S0152: unsupported f-string interpolation

Generated from rellum-diagnostics/src/db.rs.

Explanation

F-string interpolation converts String values directly and primitive scalar values through to_string(). Complex values must be converted explicitly so production strings do not accidentally depend on implicit debug-style formatting.

Common causes

• placing an Option, Result, array, tuple, record, enum, or map directly inside {...}
• expecting f-strings to format arbitrary values automatically

Canonical fixes

• convert the value explicitly before interpolating it

Before:

f"value: {maybe_n}"

After:

f"value: {to_string(maybe_n)}"

• match on complex values and interpolate a chosen String

Code example

f"value: {maybe_n}"

Links

• RellC diagnostic overview