Enum ExpandError 

pub enum ExpandError {
    UnknownFunction(Ident),
    UnknownParam(Ident, Ident),
    UnknownConstructor(Ident),
    NoConstructor {
        func: Ident,
        param: Ident,
        target: String,
    },
    TargetMismatch {
        ctor: String,
        produces: String,
        expected: String,
    },
    UnsupportedOptional {
        func: Ident,
        param: Ident,
        reason: &'static str,
    },
    ConstructOnAccessor {
        func: Ident,
    },
    ParamTypeMismatch {
        func: Ident,
        param: Ident,
        declared: String,
        actual: String,
    },
    InputCycle {
        ty: String,
    },
    UnsupportedRecursive {
        func: Ident,
        reason: &'static str,
    },
    InvalidDeclarations {
        entries: Vec<ExpandDeclError>,
    },
}

Errors surfaced while resolving Expansions.

Variants

UnknownFunction(Ident)

UnknownParam(Ident, Ident)

UnknownConstructor(Ident)

NoConstructor

Fields

func: Ident

param: Ident

target: String

TargetMismatch

Fields

ctor: String

produces: String

expected: String

UnsupportedOptional

Fields

func: Ident

param: Ident

reason: &'static str

ConstructOnAccessor

An explicit per-fn input flatten targeted a read accessor — accessors are never parameter-composed.

Fields

func: Ident

ParamTypeMismatch

A per-fn .expand_param(name, expand_param!(T)) decl whose T does not match the named parameter’s peeled type.

Fields

func: Ident

param: Ident

declared: String

actual: String

InputCycle

Recursive input reached a type already on the build chain (A → … → A).

Fields

ty: String

UnsupportedRecursive

A recursive-input shape that is declared-but-not-yet-supported (recursion under a selector-dispatched variant, or on an Option<…> parameter).

Fields

func: Ident

reason: &'static str

InvalidDeclarations

Structurally invalid declaration records — empty variant lists or duplicate targets. All offenders are collected before failing (mirrors ScanError::DeclaredNotFound).

Fields

entries: Vec<ExpandDeclError>

Trait Implementations

impl Debug for ExpandError

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

Formats the value using the given formatter.

impl Display for ExpandError

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

Formats the value using the given formatter.

impl Error for ExpandError

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 From<ExpandError> for WriteRustError

fn from(e: ExpandError) -> Self

Converts to this type from the input type.