require Copy

Avoids us impl'd for nontrivial types

Signed-off-by: Ian Jackson <ijackson@chiark.greenend.org.uk>

diff --git a/wasm/wasm.rs b/wasm/wasm.rs
index 7bea8ecf57ca92482416ad0677897d8c945b8c6f..650cbf6d41bf97a36f6a2efa98927a4141c280ae 100644 (file)
--- a/wasm/wasm.rs
+++ b/wasm/wasm.rs
@@ -15,7 +15,7 @@ trait WasmError {
   fn e(self) -> JsValue;
 }
 
-impl<E> WasmError for E where E: Display {
+impl<E> WasmError for E where E: Display+Copy {
   fn e(self) -> JsValue {
     let s = format!("{}", self);
     JsValue::from_str(&s)
@@ -26,7 +26,7 @@ trait WasmResult<V> {
   fn e(self) -> Result<V,JsValue>;
 }
 
-impl<E:Display, V> WasmResult<V> for Result<V, E> {
+impl<E:Display+Copy, V> WasmResult<V> for Result<V, E> {
   fn e(self) -> Result<V, JsValue> { self.map_err(WasmError::e) }
 }