# Parser deprecation warning
**URL:** https://discourse.julialang.org/t/parser-deprecation-warning/45416
**Category:** Internals & Design
**Created:** [August 23, 2020, 2:02pm UTC](https://discourse.julialang.org/t/parser-deprecation-warning/45416 "2020-08-23T14:02:06Z")
**Posts on this page:** 5
**Page:** 1
### Author:  [@BioTurboNick](https://discourse.julialang.org/u/BioTurboNick)
#### Post date: [August 23, 2020, 2:02pm UTC](https://discourse.julialang.org/t/parser-deprecation-warning/45416/1 "2020-08-23T14:02:07Z")
I’m trying to implement a deprecation warning in the parser. I think I’ve found the function to do it with, `parser-depwarn`. But it doesn’t appear to emit anything to the REPL. If I replace it with an `error` call, the error triggers and shows in the REPL, so the code path must be used.
Is there a different function I should be using? Or are warnings turned off in a default build?
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### Author:  [@StefanKarpinski](https://discourse.julialang.org/u/StefanKarpinski)
#### Post date: [August 23, 2020, 2:14pm UTC](https://discourse.julialang.org/t/parser-deprecation-warning/45416/2 "2020-08-23T14:14:44Z")
@jeff.bezanson is the expert on this. We haven’t had any syntax depreciations in a while but you can look at the 0.7 code to see what the correct usage was.
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### Author:  [@BioTurboNick](https://discourse.julialang.org/u/BioTurboNick)
#### Post date: [August 23, 2020, 2:53pm UTC](https://discourse.julialang.org/t/parser-deprecation-warning/45416/3 "2020-08-23T14:53:35Z")
Oh duh, it was right in front of me in jlfrontend.scm. Just needed to tune my eyeballs.
And ahhh, looks like it was turned off by default 5 months ago, to make packages with deprecation warnings run without warnings: [https://github.com/JuliaLang/julia/pull/35362](https://github.com/JuliaLang/julia/pull/35362)
That seems potentially problematic?
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### Author:  [@BioTurboNick](https://discourse.julialang.org/u/BioTurboNick)
#### Post date: [August 23, 2020, 3:32pm UTC](https://discourse.julialang.org/t/parser-deprecation-warning/45416/4 "2020-08-23T15:32:57Z")
The suggestion was that devs just had to run with --depwarn=yes, but I couldn’t find that at all by searching the documentation.
Is it possible to toggle them on/off within the REPL? And why can’t the end user just turn them off if it is a problem for their specific use, rather than create a silent failure mode for developers?
Or perhaps when `depwarn=no`, Julia could just track that there was at least one deprecation warning, emit that fact to let the user know they can turn on `depwarn`s to see the details, but be silent about the rest during that process’s lifetime?
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### Author:  [@BioTurboNick](https://discourse.julialang.org/u/BioTurboNick)
#### Post date: [August 23, 2020, 4:05pm UTC](https://discourse.julialang.org/t/parser-deprecation-warning/45416/5 "2020-08-23T16:05:07Z")
Created an issue for this: [https://github.com/JuliaLang/julia/issues/37164](https://github.com/JuliaLang/julia/issues/37164)