From 056d0db43e564e73405106e45c664bebd89fbaa6 Mon Sep 17 00:00:00 2001
From: Jim Blandy <jimb@red-bean.com>
Date: Sat, 22 Jun 2024 23:40:56 -0700
Subject: [PATCH] [naga] Use `HandleVec` in `Typeifier`.

Change `naga::front::Typifier::resolutions` to be a
`HandleVec<Expression, TypeResolution>`, not a plain `Vec`.
---
 naga/src/arena.rs     |  1 +
 naga/src/front/mod.rs | 18 +++++++++---------
 2 files changed, 10 insertions(+), 9 deletions(-)

diff --git a/naga/src/arena.rs b/naga/src/arena.rs
index 7ca8ca9455..27c858f562 100644
--- a/naga/src/arena.rs
+++ b/naga/src/arena.rs
@@ -798,6 +798,7 @@ where
 ///
 /// [`insert`]: HandleVec::insert
 /// [`HashMap::insert`]: std::collections::HashMap::insert
+#[derive(Debug)]
 pub(crate) struct HandleVec<T, U> {
     inner: Vec<U>,
     as_keys: PhantomData<T>,
diff --git a/naga/src/front/mod.rs b/naga/src/front/mod.rs
index 5e96103774..3f602f3dd0 100644
--- a/naga/src/front/mod.rs
+++ b/naga/src/front/mod.rs
@@ -15,7 +15,7 @@ pub mod spv;
 pub mod wgsl;
 
 use crate::{
-    arena::{Arena, Handle, UniqueArena},
+    arena::{Arena, Handle, HandleVec, UniqueArena},
     proc::{ResolveContext, ResolveError, TypeResolution},
     FastHashMap,
 };
@@ -52,13 +52,13 @@ use std::ops;
 /// [`LocalVariable`]: crate::LocalVariable
 #[derive(Debug, Default)]
 pub struct Typifier {
-    resolutions: Vec<TypeResolution>,
+    resolutions: HandleVec<crate::Expression, TypeResolution>,
 }
 
 impl Typifier {
     pub const fn new() -> Self {
         Typifier {
-            resolutions: Vec::new(),
+            resolutions: HandleVec::new(),
         }
     }
 
@@ -71,7 +71,7 @@ impl Typifier {
         expr_handle: Handle<crate::Expression>,
         types: &'a UniqueArena<crate::Type>,
     ) -> &'a crate::TypeInner {
-        self.resolutions[expr_handle.index()].inner_with(types)
+        self.resolutions[expr_handle].inner_with(types)
     }
 
     /// Add an expression's type to an `Arena<Type>`.
@@ -111,9 +111,9 @@ impl Typifier {
         if self.resolutions.len() <= expr_handle.index() {
             for (eh, expr) in expressions.iter().skip(self.resolutions.len()) {
                 //Note: the closure can't `Err` by construction
-                let resolution = ctx.resolve(expr, |h| Ok(&self.resolutions[h.index()]))?;
+                let resolution = ctx.resolve(expr, |h| Ok(&self.resolutions[h]))?;
                 log::debug!("Resolving {:?} = {:?} : {:?}", eh, expr, resolution);
-                self.resolutions.push(resolution);
+                self.resolutions.insert(eh, resolution);
             }
         }
         Ok(())
@@ -137,8 +137,8 @@ impl Typifier {
         } else {
             let expr = &expressions[expr_handle];
             //Note: the closure can't `Err` by construction
-            let resolution = ctx.resolve(expr, |h| Ok(&self.resolutions[h.index()]))?;
-            self.resolutions[expr_handle.index()] = resolution;
+            let resolution = ctx.resolve(expr, |h| Ok(&self.resolutions[h]))?;
+            self.resolutions[expr_handle] = resolution;
             Ok(())
         }
     }
@@ -147,7 +147,7 @@ impl Typifier {
 impl ops::Index<Handle<crate::Expression>> for Typifier {
     type Output = TypeResolution;
     fn index(&self, handle: Handle<crate::Expression>) -> &Self::Output {
-        &self.resolutions[handle.index()]
+        &self.resolutions[handle]
     }
 }