rustc_metadata: Privatize `CrateMetadata::dep_kind`

src/librustc_metadata/creader.rs

@@ -50,7 +50,7 @@ fn dump_crates(cstore: &CStore) {
         info!("  name: {}", data.root.name);
         info!("  cnum: {}", cnum);
         info!("  hash: {}", data.root.hash);
-        info!("  reqd: {:?}", *data.dep_kind.lock());
+        info!("  reqd: {:?}", data.dep_kind());
         let CrateSource { dylib, rlib, rmeta } = data.source();
         dylib.as_ref().map(|dl| info!("  dylib: {}", dl.0.display()));
         rlib.as_ref().map(|rl|  info!("   rlib: {}", rl.0.display()));
@@ -353,9 +353,7 @@ fn maybe_resolve_crate<'b>(
                 if data.root.is_proc_macro_crate() {
                     dep_kind = DepKind::UnexportedMacrosOnly;
                 }
-                data.dep_kind.with_lock(|data_dep_kind| {
-                    *data_dep_kind = cmp::max(*data_dep_kind, dep_kind);
-                });
+                data.update_dep_kind(|data_dep_kind| cmp::max(data_dep_kind, dep_kind));
                 Ok(cnum)
             }
             (LoadResult::Loaded(library), host_library) => {
@@ -503,7 +501,7 @@ fn inject_panic_runtime(&mut self, krate: &ast::Crate) {
                 // #![panic_runtime] crate.
                 self.inject_dependency_if(cnum, "a panic runtime",
                                           &|data| data.root.needs_panic_runtime);
-                runtime_found = runtime_found || *data.dep_kind.lock() == DepKind::Explicit;
+                runtime_found = runtime_found || data.dep_kind() == DepKind::Explicit;
             }
         });
 

src/librustc_metadata/rmeta/decoder.rs

@@ -99,7 +99,7 @@
     /// Same ID set as `cnum_map` plus maybe some injected crates like panic runtime.
     dependencies: Lock<Vec<CrateNum>>,
     /// How to link (or not link) this crate to the currently compiled crate.
-    crate dep_kind: Lock<DepKind>,
+    dep_kind: Lock<DepKind>,
     /// Filesystem location of this crate.
     source: CrateSource,
     /// Whether or not this crate should be consider a private dependency
@@ -1538,6 +1538,14 @@ fn get_crate_dep_node_index(&self, tcx: TyCtxt<'tcx>) -> DepNodeIndex {
     crate fn source(&self) -> &CrateSource {
         &self.source
     }
+
+    crate fn dep_kind(&self) -> DepKind {
+        *self.dep_kind.lock()
+    }
+
+    crate fn update_dep_kind(&self, f: impl FnOnce(DepKind) -> DepKind) {
+        self.dep_kind.with_lock(|dep_kind| *dep_kind = f(*dep_kind))
+    }
 }
 
 // Cannot be implemented on 'ProcMacro', as libproc_macro