runtime mixin applied to a non-callable declaration

Why this fires¶

Runtime mixins wrap callables. A struct, enum, newtype, or module has no call frame and therefore cannot be a runtime mixin target.

@mixin
fn wrapper() { super() }

@wrapper
// ^ error[TM116]
struct Unsupported { value: int }

Fix it¶

Move the decorator to a function or impl method. Use a compile-time derive or another declaration-specific decorator when the declaration itself must be transformed.

See also¶

• TM100 — super outside a mixin.
• docs/08-decorators.md — supported decorator targets.