Merge #10529

10529: Generate `PartialOrd` implementations r=Veykril a=yoshuawuyts

_co-authored with `@rylev_`

This closes #5946 (which should've been closed already, lol). This PR makes it so we generate `PartialOrd` code implementations where possible. This is the last of Rust's built-in traits that was missing codegen.

After this has been merged we should look at moving the tests to a better spot, and maybe cleaning up the implementation somewhat (it's rather copy-pasty at the moment).

Either way, this finishes up the functionality. Thanks heaps!

Co-authored-by: Yoshua Wuyts <[email protected]>

Author: bors[bot]

crates/ide_assists/src/handlers/replace_derive_with_manual_impl.rs

@@ -675,6 +675,194 @@ impl Clone for Foo {
         )
     }
 
+    #[test]
+    fn add_custom_impl_partial_ord_record_struct() {
+        check_assist(
+            replace_derive_with_manual_impl,
+            r#"
+//- minicore: ord
+#[derive(Partial$0Ord)]
+struct Foo {
+    bin: usize,
+}
+"#,
+            r#"
+struct Foo {
+    bin: usize,
+}
+
+impl PartialOrd for Foo {
+    $0fn partial_cmp(&self, other: &Self) -> Option<core::cmp::Ordering> {
+        self.bin.partial_cmp(other.bin)
+    }
+}
+"#,
+        )
+    }
+
+    #[test]
+    fn add_custom_impl_partial_ord_record_struct_multi_field() {
+        check_assist(
+            replace_derive_with_manual_impl,
+            r#"
+//- minicore: ord
+#[derive(Partial$0Ord)]
+struct Foo {
+    bin: usize,
+    bar: usize,
+    baz: usize,
+}
+"#,
+            r#"
+struct Foo {
+    bin: usize,
+    bar: usize,
+    baz: usize,
+}
+
+impl PartialOrd for Foo {
+    $0fn partial_cmp(&self, other: &Self) -> Option<core::cmp::Ordering> {
+        (self.bin, self.bar, self.baz).partial_cmp((other.bin, other.bar, other.baz))
+    }
+}
+"#,
+        )
+    }
+
+    #[test]
+    fn add_custom_impl_partial_ord_tuple_struct() {
+        check_assist(
+            replace_derive_with_manual_impl,
+            r#"
+//- minicore: ord
+#[derive(Partial$0Ord)]
+struct Foo(usize, usize, usize);
+"#,
+            r#"
+struct Foo(usize, usize, usize);
+
+impl PartialOrd for Foo {
+    $0fn partial_cmp(&self, other: &Self) -> Option<core::cmp::Ordering> {
+        (self.0, self.1, self.2).partial_cmp((other.0, other.1, other.2))
+    }
+}
+"#,
+        )
+    }
+
+    #[test]
+    fn add_custom_impl_partial_ord_enum() {
+        check_assist(
+            replace_derive_with_manual_impl,
+            r#"
+//- minicore: ord
+#[derive(Partial$0Ord)]
+enum Foo {
+    Bin,
+    Bar,
+    Baz,
+}
+"#,
+            r#"
+enum Foo {
+    Bin,
+    Bar,
+    Baz,
+}
+
+impl PartialOrd for Foo {
+    $0fn partial_cmp(&self, other: &Self) -> Option<core::cmp::Ordering> {
+        core::mem::discriminant(self).partial_cmp(core::mem::discriminant(other))
+    }
+}
+"#,
+        )
+    }
+
+    #[test]
+    fn add_custom_impl_partial_ord_record_enum() {
+        check_assist(
+            replace_derive_with_manual_impl,
+            r#"
+//- minicore: ord
+#[derive(Partial$0Ord)]
+enum Foo {
+    Bar {
+        bin: String,
+    },
+    Baz {
+        qux: String,
+        fez: String,
+    },
+    Qux {},
+    Bin,
+}
+"#,
+            r#"
+enum Foo {
+    Bar {
+        bin: String,
+    },
+    Baz {
+        qux: String,
+        fez: String,
+    },
+    Qux {},
+    Bin,
+}
+
+impl PartialOrd for Foo {
+    $0fn partial_cmp(&self, other: &Self) -> Option<core::cmp::Ordering> {
+        match (self, other) {
+            (Self::Bar { bin: l_bin }, Self::Bar { bin: r_bin }) => l_bin.partial_cmp(r_bin),
+            (Self::Baz { qux: l_qux, fez: l_fez }, Self::Baz { qux: r_qux, fez: r_fez }) => {
+                (l_qux, l_fez).partial_cmp((r_qux, r_fez))
+            }
+            _ => core::mem::discriminant(self).partial_cmp(core::mem::discriminant(other)),
+        }
+    }
+}
+"#,
+        )
+    }
+
+    #[test]
+    fn add_custom_impl_partial_ord_tuple_enum() {
+        check_assist(
+            replace_derive_with_manual_impl,
+            r#"
+//- minicore: ord
+#[derive(Partial$0Ord)]
+enum Foo {
+    Bar(String),
+    Baz(String, String),
+    Qux(),
+    Bin,
+}
+"#,
+            r#"
+enum Foo {
+    Bar(String),
+    Baz(String, String),
+    Qux(),
+    Bin,
+}
+
+impl PartialOrd for Foo {
+    $0fn partial_cmp(&self, other: &Self) -> Option<core::cmp::Ordering> {
+        match (self, other) {
+            (Self::Bar(l0), Self::Bar(r0)) => l0.partial_cmp(r0),
+            (Self::Baz(l0, l1), Self::Baz(r0, r1)) => {
+                (l0, l1).partial_cmp((r0, r1))
+            }
+            _ => core::mem::discriminant(self).partial_cmp(core::mem::discriminant(other)),
+        }
+    }
+}
+"#,
+        )
+    }
+
     #[test]
     fn add_custom_impl_partial_eq_record_struct() {
         check_assist(