$ perl -we 'print (3+4),5;'
print (...) interpreted as function at -e line 1.
Useless use of a constant (5) in void context at -e line 1.
7
$ perl -we 'print (WEEKDAYS)[1];'
print (...) interpreted as function at -e line 1.
syntax error at -e line 1, near ")["
Execution of -e aborted due to compilation errors.
$ perl -we 'print  (WEEKDAYS)[1];'
syntax error at -e line 1, near ")["
Execution of -e aborted due to compilation errors.

##</code><code>##

$ perl -we 'print +(3+4),5;'  # disambiguate
75
$ perl -we 'print((3+4),5);'  # explicit parens
75

##</code><code>##

$ perl -MO=Deparse,-p -e 'print (3+4),5;'
(print(7), '???');