sub foobar($); foobar(($)@arr); #### use warnings '+mixedtypes'; @a=(1,2); @b=(@a, [3,4]); #would give warning! #### use warnings '+mixedtypes'; @a=(1,2); $a[1]=[3,4]; #warning - mixed type assigned to @a $a[1]=($)[3,4]; #would store the ref into a scalar-typed target without warning