I thought D was beyond carrying historical baggage. DMD 2.x is not necessarily language-compatible with DMD 2.(x+1) since the language is still evolving. You can deprecate one syntax and enforce the other in a later version.
I submit that the syntax for attributes should be streamlined. Shall I go and open a Bugzilla item? -- Shriramana Sharma ஶ்ரீரமணஶர்மா श्रीरमणशर्मा