diff --git a/src/flow.rs b/src/flow.rs
index 0302084..21eae0c 100644
--- a/src/flow.rs
+++ b/src/flow.rs
@@ -1,4 +1,5 @@
 //! Data structures and algorithms, independent of [`crate::rcore`] concepts.
 
 pub mod binary;
+pub mod speculative;
 pub mod traversible;
diff --git a/src/func/speculative.rs b/src/flow/speculative.rs
similarity index 90%
rename from src/func/speculative.rs
rename to src/flow/speculative.rs
index 54d713e..8e06936 100644
--- a/src/func/speculative.rs
+++ b/src/flow/speculative.rs
@@ -1,11 +1,11 @@
-use super::*;
+use crate::func::*;
 
 type Frwa<'a, A, E0, E1, Fallible> =
     Wrap<'a, Result<WrapE<'a, A, E0, Fallible>, E1>, <Fallible as MonadFailAny<'a>>::T>;
 
 type Wwa<'a, A, E0, E1, Fallible> = WrapE<'a, WrapE<'a, A, E0, Fallible>, E1, Fallible>;
 
-pub trait SpeculativeFail<'a>: MonadFailAny<'a> {
+trait SpeculativeFailImpl<'a>: MonadFailAny<'a> {
     fn _speculative_a_wb<A: 'a, B: 'a, E0: 'a, E1: 'a>(
         a: A,
         wb: WrapE<'a, B, E0, Self>,
@@ -81,7 +81,7 @@ pub trait SpeculativeFail<'a>: MonadFailAny<'a> {
         )
     }
 
-    fn speculative<A: 'a, B: 'a, E0: 'a, E1: 'a>(
+    fn _speculative<A: 'a, B: 'a, E0: 'a, E1: 'a>(
         wwa: Wwa<'a, A, E0, E1, Self>,
         wwb: Wwa<'a, B, E0, E1, Self>,
     ) -> WrapE<'a, (A, B), Result<E0, E1>, Self> {
@@ -101,4 +101,14 @@ pub trait SpeculativeFail<'a>: MonadFailAny<'a> {
     }
 }
 
+pub trait SpeculativeFail<'a>: MonadFailAny<'a> {
+    fn speculative<A: 'a, B: 'a, E0: 'a, E1: 'a>(
+        wwa: Wwa<'a, A, E0, E1, Self>,
+        wwb: Wwa<'a, B, E0, E1, Self>,
+    ) -> WrapE<'a, (A, B), Result<E0, E1>, Self> {
+        Self::_speculative(wwa, wwb)
+    }
+}
+
+impl<'a, Fallible: ?Sized + MonadFailAny<'a>> SpeculativeFailImpl<'a> for Fallible {}
 impl<'a, Fallible: ?Sized + MonadFailAny<'a>> SpeculativeFail<'a> for Fallible {}
diff --git a/src/func.rs b/src/func.rs
index 7f78849..dcda31b 100644
--- a/src/func.rs
+++ b/src/func.rs
@@ -13,7 +13,6 @@ mod controlflow;
 pub mod copy_func;
 pub mod derivations;
 pub mod instances;
-mod speculative;
 #[cfg(test)]
 pub mod test_suite;
 #[cfg(test)]
@@ -257,13 +256,6 @@ pub trait MonadFailAnyExt<'a>: MonadFailAny<'a> {
     fn fail<E: 'a, A: 'a>(e: E) -> WrapE<'a, A, E, Self> {
         <Self::W<E> as Fail<E>>::fail(e)
     }
-
-    fn speculative<A: 'a, B: 'a, E0: 'a, E1: 'a>(
-        wwa: WrapE<'a, WrapE<'a, A, E0, Self>, E1, Self>,
-        wwb: WrapE<'a, WrapE<'a, B, E0, Self>, E1, Self>,
-    ) -> WrapE<'a, (A, B), Result<E0, E1>, Self> {
-        <Self as speculative::SpeculativeFail>::speculative(wwa, wwb)
-    }
 }
 
 impl<'a, Fallible: ?Sized + MonadFailAny<'a>> MonadFailAnyExt<'a> for Fallible {}