http://dlang.org/grammar.html#AliasDeclaration
Spec allows:
AliasDeclaration:
alias BasicType Declarator
However DMD allows storage class before the type, e.g.:
alias ref int MyRefInt;
Comment #1 by k.hara.pg — 2014-02-25T17:28:29Z
*** This issue has been marked as a duplicate of issue 11396 ***
Comment #2 by andrej.mitrovich — 2014-04-22T21:17:49Z
*** This issue has been marked as a duplicate of issue 11632 ***