Issue #20406 has been updated by Eregon (Benoit Daloze).
It seems to behave a bit like string interpolation here
Specifically: ``` $ ruby -e '# encoding: EUC-JP p ("a" + "\xC3\xA9".force_encoding("UTF-8") + "c").encoding' #<Encoding:UTF-8> ``` But it seems very much unexpected for a `/e` regexp to have a UTF-8 encoding. ---------------------------------------- Misc #20406: Question about Regexp encoding negotiation https://bugs.ruby-lang.org/issues/20406#change-107803 * Author: andrykonchin (Andrew Konchin) * Status: Open ---------------------------------------- I am wondering what are the rules to calculate Regexp literal encoding in case an encoding modifier is specified. From the documentstion:
By default, a regexp with only US-ASCII characters has US-ASCII encoding: ... A regular expression containing non-US-ASCII characters is assumed to use the source encoding. This can be overridden with one of the following modifiers. //n ... //u ... //e ... //s ...
Looking at the following examples I would assume that these rules are followed except one case: ```ruby p /\xc2\xa1/e .encoding # EUC-JP p /#{ }\xc2\xa1/e .encoding # EUC-JP p /a/e .encoding # EUC-JP p /a #{} a/e .encoding # EUC-JP p /#{} a/e .encoding # US-ASCII ``` The last Regexp `/#{} a/e` is supposed to have `EUC-JP` encoding but has `US-ASCII`. So I am wondering what rule is applied in this case. -- https://bugs.ruby-lang.org/