diff --git a/git-object/src/borrowed/id.rs b/git-object/src/borrowed/id.rs
index 47c9bb42a9d..22dafa7e5ca 100644
--- a/git-object/src/borrowed/id.rs
+++ b/git-object/src/borrowed/id.rs
@@ -64,7 +64,7 @@ impl<'de: 'a, 'a> serde::Deserialize<'de> for Id<'a> {
         }
         impl<'de: 'a, 'a> serde::de::Visitor<'de> for __Visitor<'de, 'a> {
             type Value = Id<'a>;
-            fn expecting(&self, __formatter: &mut serde::export::Formatter) -> serde::export::fmt::Result {
+            fn expecting(&self, __formatter: &mut serde::export::Formatter<'_>) -> serde::export::fmt::Result {
                 serde::export::Formatter::write_str(__formatter, "tuple struct Id")
             }
             #[inline]
diff --git a/git-tui/src/main.rs b/git-tui/src/main.rs
index 77d20c3bc3c..37876d089c9 100644
--- a/git-tui/src/main.rs
+++ b/git-tui/src/main.rs
@@ -1,4 +1,5 @@
 #![forbid(unsafe_code)]
+#![deny(rust_2018_idioms)]
 
 fn main() {
     unimplemented!();
diff --git a/git-url/src/lib.rs b/git-url/src/lib.rs
index 2ce8a327631..90a3a78f225 100644
--- a/git-url/src/lib.rs
+++ b/git-url/src/lib.rs
@@ -1,4 +1,5 @@
 #![forbid(unsafe_code)]
+#![deny(rust_2018_idioms)]
 
 use std::{convert::TryFrom, fmt};
 
diff --git a/gitoxide-core/src/lib.rs b/gitoxide-core/src/lib.rs
index dc492de9cea..2f7ed60ce13 100644
--- a/gitoxide-core/src/lib.rs
+++ b/gitoxide-core/src/lib.rs
@@ -1,4 +1,5 @@
 #![forbid(unsafe_code)]
+#![deny(rust_2018_idioms)]
 
 use std::str::FromStr;
 
diff --git a/src/plumbing-cli.rs b/src/plumbing-cli.rs
index f50b41644e2..2a28df67012 100644
--- a/src/plumbing-cli.rs
+++ b/src/plumbing-cli.rs
@@ -1,4 +1,5 @@
 #![forbid(unsafe_code)]
+#![deny(rust_2018_idioms)]
 
 mod plumbing;
 mod shared;
diff --git a/src/porcelain-cli.rs b/src/porcelain-cli.rs
index 6e7ad934046..612ca1f855e 100644
--- a/src/porcelain-cli.rs
+++ b/src/porcelain-cli.rs
@@ -1,4 +1,5 @@
 #![forbid(unsafe_code)]
+#![deny(rust_2018_idioms)]
 
 mod porcelain;
 
diff --git a/tasks.md b/tasks.md
index 9faa540e237..25da04a0072 100644
--- a/tasks.md
+++ b/tasks.md
@@ -6,7 +6,7 @@
     * [x] locate object and figure out how to deal with differences of ODBs databases
     * [x] make NLL issue work
     * [ ] Nice access to compound::Object
-  * [ ] Add #![deny(rust_2018_idioms)] everywhere
+  * [x] Add #![deny(rust_2018_idioms)] everywhere
   * [ ] alternate DB (location - it's really must following the chain until a compound DB can be created)
   * [ ] loose upgrade: jwalk powered iteration behind a feature flag
 * **git-ref**