Enum MethodCatalogError 

pub enum MethodCatalogError {
    Duplicate {
        receiver: TypePattern,
        name: &'static str,
        arity: usize,
    },
    ConflictingBound {
        method: &'static str,
        var: &'static str,
        first: Bound,
        second: Bound,
    },
    AmbiguousWithIterable {
        receiver: TypePattern,
        name: &'static str,
        arity: usize,
    },
    AmbiguousIterablePair {
        name: &'static str,
        arity: usize,
    },
    IterableOutsideReceiver {
        method: &'static str,
        arity: usize,
    },
}

Errors that can occur while building a MethodCatalog.

Variants

Duplicate

Two entries share the same (receiver, name, arity) triple. Overloads are not permitted; this is a build-time catalog bug.

Fields

receiver: TypePattern

name: &'static str

arity: usize

ConflictingBound

One entry declares two different bounds for the same type variable. A bound is a fact about the variable, so the row is asking for two incompatible things and whichever the checker happened to read first would win silently.

Fields

method: &'static str

var: &'static str

first: Bound

second: Bound

AmbiguousWithIterable

A concrete-receiver row shares a (name, arity) with a generic TypePattern::Iterable row, on a receiver the generic one accepts (ADR-127 decision 1).

Both spellings would match at the call site, and the catalog’s key is (receiver, name, arity) — so the two are not duplicates and nothing would refuse them; whichever came first in insertion order would win. That is a precedence rule, and a precedence rule is what makes “which does this call resolve to” a question at all (decision 6). The check scopes to PIPELINE_RECEIVERS deliberately: a Grid[T].map/1 beside Iterable.map/1 is allowed, because Grid is not one of the ten and §6.4 asks for that row by name.

Fields

receiver: TypePattern

name: &'static str

arity: usize

AmbiguousIterablePair

Two generic TypePattern::Iterable rows share a (name, arity), differing only in what they bound their item to (ADR-144).

This is AmbiguousWithIterable’s blind spot — join for a sequence of Text beside join for a sequence of Char. The pair is not a Duplicate, because the receivers differ; it is not a shadowing, because neither row is the concrete one. But praxis_hir::catalog::lookup matches an Iterable receiver on shape, so both hit and inference takes the first — which is a precedence rule by insertion order, exactly what ADR-127 decision 6 refuses. A sequence of Char gets a differently-named row instead.

Fields

name: &'static str

arity: usize

IterableOutsideReceiver

A row writes TypePattern::Iterable somewhere other than its receiver (ADR-127 decision 1).

The receiver generalizes; two parameters must not. zip’s argument is a Vec[U] and flat_map’s closure answers one, and the fused loop indexes both with praxis_vec_len/praxis_vec_get directly — neither has an IterPlan in scope, because neither is the source. Generalizing either would put a SetPayload under praxis_vec_get, which is the exact wrong-type read IterPlan exists to prevent. The pipeline generalizes over what it walks, not over every sequence a row mentions.

The rule is also what makes the instantiation path total: an Iterable names ten types, so pattern_to_type has no answer for one, and the receiver is the one position that never asks it for an answer.

Fields

method: &'static str

arity: usize

Trait Implementations

impl Clone for MethodCatalogError

fn clone(&self) -> MethodCatalogError

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Debug for MethodCatalogError

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl Display for MethodCatalogError

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl Eq for MethodCatalogError

impl Error for MethodCatalogError

fn source(&self) -> Option<&(dyn Error + 'static)>

Returns the lower-level source of this error, if any.

fn description(&self) -> &str

👎Deprecated since 1.42.0:

use the Display impl or to_string()

fn cause(&self) -> Option<&dyn Error>

👎Deprecated since 1.33.0:

replaced by Error::source, which can support downcasting

fn provide<'a>(&'a self, request: &mut Request<'a>)

🔬This is a nightly-only experimental API. (error_generic_member_access)

Provides type-based access to context intended for error reports.

impl PartialEq for MethodCatalogError

fn eq(&self, other: &MethodCatalogError) -> bool

Equality operator ==.

fn ne(&self, other: &Rhs) -> bool

Inequality operator !=.

impl StructuralPartialEq for MethodCatalogError