Deprecate From<EvalAltResult> for Result<T, Box<EvalAltResult>> because it is clearer for code to explicitly wrap errors in Err.

src/packages/lang_core.rs

@@ -14,7 +14,7 @@ mod core_functions {
     #[rhai_fn(name = "set_tag", set = "tag", return_raw)]
     pub fn set_tag(value: &mut Dynamic, tag: INT) -> Result<(), Box<EvalAltResult>> {
         if tag < Tag::MIN as INT {
-            EvalAltResult::ErrorArithmetic(
+            Err(EvalAltResult::ErrorArithmetic(
                 format!(
                     "{} is too small to fit into a tag (must be between {} and {})",
                     tag,
@@ -23,9 +23,9 @@ mod core_functions {
                 ),
                 Position::NONE,
             )
-            .into()
+            .into())
         } else if tag > Tag::MAX as INT {
-            EvalAltResult::ErrorArithmetic(
+            Err(EvalAltResult::ErrorArithmetic(
                 format!(
                     "{} is too large to fit into a tag (must be between {} and {})",
                     tag,
@@ -34,7 +34,7 @@ mod core_functions {
                 ),
                 Position::NONE,
             )
-            .into()
+            .into())
         } else {
             value.set_tag(tag as Tag);
             Ok(())