subst

Documentation

Overview

Package subst provides type substitution operations for generics.

These operations replace type parameters with concrete types, used during generic instantiation and Self type resolution.

Index

• func ExpandInstantiated(t typ.Type) typ.Type
• func Params(t typ.Type, params []*typ.TypeParam, args []typ.Type) typ.Type
• func Self(t typ.Type, selfType typ.Type) typ.Type
• func Substitute(t typ.Type, subs map[string]typ.Type) typ.Type

Functions

func ExpandInstantiated

func ExpandInstantiated(t typ.Type) typ.Type

ExpandInstantiated expands generic instantiations to their structural form.

For Instantiated{Generic: Array<T>, TypeArgs: [number]}, returns the Array body with T replaced by number. This enables structural comparison and field/method lookup on instantiated generics.

Does not enforce generic constraints; use subtype checking for that.

func Params

func Params(t typ.Type, params []*typ.TypeParam, args []typ.Type) typ.Type

Params replaces type parameters with corresponding type arguments.

func Self

func Self(t typ.Type, selfType typ.Type) typ.Type

Self replaces Self type references with a concrete type. Does not recurse into Interface types because Self inside an Interface is a separate binding that refers to that Interface's implementor.

func Substitute

func Substitute(t typ.Type, subs map[string]typ.Type) typ.Type

Substitute replaces type parameters with concrete types throughout a type.

Used during generic instantiation to replace TypeParam references with the corresponding type arguments. The subs map keys are type parameter names.