Add the dyn keyword before trait objects;

cranelift/frontend/src/frontend.rs

@@ -571,7 +571,7 @@ impl<'a> FunctionBuilder<'a> {
     /// Useful for debug purposes. Use it with `None` for standard printing.
     // Clippy thinks the lifetime that follows is needless, but rustc needs it
     #[cfg_attr(feature = "cargo-clippy", allow(clippy::needless_lifetimes))]
-    pub fn display<'b, I: Into<Option<&'b TargetIsa>>>(&'b self, isa: I) -> DisplayFunction {
+    pub fn display<'b, I: Into<Option<&'b dyn TargetIsa>>>(&'b self, isa: I) -> DisplayFunction {
         self.func.display(isa)
     }
 }