Bug with | operator in Regular Expressions check (QA)

Question

I have found what seems to be a bug in Trados Studio 2017 SR1 in Regular Expressions check (QA) 
 
 This is my setting: 
 
 The intention is to avoid things in target such as numbers stickings together to words in lowercase, or words to numbers. So cintur&oacute;n3 or 3cinturones in target should be WRONG. However, if source has something like 3mm , it its ok if target has 3 mm (with a space), and wrong otherwise. The weird thing comes here: in the sentence... 
 
 Notice that, instead of recognizing the symbol "|" as an OR operator, it's interpreting it LITERALLY! It's weird, because first, it does not have the "\" symbol ahead of it in order to take it literally. My only guess is that the OR operator does not work WITH Grouped conditions. I have tested the OR oeprator "|" and it definitely works in the target field in the rest of the cases. For instance, this works PERFECTLY as intended.

As far as I can guess, I see no reason for the "|" operator to be disabled in Grouped search expressions. I have not tested in Grouped search expression: Report if source and target matches. 
 So is this a bug or it is intended for some reason??? It's a shame because I love the functionality and possibilities.

Paul · Answer

Hi Ignacio Niveiro , 
 
I don't think this is a bug. Replace expressions don't use the same syntax as search expressions and in .Net which Studio uses I think only the $ has a special meaning.

Paul · Answer

So just remove the pipe symbol. The answer will be one or the other so only one backreference will ever be called. This would do it. 
 
$1$2

Paul · Answer

Unknown said: 
 I have tested the OR oeprator "|" and it definitely works in the target field in the rest of the cases. For instance, this works PERFECTLY as intended.

This works because it's not a Grouped expression using back references. It's a simple search in source and a search in target.

Paul · Answer

Unknown said: The other case is the same.. remember, we are not talking about a Search and Replace here! We are talking about a Regex Expression for source, and a Regex expression for target in both cases! 
 They are not the same. 
 One is a "Grouped Search Expression" which means it can use the results of the search in the target (via a back reference) and any other normal characters you want in the target. 
 The other is searching in both the source and the target. It does not use the results of one as the basis of a search in the other.

Paul · Answer

Unknown said: $1$2 $3 seems to work... (in my original expression there were three groups). 
 ok sorry... too small for my eyes! I used this to test: 
 (\d+[a-z])|([a-z]\d) 
 $1$2 
 There's always many ways to skin a CAT ;-)

Trados Studio > 5. Regex and XPath

Bug with | operator in Regular Expressions check (QA)