From b7bd45574a03c3f93900059d65ec7264936d5b48 Mon Sep 17 00:00:00 2001
From: Florian Diebold <flodiebold@gmail.com>
Date: Sun, 11 Jul 2021 13:22:11 +0200
Subject: [PATCH 1/2] Add workaround for #9562

This treats the consts generated by older synstructure versions like
unnamed consts. We should remove this at some point (at least after
Chalk has switched).
---
 crates/hir_def/src/item_tree/lower.rs | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/crates/hir_def/src/item_tree/lower.rs b/crates/hir_def/src/item_tree/lower.rs
index aa2dbaba1006..44bd2fa9e579 100644
--- a/crates/hir_def/src/item_tree/lower.rs
+++ b/crates/hir_def/src/item_tree/lower.rs
@@ -448,7 +448,12 @@ impl<'a> Ctx<'a> {
     }
 
     fn lower_const(&mut self, konst: &ast::Const) -> FileItemTreeId<Const> {
-        let name = konst.name().map(|it| it.as_name());
+        let mut name = konst.name().map(|it| it.as_name());
+        if name.as_ref().map_or(false, |n| n.to_string().starts_with("_DERIVE_")) {
+            // FIXME: this is a hack to treat consts generated by synstructure as unnamed
+            // remove this some time in the future
+            name = None;
+        }
         let type_ref = self.lower_type_ref_opt(konst.ty());
         let visibility = self.lower_visibility(konst);
         let ast_id = self.source_ast_id_map.ast_id(konst);

From 44d3c329221efd0f3fbc9e987d426b158aa55fa6 Mon Sep 17 00:00:00 2001
From: Florian Diebold <flodiebold@gmail.com>
Date: Sun, 11 Jul 2021 16:14:22 +0200
Subject: [PATCH 2/2] Add test for #9560

---
 crates/hir_ty/src/tests/coercion.rs | 28 +++++++++++++++++++++++++++-
 1 file changed, 27 insertions(+), 1 deletion(-)

diff --git a/crates/hir_ty/src/tests/coercion.rs b/crates/hir_ty/src/tests/coercion.rs
index aecc482cfdcd..8db1592c9160 100644
--- a/crates/hir_ty/src/tests/coercion.rs
+++ b/crates/hir_ty/src/tests/coercion.rs
@@ -500,7 +500,7 @@ fn main() {
 }
 
 #[test]
-fn coerce_unsize_expected_type() {
+fn coerce_unsize_expected_type_1() {
     check_no_mismatches(
         r#"
 //- minicore: coerce_unsized
@@ -520,6 +520,32 @@ fn main() {
     );
 }
 
+#[test]
+fn coerce_unsize_expected_type_2() {
+    // FIXME: this is wrong, #9560
+    check(
+        r#"
+//- minicore: coerce_unsized
+struct InFile<T>;
+impl<T> InFile<T> {
+    fn with_value<U>(self, value: U) -> InFile<U> { InFile }
+}
+struct RecordField;
+trait AstNode {}
+impl AstNode for RecordField {}
+
+fn takes_dyn(it: InFile<&dyn AstNode>) {}
+
+fn test() {
+    let x: InFile<()> = InFile;
+    let n = &RecordField;
+    takes_dyn(x.with_value(n));
+           // ^^^^^^^^^^^^^^^ expected InFile<&dyn AstNode>, got InFile<&RecordField>
+}
+        "#,
+    );
+}
+
 #[test]
 fn coerce_array_elems_lub() {
     check_no_mismatches(