From 7ae20bf723ee740b0f823bde99fc7c47ae1461a8 Mon Sep 17 00:00:00 2001
From: Tony Arcieri <bascule@gmail.com>
Date: Wed, 10 Dec 2025 11:30:27 -0700
Subject: [PATCH] mcf: add `PasswordHash::as_password_hash_ref`

Adds an explicit method for borrowing a `&PasswordHashRef` from
`&PasswordHash`, which is useful over `AsRef`/`Borrow`/`Deref` when
avoiding inference and being explicit is preferable.

To denote the pending breaking changes, this also bumps the version to
v0.6.0-pre, so as to match `password-hash` and `phc`'s version.
---
 Cargo.lock     |  2 +-
 mcf/Cargo.toml |  2 +-
 mcf/src/lib.rs | 23 +++++++++++++++++++----
 3 files changed, 21 insertions(+), 6 deletions(-)

diff --git a/Cargo.lock b/Cargo.lock
index 4f9a4a4ef..4f3eb7582 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -810,7 +810,7 @@ checksum = "df1d3c3b53da64cf5760482273a98e575c651a67eec7f77df96b5b642de8f039"
 
 [[package]]
 name = "mcf"
-version = "0.2.0"
+version = "0.6.0-pre"
 dependencies = [
  "base64ct",
  "hex-literal",
diff --git a/mcf/Cargo.toml b/mcf/Cargo.toml
index d9f92d7af..dd0c6fe01 100644
--- a/mcf/Cargo.toml
+++ b/mcf/Cargo.toml
@@ -1,6 +1,6 @@
 [package]
 name = "mcf"
-version = "0.2.0"
+version = "0.6.0-pre"
 authors = ["RustCrypto Developers"]
 edition = "2024"
 rust-version = "1.85"
diff --git a/mcf/src/lib.rs b/mcf/src/lib.rs
index 98dbaf057..b63852c8d 100644
--- a/mcf/src/lib.rs
+++ b/mcf/src/lib.rs
@@ -147,6 +147,15 @@ mod allocating {
             Ok(Self(s))
         }
 
+        /// Borrow the contents of this password hash as a [`PasswordHashRef`].
+        ///
+        /// Similar conversions can be performed using [`AsRef`], [`Borrow`], and [`Deref`], however
+        /// this one is useful when the return type may be ambiguous and avoiding potential
+        /// inference bugs is preferable.
+        pub fn as_password_hash_ref(&self) -> &PasswordHashRef {
+            PasswordHashRef::new_unchecked(&self.0)
+        }
+
         /// Create an [`PasswordHash`] from an identifier.
         ///
         /// # Returns
@@ -207,13 +216,13 @@ mod allocating {
 
     impl AsRef<PasswordHashRef> for PasswordHash {
         fn as_ref(&self) -> &PasswordHashRef {
-            PasswordHashRef::new_unchecked(&self.0)
+            self.as_password_hash_ref()
         }
     }
 
     impl Borrow<PasswordHashRef> for PasswordHash {
         fn borrow(&self) -> &PasswordHashRef {
-            self.as_ref()
+            self.as_password_hash_ref()
         }
     }
 
@@ -221,7 +230,7 @@ mod allocating {
         type Target = PasswordHashRef;
 
         fn deref(&self) -> &PasswordHashRef {
-            self.as_ref()
+            self.as_password_hash_ref()
         }
     }
 
@@ -231,6 +240,12 @@ mod allocating {
         }
     }
 
+    impl From<&PasswordHash> for String {
+        fn from(hash: &PasswordHash) -> Self {
+            hash.0.clone()
+        }
+    }
+
     impl FromStr for PasswordHash {
         type Err = Error;
 
@@ -267,7 +282,7 @@ mod allocating {
 
     impl<'a> From<&'a PasswordHash> for &'a PasswordHashRef {
         fn from(hash: &'a PasswordHash) -> &'a PasswordHashRef {
-            hash.as_ref()
+            hash.as_password_hash_ref()
         }
     }