Auto merge of #87900 - jackh726:issue-87429, r=nikomatsakis

Use bound vars for GAT params in param_env in check_type_bounds

Fixes #87429

6 files changed, 120 insertions, 0 deletions

diff --git a/src/test/ui/generic-associated-types/issue-87429-2.rs b/src/test/ui/generic-associated-types/issue-87429-2.rs
new file mode 100644
index 00000000000..d35bb098abd
--- /dev/null
+++ b/src/test/ui/generic-associated-types/issue-87429-2.rs
@@ -0,0 +1,20 @@
+// Derived from `issue-87429`. A test that ensures that using bound vars in the
+// predicates in the param env when checking that an associated type satisfies
+// its bounds does not cause us to not be able to use the bounds on the parameters.
+
+// check-pass
+
+#![feature(generic_associated_types)]
+
+trait Family {
+    type Member<'a, C: Eq>: for<'b> MyBound<'b, C>;
+}
+
+trait MyBound<'a, C> { }
+impl<'a, C: Eq> MyBound<'a, C> for i32 { }
+
+impl Family for () {
+    type Member<'a, C: Eq> = i32;
+}
+
+fn main() {}
diff --git a/src/test/ui/generic-associated-types/issue-87429-associated-type-default.rs b/src/test/ui/generic-associated-types/issue-87429-associated-type-default.rs
new file mode 100644
index 00000000000..9ee07c2f1e1
--- /dev/null
+++ b/src/test/ui/generic-associated-types/issue-87429-associated-type-default.rs
@@ -0,0 +1,18 @@
+// check-fail
+
+#![feature(associated_type_defaults)]
+#![feature(generic_associated_types)]
+
+trait Family {
+    // Fine, i32: PartialEq<i32>
+    type Member<'a>: for<'b> PartialEq<Self::Member<'b>> = i32;
+}
+
+struct Foo;
+trait Family2 {
+    // Not fine, not Foo: PartialEq<Foo>
+    type Member<'a>: for<'b> PartialEq<Self::Member<'b>> = Foo;
+    //~^ ERROR can't compare
+}
+
+fn main() {}
diff --git a/src/test/ui/generic-associated-types/issue-87429-associated-type-default.stderr b/src/test/ui/generic-associated-types/issue-87429-associated-type-default.stderr
new file mode 100644
index 00000000000..01cb0bfc72c
--- /dev/null
+++ b/src/test/ui/generic-associated-types/issue-87429-associated-type-default.stderr
@@ -0,0 +1,16 @@
+error[E0277]: can't compare `Foo` with `Foo`
+  --> $DIR/issue-87429-associated-type-default.rs:14:5
+   |
+LL |     type Member<'a>: for<'b> PartialEq<Self::Member<'b>> = Foo;
+   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ no implementation for `Foo == Foo`
+   |
+   = help: the trait `PartialEq` is not implemented for `Foo`
+note: required by a bound in `Family2::Member`
+  --> $DIR/issue-87429-associated-type-default.rs:14:22
+   |
+LL |     type Member<'a>: for<'b> PartialEq<Self::Member<'b>> = Foo;
+   |                      ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ required by this bound in `Family2::Member`
+
+error: aborting due to previous error
+
+For more information about this error, try `rustc --explain E0277`.
diff --git a/src/test/ui/generic-associated-types/issue-87429-specialization.rs b/src/test/ui/generic-associated-types/issue-87429-specialization.rs
new file mode 100644
index 00000000000..b365e07feb2
--- /dev/null
+++ b/src/test/ui/generic-associated-types/issue-87429-specialization.rs
@@ -0,0 +1,25 @@
+// check-fail
+
+#![feature(specialization)]
+//~^ WARN incomplete
+#![feature(generic_associated_types)]
+
+trait Family {
+    type Member<'a>: for<'b> PartialEq<Self::Member<'b>>;
+}
+
+struct I32Family;
+
+impl Family for I32Family {
+    default type Member<'a> = i32;
+}
+
+struct Foo;
+struct FooFamily;
+
+impl Family for FooFamily {
+    default type Member<'a> = Foo;
+    //~^ ERROR can't compare
+}
+
+fn main() {}
diff --git a/src/test/ui/generic-associated-types/issue-87429-specialization.stderr b/src/test/ui/generic-associated-types/issue-87429-specialization.stderr
new file mode 100644
index 00000000000..87bd35f5878
--- /dev/null
+++ b/src/test/ui/generic-associated-types/issue-87429-specialization.stderr
@@ -0,0 +1,26 @@
+warning: the feature `specialization` is incomplete and may not be safe to use and/or cause compiler crashes
+  --> $DIR/issue-87429-specialization.rs:3:12
+   |
+LL | #![feature(specialization)]
+   |            ^^^^^^^^^^^^^^
+   |
+   = note: `#[warn(incomplete_features)]` on by default
+   = note: see issue #31844 <https://github.com/rust-lang/rust/issues/31844> for more information
+   = help: consider using `min_specialization` instead, which is more stable and complete
+
+error[E0277]: can't compare `Foo` with `Foo`
+  --> $DIR/issue-87429-specialization.rs:21:5
+   |
+LL |     default type Member<'a> = Foo;
+   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ no implementation for `Foo == Foo`
+   |
+   = help: the trait `PartialEq` is not implemented for `Foo`
+note: required by a bound in `Family::Member`
+  --> $DIR/issue-87429-specialization.rs:8:22
+   |
+LL |     type Member<'a>: for<'b> PartialEq<Self::Member<'b>>;
+   |                      ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ required by this bound in `Family::Member`
+
+error: aborting due to previous error; 1 warning emitted
+
+For more information about this error, try `rustc --explain E0277`.
diff --git a/src/test/ui/generic-associated-types/issue-87429.rs b/src/test/ui/generic-associated-types/issue-87429.rs
new file mode 100644
index 00000000000..f905348ae32
--- /dev/null
+++ b/src/test/ui/generic-associated-types/issue-87429.rs
@@ -0,0 +1,15 @@
+// check-pass
+
+#![feature(generic_associated_types)]
+
+trait Family {
+    type Member<'a>: for<'b> PartialEq<Self::Member<'b>>;
+}
+
+struct I32;
+
+impl Family for I32 {
+    type Member<'a> = i32;
+}
+
+fn main() {}