Add test

Author: estebank

src/test/ui/numeric/len.rs

@@ -0,0 +1,8 @@
+fn main() {
+    let array = [1, 2, 3];
+    test(array.len()); //~ ERROR mismatched types
+}
+
+fn test(length: u32) {
+    println!("{}", length);
+}

src/test/ui/numeric/len.stderr

@@ -0,0 +1,13 @@
+error[E0308]: mismatched types
+  --> $DIR/len.rs:3:10
+   |
+LL |     test(array.len());
+   |          ^^^^^^^^^^^ expected u32, found usize
+help: you can convert an `usize` to `u32` or panic if it the converted value wouldn't fit
+   |
+LL |     test(array.len().try_into().unwrap());
+   |          ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+error: aborting due to previous error
+
+For more information about this error, try `rustc --explain E0308`.