As a note, it seems to be a convergence of issue of using unreal's Unity builds and this flag of warning as error. it's not just the E symbol causing the issue by itself

Interesting because this is not a global symbol, it is in the Noesis namespace.

Could you please paste the exact error you are getting and the unreal version?

Hey Jesus, It is actually not really on Noesis, indeed it is not a global symbol but if you enable unity build system in the unreal project it tries to optimise some of the headers and then it creates conflicts where in "standard" compilation it wouldn't.

The actual fix I did locally was to manually disable Unity build in the plugin :

public class NoesisRuntime : ModuleRules
{
    public NoesisRuntime(ReadOnlyTargetRules Target) : base(Target)
    {
        bUseUnity = false;
         //...

Changing of the name to EulerE does work but it's addressing the symptom more than the root cause.
Unreal version is 5.7.4-1277853

The error looked like this but was flaring a bit randomly (sometime on this Noesis::E sometime on Noesis::Point and rive::Point, basically any symbol that have the same signature without the namespace .

0> ShaderPermutation.h(103,39): Error C2220 : the following warning is treated as an error
0>  static int32 ToDimensionValueId(Type E)
0>                                       ^
0>ShaderPermutation.h(103,39): Warning C4459 : declaration of 'E' hides global declaration
0>Math.h(38,17): Reference  : see declaration of 'Noesis::E'
0>constexpr float E = 2.71828182845904523536028747135266249775724709369996f;
0>                ^
0> ...