Enum CaseForm 

pub enum CaseForm {
    Expression,
    Parameter,
}

What the source wrote that a Case term was built from.

A parameter written as a pattern — first (x, _) = x — is a match like any other, and it is translated as one: the parameter becomes a plain one named by pattern_parameter, and the declaration’s body a single-branch Case on it. So a backend lowers a pattern in either position the same way, and the term language keeps one binding construct, TermKind::Fun, that only ever binds a name.

This is what lets a diagnostic about the match speak about what the user wrote: a type error in a parameter’s pattern names the parameter and not a case, one in the body under it names the declaration’s body and not a case branch, and a backend refusing the match can say which of the two it is refusing.

Variants

Expression

A case … of expression.

Parameter

A parameter the declaration wrote as a pattern. The Case has exactly one branch, and its scrutinee is the local reference pattern_parameter names.

Trait Implementations

impl Clone for CaseForm

fn clone(&self) -> CaseForm

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Copy for CaseForm

impl Debug for CaseForm

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

Formats the value using the given formatter.

impl Eq for CaseForm

impl PartialEq for CaseForm

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

Equality operator ==.

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

Inequality operator !=.

impl StructuralPartialEq for CaseForm