Merge #2484

2484: DynMap r=matklad a=matklad

Implement a `DynMap` a semi-dynamic, semi-static map, which helps to thread heterogeneously typed info in a uniform way. Totally inspired by https://github.com/JetBrains/kotlin/blob/df3bee30384787d8951ea548a4257c2cb52a16a3/compiler/frontend/src/org/jetbrains/kotlin/resolve/BindingContext.java. 

@flodiebold wdyt? Seems like a potentially useful pattern for various source-map-like things.

Co-authored-by: Aleksey Kladov <[email protected]>

1 files changed, 12 insertions, 2 deletions

diff --git a/crates/ra_syntax/src/ptr.rs b/crates/ra_syntax/src/ptr.rs
index e049fce61..db6230aab 100644
--- a/crates/ra_syntax/src/ptr.rs
+++ b/crates/ra_syntax/src/ptr.rs
@@ -1,6 +1,10 @@
 //! FIXME: write short doc here
 
-use std::{iter::successors, marker::PhantomData};
+use std::{
+    hash::{Hash, Hasher},
+    iter::successors,
+    marker::PhantomData,
+};
 
 use crate::{AstNode, SyntaxKind, SyntaxNode, TextRange};
 
@@ -43,7 +47,7 @@ impl SyntaxNodePtr {
 }
 
 /// Like `SyntaxNodePtr`, but remembers the type of node
-#[derive(Debug, Hash)]
+#[derive(Debug)]
 pub struct AstPtr<N: AstNode> {
     raw: SyntaxNodePtr,
     _ty: PhantomData<fn() -> N>,
@@ -64,6 +68,12 @@ impl<N: AstNode> PartialEq for AstPtr<N> {
     }
 }
 
+impl<N: AstNode> Hash for AstPtr<N> {
+    fn hash<H: Hasher>(&self, state: &mut H) {
+        self.raw.hash(state)
+    }
+}
+
 impl<N: AstNode> AstPtr<N> {
     pub fn new(node: &N) -> AstPtr<N> {
         AstPtr { raw: SyntaxNodePtr::new(node.syntax()), _ty: PhantomData }