perl6/doc/lib/X/Syntax/UnlessElse

(title)  class X::Syntax::UnlessElse

    class X::Syntax::UnlessElse does X::Syntax { }

Syntax error thrown when an unless clause is followed by an else clause. For example

    unless 1 { } else { }

dies with

    "unless" does not take "else", please rewrite using "if"