When typechecking a selector, go/types reports the column corresponding to the begin of the selector expression, rather than name being selected:

       obj[whatever].missing(123)
       ^
       gotype reports here

The compiler instead reports the missing name:

       obj[whatever].missing(123)
                     ^
                     compiler reports here

The compiler version seems preferable, as it better highlights where the error probably lies. For instance, this is how my editor (that uses go/types) highlights a missing method:

I prepared a quick fix and this is how it looks like once go/types matches column info with the compiler:

I will submit a CL soon.