Add test for issue-64620

Author: JohnTitor

src/test/ui/generator/issue-64620-yield-array-element.rs

@@ -0,0 +1,9 @@
+// Regression test for #64620
+
+#![feature(generators)]
+
+pub fn crash(arr: [usize; 1]) {
+    yield arr[0]; //~ ERROR: yield expression outside of generator literal
+}
+
+fn main() {}

src/test/ui/generator/issue-64620-yield-array-element.stderr

@@ -0,0 +1,9 @@
+error[E0627]: yield expression outside of generator literal
+  --> $DIR/issue-64620-yield-array-element.rs:6:5
+   |
+LL |     yield arr[0];
+   |     ^^^^^^^^^^^^
+
+error: aborting due to previous error
+
+For more information about this error, try `rustc --explain E0627`.