clippy: Fix cast_lossless

rr_frontend/.cargo/config.toml

@@ -32,7 +32,6 @@ rustflags = [
     "-Aclippy::string_lit_as_bytes",
 
     # clippy::pedantic
-    "-Aclippy::cast_lossless",
     "-Aclippy::cloned_instead_of_copied",
     "-Aclippy::default_trait_access",
     "-Aclippy::doc_markdown",

rr_frontend/attribute_parse/src/parse.rs

@@ -662,7 +662,9 @@ impl BigInt {
 
     fn reserve_two_digits(&mut self) {
         let len = self.digits.len();
-        let desired = len + !self.digits.ends_with(&[0, 0]) as usize + !self.digits.ends_with(&[0]) as usize;
+        let desired =
+            len + usize::from(!self.digits.ends_with(&[0, 0])) + usize::from(!self.digits.ends_with(&[0]));
+
         self.digits.resize(desired, 0);
     }
 }

rr_frontend/translation/src/type_translator.rs

@@ -950,7 +950,7 @@ impl<'def, 'tcx: 'def> TypeTranslator<'def, 'tcx> {
                     map.insert(name, evaluated_int);
                 },
                 ty::VariantDiscr::Relative(offset) => {
-                    let idx: i128 = last_explicit_discr + (offset as i128);
+                    let idx: i128 = last_explicit_discr + i128::from(offset);
                     map.insert(name, idx);
                 },
             }