From ce11b3a2347000854604c274d5ffc8e126bc20ea Mon Sep 17 00:00:00 2001
From: Daniel Lehmann <daniel@Mac.localdomain>
Date: Mon, 2 Dec 2024 11:24:43 -0800
Subject: [PATCH] Refint hint feature

Most importantly, this now applies hint to `const fn value()`, which is
probably the most common way to access it.

Also adds integration tests for the feature.
---
 .github/workflows/test-hint.yml | 18 ++++++++++++++++++
 Cargo.toml                      |  2 +-
 src/lib.rs                      | 16 ++++++++++++++++
 3 files changed, 35 insertions(+), 1 deletion(-)
 create mode 100644 .github/workflows/test-hint.yml

diff --git a/.github/workflows/test-hint.yml b/.github/workflows/test-hint.yml
new file mode 100644
index 0000000..0ee8731
--- /dev/null
+++ b/.github/workflows/test-hint.yml
@@ -0,0 +1,18 @@
+name: test release
+run-name: ${{ github.actor }}'s patch
+on: [push]
+jobs:
+  build-and-test:
+    runs-on: ubuntu-22.04
+    steps:
+      - uses: actions/checkout@v3
+      - uses: actions/setup-node@v3
+        with:
+          node-version: '14'
+      - uses: actions-rs/toolchain@v1
+        with:
+          toolchain: stable
+      - uses: actions-rs/cargo@v1
+        with:
+          command: test
+          args: --no-default-features --features hint
\ No newline at end of file
diff --git a/Cargo.toml b/Cargo.toml
index 68d0183..96c397d 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -32,7 +32,7 @@ borsh = ["dep:borsh"]
 schemars = ["dep:schemars", "std"]
 
 # Provide a soundness promixe to the compiler that the unerlying value is always within range
-# This optimizes e.g. indexing range checks when passed in an API
+# This optimizes e.g. indexing range checks when passed in an API.
 hint = []
 
 [dependencies]
diff --git a/src/lib.rs b/src/lib.rs
index 300b8ca..c3fb502 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -129,6 +129,7 @@ impl<T: Copy, const BITS: usize> UInt<T, BITS> {
     pub const BITS: usize = BITS;
 
     /// Returns the type as a fundamental data type
+    #[cfg(not(feature = "hint"))]
     #[inline]
     pub const fn value(self) -> T {
         self.value
@@ -271,6 +272,21 @@ macro_rules! uint_impl {
                     }
                 }
 
+                /// Returns the type as a fundamental data type
+                #[cfg(feature = "hint")]
+                #[inline]
+                pub const fn value(self) -> $type {
+                    // The hint feature requires the type to be const-comparable,
+                    // which isn't possible in the generic version above. So we have
+                    // an entirely different function if this feature is enabled.
+                    // It only works for primitive types, which should be ok in practice
+                    // (but is technically an API change)
+                    unsafe {
+                        core::hint::assert_unchecked(self.value <= Self::MAX.value);
+                    }
+                    self.value
+                }
+
                 #[deprecated(note = "Use one of the specific functions like extract_u32")]
                 pub const fn extract(value: $type, start_bit: usize) -> Self {
                     assert!(start_bit + BITS <= $type::BITS as usize);