Restoring workspace containing stanfit object destabilizes R

Summary:

Restoring a workspace containing a stanfit object destabilizes R when a namespace that was available when the object was created is not available when the workspace is restored.

Description:

I'm working in a package in RStudio, call it Foo, and in my environment I have an object w2b that contains several stanfit objects within it (84 in total). I quit my R session and save my workspace. Later, I reopen the package, which restores the workspace, and see this message:

"Warning: namespace 'Foo" is not available and has been replaced by .GlobalEnv when processing object 'w2b'."

And now I find that various functions such as chol(), eigen(), determinant() no longer work. determinant(diag(2)) either crashes the system or returns NULL.

If I remove the object w2b from the environment, quit my R session (saving the workspace), and restart R, reopening the package Foo again, everything is fine.

Reproducible Steps:

Current Output:

Expected Output:

RStan Version:

2.9.0

R Version:

3.2.2

Operating System:

Windows 7

The report names no files, tests, or entry points. Start by reproducing workspace restoration with a stanfit object while its original namespace is unavailable, then verify that restoring the workspace leaves functions such as chol(), eigen(), and determinant() working without a crash or NULL result.