Improve diagnostics for non-clonable return types

codegen/ui_tests/rhai_fn_non_clonable_return.rs

@@ -0,0 +1,27 @@
+use rhai::plugin::*;
+
+struct NonClonable {
+    a: f32,
+    b: u32,
+    c: char,
+    d: bool,
+}
+
+#[export_fn]
+pub fn test_fn(input: f32) -> NonClonable {
+    NonClonable {
+        a: input,
+        b: 10,
+        c: 'a',
+        d: true,
+    }
+}
+
+fn main() {
+    let n = test_fn(20.0);
+    if n.c == 'a' {
+        println!("yes");
+    } else {
+        println!("no");
+    }
+}

codegen/ui_tests/rhai_fn_non_clonable_return.stderr

@@ -0,0 +1,10 @@
+error[E0277]: the trait bound `NonClonable: std::clone::Clone` is not satisfied
+   --> $DIR/rhai_fn_non_clonable_return.rs:11:8
+    |
+11  | pub fn test_fn(input: f32) -> NonClonable {
+    |        ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ the trait `std::clone::Clone` is not implemented for `NonClonable`
+    |
+   ::: /home/cryptkeeper/Desktop/Software/ytdl-replacement/rhai/src/any.rs:537:30
+    |
+537 |     pub fn from<T: Variant + Clone>(value: T) -> Self {
+    |                              ----- required by this bound in `rhai::Dynamic::from`

codegen/ui_tests/rhai_mod_non_clonable_return.rs

@@ -0,0 +1,29 @@
+use rhai::plugin::*;
+
+struct NonClonable {
+    a: f32,
+    b: u32,
+    c: char,
+    d: bool,
+}
+
+#[export_module]
+pub mod test_mod {
+    pub fn test_fn(input: f32) -> NonClonable {
+        NonClonable {
+            a: input,
+            b: 10,
+            c: 'a',
+            d: true,
+        }
+    }
+}
+
+fn main() {
+    let n = test_mod::test_fn(20.0);
+    if n.c == 'a' {
+        println!("yes");
+    } else {
+        println!("no");
+    }
+}