Add comment explaining why calling outer constructor in setproperties

Author: bowenszhu

src/types.jl

@@ -94,6 +94,7 @@ const SIMPLIFIED = 0x01 << 0
 function ConstructionBase.setproperties(obj::BasicSymbolic{T}, patch::NamedTuple)::BasicSymbolic{T} where T
     nt = getproperties(obj)
     nt_new = merge(nt, patch)
+    # Call outer constructor because hash consing cannot be applied in inner constructor
     @compactified obj::BasicSymbolic begin
         Sym => Sym{T}(nt_new.name; nt_new...)
         _ => Unityper.rt_constructor(obj){T}(;nt_new...)