Add a test for #44255

src/test/ui/issues/issue-44255.rs

@@ -0,0 +1,29 @@
+// run-pass
+
+use std::marker::PhantomData;
+
+fn main() {
+    let _arr = [1; <Multiply<Five, Five>>::VAL];
+}
+
+trait TypeVal<T> {
+    const VAL: T;
+}
+
+struct Five;
+
+impl TypeVal<usize> for Five {
+    const VAL: usize = 5;
+}
+
+struct Multiply<N, M> {
+    _n: PhantomData<N>,
+    _m: PhantomData<M>,
+}
+
+impl<N, M> TypeVal<usize> for Multiply<N, M>
+    where N: TypeVal<usize>,
+          M: TypeVal<usize>,
+{
+    const VAL: usize = N::VAL * M::VAL;
+}