Add test for issue-63496

Author: JohnTitor

src/test/ui/associated-const/issue-63496.rs

@@ -0,0 +1,9 @@
+trait A {
+    const C: usize;
+
+    fn f() -> ([u8; A::C], [u8; A::C]);
+    //~^ ERROR: type annotations needed: cannot resolve
+    //~| ERROR: type annotations needed: cannot resolve
+}
+
+fn main() {}

src/test/ui/associated-const/issue-63496.stderr

@@ -0,0 +1,21 @@
+error[E0283]: type annotations needed: cannot resolve `_: A`
+  --> $DIR/issue-63496.rs:4:21
+   |
+LL |     const C: usize;
+   |     --------------- required by `A::C`
+LL | 
+LL |     fn f() -> ([u8; A::C], [u8; A::C]);
+   |                     ^^^^
+
+error[E0283]: type annotations needed: cannot resolve `_: A`
+  --> $DIR/issue-63496.rs:4:33
+   |
+LL |     const C: usize;
+   |     --------------- required by `A::C`
+LL | 
+LL |     fn f() -> ([u8; A::C], [u8; A::C]);
+   |                                 ^^^^
+
+error: aborting due to 2 previous errors
+
+For more information about this error, try `rustc --explain E0283`.