1 == 2 == 3
       ^~ unexpected '=='; '==' is a non-associative operator
       ^~ unexpected '==', expecting end-of-input
       ^~ unexpected '==', ignoring it
1 != 2 != 3
       ^~ unexpected '!='; '!=' is a non-associative operator
       ^~ unexpected '!=', expecting end-of-input
       ^~ unexpected '!=', ignoring it
1 === 2 === 3
        ^~~ unexpected '==='; '===' is a non-associative operator
        ^~~ unexpected '===', expecting end-of-input
        ^~~ unexpected '===', ignoring it
1 =~ 2 =~ 3
       ^~ unexpected '=~'; '=~' is a non-associative operator
       ^~ unexpected '=~', expecting end-of-input
       ^~ unexpected '=~', ignoring it
1 !~ 2 !~ 3
       ^~ unexpected '!~'; '!~' is a non-associative operator
       ^~ unexpected '!~', expecting end-of-input
       ^~ unexpected '!~', ignoring it
1 <=> 2 <=> 3
        ^~~ unexpected '<=>'; '<=>' is a non-associative operator
        ^~~ unexpected '<=>', expecting end-of-input
        ^~~ unexpected '<=>', ignoring it