Move the blanket `impl` outside of `extension_trait`.

src/future/future/mod.rs

@@ -285,3 +285,6 @@ extension_trait! {
         }
     }
 }
+
+impl<T: Future + ?Sized> FutureExt for T {}
+

src/io/buf_read/mod.rs

@@ -239,6 +239,8 @@ extension_trait! {
     }
 }
 
+impl<T: BufRead + ?Sized> BufReadExt for T {}
+
 pub fn read_until_internal<R: BufReadExt + ?Sized>(
     mut reader: Pin<&mut R>,
     cx: &mut Context<'_>,

src/io/read/mod.rs

@@ -372,10 +372,11 @@ extension_trait! {
         fn chain<R: Read>(self, next: R) -> Chain<Self, R> where Self: Sized {
             Chain { first: self, second: next, done_first: false }
         }
-
     }
 }
 
+impl<T: Read + ?Sized> ReadExt for T {}
+
 /// Initializes a buffer if necessary.
 ///
 /// Currently, a buffer is always initialized because `read_initializer`

src/io/seek/mod.rs

@@ -48,3 +48,5 @@ extension_trait! {
         }
     }
 }
+
+impl<T: Seek + ?Sized> SeekExt for T {}

src/io/write/mod.rs

@@ -185,3 +185,5 @@ extension_trait! {
         }
     }
 }
+
+impl<T: Write + ?Sized> WriteExt for T {}

src/stream/stream/mod.rs

@@ -2307,3 +2307,6 @@ extension_trait! {
         }
     }
 }
+
+impl<T: Stream + ?Sized> StreamExt for T {}
+

src/utils.rs

@@ -265,9 +265,6 @@ macro_rules! extension_trait {
         pub trait $ext: $name {
             extension_trait!(@ext [$($body_ext)*] -> []);
         }
-
-        // Blanket implementation of the extension trait for any type implementing the base trait.
-        impl<T: $name + ?Sized> $ext for T {}
     };
 
     // Parse the return type in an extension method.