From 55b9bb15b22c7b6f4fb208105357330aee05b339 Mon Sep 17 00:00:00 2001
From: Jelte Fennema-Nio <github-tech@jeltef.nl>
Date: Tue, 2 Jul 2024 17:07:49 +0200
Subject: [PATCH] Add #[track_caller] to Add/Mul(Assign) derives (#378)

Resolves #364

## Synopsis

In debug builds overflows cause panics. With our derives it's hard to
spot where these panics happen when RUST_BACKTRACE is not set.

## Solution

This fixes that by marking our trait methods for Add/Mul(Assign) as
`#[track_caller].

## Checklist

~- [ ] Documentation is updated (if required)~
~- [ ] Tests are added/updated (if required)~
- [x] [CHANGELOG entry][l:1] is added (if required)

[l:1]: /CHANGELOG.md
---
 CHANGELOG.md                | 3 +++
 impl/src/add_assign_like.rs | 1 +
 impl/src/add_like.rs        | 1 +
 impl/src/mul_assign_like.rs | 1 +
 impl/src/mul_like.rs        | 1 +
 5 files changed, 7 insertions(+)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index a9805322..e10b5014 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -71,6 +71,9 @@ and this project adheres to [Semantic Versioning](http://semver.org/).
   ([#300](https://github.com/JelteF/derive_more/pull/300))
 - `#[inline]` attributes to `IsVariant` and `Debug` implementations.
   ([#334](https://github.com/JelteF/derive_more/pull/334)
+- Add `#[track_caller]` to `Add`, `Mul`, `AddAssign` and `MulAssign` derives
+  ([#378](https://github.com/JelteF/derive_more/pull/378)
+
 
 ### Changed
 
diff --git a/impl/src/add_assign_like.rs b/impl/src/add_assign_like.rs
index 49510eb7..7d476732 100644
--- a/impl/src/add_assign_like.rs
+++ b/impl/src/add_assign_like.rs
@@ -31,6 +31,7 @@ pub fn expand(input: &DeriveInput, trait_name: &str) -> TokenStream {
         #[automatically_derived]
         impl #impl_generics derive_more::#trait_ident for #input_type #ty_generics #where_clause {
             #[inline]
+            #[track_caller]
             fn #method_ident(&mut self, rhs: #input_type #ty_generics) {
                 #( #exprs; )*
             }
diff --git a/impl/src/add_like.rs b/impl/src/add_like.rs
index 095bf37f..097a89c6 100644
--- a/impl/src/add_like.rs
+++ b/impl/src/add_like.rs
@@ -46,6 +46,7 @@ pub fn expand(input: &DeriveInput, trait_name: &str) -> TokenStream {
             type Output = #output_type;
 
             #[inline]
+            #[track_caller]
             fn #method_ident(self, rhs: #input_type #ty_generics) -> #output_type {
                 #block
             }
diff --git a/impl/src/mul_assign_like.rs b/impl/src/mul_assign_like.rs
index 8e3f2cb7..b5fb4e50 100644
--- a/impl/src/mul_assign_like.rs
+++ b/impl/src/mul_assign_like.rs
@@ -55,6 +55,7 @@ pub fn expand(input: &DeriveInput, trait_name: &'static str) -> Result<TokenStre
         #[automatically_derived]
         impl #impl_generics #trait_path<#scalar_ident> for #input_type #ty_generics #where_clause {
             #[inline]
+            #[track_caller]
             fn #method_ident(&mut self, rhs: #scalar_ident) {
                 #( #exprs; )*
             }
diff --git a/impl/src/mul_like.rs b/impl/src/mul_like.rs
index d06372f3..c8a2ffac 100644
--- a/impl/src/mul_like.rs
+++ b/impl/src/mul_like.rs
@@ -53,6 +53,7 @@ pub fn expand(input: &DeriveInput, trait_name: &'static str) -> Result<TokenStre
             type Output = #input_type #ty_generics;
 
             #[inline]
+            #[track_caller]
             fn #method_ident(self, rhs: #scalar_ident) -> #input_type #ty_generics {
                 #body
             }