Module pat

As explained in crate::usefulness, values and patterns are made from constructors applied to fields. This file defines types that represent patterns in this way.

Structs

• DeconstructedPat
  Values and patterns can be represented as a constructor applied to some fields. This represents a pattern in this form. A DeconstructedPat will almost always come from user input; the only exception are some Wildcards introduced during pattern lowering.
• IndexedPat
  A pattern with an index denoting which field it corresponds to.
• WitnessPat
  Same idea as DeconstructedPat, except this is a fictitious pattern built up for diagnostics purposes. As such they don’t use interning and can be cloned.