Auto merge of #1094 - photoszzt:fix_hash_incomplete_arr, r=emilio

Fix mistakenly derive hash for struct that contains IncompleteArrayField

Fix #1093

r? @fitzgen  or @emilio

1 files changed, 4 insertions, 1 deletions

diff --git a/src/ir/analysis/derive_hash.rs b/src/ir/analysis/derive_hash.rs
index 569c7246..d2eac677 100644
--- a/src/ir/analysis/derive_hash.rs
+++ b/src/ir/analysis/derive_hash.rs
@@ -187,7 +187,10 @@ impl<'ctx> MonotoneFramework for CannotDeriveHash<'ctx> {
                     return self.insert(id);
                 }
 
-                if len <= RUST_DERIVE_IN_ARRAY_LIMIT {
+                if len == 0 {
+                    trace!("    cannot derive `Hash` for incomplete arrays");
+                    self.insert(id)
+                } else if len <= RUST_DERIVE_IN_ARRAY_LIMIT {
                     trace!("    array is small enough to derive Hash");
                     ConstrainResult::Same
                 } else {