From 205dd6f50b02cdd32b3d8b883776d690596a9a92 Mon Sep 17 00:00:00 2001
From: Takayuki Maeda <takoyaki0316@gmail.com>
Date: Wed, 8 Apr 2026 23:55:26 +0900
Subject: [PATCH] reduce ICE reproducer

---
 ...type-notation-where-clause-doesnt-apply.rs | 34 +++------
 ...-notation-where-clause-doesnt-apply.stderr | 72 ++++++-------------
 2 files changed, 33 insertions(+), 73 deletions(-)

diff --git a/tests/ui/traits/next-solver/diagnostics/return-type-notation-where-clause-doesnt-apply.rs b/tests/ui/traits/next-solver/diagnostics/return-type-notation-where-clause-doesnt-apply.rs
index ecef5bd4f11c..a12e8235662b 100644
--- a/tests/ui/traits/next-solver/diagnostics/return-type-notation-where-clause-doesnt-apply.rs
+++ b/tests/ui/traits/next-solver/diagnostics/return-type-notation-where-clause-doesnt-apply.rs
@@ -3,30 +3,16 @@
 
 #![feature(return_type_notation)]
 
-pub trait Foo {
-    async fn bar();
-}
-trait Bar {}
-
-impl<T: Foo<bar(..): Send>> Foo for T where T: Bar {}
-//~^ ERROR not all trait items implemented, missing: `bar`
-
-fn needs_foo(_: impl Foo) {}
-
-trait Mirror {
-    type Mirror;
-}
-impl<T> Mirror for T {
-    type Mirror = T;
+pub trait Trait {
+    async fn func();
 }
 
-fn hello<T>()
-where
-    <T as Mirror>::Mirror: Foo,
-{
-    needs_foo(());
-    //~^ ERROR the trait bound `(): Foo` is not satisfied
-    //~| ERROR overflow evaluating the requirement
-}
+impl<T: Trait<func(..): Send>> Trait for T {}
+//~^ ERROR not all trait items implemented, missing: `func`
 
-fn main() {}
+fn check(_: impl Trait) {}
+
+fn main() {
+    check(());
+    //~^ ERROR overflow evaluating the requirement
+}
diff --git a/tests/ui/traits/next-solver/diagnostics/return-type-notation-where-clause-doesnt-apply.stderr b/tests/ui/traits/next-solver/diagnostics/return-type-notation-where-clause-doesnt-apply.stderr
index 5a47ca1d8455..84697aecfc63 100644
--- a/tests/ui/traits/next-solver/diagnostics/return-type-notation-where-clause-doesnt-apply.stderr
+++ b/tests/ui/traits/next-solver/diagnostics/return-type-notation-where-clause-doesnt-apply.stderr
@@ -1,60 +1,34 @@
-error[E0046]: not all trait items implemented, missing: `bar`
-  --> $DIR/return-type-notation-where-clause-doesnt-apply.rs:11:1
+error[E0046]: not all trait items implemented, missing: `func`
+  --> $DIR/return-type-notation-where-clause-doesnt-apply.rs:10:1
    |
-LL |     async fn bar();
-   |     --------------- `bar` from trait
+LL |     async fn func();
+   |     ---------------- `func` from trait
 ...
-LL | impl<T: Foo<bar(..): Send>> Foo for T where T: Bar {}
-   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ missing `bar` in implementation
+LL | impl<T: Trait<func(..): Send>> Trait for T {}
+   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ missing `func` in implementation
 
-error[E0277]: the trait bound `(): Foo` is not satisfied
-  --> $DIR/return-type-notation-where-clause-doesnt-apply.rs:27:15
+error[E0275]: overflow evaluating the requirement `impl Future<Output = ()> { <() as Trait>::func(..) } == _`
+  --> $DIR/return-type-notation-where-clause-doesnt-apply.rs:16:5
    |
-LL |     needs_foo(());
-   |     --------- ^^ the trait `Bar` is not implemented for `()`
-   |     |
-   |     required by a bound introduced by this call
+LL |     check(());
+   |     ^^^^^^^^^
    |
-help: this trait has no implementations, consider adding one
-  --> $DIR/return-type-notation-where-clause-doesnt-apply.rs:9:1
+note: required for `()` to implement `Trait`
+  --> $DIR/return-type-notation-where-clause-doesnt-apply.rs:10:32
    |
-LL | trait Bar {}
-   | ^^^^^^^^^
-note: required for `()` to implement `Foo`
-  --> $DIR/return-type-notation-where-clause-doesnt-apply.rs:11:29
-   |
-LL | impl<T: Foo<bar(..): Send>> Foo for T where T: Bar {}
-   |                             ^^^     ^          --- unsatisfied trait bound introduced here
+LL | impl<T: Trait<func(..): Send>> Trait for T {}
+   |                         ----   ^^^^^     ^
+   |                         |
+   |                         unsatisfied trait bound introduced here
    = note: 1 redundant requirement hidden
-   = note: required for `()` to implement `Foo`
-note: required by a bound in `needs_foo`
-  --> $DIR/return-type-notation-where-clause-doesnt-apply.rs:14:22
+   = note: required for `()` to implement `Trait`
+note: required by a bound in `check`
+  --> $DIR/return-type-notation-where-clause-doesnt-apply.rs:13:18
    |
-LL | fn needs_foo(_: impl Foo) {}
-   |                      ^^^ required by this bound in `needs_foo`
+LL | fn check(_: impl Trait) {}
+   |                  ^^^^^ required by this bound in `check`
 
-error[E0275]: overflow evaluating the requirement `impl Future<Output = ()> { <() as Foo>::bar(..) } == _`
-  --> $DIR/return-type-notation-where-clause-doesnt-apply.rs:27:5
-   |
-LL |     needs_foo(());
-   |     ^^^^^^^^^^^^^
-   |
-note: required for `()` to implement `Foo`
-  --> $DIR/return-type-notation-where-clause-doesnt-apply.rs:11:29
-   |
-LL | impl<T: Foo<bar(..): Send>> Foo for T where T: Bar {}
-   |                      ----   ^^^     ^
-   |                      |
-   |                      unsatisfied trait bound introduced here
-   = note: 1 redundant requirement hidden
-   = note: required for `()` to implement `Foo`
-note: required by a bound in `needs_foo`
-  --> $DIR/return-type-notation-where-clause-doesnt-apply.rs:14:22
-   |
-LL | fn needs_foo(_: impl Foo) {}
-   |                      ^^^ required by this bound in `needs_foo`
+error: aborting due to 2 previous errors
 
-error: aborting due to 3 previous errors
-
-Some errors have detailed explanations: E0046, E0275, E0277.
+Some errors have detailed explanations: E0046, E0275.
 For more information about an error, try `rustc --explain E0046`.