diff --git a/src/lib.rs b/src/lib.rs
index 8b96313..74fe1ba 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -230,6 +230,7 @@ impl<A: SpongeAPI, I: List> Drop for ExtraSponge<A, I> {
 }
 
 #[cfg(test)]
+/// Unit tests for the Sponge API.
 pub mod unit_tests;
 
 #[cfg(test)]
diff --git a/src/unit_tests/compilation/consume.stderr b/src/unit_tests/compilation/consume.stderr
index 4acdc1e..01b2570 100644
--- a/src/unit_tests/compilation/consume.stderr
+++ b/src/unit_tests/compilation/consume.stderr
@@ -2,13 +2,36 @@ error[E0277]: the trait bound `UTerm: PrivateSub<UInt<UTerm, B1>>` is not satisf
  --> src/unit_tests/compilation/consume.rs:9:9
   |
 9 |         Use<iopat![Absorb<U3>, Squeeze<U1>, Absorb<U1>], Absorb<U6>>,
-  |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ the trait `PrivateSub<UInt<UTerm, B1>>` is not implemented for `UTerm`
+  |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ the trait `PrivateSub<UInt<UTerm, B1>>` is not implemented for `UTerm`, which is required by `Cons<extra_safe::traits::Absorb<UInt<UInt<UTerm, B1>, B1>>, Cons<extra_safe::traits::Squeeze<UInt<UTerm, B1>>, Cons<extra_safe::traits::Absorb<UInt<UTerm, B1>>, Nil>>>: Consume<extra_safe::traits::Absorb<UInt<UInt<UInt<UTerm, B1>, B1>, B0>>>`
   |
   = help: the following other types implement trait `PrivateSub<Rhs>`:
-            <UInt<Ul, B0> as PrivateSub<UInt<Ur, B0>>>
-            <UInt<Ul, B0> as PrivateSub<UInt<Ur, B1>>>
-            <UInt<Ul, B1> as PrivateSub<UInt<Ur, B0>>>
-            <UInt<Ul, B1> as PrivateSub<UInt<Ur, B1>>>
+            `UInt<Ul, B0>` implements `PrivateSub<UInt<Ur, B0>>`
+            `UInt<Ul, B0>` implements `PrivateSub<UInt<Ur, B1>>`
+            `UInt<Ul, B1>` implements `PrivateSub<UInt<Ur, B0>>`
+            `UInt<Ul, B1>` implements `PrivateSub<UInt<Ur, B1>>`
   = note: required for `UInt<UTerm, B1>` to implement `PrivateSub<UInt<UInt<UTerm, B1>, B1>>`
   = note: required for `UInt<UInt<UTerm, B1>, B1>` to implement `Sub<UInt<UInt<UInt<UTerm, B1>, B1>, B0>>`
   = note: required for `Cons<Absorb<UInt<UInt<UTerm, B1>, B1>>, Cons<Squeeze<UInt<UTerm, B1>>, Cons<Absorb<UInt<UTerm, B1>>, Nil>>>` to implement `Consume<extra_safe::traits::Absorb<UInt<UInt<UInt<UTerm, B1>, B1>, B0>>>`
+  = note: the full name for the type has been written to '$DIR/target/tests/trybuild/aarch64-apple-darwin/debug/deps/$CRATE-b4d682b1f57e5d44.long-type-3642229067816383729.txt'
+  = note: consider using `--verbose` to print the full type name to the console
+
+error[E0277]: the trait bound `UTerm: PrivateSub<UInt<UTerm, B1>>` is not satisfied
+  --> src/unit_tests/compilation/consume.rs:8:5
+   |
+8  | /     assert_type_eq!(
+9  | |         Use<iopat![Absorb<U3>, Squeeze<U1>, Absorb<U1>], Absorb<U6>>,
+10 | |         iopat![Squeeze<U1>, Absorb<U1>]
+11 | |     );
+   | |_____^ the trait `PrivateSub<UInt<UTerm, B1>>` is not implemented for `UTerm`, which is required by `Cons<extra_safe::traits::Absorb<UInt<UInt<UTerm, B1>, B1>>, Cons<extra_safe::traits::Squeeze<UInt<UTerm, B1>>, Cons<extra_safe::traits::Absorb<UInt<UTerm, B1>>, Nil>>>: Consume<extra_safe::traits::Absorb<UInt<UInt<UInt<UTerm, B1>, B1>, B0>>>`
+   |
+   = help: the following other types implement trait `PrivateSub<Rhs>`:
+             `UInt<Ul, B0>` implements `PrivateSub<UInt<Ur, B0>>`
+             `UInt<Ul, B0>` implements `PrivateSub<UInt<Ur, B1>>`
+             `UInt<Ul, B1>` implements `PrivateSub<UInt<Ur, B0>>`
+             `UInt<Ul, B1>` implements `PrivateSub<UInt<Ur, B1>>`
+   = note: required for `UInt<UTerm, B1>` to implement `PrivateSub<UInt<UInt<UTerm, B1>, B1>>`
+   = note: required for `UInt<UInt<UTerm, B1>, B1>` to implement `Sub<UInt<UInt<UInt<UTerm, B1>, B1>, B0>>`
+   = note: required for `Cons<Absorb<UInt<UInt<UTerm, B1>, B1>>, Cons<Squeeze<UInt<UTerm, B1>>, Cons<Absorb<UInt<UTerm, B1>>, Nil>>>` to implement `Consume<extra_safe::traits::Absorb<UInt<UInt<UInt<UTerm, B1>, B1>, B0>>>`
+   = note: the full name for the type has been written to '$DIR/target/tests/trybuild/aarch64-apple-darwin/debug/deps/$CRATE-b4d682b1f57e5d44.long-type-3642229067816383729.txt'
+   = note: consider using `--verbose` to print the full type name to the console
+   = note: this error originates in the macro `assert_type_eq` (in Nightly builds, run with -Z macro-backtrace for more info)
diff --git a/src/unit_tests/compilation/consume_head.stderr b/src/unit_tests/compilation/consume_head.stderr
index 3f8740a..ac1dcb1 100644
--- a/src/unit_tests/compilation/consume_head.stderr
+++ b/src/unit_tests/compilation/consume_head.stderr
@@ -4,13 +4,38 @@ error[E0277]: cannot subtract `B1` from `UInt<UTerm, B0>`
 9 |         Use<iopat![Absorb<U5>, Squeeze<U0>, Absorb<U1>], Absorb<U6>>,
   |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ no implementation for `UInt<UTerm, B0> - B1`
   |
-  = help: the trait `Sub<B1>` is not implemented for `UInt<UTerm, B0>`
+  = help: the trait `Sub<B1>` is not implemented for `UInt<UTerm, B0>`, which is required by `Cons<extra_safe::traits::Absorb<UInt<UInt<UInt<UTerm, B1>, B0>, B1>>, Cons<extra_safe::traits::Squeeze<UTerm>, Cons<extra_safe::traits::Absorb<UInt<UTerm, B1>>, Nil>>>: Consume<extra_safe::traits::Absorb<UInt<UInt<UInt<UTerm, B1>, B1>, B0>>>`
   = help: the following other types implement trait `Sub<Rhs>`:
-            <UInt<U, B0> as Sub<B1>>
-            <UInt<U, B> as Sub<B0>>
-            <UInt<UInt<U, B>, B1> as Sub<B1>>
-            <UInt<UTerm, B1> as Sub<B1>>
-            <UInt<Ul, Bl> as Sub<Ur>>
+            `UInt<U, B0>` implements `Sub<B1>`
+            `UInt<U, B>` implements `Sub<B0>`
+            `UInt<UInt<U, B>, B1>` implements `Sub<B1>`
+            `UInt<UTerm, B1>` implements `Sub<B1>`
+            `UInt<Ul, Bl>` implements `Sub<Ur>`
   = note: required for `UInt<UInt<UTerm, B1>, B0>` to implement `PrivateSub<UInt<UInt<UTerm, B1>, B1>>`
   = note: required for `UInt<UInt<UInt<UTerm, B1>, B0>, B1>` to implement `Sub<UInt<UInt<UInt<UTerm, B1>, B1>, B0>>`
   = note: required for `Cons<Absorb<UInt<UInt<UInt<UTerm, B1>, B0>, B1>>, Cons<Squeeze<UTerm>, Cons<Absorb<UInt<UTerm, B1>>, Nil>>>` to implement `Consume<extra_safe::traits::Absorb<UInt<UInt<UInt<UTerm, B1>, B1>, B0>>>`
+  = note: the full name for the type has been written to '$DIR/target/tests/trybuild/aarch64-apple-darwin/debug/deps/$CRATE-901c64bc5947f6da.long-type-12175079161346788738.txt'
+  = note: consider using `--verbose` to print the full type name to the console
+
+error[E0277]: cannot subtract `B1` from `UInt<UTerm, B0>`
+  --> src/unit_tests/compilation/consume_head.rs:8:5
+   |
+8  | /     assert_type_eq!(
+9  | |         Use<iopat![Absorb<U5>, Squeeze<U0>, Absorb<U1>], Absorb<U6>>,
+10 | |         Nil
+11 | |     );
+   | |_____^ no implementation for `UInt<UTerm, B0> - B1`
+   |
+   = help: the trait `Sub<B1>` is not implemented for `UInt<UTerm, B0>`, which is required by `Cons<extra_safe::traits::Absorb<UInt<UInt<UInt<UTerm, B1>, B0>, B1>>, Cons<extra_safe::traits::Squeeze<UTerm>, Cons<extra_safe::traits::Absorb<UInt<UTerm, B1>>, Nil>>>: Consume<extra_safe::traits::Absorb<UInt<UInt<UInt<UTerm, B1>, B1>, B0>>>`
+   = help: the following other types implement trait `Sub<Rhs>`:
+             `UInt<U, B0>` implements `Sub<B1>`
+             `UInt<U, B>` implements `Sub<B0>`
+             `UInt<UInt<U, B>, B1>` implements `Sub<B1>`
+             `UInt<UTerm, B1>` implements `Sub<B1>`
+             `UInt<Ul, Bl>` implements `Sub<Ur>`
+   = note: required for `UInt<UInt<UTerm, B1>, B0>` to implement `PrivateSub<UInt<UInt<UTerm, B1>, B1>>`
+   = note: required for `UInt<UInt<UInt<UTerm, B1>, B0>, B1>` to implement `Sub<UInt<UInt<UInt<UTerm, B1>, B1>, B0>>`
+   = note: required for `Cons<Absorb<UInt<UInt<UInt<UTerm, B1>, B0>, B1>>, Cons<Squeeze<UTerm>, Cons<Absorb<UInt<UTerm, B1>>, Nil>>>` to implement `Consume<extra_safe::traits::Absorb<UInt<UInt<UInt<UTerm, B1>, B1>, B0>>>`
+   = note: the full name for the type has been written to '$DIR/target/tests/trybuild/aarch64-apple-darwin/debug/deps/$CRATE-901c64bc5947f6da.long-type-12175079161346788738.txt'
+   = note: consider using `--verbose` to print the full type name to the console
+   = note: this error originates in the macro `assert_type_eq` (in Nightly builds, run with -Z macro-backtrace for more info)
diff --git a/src/unit_tests/compilation/normalize.stderr b/src/unit_tests/compilation/normalize.stderr
index ed7b3b3..86a07d7 100644
--- a/src/unit_tests/compilation/normalize.stderr
+++ b/src/unit_tests/compilation/normalize.stderr
@@ -5,3 +5,11 @@ error[E0277]: the trait bound `Cons<extra_safe::traits::Absorb<UInt<UInt<UInt<UT
   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ the trait `Same<Cons<extra_safe::traits::Absorb<UInt<UInt<UInt<UTerm, B1>, B0>, B0>>, Nil>>` is not implemented for `Cons<extra_safe::traits::Absorb<UInt<UInt<UInt<UTerm, B1>, B0>, B1>>, Nil>`
   |
   = note: this error originates in the macro `assert_type_eq` (in Nightly builds, run with -Z macro-backtrace for more info)
+
+error[E0277]: the trait bound `Cons<extra_safe::traits::Absorb<UInt<UInt<UInt<UTerm, B1>, B0>, B1>>, Nil>: Same<Cons<extra_safe::traits::Absorb<UInt<UInt<UInt<UTerm, B1>, B0>, B0>>, Nil>>` is not satisfied
+ --> src/unit_tests/compilation/normalize.rs:7:5
+  |
+7 |     assert_type_eq!(Norm<iopat![Absorb<U2>, Absorb<U3>]>, iopat![Absorb<U4>]);
+  |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ the trait `Same<Cons<extra_safe::traits::Absorb<UInt<UInt<UInt<UTerm, B1>, B0>, B0>>, Nil>>` is not implemented for `Cons<extra_safe::traits::Absorb<UInt<UInt<UInt<UTerm, B1>, B0>, B1>>, Nil>`
+  |
+  = note: this error originates in the macro `assert_type_eq` (in Nightly builds, run with -Z macro-backtrace for more info)
diff --git a/src/unit_tests/compilation/normalize_complex.stderr b/src/unit_tests/compilation/normalize_complex.stderr
index 27c66f5..dc3ada2 100644
--- a/src/unit_tests/compilation/normalize_complex.stderr
+++ b/src/unit_tests/compilation/normalize_complex.stderr
@@ -8,3 +8,14 @@ error[E0277]: the trait bound `Cons<extra_safe::traits::Absorb<UInt<UInt<UInt<UI
    | |_____^ the trait `Same<Cons<extra_safe::traits::Absorb<UInt<UInt<UTerm, B1>, B0>>, Cons<extra_safe::traits::Absorb<UInt<UInt<UInt<UTerm, B1>, B1>, B0>>, Nil>>>` is not implemented for `Cons<extra_safe::traits::Absorb<UInt<UInt<UInt<UInt<UTerm, B1>, B0>, B0>, B0>>, Nil>`
    |
    = note: this error originates in the macro `assert_type_eq` (in Nightly builds, run with -Z macro-backtrace for more info)
+
+error[E0277]: the trait bound `Cons<extra_safe::traits::Absorb<UInt<UInt<UInt<UInt<UTerm, B1>, B0>, B0>, B0>>, Nil>: Same<Cons<extra_safe::traits::Absorb<UInt<UInt<UTerm, B1>, B0>>, Cons<extra_safe::traits::Absorb<UInt<UInt<UInt<UTerm, B1>, B1>, B0>>, Nil>>>` is not satisfied
+  --> src/unit_tests/compilation/normalize_complex.rs:7:5
+   |
+7  | /     assert_type_eq!(
+8  | |         Norm<iopat![Absorb<U2>, Squeeze<U0>, Absorb<U3>, Absorb<U3>]>,
+9  | |         iopat![Absorb<U2>, Absorb<U6>]
+10 | |     );
+   | |_____^ the trait `Same<Cons<extra_safe::traits::Absorb<UInt<UInt<UTerm, B1>, B0>>, Cons<extra_safe::traits::Absorb<UInt<UInt<UInt<UTerm, B1>, B1>, B0>>, Nil>>>` is not implemented for `Cons<extra_safe::traits::Absorb<UInt<UInt<UInt<UInt<UTerm, B1>, B0>, B0>, B0>>, Nil>`
+   |
+   = note: this error originates in the macro `assert_type_eq` (in Nightly builds, run with -Z macro-backtrace for more info)
diff --git a/src/unit_tests/compilation/sponge_bad_api.stderr b/src/unit_tests/compilation/sponge_bad_api.stderr
index fff05e9..c35931e 100644
--- a/src/unit_tests/compilation/sponge_bad_api.stderr
+++ b/src/unit_tests/compilation/sponge_bad_api.stderr
@@ -4,13 +4,13 @@ error[E0277]: cannot subtract `B1` from `UInt<UInt<UTerm, B0>, B0>`
 89 |         extra_sponge.absorb(Array::from_core_array(five_array), &mut Vec::default());
    |                      ^^^^^^ no implementation for `UInt<UInt<UTerm, B0>, B0> - B1`
    |
-   = help: the trait `Sub<B1>` is not implemented for `UInt<UInt<UTerm, B0>, B0>`
+   = help: the trait `Sub<B1>` is not implemented for `UInt<UInt<UTerm, B0>, B0>`, which is required by `Cons<extra_safe::traits::Absorb<UInt<UInt<UInt<UTerm, B1>, B0>, B0>>, Cons<extra_safe::traits::Squeeze<UInt<UInt<UTerm, B1>, B1>>, Nil>>: Consume<extra_safe::traits::Absorb<UInt<UInt<UInt<UTerm, B1>, B0>, B1>>>`
    = help: the following other types implement trait `Sub<Rhs>`:
-             <UInt<U, B0> as Sub<B1>>
-             <UInt<U, B> as Sub<B0>>
-             <UInt<UInt<U, B>, B1> as Sub<B1>>
-             <UInt<UTerm, B1> as Sub<B1>>
-             <UInt<Ul, Bl> as Sub<Ur>>
+             `UInt<U, B0>` implements `Sub<B1>`
+             `UInt<U, B>` implements `Sub<B0>`
+             `UInt<UInt<U, B>, B1>` implements `Sub<B1>`
+             `UInt<UTerm, B1>` implements `Sub<B1>`
+             `UInt<Ul, Bl>` implements `Sub<Ur>`
    = note: required for `UInt<UInt<UInt<UTerm, B1>, B0>, B0>` to implement `PrivateSub<UInt<UInt<UInt<UTerm, B1>, B0>, B1>>`
    = note: required for `UInt<UInt<UInt<UTerm, B1>, B0>, B0>` to implement `Sub<UInt<UInt<UInt<UTerm, B1>, B0>, B1>>`
    = note: required for `Cons<extra_safe::traits::Absorb<UInt<UInt<UInt<UTerm, B1>, B0>, B0>>, Cons<extra_safe::traits::Squeeze<UInt<UInt<UTerm, B1>, B1>>, Nil>>` to implement `Consume<extra_safe::traits::Absorb<UInt<UInt<UInt<UTerm, B1>, B0>, B1>>>`
diff --git a/src/unit_tests/compilation/sponge_creation.stderr b/src/unit_tests/compilation/sponge_creation.stderr
index c043ccb..19c977f 100644
--- a/src/unit_tests/compilation/sponge_creation.stderr
+++ b/src/unit_tests/compilation/sponge_creation.stderr
@@ -8,7 +8,8 @@ error[E0308]: mismatched types
 83 | |             basic_sponge,
 84 | |             &mut start_acc,
 85 | |         );
-   | |_________^ expected struct `UTerm`, found struct `UInt`
+   | |_________^ expected `UTerm`, found `UInt<UTerm, B1>`
    |
    = note: expected struct `ExtraSponge<BasicSponge, Cons<Absorb<UInt<UInt<UTerm, B1>, B0>>, Cons<Absorb<UInt<..., ...>>, ...>>>`
               found struct `ExtraSponge<_, Cons<extra_safe::traits::Absorb<UInt<UInt<UInt<UTerm, B1>, B0>, B1>>, Cons<extra_safe::traits::Squeeze<UInt<UInt<UTerm, B1>, B1>>, Nil>>>`
+   = note: consider using `--verbose` to print the full type name to the console