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Possibly a lazyweb question but is it possible to report diagnostics in FIR with a dynamically computed string? For example - a string that contains more specific context/references to the code being reported. All the examples I’ve seen just maintain a static mapping of diagnostics to message strings

You can declare your diagnostic as diagnostics with parameters (up to 4) and configure its message with these arguments

Take, for example, `TYPEALIAS_EXPANSION_DEPRECATION_ERROR`
It's <https://github.com/JetBrains/kotlin/blob/a290dba3b591c682a5aa9d64dd194a724c493902/compiler/fir/checkers/gen/org/jetbrains/kotlin/fir/analysis/diagnostics/FirErrors.kt#L207|declared> as `KtDiagnosticFactory3` with three parameters
Its <https://github.com/JetBrains/kotlin/blob/a290dba3b591c682a5aa9d64dd194a724c493902/compiler/fir/checkers/src/org/jetbrains/kotlin/fir/analysis/diagnostics/FirErrorsDefaultMessages.kt#L842|message> `"''{0}'' uses ''{1}'', which is an error. {2}."` contains `{0}`, `{1}` and `{2}` as placeholders for actual arguments

In each parameter you can use whatever type you want, just provide the proper renderer for them (renderer is a basically `(T) -> String` converter)

You can even create a diagnostic with a one `String` parameter, declare its message as `"{0}"` and compute the whole message at the reporting side