From 9918693037dce8aa4bb6f08741b6812923486c18 Mon Sep 17 00:00:00 2001
From: Daniel Baumann <daniel.baumann@progress-linux.org>
Date: Wed, 19 Jun 2024 11:26:03 +0200
Subject: Merging upstream version 1.76.0+dfsg1.

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
---
 .../assemble-normalizing-self-ty-impl-ambiguity.rs | 27 ++++++++++++++++++++++
 .../assembly/runaway-impl-candidate-selection.rs   | 15 ++++++++++++
 .../runaway-impl-candidate-selection.stderr        | 16 +++++++++++++
 3 files changed, 58 insertions(+)
 create mode 100644 tests/ui/traits/next-solver/assembly/assemble-normalizing-self-ty-impl-ambiguity.rs
 create mode 100644 tests/ui/traits/next-solver/assembly/runaway-impl-candidate-selection.rs
 create mode 100644 tests/ui/traits/next-solver/assembly/runaway-impl-candidate-selection.stderr

(limited to 'tests/ui/traits/next-solver/assembly')

diff --git a/tests/ui/traits/next-solver/assembly/assemble-normalizing-self-ty-impl-ambiguity.rs b/tests/ui/traits/next-solver/assembly/assemble-normalizing-self-ty-impl-ambiguity.rs
new file mode 100644
index 000000000..4401abd07
--- /dev/null
+++ b/tests/ui/traits/next-solver/assembly/assemble-normalizing-self-ty-impl-ambiguity.rs
@@ -0,0 +1,27 @@
+// compile-flags: -Znext-solver
+// check-pass
+
+// Checks that we do not get ambiguity by considering an impl
+// multiple times if we're able to normalize the self type.
+
+trait Trait<'a> {}
+
+impl<'a, T: 'a> Trait<'a> for T {}
+
+fn impls_trait<'a, T: Trait<'a>>() {}
+
+trait Id {
+    type Assoc;
+}
+impl<T> Id for T {
+    type Assoc = T;
+}
+
+fn call<T>() {
+    impls_trait::<<T as Id>::Assoc>();
+}
+
+fn main() {
+    call::<()>();
+    impls_trait::<<<() as Id>::Assoc as Id>::Assoc>();
+}
diff --git a/tests/ui/traits/next-solver/assembly/runaway-impl-candidate-selection.rs b/tests/ui/traits/next-solver/assembly/runaway-impl-candidate-selection.rs
new file mode 100644
index 000000000..1edc1a8c5
--- /dev/null
+++ b/tests/ui/traits/next-solver/assembly/runaway-impl-candidate-selection.rs
@@ -0,0 +1,15 @@
+// compile-flags: -Znext-solver
+
+// In the new solver, we are trying to select `<?0 as Iterator>::Item: Debug`,
+// which, naively can be unified with every impl of `Debug` if we're not careful.
+// This test makes sure that we treat projections with inference var substs as
+// placeholders during fast reject.
+
+fn iter<T: Iterator>() -> <T as Iterator>::Item {
+    todo!()
+}
+
+fn main() {
+    println!("{:?}", iter::<_>());
+    //~^ ERROR type annotations needed
+}
diff --git a/tests/ui/traits/next-solver/assembly/runaway-impl-candidate-selection.stderr b/tests/ui/traits/next-solver/assembly/runaway-impl-candidate-selection.stderr
new file mode 100644
index 000000000..4bd55ee80
--- /dev/null
+++ b/tests/ui/traits/next-solver/assembly/runaway-impl-candidate-selection.stderr
@@ -0,0 +1,16 @@
+error[E0283]: type annotations needed
+  --> $DIR/runaway-impl-candidate-selection.rs:13:22
+   |
+LL |     println!("{:?}", iter::<_>());
+   |                      ^^^^^^^^^ cannot infer type of the type parameter `T` declared on the function `iter`
+   |
+   = note: cannot satisfy `_: Iterator`
+note: required by a bound in `iter`
+  --> $DIR/runaway-impl-candidate-selection.rs:8:12
+   |
+LL | fn iter<T: Iterator>() -> <T as Iterator>::Item {
+   |            ^^^^^^^^ required by this bound in `iter`
+
+error: aborting due to 1 previous error
+
+For more information about this error, try `rustc --explain E0283`.
-- 
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