/in/foo.cc:2:7: error: expected nested-name-specifier before 'comespace'
 using comespace std;
       ^~~~~~~~~
/in/foo.cc:3:5: warning: decomposition declaration only available with -std=c++1z or -std=gnu++1z
 int [a];
     ^
/in/foo.cc:3:5: error: decomposition declaration cannot be declared with type 'int'
 int [a];
     ^~~
/in/foo.cc:3:5: note: type must be cv-qualified 'auto' or reference to cv-qualified 'auto'
/in/foo.cc:3:8: error: expected initializer before ';' token
 int [a];
        ^
/in/foo.cc:4:1: error: expected unqualified-id before '{' token
 {
 ^