From 2f94004f5baede604505da353e347bf807696fbf Mon Sep 17 00:00:00 2001
From: Alex Kirszenberg <alex.kirszenberg@vercel.com>
Date: Thu, 24 Aug 2023 11:11:06 +0200
Subject: [PATCH] Automatically derive ValueDefault for primitive value types

---
 crates/turbo-tasks-macros/src/primitive_macro.rs | 12 ++++++++++++
 crates/turbo-tasks/src/primitives.rs             |  9 +++------
 crates/turbo-tasks/src/unit.rs                   | 11 ++---------
 3 files changed, 17 insertions(+), 15 deletions(-)

diff --git a/crates/turbo-tasks-macros/src/primitive_macro.rs b/crates/turbo-tasks-macros/src/primitive_macro.rs
index e6a2590805162e..2d0b99e857ae64 100644
--- a/crates/turbo-tasks-macros/src/primitive_macro.rs
+++ b/crates/turbo-tasks-macros/src/primitive_macro.rs
@@ -48,10 +48,22 @@ pub fn primitive(input: TokenStream) -> TokenStream {
         },
     );
 
+    let value_default_impl = quote! {
+        #[turbo_tasks::value_impl]
+        impl turbo_tasks::ValueDefault for #ty {
+            #[turbo_tasks::function]
+            fn value_default() -> Vc<Self> {
+                Vc::cell(Default::default())
+            }
+        }
+    };
+
     quote! {
         #value_type_and_register
 
         #value_debug_impl
+
+        #value_default_impl
     }
     .into()
 }
diff --git a/crates/turbo-tasks/src/primitives.rs b/crates/turbo-tasks/src/primitives.rs
index ccb89fc209fe86..b14773ecb8eddf 100644
--- a/crates/turbo-tasks/src/primitives.rs
+++ b/crates/turbo-tasks/src/primitives.rs
@@ -18,6 +18,7 @@ fn empty_string() -> Vc<String> {
 }
 
 impl Vc<String> {
+    #[deprecated(note = "use Default::default() instead")]
     #[inline(always)]
     pub fn empty() -> Vc<String> {
         empty_string()
@@ -33,6 +34,7 @@ fn empty_string_vec() -> Vc<Vec<String>> {
 }
 
 impl Vc<Vec<String>> {
+    #[deprecated(note = "use Default::default() instead")]
     #[inline(always)]
     pub fn empty() -> Vc<Vec<String>> {
         empty_string_vec()
@@ -47,17 +49,12 @@ fn option_string_none() -> Vc<Option<String>> {
 }
 
 impl Vc<Option<String>> {
+    #[deprecated(note = "use Default::default() instead")]
     pub fn none() -> Self {
         option_string_none()
     }
 }
 
-impl Default for Vc<Option<String>> {
-    fn default() -> Self {
-        Self::none()
-    }
-}
-
 __turbo_tasks_internal_primitive!(bool);
 __turbo_tasks_internal_primitive!(u8);
 __turbo_tasks_internal_primitive!(u16);
diff --git a/crates/turbo-tasks/src/unit.rs b/crates/turbo-tasks/src/unit.rs
index d3af9af7b84a92..15e6a2f4c0ebef 100644
--- a/crates/turbo-tasks/src/unit.rs
+++ b/crates/turbo-tasks/src/unit.rs
@@ -1,15 +1,8 @@
-use crate::{ValueDefault, Vc};
+use crate::Vc;
 
 // TODO(alexkirsz) Should this be `#[turbo_tasks::function]` or is it okay to
 // always return a new `Vc`?
+#[deprecated(note = "use Default::default() instead")]
 pub fn unit() -> Vc<()> {
     Vc::cell(())
 }
-
-impl ValueDefault for () {
-    // TODO(alexkirsz) Should this be `#[turbo_tasks::function]` or is it
-    // preferrable to always return a new `Vc`?
-    fn value_default() -> Vc<Self> {
-        Vc::cell(())
-    }
-}