Work around rust < 1.78 crash

glandium · glandium · commit df040ea97106 · 2024-12-26T09:54:32.000+09:00
Somehow the DWARF info generated by the compiler for the
`hash`-replacement assignment is confusing to LLVM, which crashes.

By using a different form for the same operation, the compiler is happy.
diff --git a/mls-rs/src/tree_kem/parent_hash.rs b/mls-rs/src/tree_kem/parent_hash.rs
@@ -135,7 +135,7 @@ impl TreeKemPublic {
             )
             .await?;
 
-            (parent.parent_hash, hash) = (hash, calculated);
+            parent.parent_hash = std::mem::replace(&mut hash, calculated);
         }
 
         Ok(hash)

Original file line number	Diff line number	Diff line change
`@@ -135,7 +135,7 @@ impl TreeKemPublic {`
`135`	`135`	`)`
`136`	`136`	`.await?;`
`137`	`137`
`138`		`- (parent.parent_hash, hash) = (hash, calculated);`
	`138`	`+ parent.parent_hash = std::mem::replace(&mut hash, calculated);`
`139`	`139`	`}`
`140`	`140`
`141`	`141`	`Ok(hash)`