Do not ICE if some foreign expansions were not encoded.

cjgillot · cjgillot · commit 4028b093e468 · 2021-10-06T19:10:08.000+02:00
The metadata encoder does not necessarily encode all expansions, only
those which are referenced in other metadata fields.
diff --git a/compiler/rustc_metadata/src/rmeta/decoder.rs b/compiler/rustc_metadata/src/rmeta/decoder.rs
@@ -1646,8 +1646,6 @@ impl<'a, 'tcx> CrateMetadataRef<'a> {
                     let i = ExpnIndex::from_u32(i);
                     if let Some(hash) = self.root.expn_hashes.get(self, i) {
                         map.insert(hash.decode(self), i);
-                    } else {
-                        panic!("Missing expn_hash entry for {:?}", i);
                     }
                 }
                 map

Original file line number	Diff line number	Diff line change
`@@ -1646,8 +1646,6 @@ impl<'a, 'tcx> CrateMetadataRef<'a> {`
`1646`	`1646`	`let i = ExpnIndex::from_u32(i);`
`1647`	`1647`	`if let Some(hash) = self.root.expn_hashes.get(self, i) {`
`1648`	`1648`	`map.insert(hash.decode(self), i);`
`1649`		`- } else {`
`1650`		`- panic!("Missing expn_hash entry for {:?}", i);`
`1651`	`1649`	`}`
`1652`	`1650`	`}`
`1653`	`1651`	`map`