Enum Constraint 

pub enum Constraint {
    Equal(InferType, InferType, Span),
    IsSigned(InferType, Span),
    IsInteger(InferType, Span),
    IsUnsigned(InferType, Span),
    IsNumeric(InferType, Span),
}

A type constraint generated during analysis.

Constraints express relationships between types that must hold. They are collected during constraint generation and then solved during unification.

Variants

Equal(InferType, InferType, Span)

Two types must be equal: τ₁ = τ₂.

This is the primary constraint type. Generated for:

• Binary operations (both operands must have same type)
• Assignments (value type must match variable type)
• Function calls (argument types must match parameter types)
• Return statements (returned type must match declared return type)

IsSigned(InferType, Span)

Type must be a signed integer: τ ∈ {i8, i16, i32, i64}.

Generated for unary negation which requires signed types. Unsigned integers cannot be negated.

IsInteger(InferType, Span)

Type must be an integer (signed or unsigned): τ ∈ {i8, i16, i32, i64, u8, u16, u32, u64}.

Generated for bitwise NOT which works on any integer type.

IsUnsigned(InferType, Span)

Type must be an unsigned integer: τ ∈ {u8, u16, u32, u64}.

Generated for array indexing which requires non-negative indices.

IsNumeric(InferType, Span)

Type must be numeric (integer or float): τ ∈ {i8..i64, u8..u64, isize, usize, f16..f64}.

Generated for arithmetic operators (+, -, *, /, %) which work on both integer and floating-point types.

Implementations

impl Constraint

pub fn equal(lhs: InferType, rhs: InferType, span: Span) -> Self

Create an equality constraint.

pub fn is_signed(ty: InferType, span: Span) -> Self

Create a “must be signed” constraint.

pub fn is_integer(ty: InferType, span: Span) -> Self

Create a “must be integer” constraint.

pub fn is_unsigned(ty: InferType, span: Span) -> Self

Create a “must be unsigned” constraint.

pub fn is_numeric(ty: InferType, span: Span) -> Self

Create a “must be numeric” constraint (integer or float).

pub fn span(&self) -> Span

Get the span for this constraint (for error reporting).

Trait Implementations

impl Clone for Constraint

fn clone(&self) -> Constraint

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for Constraint

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

Formats the value using the given formatter.