Sifr Diagnostic Code Reference for All Error Families

Sifr organizes every diagnostic into a named family. Each code follows the format SIFR-<FAMILY>-dddd, where the four-digit number is scoped within its family. This page lists every active diagnostic family and links each code to a dedicated reference page. Use sifr --explain <CODE> in your terminal to get the exact renderer template and suggestions for your installed compiler version.

PARSE — Parsing and source syntax

The PARSE family covers errors that the parser encounters before any semantic analysis. These diagnostics fire when your source file contains syntax the Sifr parser cannot recover from.

Code	Severity	Description
`SIFR-PARSE-0002`	Error	Expected token or generic parser recovery failure.
`SIFR-PARSE-0003`	Error	Lexical or interpolated string parser failure.
`SIFR-PARSE-0004`	Error	Indentation or same-line statement layout parser failure.
`SIFR-PARSE-0005`	Error	Invalid assignment, delete, starred, or named-expression target syntax.
`SIFR-PARSE-0006`	Error	Invalid call argument order or unpacking syntax.
`SIFR-PARSE-0007`	Error	Empty or malformed declaration list syntax.
`SIFR-PARSE-0008`	Error	Invalid match-pattern syntax.
`SIFR-PARSE-0009`	Error	Unsupported parser syntax or interactive-only syntax.

NAME — Name binding and resolution

The NAME family covers errors that arise when the compiler cannot resolve an identifier — a variable, function, type, or member — to a known declaration.

Code	Severity	Description
`SIFR-NAME-0001`	Error	Undefined variable.
`SIFR-NAME-0002`	Error	Undefined function or callable.
`SIFR-NAME-0003`	Error	Unknown type or generic type name.
`SIFR-NAME-0004`	Error	Missing module or class member.
`SIFR-NAME-0005`	Error	Duplicate function definition in a module.
`SIFR-NAME-0006`	Error	Variable declaration lacks a required initializer.

IMPORT — Module import and path resolution

The IMPORT family covers errors that occur when resolving import and from … import statements. These diagnostics fire before type-checking when the module graph cannot be built.

Code	Severity	Description
`SIFR-IMPORT-0001`	Error	Forbidden private sysroot declaration import.
`SIFR-IMPORT-0002`	Error	Unknown source module import target.
`SIFR-IMPORT-0003`	Error	Unsupported import statement form.
`SIFR-IMPORT-0004`	Error	Private module member import.
`SIFR-IMPORT-0005`	Error	Ambiguous source module import target.
`SIFR-IMPORT-0006`	Error	Source module namespace and file import collision.
`SIFR-IMPORT-0007`	Error	Circular source module import graph.
`SIFR-IMPORT-0008`	Error	Bare CPython-style stdlib import attempt.
`SIFR-IMPORT-0009`	Error	Unsupported legacy Sifr stdlib module import.

SIFR-IMPORT-0008 fires when you write from math import floor instead of from sifr.math import floor. Sifr’s standard library lives under the sifr.* namespace.

TYPE — Static type compatibility and inference

The TYPE family covers type system violations detected during static analysis and lowering. These diagnostics indicate that the inferred or annotated types in your program are not compatible with each other or with the operation being performed.

Code	Severity	Description
`SIFR-TYPE-0002`	Error	Expected and actual types are incompatible.
`SIFR-TYPE-0003`	Error	If-expression or conditional branches have incompatible types.
`SIFR-TYPE-0004`	Error	A required type annotation is missing.
`SIFR-TYPE-0005`	Error	Unsupported operator or operand types.
`SIFR-TYPE-0006`	Error	Int and bigint are mixed without an explicit conversion.
`SIFR-TYPE-0007`	Error	Invalid type annotation shape.
`SIFR-TYPE-0008`	Error	Container literal elements, keys, or values have conflicting types.
`SIFR-TYPE-0009`	Error	Tuple or list unpacking shape mismatch.
`SIFR-TYPE-0010`	Error	TypeVar constraints are not satisfied by the inferred concrete type.
`SIFR-TYPE-0011`	Error	Unsupported default argument expression.
`SIFR-TYPE-0012`	Error	Unsupported expression form.
`SIFR-TYPE-0901`	Warning	Integer arithmetic may overflow at runtime.
`SIFR-TYPE-0902`	Note	Reveal the inferred static type of an expression.

ASYNC — Async effect and awaitability

The ASYNC family covers violations of Sifr’s async effect system. Sifr tracks whether functions perform real suspension, and it enforces that blocking or CPU-heavy work is never called directly from an async context.

Code	Severity	Description
`SIFR-ASYNC-0001`	Error	Async function body has no real suspension effect.
`SIFR-ASYNC-0002`	Error	Awaited same-task coroutine has no real suspension effect.
`SIFR-ASYNC-0003`	Error	Blocking I/O function called directly from async context.
`SIFR-ASYNC-0004`	Error	CPU-heavy function called directly from async context.
`SIFR-ASYNC-0005`	Error	Blocking offload target is not classified as blocking I/O or CPU-heavy work.
`SIFR-ASYNC-0006`	Error	Synchronous workload annotation applied to async function.
`SIFR-ASYNC-0007`	Error	Shell execution function called directly from async context.

PYENV — Embedded CPython environment

The PYENV family covers root Python environment selection and live interpreter probe failures for embedded CPython interop.

Code	Severity	Description
`SIFR-PYENV-0001`	Error	Python environment configuration is malformed.
`SIFR-PYENV-0002`	Error	Package graph selects more than one Python virtual environment.
`SIFR-PYENV-0003`	Error	A package graph requires Python but no root environment is selected.
`SIFR-PYENV-0004`	Error	Selected Python interpreter probe failed or returned invalid JSON.
`SIFR-PYENV-0005`	Error	Selected Python interpreter is not supported CPython.
`SIFR-PYENV-0006`	Error	Selected interpreter does not belong to the configured virtual environment.
`SIFR-PYENV-0007`	Error	Selected Python environment has no site-packages path.
`SIFR-PYENV-0008`	Error	Declared Python import root is missing from the selected environment.
`SIFR-PYENV-0009`	Error	Trusted native Python import root failed to load.
`SIFR-PYENV-0010`	Error	Free-threaded CPython is not supported for embedded interop.
`SIFR-PYENV-0011`	Error	Configured Python project or lockfile is missing or stale.

PYTRUST — Embedded Python trust policy

The PYTRUST family covers import-root and native-extension trust policy for embedded Python interop.

Code	Severity	Description
`SIFR-PYTRUST-0001`	Error	Dependency package declares a wildcard Python trust root.
`SIFR-PYTRUST-0003`	Error	Native Python import root is trusted but not required.
`SIFR-PYTRUST-0004`	Error	Dynamic Python import requires an explicit trust annotation.
`SIFR-PYTRUST-0005`	Error	Required Python import root is not authorized by the root application.

The PYIMP, PYCALL, PYCONV, PYRES, PYCTX, PYCB, and PYZC families are active compiler-emitted Python interop diagnostics. PYCTX covers context-manager entry, exit, suppression, and cause contracts. PYZC covers typed buffer, Arrow, and DLPack declaration, ownership, layout or stream policy, transfer, and hidden-copy errors. Runtime failures at active boundaries are returned as structured PythonError values.

RUST — Rust interop

The SIFR-RUST-* families cover declaration-level Rust interop through Cargo. These diagnostics are emitted by the same compiler path used by sifr check, sifr bridge check, package build, and package publish validation.

Code	Severity	Description
`SIFR-RUST-CONFIG-0001`	Error	Malformed Rust interop decorator.
`SIFR-RUST-RESOLVE-0001`	Error	Unresolved Rust target path.
`SIFR-RUST-TRUST-0001`	Error	Missing Rust interop trust declaration.
`SIFR-RUST-TYPE-0001`	Error	Unsupported Rust bridge type.
`SIFR-RUST-HANDLE-0001`	Error	Invalid opaque handle contract.
`SIFR-RUST-ASYNC-0001`	Error	Invalid Rust async or thread-affinity contract.
`SIFR-RUST-ZC-0001`	Error	Invalid zero-copy or view lifetime contract.
`SIFR-RUST-CB-0001`	Error	Invalid callback lifetime or threading contract.
`SIFR-RUST-PANIC-0001`	Error	Incompatible Rust panic strategy or poisoned handle.
`SIFR-RUST-CARGO-0001`	Error	Cargo metadata, lockfile, or profile mismatch.

DECIMAL — Decimal and fixed-point arithmetic

The DECIMAL family covers errors in Sifr’s Decimal and BigDecimal numeric types. Sifr’s decimal types are distinct from Python floats and have their own literal syntax, scale rules, and construction constraints.

Code	Severity	Description
`SIFR-DECIMAL-0001`	Error	Invalid `Decimal` exact literal.
`SIFR-DECIMAL-0002`	Error	Invalid `BigDecimal` exact literal.
`SIFR-DECIMAL-0003`	Error	Float mixed with a decimal numeric type.
`SIFR-DECIMAL-0004`	Error	`Decimal` and `BigDecimal` mixed in one operation.
`SIFR-DECIMAL-0005`	Error	`Decimal` float construction or conversion is forbidden.
`SIFR-DECIMAL-0006`	Error	`BigDecimal` float construction or conversion is forbidden.
`SIFR-DECIMAL-0007`	Error	`Decimal` scale argument is invalid.
`SIFR-DECIMAL-0008`	Error	`BigDecimal` scale or context argument is invalid.

INT — Exact and fixed-width integer model

The INT family covers errors in Sifr’s exact integer (int) and fixed-width integer types (i8–i128, u8–u128). Sifr enforces explicit conversions and overflow handling rather than silently wrapping or truncating.

Code	Severity	Description
`SIFR-INT-0001`	Error	Fixed-width integer literal or const expression is out of range.
`SIFR-INT-0003`	Error	Reserved integer width name used before support lands.
`SIFR-INT-0004`	Error	Compile-time integer evaluation budget exceeded.
`SIFR-INT-0005`	Error	Integer division, modulo, or exponentiation requires handling a typed failure.
`SIFR-INT-0006`	Error	Exact integer to float conversion requires handling precision loss.
`SIFR-INT-0007`	Error	Bool and integer comparison requires explicit conversion.
`SIFR-INT-0011`	Warning	Temporary bigint transition alias used.

IO — File and stream text/binary boundary

The IO family covers errors at the boundary between text-mode and binary-mode file operations. Sifr requires that text-mode file opens declare an explicit encoding at compile time.

Code	Severity	Description
`SIFR-IO-0801`	Error	Text-mode `open` requires an explicit encoding.
`SIFR-IO-0802`	Error	Open mode must be statically known.

ENCODING — Text encoding and error handlers

The ENCODING family covers errors related to text encoding configuration. Sifr requires that encoding error handlers be statically known so that encoding behavior is predictable and verifiable at compile time.

Code	Severity	Description
`SIFR-ENCODING-0803`	Error	Encoding error handler must be statically known.

CALL — Function and method call diagnostics

The CALL family covers errors at call sites: wrong argument counts, unexpected keyword arguments, duplicate arguments, missing required arguments, and uncallable expressions.

Code	Severity	Description
`SIFR-CALL-0001`	Error	Wrong positional argument count.
`SIFR-CALL-0002`	Error	Unexpected keyword argument.
`SIFR-CALL-0003`	Error	Duplicate argument from positional and keyword overlap.
`SIFR-CALL-0004`	Error	Missing required argument.
`SIFR-CALL-0005`	Error	Callable arity failure or expression is not callable.

OWN — Ownership, borrow, move, and lifetime

The OWN family covers violations of Sifr’s ownership and borrow model. Because Sifr compiles to Rust, it enforces that values are not used after being moved, that borrows do not conflict, and that values respect sendability and shareability boundaries across task and channel boundaries.

Code	Severity	Description
`SIFR-OWN-0001`	Error	Use after move.
`SIFR-OWN-0002`	Error	Conflicting borrow.
`SIFR-OWN-0003`	Error	Borrowed parameter escapes by return or store.
`SIFR-OWN-0004`	Error	Moved value is reused across loop iterations.
`SIFR-OWN-0005`	Error	Immutable parameter is mutated.
`SIFR-OWN-0006`	Error	Immutable parameter is reassigned.
`SIFR-OWN-0007`	Error	Immutable bytes value is mutated.
`SIFR-OWN-0008`	Error	Immutable bytes value is mutated by augmented assignment.
`SIFR-OWN-0009`	Error	Mutable borrow remains live across an `await` point.
`SIFR-OWN-0010`	Error	Non-sendable value crosses a spawned task boundary.
`SIFR-OWN-0011`	Error	Non-sendable value is sent through a channel.
`SIFR-OWN-0012`	Error	Non-share-safe value is wrapped in `sync.Shared`.
`SIFR-OWN-0013`	Error	Non-IPC-serializable value is used as a typed IPC payload.

FLOW — Control flow and reachability

The FLOW family covers control-flow correctness: invalid break/continue placement, missing return values, unsupported loop forms, and constructs that HIR lowering cannot represent.

Code	Severity	Description
`SIFR-FLOW-0001`	Error	`break` outside a loop.
`SIFR-FLOW-0002`	Error	`continue` outside a loop.
`SIFR-FLOW-0003`	Error	Invalid `nonlocal` or nested-function flow.
`SIFR-FLOW-0004`	Error	Function may finish without returning a required value.
`SIFR-FLOW-0005`	Error	Control-flow condition has an unsupported type.
`SIFR-FLOW-0006`	Error	Statement form is unsupported by HIR lowering.
`SIFR-FLOW-0007`	Error	Assignment target form is unsupported by HIR lowering.
`SIFR-FLOW-0008`	Error	For-loop iteration form or source is invalid.
`SIFR-FLOW-0901`	Warning	Unreachable statement ignored during lowering.

FMT — Source formatting

The FMT family covers formatting enforcement. It fires when sifr fmt --check detects that one or more source files have drifted from canonical Sifr formatting.

Code	Severity	Description
`SIFR-FMT-0001`	Error	Source formatting drift detected by `sifr fmt --check`.

Run sifr fmt (without --check) to automatically rewrite all files to canonical formatting and resolve SIFR-FMT-0001.

LINT — Suppressible policy-rule diagnostics

The LINT family covers the policy-rule engine (sifr lint). These are Warning-severity diagnostics that can be suppressed per-line with # sifr: ignore[rule-id]. The family also includes meta-diagnostics about suppression hygiene.

Code	Severity	Description
`SIFR-LINT-0001`	Warning	Suppression references an unknown policy rule ID.
`SIFR-LINT-0002`	Warning	Suppression did not suppress any diagnostic.
`SIFR-LINT-0003`	Warning	Suppression must list explicit Sifr policy rule IDs.
`SIFR-LINT-0004`	Warning	Line ends with trailing horizontal whitespace.
`SIFR-LINT-0005`	Warning	Comment contains a tracked TODO or FIXME marker.
`SIFR-LINT-0006`	Warning	Call passes a boolean literal positionally.
`SIFR-LINT-0007`	Warning	Function has more parameters than the policy limit.
`SIFR-LINT-0008`	Warning	Import duplicates a module/name pair already imported in the same source file.

MATCH — Pattern matching and exhaustiveness

The MATCH family covers match statement correctness. Sifr requires that match statements are exhaustive over enum types and that patterns are well-formed.

Code	Severity	Description
`SIFR-MATCH-0001`	Error	Non-exhaustive match — one or more enum variants are not covered.
`SIFR-MATCH-0002`	Error	Match guard must be `bool`.
`SIFR-MATCH-0003`	Error	Invalid class pattern field.
`SIFR-MATCH-0004`	Error	Invalid or unsupported match pattern form.

PROTO — Protocol and structural conformance

The PROTO family covers violations of Sifr’s structural protocol system: iterator and reversible protocols, context-manager protocols, and hashability/comparability constraints.

Code	Severity	Description
`SIFR-PROTO-0001`	Error	Protocol bound or conformance failure.
`SIFR-PROTO-0002`	Error	Invalid iterator or reversible protocol signature.
`SIFR-PROTO-0003`	Error	Context-manager protocol is missing (`__enter__` or `__exit__` absent).
`SIFR-PROTO-0004`	Error	Hashable or comparable protocol is required.

CLASS — Class declaration, fields, and methods

The CLASS family covers class-level structural errors: missing field initializers, field ordering violations, duplicate enum variants, invalid base classes, and unsupported class forms.

Code	Severity	Description
`SIFR-CLASS-0001`	Error	Class fields require an initializer or super initializer.
`SIFR-CLASS-0002`	Error	Required field declared after a defaulted field.
`SIFR-CLASS-0003`	Error	Duplicate enum or class value, or invalid variant.
`SIFR-CLASS-0004`	Error	Missing class field.
`SIFR-CLASS-0005`	Error	Invalid class base.
`SIFR-CLASS-0006`	Error	Unsupported class declaration.

RESULT — Result, Option, and checked error flow

The RESULT family covers Sifr’s checked error-handling model. Sifr requires that Result values are explicitly handled, that error types are valid, and that try/except blocks cover all possible error types from the try body.

Code	Severity	Description
`SIFR-RESULT-0001`	Error	Unused `Result` value.
`SIFR-RESULT-0002`	Error	Invalid `Result` error type.
`SIFR-RESULT-0003`	Error	Invalid `raise` expression.
`SIFR-RESULT-0004`	Error	`except` arm references an unknown error type.
`SIFR-RESULT-0005`	Error	`try` body error types are not fully covered by `except` arms.
`SIFR-RESULT-0006`	Error	`except` arm type expression has an unsupported form.

SIFR-RESULT-0001 fires whenever you call a function that returns Result and discard the return value without handling it. Use match, unwrap(), or propagate the result with ? syntax to resolve it.

STDLIB — Standard library surface and intrinsics

The STDLIB family covers errors related to Sifr’s embedded standard library. These diagnostics fire when a stdlib constructor or method is called in an unsupported way, or when the stdlib bootstrap or cache has a problem.

Code	Severity	Description
`SIFR-STDLIB-0001`	Error	Unsupported standard-library constructor, method, or surface.
`SIFR-STDLIB-0003`	Error	Embedded standard-library bootstrap failure.
`SIFR-STDLIB-0004`	Error	Standard-library cache build or reuse failure.

WORKSPACE — Workspace manifest and project discovery

The WORKSPACE family covers errors in workspace configuration: malformed manifests, source roots that escape the workspace boundary, and invalid source root entries. It also includes legacy import resolution errors that mirror the IMPORT family for workspaces not yet migrated to the current module system.

Code	Severity	Description
`SIFR-WORKSPACE-0001`	Error	Malformed workspace manifest.
`SIFR-WORKSPACE-0002`	Error	Workspace source root escapes the workspace root.
`SIFR-WORKSPACE-0003`	Error	Workspace source root is not a directory.
`SIFR-WORKSPACE-0004`	Error	Workspace source root entry has an invalid shape or path.
`SIFR-WORKSPACE-0101`	Error	Legacy workspace import target could not be resolved.
`SIFR-WORKSPACE-0102`	Error	Legacy workspace import target is ambiguous.
`SIFR-WORKSPACE-0103`	Error	Legacy workspace namespace package collision.
`SIFR-WORKSPACE-0104`	Error	Legacy workspace import graph cycle.

PACKAGE — Cargo-backed package coordination

The PACKAGE family is the largest family and covers the full lifecycle of Sifr packages: manifest validation, dependency resolution, import scope enforcement, trust policy, archive integrity, and publish guardrails.

Code	Severity	Description
`SIFR-PACKAGE-0001`	Error	Missing or invalid Cargo Sifr discovery metadata.
`SIFR-PACKAGE-0002`	Error	Missing or invalid `sifr.toml` package manifest.
`SIFR-PACKAGE-0003`	Error	Unsupported Sifr compiler metadata appears in Cargo metadata.
`SIFR-PACKAGE-0101`	Error	Cargo command invocation failed.
`SIFR-PACKAGE-0102`	Error	A selected Cargo package is Rust-only.
`SIFR-PACKAGE-0103`	Error	Cargo metadata parsing or normalization failed.
`SIFR-PACKAGE-0104`	Error	Package source is unavailable in offline or frozen mode.
`SIFR-PACKAGE-0106`	Error	Rust-only package depends directly on a Sifr source package.
`SIFR-PACKAGE-0201`	Error	Direct package import root resolves to multiple package instances.
`SIFR-PACKAGE-0202`	Error	Package imports a module outside its direct dependency scope.
`SIFR-PACKAGE-0203`	Error	Package imports a private module from another package.
`SIFR-PACKAGE-0204`	Error	Type identity crosses resolved package instances.
`SIFR-PACKAGE-0301`	Error	Backend Rust crate is not allowed by the Sifr trust policy.
`SIFR-PACKAGE-0305`	Error	Trust policy names a backend crate that is not a direct dependency.
`SIFR-PACKAGE-0401`	Error	Cargo package archive is missing required Sifr source.
`SIFR-PACKAGE-0402`	Error	Package publish or archive validation failed.
`SIFR-PACKAGE-0403`	Error	Cargo include/exclude rules omit required Sifr files.
`SIFR-PACKAGE-0404`	Error	Cargo package archive contains an unsafe path.
`SIFR-PACKAGE-0501`	Error	Pure Sifr Rust marker contains implementation.
`SIFR-PACKAGE-0601`	Error	Package selector is ambiguous or invalid.
`SIFR-PACKAGE-0602`	Error	Workspace selection contains duplicate import roots.
`SIFR-PACKAGE-0603`	Error	Changed file could not be mapped to a package.
`SIFR-PACKAGE-0604`	Error	Outdated query cannot inspect this Cargo source.
`SIFR-PACKAGE-0605`	Error	Runnable package target or script selection is missing or ambiguous.
`SIFR-PACKAGE-0606`	Error	Discovered app target name is invalid.
`SIFR-PACKAGE-0607`	Error	Selected workspace members use the same Sifr package name.
`SIFR-PACKAGE-0701`	Error	Production `sifr.toml` uses manifest-level exports.
`SIFR-PACKAGE-0703`	Error	Sifr-managed Cargo projection manifest pointer drift.
`SIFR-PACKAGE-0704`	Error	Sifr-managed Cargo projection include rules omit required package files.
`SIFR-PACKAGE-0709`	Error	Pure package marker is missing from Sifr-managed projection.
`SIFR-PACKAGE-0710`	Error	Explicit Sifr file target is outside the package source root.
`SIFR-PACKAGE-0711`	Error	Production `sifr.toml` uses manifest binary target tables.
`SIFR-PACKAGE-0713`	Error	Public API symbol is exported more than once.
`SIFR-PACKAGE-0714`	Error	Package script expansion attempted to invoke another script.

CODEGEN — Rust lowering and code generation

The CODEGEN family is reserved for diagnostics that arise during the Rust lowering and code-generation phase, after HIR construction. No codes are active yet; this family is reserved for future use.

Code	Severity	Description
(no active codes)	—	This family has no active codes in the current release.

BUILD — Build orchestration and artifacts

The BUILD family covers failures in Sifr’s build pipeline: file materialization, temporary workspace creation, Cargo manifest generation, Rustc/Cargo execution, and missing artifacts.

Code	Severity	Description
`SIFR-BUILD-0002`	Error	Build file materialization failed.
`SIFR-BUILD-0003`	Error	Temporary build workspace creation failed.
`SIFR-BUILD-0004`	Error	Cargo manifest generation failed.
`SIFR-BUILD-0005`	Error	Rustc or Cargo execution failed.
`SIFR-BUILD-0006`	Error	Expected build artifact was not produced.
`SIFR-BUILD-0901`	Error	Standalone install receipt is missing or outside the self-update rules.

INTERNAL — Compiler invariant and internal failures

The INTERNAL family covers compiler-internal failures that escape the panic boundary. If you see an INTERNAL diagnostic, it indicates a compiler bug rather than a problem with your source code.

Code	Severity	Description
`SIFR-INTERNAL-0001`	Error	Unclassified compiler panic after a panic boundary.
`SIFR-INTERNAL-0002`	Note	Structured recovery-cap omission summary.

SIFR-INTERNAL-0001 always indicates a compiler bug. If you encounter it, please file a report with the Sifr issue tracker and include a minimal reproduction of the failing source file.

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Sifr Diagnostic Code Reference for All Error Families