AL compiler allows developers to add custom diagnostics. We can develop our own custom analyzers and provide paths to external assemblies, which are imported to extend the standard rulesets. Thanks to this capability, the BC community develops and maintains LinterCop, a popular set of custom diagnostic rules.

AL code action service, on the other hand, does not import external assemblies and does not allow extending code fix providers or refactoring providers, therefore, custom diagnostics cannot have quick fixes associated with rules.

Idea: import code fix providers and refactoring providers similarly to importing diagnostic analyzers, to allow third party code actions in the AL compiler.