diff --git a/deltachat-ffi/build.rs b/deltachat-ffi/build.rs
index 58e4a2258..0825c1645 100644
--- a/deltachat-ffi/build.rs
+++ b/deltachat-ffi/build.rs
@@ -19,10 +19,10 @@ fn main() {
         include_str!("deltachat.pc.in"),
         name = "deltachat",
         description = env::var("CARGO_PKG_DESCRIPTION").unwrap(),
-        url = env::var("CARGO_PKG_HOMEPAGE").unwrap_or("".to_string()),
+        url = env::var("CARGO_PKG_HOMEPAGE").unwrap_or_else(|_| "".to_string()),
         version = env::var("CARGO_PKG_VERSION").unwrap(),
         libs_priv = libs_priv,
-        prefix = env::var("PREFIX").unwrap_or("/usr/local".to_string()),
+        prefix = env::var("PREFIX").unwrap_or_else(|_| "/usr/local".to_string()),
     );
 
     fs::create_dir_all(target_path.join("pkgconfig")).unwrap();
diff --git a/deltachat-ffi/src/lib.rs b/deltachat-ffi/src/lib.rs
index 176505e69..8578548f9 100644
--- a/deltachat-ffi/src/lib.rs
+++ b/deltachat-ffi/src/lib.rs
@@ -487,7 +487,7 @@ pub unsafe extern "C" fn dc_get_next_event(events: *mut dc_event_emitter_t) -> *
     events
         .recv_sync()
         .map(|ev| Box::into_raw(Box::new(ev)))
-        .unwrap_or_else(|| ptr::null_mut())
+        .unwrap_or_else(ptr::null_mut)
 }
 
 #[no_mangle]
diff --git a/deltachat-ffi/src/string.rs b/deltachat-ffi/src/string.rs
index db9baa7bb..7446e419f 100644
--- a/deltachat-ffi/src/string.rs
+++ b/deltachat-ffi/src/string.rs
@@ -105,8 +105,9 @@ impl<T: AsRef<std::ffi::OsStr>> OsStrExt for T {
     #[cfg(not(target_os = "windows"))]
     fn to_c_string(&self) -> Result<CString, CStringError> {
         use std::os::unix::ffi::OsStrExt;
-        CString::new(self.as_ref().as_bytes()).map_err(|err| match err {
-            std::ffi::NulError { .. } => CStringError::InteriorNullByte,
+        CString::new(self.as_ref().as_bytes()).map_err(|err| {
+            let std::ffi::NulError { .. } = err;
+            CStringError::InteriorNullByte
         })
     }
 
@@ -122,8 +123,9 @@ fn os_str_to_c_string_unicode(
     os_str: &dyn AsRef<std::ffi::OsStr>,
 ) -> Result<CString, CStringError> {
     match os_str.as_ref().to_str() {
-        Some(val) => CString::new(val.as_bytes()).map_err(|err| match err {
-            std::ffi::NulError { .. } => CStringError::InteriorNullByte,
+        Some(val) => CString::new(val.as_bytes()).map_err(|err| {
+            let std::ffi::NulError { .. } = err;
+            CStringError::InteriorNullByte
         }),
         None => Err(CStringError::NotUnicode),
     }