# GNAT 15: (style) redundant parentheses \[-gnatyz\]
**URL:** https://forum.ada-lang.io/t/gnat-15-style-redundant-parentheses-gnatyz/4395
**Category:** Help
**Tags:** gnat
**Created:** [May 6, 2026, 2:57pm UTC](https://forum.ada-lang.io/t/gnat-15-style-redundant-parentheses-gnatyz/4395 "2026-05-06T14:57:22Z")
**Posts on this page:** 11
**Page:** 1
### Author:  [@saper](https://forum.ada-lang.io/u/saper)
#### Post date: [May 6, 2026, 2:57pm UTC](https://forum.ada-lang.io/t/gnat-15-style-redundant-parentheses-gnatyz/4395/1 "2026-05-06T14:57:23Z")
asn1scc generated code includes the [adasn1rtl.ads](https://github.com/esa/asn1scc/blob/bf364aac88b69ac6be9282027c1b70b8d6d95ce4/ADA_RTL2/src/adaasn1rtl.ads#L90-L95) file, which contains this:
```ada
function Asn1Real_Equal (Left, Right : Asn1Real) return Boolean is
(if Left = Right then True elsif Left = 0.0 then Right = 0.0
elsif (Left > 0.0 and Right < 0.0) or (Left < 0.0 and Right > 0.0) then
False
elsif abs (Left) > abs (Right) then abs (Right) / abs (Left) >= 0.99999
else abs (Left) / abs (Right) >= 0.99999);
```
GNAT 15.2.0 complains about the parentheses around `abs`
```ada
/usr/local/gnat15/bin/gcc -c -x ada -gnatA -gnatwae -gnat2012 -g -gnatf -gnaty -gnatwa -gnatg -fstack-check -g -O0 -gnatwe -gnatwa -gnat2012 -gnatec=/tmp/GPR.64851/GNAT-TEMP-000003.TMP -gnatem=/tmp/GPR.64851/GNAT-TEMP-000004.TMP mainprogram.adb
adaasn1rtl.ads:94:17: (style) redundant parentheses [-gnatyz]
adaasn1rtl.ads:94:30: (style) redundant parentheses [-gnatyz]
adaasn1rtl.ads:94:47: (style) redundant parentheses [-gnatyz]
adaasn1rtl.ads:94:61: (style) redundant parentheses [-gnatyz]
adaasn1rtl.ads:95:16: (style) redundant parentheses [-gnatyz]
adaasn1rtl.ads:95:29: (style) redundant parentheses [-gnatyz]
```
why? it was ok under GNAT 14
I find it personally more readable with the parentheses.
---
### Author:  [@liampwll](https://forum.ada-lang.io/u/liampwll)
#### Post date: [May 6, 2026, 3:23pm UTC](https://forum.ada-lang.io/t/gnat-15-style-redundant-parentheses-gnatyz/4395/2 "2026-05-06T15:23:11Z")
Why not just turn the warning off if you don’t care about it?
---
### Author:  [@AJ-Ianozi](https://forum.ada-lang.io/u/AJ-Ianozi)
#### Post date: [May 6, 2026, 3:47pm UTC](https://forum.ada-lang.io/t/gnat-15-style-redundant-parentheses-gnatyz/4395/3 "2026-05-06T15:47:53Z")
It looks like this is where it came from:
> **[\[gcc r15-6860\] ada: Remove redundant parentheses inside unary operators (cont.)](https://gcc.gnu.org/pipermail/gcc-cvs/2025-January/415762.html)**
With rationale being:
> GNAT already emits a style warning when redundant parentheses appear inside
> logical and short-circuit operators. A similar warning will be soon emitted for
> unary operators as well. This patch removes the redundant parentheses to avoid
> build errors.
I’d probably end up doing something like this for readability:
```ada
function Asn1Real_Equal (Left, Right : Asn1Real)
return
Boolean
is
(if Left = Right then
True
elsif Left = 0.0 then
Right = 0.0
elsif
Left > 0.0 and Right < 0.0 or
Left < 0.0 and Right > 0.0
then
False
elsif abs (Left) > abs (Right) then
abs (Right) / abs (Left) >= 0.99999
else
abs (Left) / abs (Right) >= 0.99999);
```
---
### Author:  [@saper](https://forum.ada-lang.io/u/saper)
#### Post date: [May 6, 2026, 4:09pm UTC](https://forum.ada-lang.io/t/gnat-15-style-redundant-parentheses-gnatyz/4395/4 "2026-05-06T16:09:10Z")
> [@AJ-Ianozi](#):
>
> ```ada
> Left > 0.0 and Right < 0.0 or
> Left < 0.0 and Right > 0.0
>
> ```
Barnes 2022 writes,
> However, although the precedences are equal, **and** , **or** and **xor** cannot be mixed up in an expression without using parentheses (unlike + and - for instance).
indeed this gives
```
error: mixed logical operators in expression
```
> **[Expressions](https://www.adaic.org/resources/add_content/standards/05rm/html/RM-4-4.html#I2454)**
AdaRM allows repeating
simple\_expression ::= [[unary\_adding\_operator](https://www.adaic.org/resources/add_content/standards/05rm/html/RM-4-5.html#S0124)] [term](https://www.adaic.org/resources/add_content/standards/05rm/html/RM-4-4.html#S0118) {[binary\_adding\_operator](https://www.adaic.org/resources/add_content/standards/05rm/html/RM-4-5.html#S0123) [term](https://www.adaic.org/resources/add_content/standards/05rm/html/RM-4-4.html#S0118)}
but not
expression ::=
[relation](https://www.adaic.org/resources/add_content/standards/05rm/html/RM-4-4.html#S0116) { **and** [relation](https://www.adaic.org/resources/add_content/standards/05rm/html/RM-4-4.html#S0116)} | [relation](https://www.adaic.org/resources/add_content/standards/05rm/html/RM-4-4.html#S0116) { **and** **then** [relation](https://www.adaic.org/resources/add_content/standards/05rm/html/RM-4-4.html#S0116)}
| [relation](https://www.adaic.org/resources/add_content/standards/05rm/html/RM-4-4.html#S0116) { **or** [relation](https://www.adaic.org/resources/add_content/standards/05rm/html/RM-4-4.html#S0116)} | [relation](https://www.adaic.org/resources/add_content/standards/05rm/html/RM-4-4.html#S0116) { **or** **else** [relation](https://www.adaic.org/resources/add_content/standards/05rm/html/RM-4-4.html#S0116)}
| [relation](https://www.adaic.org/resources/add_content/standards/05rm/html/RM-4-4.html#S0116) { **xor** [relation](https://www.adaic.org/resources/add_content/standards/05rm/html/RM-4-4.html#S0116)}
---
### Author:  [@AJ-Ianozi](https://forum.ada-lang.io/u/AJ-Ianozi)
#### Post date: [May 6, 2026, 4:59pm UTC](https://forum.ada-lang.io/t/gnat-15-style-redundant-parentheses-gnatyz/4395/5 "2026-05-06T16:59:46Z")
EDIT I clearly haven’t had enough coffee and it’s impacting my reading comprehension, I just realized that it’s complaining about using them around **abs**. Just disregard my response. I’ll leave my posts up as a monument to my shame.
---
### Author:  [@saper](https://forum.ada-lang.io/u/saper)
#### Post date: [May 6, 2026, 5:04pm UTC](https://forum.ada-lang.io/t/gnat-15-style-redundant-parentheses-gnatyz/4395/6 "2026-05-06T17:04:36Z")
No worries, we are all learning here. Your answer actually made me look up Ada RM, something I should be doing more often.
---
### Author:  [@saper](https://forum.ada-lang.io/u/saper)
#### Post date: [May 6, 2026, 5:13pm UTC](https://forum.ada-lang.io/t/gnat-15-style-redundant-parentheses-gnatyz/4395/7 "2026-05-06T17:13:08Z")
Now I understand that we have a concept of [highest preference operators](https://www.adaic.org/resources/add_content/standards/05rm/html/RM-4-5-6.html) and therefore **abs** **not** and **\*\*** need no parentheses. Thank you.
---
### Author:  [@dmitry-kazakov](https://forum.ada-lang.io/u/dmitry-kazakov)
#### Post date: [May 6, 2026, 5:28pm UTC](https://forum.ada-lang.io/t/gnat-15-style-redundant-parentheses-gnatyz/4395/8 "2026-05-06T17:28:31Z")
No operators need parenthesis unless association is forbidden. E.g. in `A + -B` or `1 ** +2`.
Precedence plays little role. Example: `1*-2` is illegal.
---
### Author:  [@AdaOrbit](https://forum.ada-lang.io/u/AdaOrbit)
#### Post date: [May 6, 2026, 6:26pm UTC](https://forum.ada-lang.io/t/gnat-15-style-redundant-parentheses-gnatyz/4395/9 "2026-05-06T18:26:25Z")
Side note: when building the bare\_runtime crate using gnat15 you also have to remove all of the redundant parentheses since style warnings are treated as errors for runtime systems. Guess how I know 🙃
---
### Author:  [@kevlar700](https://forum.ada-lang.io/u/kevlar700)
#### Post date: [May 7, 2026, 8:40am UTC](https://forum.ada-lang.io/t/gnat-15-style-redundant-parentheses-gnatyz/4395/10 "2026-05-07T08:40:56Z")
I would guess Ada does better here but I never rely on precedence (since before the Linux kernel rules added that you shouldn’t) which can be the cause of bugs through unnecessary complexity. I remove them when the Gnat compiler assures me it’s all good though with some knee jerk annoyance that’s fading.
---
### Author:  [@system](https://forum.ada-lang.io/u/system)
#### Post date: [May 8, 2026, 8:41am UTC](https://forum.ada-lang.io/t/gnat-15-style-redundant-parentheses-gnatyz/4395/11 "2026-05-08T08:41:17Z")
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