3 files changed, 108 insertions, 0 deletions
diff --git a/src/test/ui/const-generics/generic_const_exprs/issue-99705.rs b/src/test/ui/const-generics/generic_const_exprs/issue-99705.rs
new file mode 100644
index 00000000000..75b57b621bb
--- /dev/null
+++ b/src/test/ui/const-generics/generic_const_exprs/issue-99705.rs
@@ -0,0 +1,33 @@
+// check-pass
+#![crate_type = "lib"]
+#![feature(generic_const_exprs)]
+#![allow(incomplete_features)]
+pub trait MyIterator {
+    type Output;
+}
+
+pub trait Foo {
+    const ABC: usize;
+}
+
+pub struct IteratorStruct<const N: usize>{
+
+}
+
+pub struct Bar<const N: usize> {
+    pub data: [usize; N]
+}
+
+impl<const N: usize> MyIterator for IteratorStruct<N> {
+    type Output = Bar<N>;
+}
+
+pub fn test1<T: Foo>() -> impl MyIterator<Output = Bar<{T::ABC}>> where [(); T::ABC]: Sized {
+    IteratorStruct::<{T::ABC}>{}
+}
+
+pub trait Baz<const N: usize>{}
+impl<const N: usize> Baz<N> for Bar<N> {}
+pub fn test2<T: Foo>() -> impl MyIterator<Output = impl Baz<{ T::ABC }>> where [(); T::ABC]: Sized {
+    IteratorStruct::<{T::ABC}>{}
+}
diff --git a/src/test/ui/consts/issue-103790.rs b/src/test/ui/consts/issue-103790.rs
new file mode 100644
index 00000000000..ea3cac605b1
--- /dev/null
+++ b/src/test/ui/consts/issue-103790.rs
@@ -0,0 +1,10 @@
+#![feature(generic_const_exprs)]
+#![allow(incomplete_features)]
+
+struct S<const S: (), const S: S = { S }>;
+//~^ ERROR the name `S` is already used for a generic parameter in this item's generic parameters
+//~| ERROR missing generics for struct `S`
+//~| ERROR cycle detected when computing type of `S::S`
+//~| ERROR cycle detected when computing type of `S`
+
+fn main() {}
diff --git a/src/test/ui/consts/issue-103790.stderr b/src/test/ui/consts/issue-103790.stderr
new file mode 100644
index 00000000000..41b0816dc32
--- /dev/null
+++ b/src/test/ui/consts/issue-103790.stderr
@@ -0,0 +1,65 @@
+error[E0403]: the name `S` is already used for a generic parameter in this item's generic parameters
+  --> $DIR/issue-103790.rs:4:29
+   |
+LL | struct S<const S: (), const S: S = { S }>;
+   |                -            ^ already used
+   |                |
+   |                first use of `S`
+
+error[E0107]: missing generics for struct `S`
+  --> $DIR/issue-103790.rs:4:32
+   |
+LL | struct S<const S: (), const S: S = { S }>;
+   |                                ^ expected at least 1 generic argument
+   |
+note: struct defined here, with at least 1 generic parameter: `S`
+  --> $DIR/issue-103790.rs:4:8
+   |
+LL | struct S<const S: (), const S: S = { S }>;
+   |        ^ -----------
+help: add missing generic argument
+   |
+LL | struct S<const S: (), const S: S<S> = { S }>;
+   |                                ~~~~
+
+error[E0391]: cycle detected when computing type of `S::S`
+  --> $DIR/issue-103790.rs:4:32
+   |
+LL | struct S<const S: (), const S: S = { S }>;
+   |                                ^
+   |
+   = note: ...which immediately requires computing type of `S::S` again
+note: cycle used when computing type of `S`
+  --> $DIR/issue-103790.rs:4:1
+   |
+LL | struct S<const S: (), const S: S = { S }>;
+   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+error[E0391]: cycle detected when computing type of `S`
+  --> $DIR/issue-103790.rs:4:1
+   |
+LL | struct S<const S: (), const S: S = { S }>;
+   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+   |
+note: ...which requires computing type of `S::S`...
+  --> $DIR/issue-103790.rs:4:32
+   |
+LL | struct S<const S: (), const S: S = { S }>;
+   |                                ^
+   = note: ...which again requires computing type of `S`, completing the cycle
+note: cycle used when collecting item types in top-level module
+  --> $DIR/issue-103790.rs:1:1
+   |
+LL | / #![feature(generic_const_exprs)]
+LL | | #![allow(incomplete_features)]
+LL | |
+LL | | struct S<const S: (), const S: S = { S }>;
+...  |
+LL | |
+LL | | fn main() {}
+   | |____________^
+
+error: aborting due to 4 previous errors
+
+Some errors have detailed explanations: E0107, E0391, E0403.
+For more information about an error, try `rustc --explain E0107`.