warning: control reaches end of non-void function [-Wreturn-type]

[ryandesign]

Building the latest code from the repo on Linux with cmake (which uses -Wall -Wextra) and g++ 11.4.0, I get these warnings:

.../CLK/Components/9918/Implementation/../Implementation/PersonalityTraits.hpp: In function ‘constexpr size_t TI::TMS::memory_size(TI::TMS::Personality)’:
.../CLK/Components/9918/Implementation/../Implementation/PersonalityTraits.hpp:41:1: warning: control reaches end of non-void function [-Wreturn-type]
   41 | }
      | ^

.../CLK/Machines/Acorn/Archimedes/../../../InstructionSets/ARM/Registers.hpp: In static member function ‘static constexpr uint32_t InstructionSet::ARM::Registers::pc_offset_during(InstructionSet::ARM::Registers::Exception)’:
.../CLK/Machines/Acorn/Archimedes/../../../InstructionSets/ARM/Registers.hpp:188:17: warning: control reaches end of non-void function [-Wreturn-type]
  188 |                 }
      |                 ^

I think this is because although you've handled all the enumeration cases, you haven't handled the hypothetical case of a some other integer being passed to these functions. While that situation probably doesn't arise, the warning could be silenced by adding a default case. In other functions I've seen you use:

https://github.com/TomHarte/CLK/blob/018f0e097fabe264695561e4e18cb46297cc083b/InstructionSets/M50740/Parser.hpp#L68

[ryandesign]

Although now I learn that if you do add a default to a switch where you've handled all the enumeration cases, clang (if using -Weverything or just -Wcovered-switch-default) will say warning: default label in switch which covers all enumeration values. And there is a concern that if you add a default now and add more values to the enumeration later, you will not be warned that you haven't handled them separately in the switch. So perhaps just a return at the end of the function is the answer.