From 85b7d646cd9b2deb6e65b3bd4aa045a71a6415b4 Mon Sep 17 00:00:00 2001
From: Shoyu Vanilla <modulo641@gmail.com>
Date: Mon, 27 Oct 2025 02:18:52 +0900
Subject: [PATCH] Add regression tests for some fixed `A-ty` issues

---
 .../hir-ty/src/tests/regression/new_solver.rs | 52 +++++++++++++++
 .../src/handlers/mismatched_arg_count.rs      | 23 +++++++
 .../crates/ide/src/goto_definition.rs         | 64 +++++++++++++++++++
 3 files changed, 139 insertions(+)

diff --git a/src/tools/rust-analyzer/crates/hir-ty/src/tests/regression/new_solver.rs b/src/tools/rust-analyzer/crates/hir-ty/src/tests/regression/new_solver.rs
index 5983ec764790..f8b73cd50551 100644
--- a/src/tools/rust-analyzer/crates/hir-ty/src/tests/regression/new_solver.rs
+++ b/src/tools/rust-analyzer/crates/hir-ty/src/tests/regression/new_solver.rs
@@ -472,3 +472,55 @@ where
 "#,
     );
 }
+
+#[test]
+fn regression_16282() {
+    check_infer(
+        r#"
+//- minicore: coerce_unsized, dispatch_from_dyn
+trait MapLookup<Q> {
+    type MapValue;
+}
+
+impl<K> MapLookup<K> for K {
+    type MapValue = K;
+}
+
+trait Map: MapLookup<<Self as Map>::Key> {
+    type Key;
+}
+
+impl<K> Map for K {
+    type Key = K;
+}
+
+
+fn main() {
+    let _ = &()
+        as &dyn Map<Key=u32,MapValue=u32>;
+}
+"#,
+        expect![[r#"
+            210..272 '{     ...32>; }': ()
+            220..221 '_': &'? (dyn Map<MapValue = u32, Key = u32> + '?)
+            224..227 '&()': &'? ()
+            224..269 '&()   ...e=u32>': &'? (dyn Map<MapValue = u32, Key = u32> + 'static)
+            225..227 '()': ()
+        "#]],
+    );
+}
+
+#[test]
+fn regression_18692() {
+    check_no_mismatches(
+        r#"
+//- minicore: coerce_unsized, dispatch_from_dyn, send
+trait Trait: Send {}
+
+fn f(_: *const (dyn Trait + Send)) {}
+fn g(it: *const (dyn Trait)) {
+    f(it);
+}
+"#,
+    );
+}
diff --git a/src/tools/rust-analyzer/crates/ide-diagnostics/src/handlers/mismatched_arg_count.rs b/src/tools/rust-analyzer/crates/ide-diagnostics/src/handlers/mismatched_arg_count.rs
index 25c1e633ba3b..4ed71f0d3fb8 100644
--- a/src/tools/rust-analyzer/crates/ide-diagnostics/src/handlers/mismatched_arg_count.rs
+++ b/src/tools/rust-analyzer/crates/ide-diagnostics/src/handlers/mismatched_arg_count.rs
@@ -485,6 +485,29 @@ fn foo((): (), (): ()) {
     foo(1);
       // ^ error: expected 2 arguments, found 1
 }
+"#,
+        );
+    }
+
+    #[test]
+    fn regression_17233() {
+        check_diagnostics(
+            r#"
+pub trait A {
+    type X: B;
+}
+pub trait B: A {
+    fn confused_name(self, _: i32);
+}
+
+pub struct Foo;
+impl Foo {
+    pub fn confused_name(&self) {}
+}
+
+pub fn repro<T: A>() {
+    Foo.confused_name();
+}
 "#,
         );
     }
diff --git a/src/tools/rust-analyzer/crates/ide/src/goto_definition.rs b/src/tools/rust-analyzer/crates/ide/src/goto_definition.rs
index e335989ab2b0..0ee9795af580 100644
--- a/src/tools/rust-analyzer/crates/ide/src/goto_definition.rs
+++ b/src/tools/rust-analyzer/crates/ide/src/goto_definition.rs
@@ -4015,4 +4015,68 @@ fn bar() {
         "##,
         );
     }
+
+    #[test]
+    fn regression_20038() {
+        check(
+            r#"
+//- minicore: clone, fn
+struct Map<Fut, F>(Fut, F);
+
+struct InspectFn<F>(F);
+
+trait FnOnce1<A> {
+    type Output;
+}
+
+trait Future1 {
+    type Output;
+}
+
+trait FusedFuture1: Future1 {
+    fn is_terminated(&self) -> bool;
+     //^^^^^^^^^^^^^
+}
+
+impl<T, A, R> FnOnce1<A> for T
+where
+    T: FnOnce(A) -> R,
+{
+    type Output = R;
+}
+
+impl<F, A> FnOnce1<A> for InspectFn<F>
+where
+    F: for<'a> FnOnce1<&'a A, Output = ()>,
+{
+    type Output = A;
+}
+
+impl<Fut, F, T> Future1 for Map<Fut, F>
+where
+    Fut: Future1,
+    F: FnOnce1<Fut::Output, Output = T>,
+{
+    type Output = T;
+}
+
+impl<Fut, F, T> FusedFuture1 for Map<Fut, F>
+where
+    Fut: Future1,
+    F: FnOnce1<Fut::Output, Output = T>,
+{
+    fn is_terminated(&self) -> bool {
+        false
+    }
+}
+
+fn overflows<Fut, F>(inner: &Map<Fut, InspectFn<F>>)
+where
+    Map<Fut, InspectFn<F>>: FusedFuture1
+{
+    let _x = inner.is_terminated$0();
+}
+"#,
+        )
+    }
 }