Retrieve DefKind from HIR map to reduce chance of cycles

`tcx.def_kind()` could theoretically invoke another query, which could
cause an infinite query loop. Accessing the HIR map directly makes that
less likely to happen.

I also changed it to use `as_local()` (`tcx.def_kind()` seems to
implicitly call `expect_local()`) and `opt_def_kind()` to reduce the
chance of panicking on valid code.

Author: camelid

compiler/rustc_query_impl/src/plumbing.rs

@@ -338,10 +338,12 @@ macro_rules! define_queries {
                     Some(key.default_span(*tcx))
                 };
                 let def_id = key.key_as_def_id();
-                let def_kind = def_id.map(|def_id| {
-                    let def_kind = tcx.def_kind(def_id);
-                    $crate::util::def_kind_to_simple_def_kind(def_kind)
-                });
+                let def_kind = def_id
+                    .and_then(|def_id| def_id.as_local())
+                    // Use `tcx.hir().opt_def_kind()` to reduce the chance of
+                    // accidentally triggering an infinite query loop.
+                    .and_then(|def_id| tcx.hir().opt_def_kind(def_id))
+                    .map(|def_kind| $crate::util::def_kind_to_simple_def_kind(def_kind));
                 let hash = || {
                     let mut hcx = tcx.create_stable_hashing_context();
                     let mut hasher = StableHasher::new();