https://issues.dlang.org/show_bug.cgi?id=13664

          Issue ID: 13664
           Summary: Grammar does not allow @<template_instance> UDAs
           Product: D
           Version: D2
          Hardware: x86_64
                OS: Windows
            Status: NEW
          Severity: normal
          Priority: P1
         Component: websites
          Assignee: nobody@puremagic.com
          Reporter: bruno.do.medeiros+deebugz@gmail.com

An UDA such as `@X!3` or `@X!(3)` is not allowed by the grammar.

http://dlang.org/attribute.html#UserDefinedAttribute

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