diff --git a/.github/workflows/test.yml b/.github/workflows/test.yml
index 2a7bf850c08..f66071db0c5 100644
--- a/.github/workflows/test.yml
+++ b/.github/workflows/test.yml
@@ -52,7 +52,7 @@ jobs:
       - name: Install clippy
         run: rustup component add clippy
       - name: "clippy --all"
-        run: cargo clippy --all --tests
+        run: cargo clippy --all --tests -- -D warnings
 
   fmt:
     name: fmt
@@ -64,8 +64,8 @@ jobs:
       - uses: Swatinem/rust-cache@v1
       - name: Install rustfmt
         run: rustup component add rustfmt
-
-      - run: cargo fmt
+      - name: Run
+        run: cargo fmt --all -- --check
 
   miri-checks:
     name: Miri
diff --git a/src/array/mod.rs b/src/array/mod.rs
index f13b0a4eb00..ce5132b80e6 100644
--- a/src/array/mod.rs
+++ b/src/array/mod.rs
@@ -174,23 +174,6 @@ macro_rules! fmt_dyn {
     }};
 }
 
-macro_rules! with_match_dictionary_key_type {(
-    $key_type:expr, | $_:tt $T:ident | $($body:tt)*
-) => ({
-    macro_rules! __with_ty__ {( $_ $T:ident ) => ( $($body)* )}
-    match $key_type {
-        DataType::Int8 => __with_ty__! { i8 },
-        DataType::Int16 => __with_ty__! { i16 },
-        DataType::Int32 => __with_ty__! { i32 },
-        DataType::Int64 => __with_ty__! { i64 },
-        DataType::UInt8 => __with_ty__! { u8 },
-        DataType::UInt16 => __with_ty__! { u16 },
-        DataType::UInt32 => __with_ty__! { u32 },
-        DataType::UInt64 => __with_ty__! { u64 },
-        _ => ::core::unreachable!("A dictionary key type can only be of integer types"),
-    }
-})}
-
 macro_rules! with_match_physical_dictionary_key_type {(
     $key_type:expr, | $_:tt $T:ident | $($body:tt)*
 ) => ({
diff --git a/src/datatypes/field.rs b/src/datatypes/field.rs
index af18073070a..29a2248e2af 100644
--- a/src/datatypes/field.rs
+++ b/src/datatypes/field.rs
@@ -281,16 +281,3 @@ impl std::fmt::Display for Field {
 
 pub(crate) type Metadata = Option<BTreeMap<String, String>>;
 pub(crate) type Extension = Option<(String, Option<String>)>;
-
-pub(crate) fn get_extension(metadata: &Option<BTreeMap<String, String>>) -> Extension {
-    if let Some(metadata) = metadata {
-        if let Some(name) = metadata.get("ARROW:extension:name") {
-            let metadata = metadata.get("ARROW:extension:metadata").cloned();
-            Some((name.clone(), metadata))
-        } else {
-            None
-        }
-    } else {
-        None
-    }
-}
diff --git a/src/datatypes/mod.rs b/src/datatypes/mod.rs
index d8fbabe1e3d..b99d76c976a 100644
--- a/src/datatypes/mod.rs
+++ b/src/datatypes/mod.rs
@@ -8,7 +8,7 @@ pub use field::Field;
 pub use physical_type::*;
 pub use schema::Schema;
 
-pub(crate) use field::{get_extension, Extension, Metadata};
+pub(crate) use field::{Extension, Metadata};
 
 /// The set of supported logical types.
 /// Each variant uniquely identifies a logical type, which define specific semantics to the data (e.g. how it should be represented).