The following documentation comment has been logged on the website: Page: https://www.postgresql.org/docs/11/functions-matching.html Description:
SELECT ' ' SIMILAR TO '[\s]'; returns true SELECT ' ' SIMILAR TO '[\q]'; generates an error: [2201B]: ERROR: invalid regular expression: invalid escape \ sequence \s is not mentioned in the SIMILAR TO section (https://www.postgresql.org/docs/current/functions-matching.html#FUNCTIONS-SIMILARTO-REGEXP). If it’s officially supported (which would be useful for my current task), it should be documented. Otherwise the server should generate an error like for other invalid escapes.