SIFR-PROTO-0006: Fixed Rust trait receiver mutation is unsupported. - Sifr

SIFR-PROTO-0006 belongs to the Protocols diagnostic family. It means: fixed Rust trait receiver mutation is unsupported.

Why It Happens

A value does not satisfy the structural protocol required by the operation, such as iteration, context management, or indexing.

Use sifr --explain SIFR-PROTO-0006 locally to see the renderer’s exact message template and any machine-applicable suggestions for the compiler version you are running.

Erroneous Code

class Counter:
    value: int

    def __str__(self) -> str:
        self.value += 1
        return str(self.value)

How To Fix It

Keep operator and display methods read-only because their Rust trait receiver shape is fixed.

Fixed Code

class Counter:
    value: int

    def __str__(self) -> str:
        return str(self.value)

Details

Field	Value
Code	`SIFR-PROTO-0006`
Family	`PROTO`
Severity	Error
Stability	stable
Owner	`sifr_lowering::lower::method_receiver_analysis`
Representative fixture	`crates/sifr/tests/e2e/fail/operator_receiver_mutation_rejected.sifr`

See the Error Codes index for the complete catalog.