Compile a Modelsim Project

The status for thel files not yet compiled is displayed in the Project window

In the Transcript window (it can be opened from the View -> Transcript menu) execute the following command:
project compileall

The compilation results can be viewed in the Transcript window's output as well as in the Project window.
Successful compilations are marked correspondingly using green messages.
Erroneous compilations are signaled by red-coloured messages.

Right click on the source file that was compiled with errors and select Compile->Compile Report...

The error message indicate a missing or misplaced semicolon. Although the message contains a line indicator, in fact this error was generated because of a missing semicolon in the previous line. The line indication for an error is not always precise.

Correct the errors, save and recompile with the "project compileall" command.