SIFR-CLASS-0005: Invalid class base. - Sifr

SIFR-CLASS-0005 belongs to the Classes and declarations diagnostic family. It means: invalid class base.

Why It Happens

The class declaration cannot be lowered into a safe Rust-backed representation. Check field initialization, methods, inheritance constraints, and constructor shape.

Use sifr --explain SIFR-CLASS-0005 locally to see the renderer’s exact message template and any machine-applicable suggestions for the compiler version you are running.

Erroneous Code

class User:
    name: str

user = User()

How To Fix It

Give class declarations a shape the compiler can lower: initialized fields, valid bases, unique variants, and supported field ordering.

Fixed Code

class User:
    name: str

    def __init__(self, name: str):
        self.name = name

user = User("Ada")

Details

Field	Value
Code	`SIFR-CLASS-0005`
Family	`CLASS`
Severity	Error
Stability	stable
Owner	`sifr_lowering::lower::classes`
Representative fixture	`crates/sifr/tests/e2e/fail/class_unknown_parent.sifr`

See the Error Codes index for the complete catalog.