear-in-a-nested-loop/72646/6 "2021-12-06T11:49:04Z")
Uhm… not sure if I understand. In that case there would be no “error”, the variable would be modified as intended:
```julia
julia> function f()
i = 1
for j in 1:2
i += 1
end
@show i
end
f (generic function with 1 method)
julia> f()
i = 3
3
julia> let
i = 1
for j in 1:2
i += 1
end
@show i
end
i = 3
3
```
Take a look at this: [Scope of loops · JuliaNotes.jl](https://m3g.github.io/JuliaNotes.jl/stable/loopscopes/)
---
### Author:  [@iago-lito](https://discourse.julialang.org/u/iago-lito)
#### Post date: [December 6, 2021, 11:58am UTC](https://discourse.julialang.org/t/why-does-the-soft-scope-warning-not-appear-in-a-nested-loop/72646/7 "2021-12-06T11:58:26Z")
Haha yes exactly, but my intent was _not_ to modify it 🙂 Picking `i` for the inner loop variable was an unfortunate name clash in my case. I’ll be more careful in the future ^ ^
---
### Author:  [@Nathan\_Boyer](https://discourse.julialang.org/u/Nathan_Boyer)
#### Post date: [December 6, 2021, 2:44pm UTC](https://discourse.julialang.org/t/why-does-the-soft-scope-warning-not-appear-in-a-nested-loop/72646/8 "2021-12-06T14:44:01Z")
You can always declare a variable as `local` to avoid it picking up any previous definitions:
```julia
function f()
i = 100
for j in 1:2
local i = 0
i = i + j
end
println(i)
end
julia> f()
100
```