Module chalk_ir::fold

Traits for transforming bits of IR.

Re-exports

• pub use self::shift::Shift;

Modules

• binder_impls 🔒
  This module contains impls of TypeFoldable for those types that introduce binders.
• boring_impls 🔒
  This module contains “rote and uninteresting” impls of TypeFoldable for various types. In general, we prefer to derive TypeFoldable, but sometimes that doesn’t work for whatever reason.
• in_place 🔒
  Subroutines to help implementers of TypeFoldable avoid unnecessary heap allocations.
• shift
  Shifting of debruijn indices
• subst 🔒

Structs

• Subst
  Substitution used during folding

Traits

• FallibleTypeFolder
  A “folder” is a transformer that can be used to make a copy of some term – that is, some bit of IR, such as a Goal – with certain changes applied. The idea is that it contains methods that let you swap types/lifetimes for new types/lifetimes; meanwhile, each bit of IR implements the TypeFoldable trait which, given a FallibleTypeFolder, will reconstruct itself, invoking the folder’s methods to transform each of the types/lifetimes embedded within.
• TypeFoldable
  Applies the given TypeFolder to a value, producing a folded result of type Self::Result. The result type is typically the same as the source type, but in some cases we convert from borrowed to owned as well (e.g., the folder for &T will fold to a fresh T; well, actually T::Result).
• TypeFolder
  A “folder” is a transformer that can be used to make a copy of some term – that is, some bit of IR, such as a Goal – with certain changes applied. The idea is that it contains methods that let you swap types/lifetimes for new types/lifetimes; meanwhile, each bit of IR implements the TypeFoldable trait which, given a TypeFolder, will reconstruct itself, invoking the folder’s methods to transform each of the types/lifetimes embedded within.
• TypeSuperFoldable
  For types where “fold” invokes a callback on the TypeFolder, the TypeSuperFoldable trait captures the recursive behavior that folds all the contents of the type.