Ran across a fun one this morning and thought I’d offer my findings up to the Google god in case others out there suffer from the same affliction. We’ve got all our interfaces in one assembly and all our WCF services that implement said interfaces in another assembly. I rolled out some changes this morning and then tried to hit the services. Unfortunately, I started getting System.TypeLoadException asserting that “Method X in type Y from assembly Z does not have an implementation.” Except that it did have an implementation.

After an hour of frustration and banging my head against my keyboard chanting “But my method DOES have an implementation” which only served to give me a headache, I ran across this forum post that says the compiler/linker sometimes gets its panties in a wad and that I should try doing a full rebuild instead of just a build. I gave that a try, rolled out the services and whaddaya know, it worked.

If only they were all that easy.