From 0623bb4d71725d6b07e8cef5665094581f951fc0 Mon Sep 17 00:00:00 2001
From: Florian Diebold <flodiebold@gmail.com>
Date: Sat, 20 Mar 2021 15:26:42 +0100
Subject: Test for a Salsa bug

---
 crates/hir_ty/src/tests/traits.rs | 51 +++++++++++++++++++++++++++++++++++++++
 1 file changed, 51 insertions(+)

(limited to 'crates/hir_ty/src/tests')

diff --git a/crates/hir_ty/src/tests/traits.rs b/crates/hir_ty/src/tests/traits.rs
index 8f2bdffc0..1bb6dff95 100644
--- a/crates/hir_ty/src/tests/traits.rs
+++ b/crates/hir_ty/src/tests/traits.rs
@@ -2271,6 +2271,57 @@ fn test<T, U>() where T: Trait<U::Item>, U: Trait<T::Item> {
     );
 }
 
+#[test]
+fn unselected_projection_in_trait_env_cycle_3() {
+    // this is a cycle, although it would be possible to handle if we didn't go
+    // into bindings when looking for traits
+    check_types(
+        r#"
+//- /main.rs
+trait Trait {
+    type Item;
+    type OtherItem;
+}
+
+fn test<T>() where T: Trait<OtherItem = T::Item> {
+    let x: T::Item = no_matter;
+}                   //^ {unknown}
+"#,
+    );
+}
+
+#[test]
+fn unselected_projection_in_trait_env_no_cycle() {
+    // this is not a cycle
+    check_types(
+        r#"
+//- /main.rs
+trait Index {
+    type Output;
+}
+
+type Key<S: UnificationStoreBase> = <S as UnificationStoreBase>::Key;
+
+pub trait UnificationStoreBase: Index<Output = Key<Self>> {
+    type Key;
+
+    fn len(&self) -> usize;
+}
+
+pub trait UnificationStoreMut: UnificationStoreBase {
+    fn push(&mut self, value: Self::Key);
+}
+
+fn test<T>(t: T) where T: UnificationStoreMut {
+    let x;
+    t.push(x);
+    let y: Key<T>;
+    (x, y);
+}      //^ (UnificationStoreBase::Key<T>, UnificationStoreBase::Key<T>)
+"#,
+    );
+}
+
 #[test]
 fn inline_assoc_type_bounds_1() {
     check_types(
-- 
cgit v1.2.3


From d8f8b495ad5c9e3676ddf7af53b23bb5b7f2fde0 Mon Sep 17 00:00:00 2001
From: Florian Diebold <flodiebold@gmail.com>
Date: Sat, 20 Mar 2021 20:07:36 +0100
Subject: Ignore type bindings in generic_predicates_for_param

This allows us to handle more cases without a query cycle, which
includes certain cases that rustc accepted. That in turn means we avoid
triggering salsa-rs/salsa#257 on valid code (it will still happen if the
user writes an actual cycle).

We actually accept more definitions than rustc now; that's because rustc
only ignores bindings when looking up super traits, whereas we now also
ignore them when looking for predicates to disambiguate associated type
shorthand. We could introduce a separate query for super traits if
necessary, but for now I think this should be fine.
---
 crates/hir_ty/src/tests/traits.rs | 5 ++---
 1 file changed, 2 insertions(+), 3 deletions(-)

(limited to 'crates/hir_ty/src/tests')

diff --git a/crates/hir_ty/src/tests/traits.rs b/crates/hir_ty/src/tests/traits.rs
index 1bb6dff95..37cd04c6f 100644
--- a/crates/hir_ty/src/tests/traits.rs
+++ b/crates/hir_ty/src/tests/traits.rs
@@ -2273,8 +2273,7 @@ fn test<T, U>() where T: Trait<U::Item>, U: Trait<T::Item> {
 
 #[test]
 fn unselected_projection_in_trait_env_cycle_3() {
-    // this is a cycle, although it would be possible to handle if we didn't go
-    // into bindings when looking for traits
+    // this is a cycle for rustc; we currently accept it
     check_types(
         r#"
 //- /main.rs
@@ -2285,7 +2284,7 @@ trait Trait {
 
 fn test<T>() where T: Trait<OtherItem = T::Item> {
     let x: T::Item = no_matter;
-}                   //^ {unknown}
+}                   //^ Trait::Item<T>
 "#,
     );
 }
-- 
cgit v1.2.3