[gcc r17-4352] gccrs: Fix bad derive of Ord to use Self instead of raw type-name

[Arthur Cohen via Gcc-cvs]

https://gcc.gnu.org/g:18ad6345e6df72ca010952d972dfadef3195a64b

commit r17-4352-g18ad6345e6df72ca010952d972dfadef3195a64b
Author: Philip Herron <herron.phi...@googlemail.com>
Date:   Thu Sep 10 21:02:28 2026 +0100

    gccrs: Fix bad derive of Ord to use Self instead of raw type-name
    
    The raw type name doesnt capture the generic state of the impl but Self
    does.
    
    Fixes Rust-GCC/gccrs#4879
    
    gcc/rust/ChangeLog:
    
            * expand/rust-derive-ord.cc (DeriveOrd::cmp_fn): use Self
    
    gcc/testsuite/ChangeLog:
    
            * rust/compile/issue-4879.rs: New test.
    
    Signed-off-by: Philip Herron <herron.phi...@googlemail.com>

Diff:
---
 gcc/rust/expand/rust-derive-ord.cc       | 13 ++++---
 gcc/testsuite/rust/compile/issue-4879.rs | 65 ++++++++++++++++++++++++++++++++
 2 files changed, 73 insertions(+), 5 deletions(-)

diff --git a/gcc/rust/expand/rust-derive-ord.cc 
b/gcc/rust/expand/rust-derive-ord.cc
index aae7f8414814..7960d2978dab 100644
--- a/gcc/rust/expand/rust-derive-ord.cc
+++ b/gcc/rust/expand/rust-derive-ord.cc
@@ -100,11 +100,14 @@ DeriveOrd::cmp_fn (std::unique_ptr<BlockExpr> &&block, 
Identifier type_name)
     }
 
   // &self, other: &Self
-  auto params = vec (
-    builder.self_ref_param (),
-    builder.function_param (builder.identifier_pattern ("other"),
-                           builder.reference_type (ptrify (
-                             builder.type_path (type_name.as_string ())))));
+  //
+  // this must be Self for a generic type Wrapping<T> the bare struct name has
+  // no type arguments
+  auto params
+    = vec (builder.self_ref_param (),
+          builder.function_param (builder.identifier_pattern ("other"),
+                                  builder.reference_type (
+                                    ptrify (builder.type_path ("Self")))));
 
   auto function_name = fn (ordering);
 
diff --git a/gcc/testsuite/rust/compile/issue-4879.rs 
b/gcc/testsuite/rust/compile/issue-4879.rs
new file mode 100644
index 000000000000..e2e8ac1078bc
--- /dev/null
+++ b/gcc/testsuite/rust/compile/issue-4879.rs
@@ -0,0 +1,65 @@
+#![feature(no_core, lang_items)]
+#![no_core]
+
+#[lang = "sized"]
+pub trait Sized {}
+
+#[lang = "structural_peq"]
+pub trait StructuralPartialEq {}
+
+#[lang = "structural_teq"]
+pub trait StructuralEq {}
+
+#[lang = "phantom_data"]
+pub struct PhantomData<T: ?Sized>;
+
+pub mod option {
+    pub enum Option<T> {
+        #[lang = "None"]
+        None,
+        #[lang = "Some"]
+        Some(T),
+    }
+}
+
+pub use option::Option;
+
+pub mod cmp {
+    use crate::Sized;
+
+    #[lang = "eq"]
+    pub trait PartialEq<Rhs: ?Sized = Self> {
+        fn eq(&self, other: &Rhs) -> bool;
+        fn ne(&self, other: &Rhs) -> bool {
+            !self.eq(other)
+        }
+    }
+
+    pub trait Eq: PartialEq<Self> {
+        fn assert_receiver_is_total_eq(&self) {}
+    }
+
+    pub enum Ordering {
+        Less = -1,
+        Equal = 0,
+        Greater = 1,
+    }
+
+    #[lang = "partial_ord"]
+    pub trait PartialOrd<Rhs: ?Sized = Self>: PartialEq<Rhs> {
+        fn partial_cmp(&self, other: &Rhs) -> crate::Option<Ordering>;
+    }
+
+    pub trait Ord: Eq + PartialOrd<Self> {
+        fn cmp(&self, other: &Self) -> Ordering;
+    }
+}
+
+use cmp::{Eq, Ord, PartialEq, PartialOrd};
+
+#[derive(PartialEq, PartialOrd, Eq, Ord)]
+pub struct Wrapping<T>(pub T);
+
+fn main() -> i32 {
+    0
+}