From ee5f77326cf1a46f81d820567882942b99aae2f2 Mon Sep 17 00:00:00 2001
From: Albin Hedman <albin9604@gmail.com>
Date: Wed, 19 Nov 2025 23:04:34 +0100
Subject: [PATCH] Rename Dummy to TaskArg

---
 rtic-macros/src/codegen/util.rs |  6 +++---
 rtic/src/export.rs              |  2 +-
 rtic/src/export/dummy.rs        | 15 ---------------
 rtic/src/export/task_arg.rs     | 22 ++++++++++++++++++++++
 4 files changed, 26 insertions(+), 19 deletions(-)
 delete mode 100644 rtic/src/export/dummy.rs
 create mode 100644 rtic/src/export/task_arg.rs

diff --git a/rtic-macros/src/codegen/util.rs b/rtic-macros/src/codegen/util.rs
index c94fd8b459b..1a7f18b94f5 100644
--- a/rtic-macros/src/codegen/util.rs
+++ b/rtic-macros/src/codegen/util.rs
@@ -35,7 +35,7 @@ pub fn link_section_uninit() -> TokenStream2 {
 pub fn regroup_inputs(
     inputs: &[PatType],
 ) -> (
-    // Generic args e.g. &[`_0: impl Dummy<T=i32>`, `_1: impl Dummy<T=i64>`]
+    // Generic args e.g. &[`_0: impl TaskArg<T=i32>`, `_1: impl TaskArg<T=i64>`]
     Vec<TokenStream2>,
     // args e.g. &[`_0`],  &[`_0: i32`, `_1: i64`]
     Vec<TokenStream2>,
@@ -50,7 +50,7 @@ pub fn regroup_inputs(
         let ty = &inputs[0].ty;
 
         (
-            vec![quote!(_0: impl rtic::export::dummy::Dummy<T=#ty> + Send + Sync)],
+            vec![quote!(_0: impl rtic::export::task_arg::TaskArg<T=#ty> + Send + Sync)],
             vec![quote!(_0: #ty)],
             quote!(_0),
             vec![quote!(_0)],
@@ -66,7 +66,7 @@ pub fn regroup_inputs(
             let i = Ident::new(&format!("_{i}"), Span::call_site());
             let ty = &input.ty;
 
-            generic_args.push(quote!(#i: impl rtic::export::dummy::Dummy<T=#ty> + Send + Sync));
+            generic_args.push(quote!(#i: impl rtic::export::task_arg::TaskArg<T=#ty> + Send + Sync));
 
             args.push(quote!(#i: #ty));
 
diff --git a/rtic/src/export.rs b/rtic/src/export.rs
index 0beeafbba92..c6b0dafa544 100644
--- a/rtic/src/export.rs
+++ b/rtic/src/export.rs
@@ -1,8 +1,8 @@
 pub use critical_section::CriticalSection;
 pub use portable_atomic as atomic;
 
-pub mod dummy;
 pub mod executor;
+pub mod task_arg;
 
 // Cortex-M target (any)
 #[cfg(feature = "cortex-m")]
diff --git a/rtic/src/export/dummy.rs b/rtic/src/export/dummy.rs
deleted file mode 100644
index be16aeb5ae1..00000000000
--- a/rtic/src/export/dummy.rs
+++ /dev/null
@@ -1,15 +0,0 @@
-// TODO: What should we name this?
-
-/// Dummy trait which will only ever be implemented where type T is Self
-pub trait Dummy {
-    /// This should always be same as `Self`
-    type T;
-    fn to(self) -> Self::T;
-}
-
-impl<T> Dummy for T {
-    type T = T;
-    fn to(self) -> T {
-        self
-    }
-}
diff --git a/rtic/src/export/task_arg.rs b/rtic/src/export/task_arg.rs
new file mode 100644
index 00000000000..05fa59a2593
--- /dev/null
+++ b/rtic/src/export/task_arg.rs
@@ -0,0 +1,22 @@
+/// A trait for types that can be passed as arguments when spawning tasks
+///
+/// This trait will only ever be implemented where type `Self::T` is `Self`
+///
+/// The global `my_task::spawn` requires its args to be `Send`. This trait has to
+/// be used because we can not have a function with a where clause which
+/// requires a concrete type to be `Send` if that type is not `Send`. The compiler
+/// will error out on us. However hiding that behind a dummy trait which is
+/// only implemented for that same type enables us to defer the error to when
+/// the user erroneously tries to call the function.
+pub trait TaskArg {
+    /// This should always be same as `Self`
+    type T;
+    fn to(self) -> Self::T;
+}
+
+impl<T> TaskArg for T {
+    type T = T;
+    fn to(self) -> T {
+        self
+    }
+}