Add test for 113326

Author: clubby789

tests/ui/type-alias-impl-trait/issue-113326.rs

@@ -0,0 +1,25 @@
+#![allow(incomplete_features)]
+#![feature(const_trait_impl)]
+#![feature(const_closures)]
+#![feature(const_refs_to_cell)]
+#![feature(type_alias_impl_trait)]
+
+pub type Diff = impl ~const std::marker::Destruct + ~const Fn(usize) -> usize;
+//~^ ERROR: ~const can only be applied to `#[const_trait]` traits
+
+pub const fn lift(n: usize) -> Diff {
+    const move |m: usize| m + n
+}
+
+pub const fn reify(n: Diff) -> usize {
+    n(0)
+}
+
+pub const fn add(
+    n: Diff,
+    m: Diff,
+) -> Diff {
+    const move |x: usize| m(n(x))
+}
+
+fn main() {}

tests/ui/type-alias-impl-trait/issue-113326.stderr

@@ -0,0 +1,8 @@
+error: ~const can only be applied to `#[const_trait]` traits
+  --> $DIR/issue-113326.rs:7:60
+   |
+LL | pub type Diff = impl ~const std::marker::Destruct + ~const Fn(usize) -> usize;
+   |                                                            ^^^^^^^^^^^^^^^^^^
+
+error: aborting due to previous error
+