Hash during lowering.

compiler/rustc_hir/src/hir.rs

@@ -9,6 +9,7 @@ use rustc_ast::{Attribute, FloatTy, IntTy, Label, LitKind, StrStyle, TraitObject
 pub use rustc_ast::{BorrowKind, ImplPolarity, IsAuto};
 pub use rustc_ast::{CaptureBy, Movability, Mutability};
 use rustc_ast::{InlineAsmOptions, InlineAsmTemplatePiece};
+use rustc_data_structures::fingerprint::Fingerprint;
 use rustc_data_structures::fx::FxHashMap;
 use rustc_index::vec::IndexVec;
 use rustc_macros::HashStable_Generic;
@@ -670,6 +671,10 @@ pub struct OwnerInfo<'hir> {
     /// Map indicating what traits are in scope for places where this
     /// is relevant; generated by resolve.
     pub trait_map: FxHashMap<ItemLocalId, Box<[TraitCandidate]>>,
+    /// Pre-computed hash of the full HIR.
+    pub hash: Fingerprint,
+    /// Pre-computed hash of the top node.
+    pub node_hash: Fingerprint,
 }
 
 /// The top-level data structure that stores the entire contents of