Certain languages rely heavily on input methods (two examples I have
encountered are APL and Agda), and the default behaviour of Xref when
prompting an identifier can be annoying since the user is required to
manually enable the input method, if they want to look up an identifier
that contains "non-ASCII" characters.  For that reason I think it should
be OK to set the INHERIT-INPUT-METHOD argument when calling
`completing-read'.