diff --git a/src/dc_imex.rs b/src/dc_imex.rs
index e03df63ba..d27f397f7 100644
--- a/src/dc_imex.rs
+++ b/src/dc_imex.rs
@@ -1016,7 +1016,7 @@ unsafe fn export_backup(context: &Context, dir: *const libc::c_char) -> libc::c_
                                     context,
                                     0,
                                     "Backup: Cannot copy from blob-directory \"{}\".",
-                                    context.get_blobdir(),
+                                    as_str(context.get_blobdir()),
                                 );
                             } else {
                                 let dir_handle = dir_handle.unwrap();
diff --git a/src/dc_jobthread.rs b/src/dc_jobthread.rs
index 6ff7100b7..2d38ede83 100644
--- a/src/dc_jobthread.rs
+++ b/src/dc_jobthread.rs
@@ -6,7 +6,6 @@ use crate::dc_sqlite3::*;
 use crate::imap::Imap;
 use crate::types::*;
 use crate::x::*;
-use std::ffi::CString;
 
 #[repr(C)]
 pub struct dc_jobthread_t {
@@ -142,12 +141,8 @@ unsafe fn connect_to_imap(context: &Context, jobthread: &dc_jobthread_t) -> libc
             if dc_sqlite3_get_config_int(context, &context.sql, "folders_configured", 0) < 3 {
                 jobthread.imap.configure_folders(context, 0x1);
             }
-            let mvbox_name = dc_sqlite3_get_config(
-                context,
-                &context.sql,
-                as_str(&jobthread.folder_config_name[..]),
-                None,
-            );
+            let mvbox_name =
+                dc_sqlite3_get_config(context, &context.sql, jobthread.folder_config_name, None);
             if let Some(name) = mvbox_name {
                 jobthread.imap.set_watch_folder(name);
             } else {
diff --git a/src/imap.rs b/src/imap.rs
index 9a8149bce..5e612edc2 100644
--- a/src/imap.rs
+++ b/src/imap.rs
@@ -555,7 +555,7 @@ impl Imap {
                         Event::IMAP_CONNECTED,
                         0,
                         "IMAP-LOGIN as {} ok",
-                        as_str(lp.mail_user),
+                        lp.mail_user,
                     );
                     info!(context, 0, "IMAP-capabilities:{}", caps_list);
 
diff --git a/src/peerstate.rs b/src/peerstate.rs
index 8de64ad77..ba087323e 100644
--- a/src/peerstate.rs
+++ b/src/peerstate.rs
@@ -9,7 +9,6 @@ use crate::context::Context;
 use crate::dc_chat::*;
 use crate::dc_sqlite3::*;
 use crate::key::*;
-use crate::types::uintptr_t;
 
 /// Peerstate represents the state of an Autocrypt peer.
 pub struct Peerstate<'a> {
@@ -515,9 +514,9 @@ mod tests {
     unsafe extern "C" fn cb(
         _context: &Context,
         _event: Event,
-        _data1: uintptr_t,
-        _data2: uintptr_t,
-    ) -> uintptr_t {
+        _data1: libc::uintptr_t,
+        _data2: libc::uintptr_t,
+    ) -> libc::uintptr_t {
         0
     }
 
diff --git a/src/smtp.rs b/src/smtp.rs
index 5eb0d93ca..9b902e428 100644
--- a/src/smtp.rs
+++ b/src/smtp.rs
@@ -6,7 +6,6 @@ use crate::constants::*;
 use crate::context::Context;
 use crate::dc_loginparam::*;
 use crate::oauth2::*;
-use crate::types::*;
 
 pub struct Smtp {
     transport: Option<lettre::smtp::SmtpTransport>,
@@ -115,7 +114,7 @@ impl Smtp {
                     Event::SMTP_CONNECTED,
                     0,
                     "SMTP-LOGIN as {} ok",
-                    as_str(lp.send_user),
+                    lp.send_user,
                 );
                 1
             }