Cache invalidation issue with AstGen errors and imports

[SuperAuguste]

Zig Version

0.13.0 to 0.14.0-dev.32+4aa15440c

Steps to Reproduce and Observed Behavior

I've put this all in a repo for ease of reproduction: https://github.com/SuperAuguste/cache-invalidation-astgen-repro.

In short, this bug hinges on an AstGen error (a control flow diversion was chosen here, but I believe it works with other AstGen errors as well) present in an import analyzed by AstGen but not Sema.

On the first zig build, no control flow diversion error appears. All is well.

But, if you uncomment the @compileError causing the control flow diversion, instead of the error appearing, compilation still succeeds.

Thank you nitanmarcel on the Zig Discord for finding this bug!

Expected Behavior

An error occurs when the @compileError is introduced.