Enable strings as steps based on descriptive-gate feature.

Usually !debug_assertions => compact-gate, but that is not the case when
profiling.

Cargo.toml

@@ -6,12 +6,8 @@ members = ["ipa-core", "ipa-macros"]
 incremental = true
 lto = "thin"
 
-[profile.bench]
-debug-assertions = true
-
 [profile.bench-dhat]
 inherits = "bench"
-debug-assertions = false
 incremental = true
 lto = "thin"
 debug = 1

ipa-core/src/ff/curve_points.rs

@@ -197,11 +197,7 @@ mod test {
     use typenum::U32;
 
     use crate::{
-        ff::{
-            curve_points::{NonCanonicalEncoding, RP25519},
-            ec_prime_field::Fp25519,
-            Serializable,
-        },
+        ff::{curve_points::RP25519, ec_prime_field::Fp25519, Serializable},
         secret_sharing::SharedValue,
     };
 
@@ -258,7 +254,10 @@ mod test {
     }
 
     #[test]
+    #[cfg(debug_assertions)]
     fn non_canonical() {
+        use crate::ff::curve_points::NonCanonicalEncoding;
+
         const ZERO: u128 = 0;
         // 0xFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFF is not a valid Ristretto point
         let buf: [u8; 32] = unsafe { std::mem::transmute([!ZERO, !ZERO]) };

ipa-core/src/ff/galois_field.rs

@@ -530,8 +530,14 @@ macro_rules! bit_array_impl {
                 }
 
                 #[test]
+                #[cfg(debug_assertions)]
                 #[should_panic(expected = "index < usize::try_from")]
                 pub fn out_of_count_index() {
+                    // With debug assertions enabled, this test will panic on any out-of-bounds
+                    // access. Without debug assertions, it will not panic on access to the unused
+                    // bits for non-multiple-of-8 bitwidths. Enable the test only with debug
+                    // assertions, rather than try to do something conditioned on the bit width.
+
                     let s = $name::try_from(1_u128).unwrap();
                     // Below assert doesn't matter. The indexing should panic
                     assert_eq!(s[<$name>::BITS as usize], false);

ipa-core/src/protocol/step/mod.rs

@@ -36,10 +36,10 @@ pub trait StepNarrow<S: Step + ?Sized> {
 pub trait Step: AsRef<str> {}
 
 // In test code, allow a string (or string reference) to be used as a `Step`.
-#[cfg(any(feature = "test-fixture", debug_assertions))]
+#[cfg(feature = "descriptive-gate")]
 impl Step for String {}
 
-#[cfg(any(feature = "test-fixture", debug_assertions))]
+#[cfg(feature = "descriptive-gate")]
 impl Step for str {}
 
 /// A step generator for bitwise secure operations.