Order of scope evaluation

[Matthewar]

Use of maps when building scope tree could cause out-of-order scope evaluation, which leads to errors when scope names overwrite each other.

• Currently overwriting scope objects with new ones if there is an overlap
• This will cause unreliable scopes where it is indeterminate as to what object ends up in the scope
• Should error when scope overlaps
• Without correct scope ordering errors could point to wrong position
• Should probably also change from using maps for scope
  Need to evaluate maps ordering and assess if this is an issue