User-defined types - Mandatory property based on value from another property

**Is your feature request related to a problem? Please describe.**
Hi, is there a way to define property to be mandatory only if another property is set to certain value?
Also let's say I have property property1 that is not mandatory and has default value of foo1. The allowed values for property1 are foo1 and foo2. If the value is foo1 than property2 is mandatory if value is foo2, property 3 is mandatory. Also is there a way that if I do not define the value of property1 because it has default value to signal in intelliisense that property2 is mandatory?

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The issue names no files, tests, or entry points; begin by reviewing the discussion around user-defined types and IntelliSense in the Bicep repository. Clarify the conditional rules, default-value behavior, diagnostics, and completion behavior before implementation. Done should include an agreed specification and corresponding tests.

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