Predicates works in a very weird manner

[ksmolyanin]

Predicates works in a very weird manner. For example this doesn't work as expected:
static_content_symbol: ( / [^\{] / | "{" !"{" | "{" !"*" )+
but this (which is logically equivalent) works fine:
static_content_symbol: ( / [^\{] / | "{" !( "{" | "*" ) )+
and this is not because of several predicates in the same rule, because this one works ok:
comment_content: ( / [^\*\{] / | "*" !"}" | "{" !"*" ) comment_content | comment comment_content | ""
Maybe this is because of the same start "{" of both alternatives in the first (nonworking) example?
Full grammar and test sample see in description of bug #6.

[mzolus]

The subexpression "{" !"{" | "{" !"*" isn't equivalent to "{" !( "{" | "*") in the general case. The first reads, "accept { if it is not followed by {, or else accept { if it is not followed by *". The string "{{" would fail the first branch, but succeed the second ( "{{" is a { not followed by a *).

The second variant effectively reads, "accept { if it is not followed by either { or *" -- a clearly different expression.