I've been frustrated for a while about this...
SQL dbml error: CS0029 : Cannot implicitly convert type 'int' to 'System.Data.Linq.Link<int>'
Every time I change the DBML file, some errors appeared in the generated code... then I had to correct the problem in the code manually..... (the link fields needed '.Value' added to the assigned variable).
No more, me says - finally stopped being lazy and checked what the problematic fields had in common and a few seconds later, all was calm, and error free compilations were ahead.
Solution: Set 'Delay Loaded' property of the problematic field to 'False'. All done!
