https://gcc.gnu.org/bugzilla/show_bug.cgi?id=52393
--- Comment #7 from Dominique d'Humieres <dominiq at lps dot ens.fr> --- > The code in #5 is missing the initial parenthesised expression that exposes > the flaw in parsing logic - the left hand operand of the string concatenation > needs to be `('(')`, and not just the string literal. Indeed! Note that gfortran accepts '(' // ('A)'), or ('(' // 'A)'). AFAICT the problem occurs only when the first substring is enclosed in parentheses.