Make DefPathHash->DefId panic for if the mapping fails.

We only use this mapping for cases where we know that it must succeed.
Letting it panic otherwise makes it harder to use the API in unsupported
ways.

8 files changed, 18 insertions, 25 deletions

diff --git a/compiler/rustc_hir/src/definitions.rs b/compiler/rustc_hir/src/definitions.rs
index 72a0318479f..ca29351455e 100644
--- a/compiler/rustc_hir/src/definitions.rs
+++ b/compiler/rustc_hir/src/definitions.rs
@@ -443,12 +443,13 @@ impl Definitions {
     }
 
     #[inline(always)]
-    pub fn local_def_path_hash_to_def_id(&self, hash: DefPathHash) -> Option<LocalDefId> {
+    pub fn local_def_path_hash_to_def_id(&self, hash: DefPathHash) -> LocalDefId {
         debug_assert!(hash.stable_crate_id() == self.stable_crate_id);
         self.table
             .def_path_hash_to_index
             .get(&hash)
             .map(|local_def_index| LocalDefId { local_def_index })
+            .unwrap()
     }
 
     pub fn def_path_hash_to_def_index_map(&self) -> &DefPathHashMap {
diff --git a/compiler/rustc_metadata/src/rmeta/decoder.rs b/compiler/rustc_metadata/src/rmeta/decoder.rs
index d925e3102f2..51a8dcc9db4 100644
--- a/compiler/rustc_metadata/src/rmeta/decoder.rs
+++ b/compiler/rustc_metadata/src/rmeta/decoder.rs
@@ -1622,7 +1622,7 @@ impl<'a, 'tcx> CrateMetadataRef<'a> {
     }
 
     #[inline]
-    fn def_path_hash_to_def_index(&self, hash: DefPathHash) -> Option<DefIndex> {
+    fn def_path_hash_to_def_index(&self, hash: DefPathHash) -> DefIndex {
         self.def_path_hash_map.def_path_hash_to_def_index(&hash)
     }
 
diff --git a/compiler/rustc_metadata/src/rmeta/decoder/cstore_impl.rs b/compiler/rustc_metadata/src/rmeta/decoder/cstore_impl.rs
index 4885de103a0..70952d388d5 100644
--- a/compiler/rustc_metadata/src/rmeta/decoder/cstore_impl.rs
+++ b/compiler/rustc_metadata/src/rmeta/decoder/cstore_impl.rs
@@ -517,10 +517,9 @@ impl CrateStore for CStore {
         self.get_crate_data(def.krate).def_path_hash(def.index)
     }
 
-    fn def_path_hash_to_def_id(&self, cnum: CrateNum, hash: DefPathHash) -> Option<DefId> {
-        self.get_crate_data(cnum)
-            .def_path_hash_to_def_index(hash)
-            .map(|index| DefId { krate: cnum, index })
+    fn def_path_hash_to_def_id(&self, cnum: CrateNum, hash: DefPathHash) -> DefId {
+        let def_index = self.get_crate_data(cnum).def_path_hash_to_def_index(hash);
+        DefId { krate: cnum, index: def_index }
     }
 
     fn expn_hash_to_expn_id(&self, cnum: CrateNum, index_guess: u32, hash: ExpnHash) -> ExpnId {
diff --git a/compiler/rustc_metadata/src/rmeta/def_path_hash_map.rs b/compiler/rustc_metadata/src/rmeta/def_path_hash_map.rs
index 3f500fce334..e2095d553f5 100644
--- a/compiler/rustc_metadata/src/rmeta/def_path_hash_map.rs
+++ b/compiler/rustc_metadata/src/rmeta/def_path_hash_map.rs
@@ -15,9 +15,9 @@ crate enum DefPathHashMap<'tcx> {
 
 impl DefPathHashMap<'tcx> {
     #[inline]
-    pub fn def_path_hash_to_def_index(&self, def_path_hash: &DefPathHash) -> Option<DefIndex> {
+    pub fn def_path_hash_to_def_index(&self, def_path_hash: &DefPathHash) -> DefIndex {
         match *self {
-            DefPathHashMap::OwnedFromMetadata(ref map) => map.get(def_path_hash),
+            DefPathHashMap::OwnedFromMetadata(ref map) => map.get(def_path_hash).unwrap(),
             DefPathHashMap::BorrowedFromTcx(_) => {
                 panic!("DefPathHashMap::BorrowedFromTcx variant only exists for serialization")
             }
diff --git a/compiler/rustc_middle/src/dep_graph/dep_node.rs b/compiler/rustc_middle/src/dep_graph/dep_node.rs
index 3f28cd51af7..e788dd4be85 100644
--- a/compiler/rustc_middle/src/dep_graph/dep_node.rs
+++ b/compiler/rustc_middle/src/dep_graph/dep_node.rs
@@ -336,7 +336,11 @@ impl DepNodeExt for DepNode {
     /// has been removed.
     fn extract_def_id(&self, tcx: TyCtxt<'tcx>) -> Option<DefId> {
         if self.kind.can_reconstruct_query_key() {
-            tcx.on_disk_cache.as_ref()?.def_path_hash_to_def_id(tcx, DefPathHash(self.hash.into()))
+            Some(
+                tcx.on_disk_cache
+                    .as_ref()?
+                    .def_path_hash_to_def_id(tcx, DefPathHash(self.hash.into())),
+            )
         } else {
             None
         }
diff --git a/compiler/rustc_middle/src/middle/cstore.rs b/compiler/rustc_middle/src/middle/cstore.rs
index b66260c5de3..81c44b27033 100644
--- a/compiler/rustc_middle/src/middle/cstore.rs
+++ b/compiler/rustc_middle/src/middle/cstore.rs
@@ -202,7 +202,7 @@ pub trait CrateStore: std::fmt::Debug {
     fn stable_crate_id_to_crate_num(&self, stable_crate_id: StableCrateId) -> CrateNum;
 
     /// Fetch a DefId from a DefPathHash for a foreign crate.
-    fn def_path_hash_to_def_id(&self, cnum: CrateNum, hash: DefPathHash) -> Option<DefId>;
+    fn def_path_hash_to_def_id(&self, cnum: CrateNum, hash: DefPathHash) -> DefId;
     fn expn_hash_to_expn_id(&self, cnum: CrateNum, index_guess: u32, hash: ExpnHash) -> ExpnId;
 
     // utility functions
diff --git a/compiler/rustc_middle/src/ty/context.rs b/compiler/rustc_middle/src/ty/context.rs
index a13fe75fd4d..706c3959433 100644
--- a/compiler/rustc_middle/src/ty/context.rs
+++ b/compiler/rustc_middle/src/ty/context.rs
@@ -83,11 +83,7 @@ pub trait OnDiskCache<'tcx>: rustc_data_structures::sync::Sync {
     /// Converts a `DefPathHash` to its corresponding `DefId` in the current compilation
     /// session, if it still exists. This is used during incremental compilation to
     /// turn a deserialized `DefPathHash` into its current `DefId`.
-    fn def_path_hash_to_def_id(
-        &self,
-        tcx: TyCtxt<'tcx>,
-        def_path_hash: DefPathHash,
-    ) -> Option<DefId>;
+    fn def_path_hash_to_def_id(&self, tcx: TyCtxt<'tcx>, def_path_hash: DefPathHash) -> DefId;
 
     fn drop_serialized_data(&self, tcx: TyCtxt<'tcx>);
 
diff --git a/compiler/rustc_query_impl/src/on_disk_cache.rs b/compiler/rustc_query_impl/src/on_disk_cache.rs
index 82cc81ec4c3..f9456a6f2cd 100644
--- a/compiler/rustc_query_impl/src/on_disk_cache.rs
+++ b/compiler/rustc_query_impl/src/on_disk_cache.rs
@@ -361,7 +361,7 @@ impl<'sess> rustc_middle::ty::OnDiskCache<'sess> for OnDiskCache<'sess> {
         })
     }
 
-    fn def_path_hash_to_def_id(&self, tcx: TyCtxt<'tcx>, hash: DefPathHash) -> Option<DefId> {
+    fn def_path_hash_to_def_id(&self, tcx: TyCtxt<'tcx>, hash: DefPathHash) -> DefId {
         debug!("def_path_hash_to_def_id({:?})", hash);
 
         let stable_crate_id = hash.stable_crate_id();
@@ -369,9 +369,7 @@ impl<'sess> rustc_middle::ty::OnDiskCache<'sess> for OnDiskCache<'sess> {
         // If this is a DefPathHash from the local crate, we can look up the
         // DefId in the tcx's `Definitions`.
         if stable_crate_id == tcx.sess.local_stable_crate_id() {
-            tcx.definitions_untracked()
-                .local_def_path_hash_to_def_id(hash)
-                .map(LocalDefId::to_def_id)
+            tcx.definitions_untracked().local_def_path_hash_to_def_id(hash).to_def_id()
         } else {
             // If this is a DefPathHash from an upstream crate, let the CrateStore map
             // it to a DefId.
@@ -779,12 +777,7 @@ impl<'a, 'tcx> Decodable<CacheDecoder<'a, 'tcx>> for DefId {
         // If we get to this point, then all of the query inputs were green,
         // which means that the definition with this hash is guaranteed to
         // still exist in the current compilation session.
-        Ok(d.tcx()
-            .on_disk_cache
-            .as_ref()
-            .unwrap()
-            .def_path_hash_to_def_id(d.tcx(), def_path_hash)
-            .unwrap())
+        Ok(d.tcx().on_disk_cache.as_ref().unwrap().def_path_hash_to_def_id(d.tcx(), def_path_hash))
     }
 }