For the 1st five errors, clicking the the entry goes to the affected line;
For the last 3 entries - “previous declaration of…” - clicking does not work.
So it is not (easily) possible to see where the previous declarations are.
You have to go to the Console window, and plough through the stuff there to find:
This is actually an Eclipse built-in error parser behavior: when the error points to a location which is out of the project, it is reported to be an “external location” (cf the “Line” column in the problems view).
To access to the file, the user has to right-click + select “Open External Location”
Will raise a ticket on Eclipse side to check if they can add a double-click action in such a case.