diff --git a/deltachat-ffi/src/lib.rs b/deltachat-ffi/src/lib.rs
index c042ded02..20b61f50a 100644
--- a/deltachat-ffi/src/lib.rs
+++ b/deltachat-ffi/src/lib.rs
@@ -2152,7 +2152,7 @@ pub unsafe extern "C" fn dc_msg_is_sent(msg: *mut dc_msg_t) -> libc::c_int {
         return 0;
     }
     let ffi_msg = &*msg;
-    message::dc_msg_is_sent(&ffi_msg.message)
+    message::dc_msg_is_sent(&ffi_msg.message).into()
 }
 
 #[no_mangle]
@@ -2172,7 +2172,7 @@ pub unsafe extern "C" fn dc_msg_is_forwarded(msg: *mut dc_msg_t) -> libc::c_int
         return 0;
     }
     let ffi_msg = &*msg;
-    message::dc_msg_is_forwarded(&ffi_msg.message)
+    message::dc_msg_is_forwarded(&ffi_msg.message).into()
 }
 
 #[no_mangle]
@@ -2182,7 +2182,7 @@ pub unsafe extern "C" fn dc_msg_is_info(msg: *mut dc_msg_t) -> libc::c_int {
         return 0;
     }
     let ffi_msg = &*msg;
-    message::dc_msg_is_info(&ffi_msg.message)
+    message::dc_msg_is_info(&ffi_msg.message).into()
 }
 
 #[no_mangle]
@@ -2192,7 +2192,7 @@ pub unsafe extern "C" fn dc_msg_is_increation(msg: *mut dc_msg_t) -> libc::c_int
         return 0;
     }
     let ffi_msg = &*msg;
-    message::dc_msg_is_increation(&ffi_msg.message)
+    message::dc_msg_is_increation(&ffi_msg.message).into()
 }
 
 #[no_mangle]
@@ -2202,7 +2202,7 @@ pub unsafe extern "C" fn dc_msg_is_setupmessage(msg: *mut dc_msg_t) -> libc::c_i
         return 0;
     }
     let ffi_msg = &*msg;
-    message::dc_msg_is_setupmessage(&ffi_msg.message) as libc::c_int
+    message::dc_msg_is_setupmessage(&ffi_msg.message).into()
 }
 
 #[no_mangle]
diff --git a/examples/repl/cmdline.rs b/examples/repl/cmdline.rs
index 8f6ea5a5e..8e0923f06 100644
--- a/examples/repl/cmdline.rs
+++ b/examples/repl/cmdline.rs
@@ -248,11 +248,7 @@ unsafe fn log_msg(context: &Context, prefix: impl AsRef<str>, msg: &Message) {
         } else {
             "[FRESH]"
         },
-        if 0 != dc_msg_is_info(msg) {
-            "[INFO]"
-        } else {
-            ""
-        },
+        if dc_msg_is_info(msg) { "[INFO]" } else { "" },
         statestr,
         &temp2,
     );
diff --git a/src/chat.rs b/src/chat.rs
index 243f1f88f..4442cb350 100644
--- a/src/chat.rs
+++ b/src/chat.rs
@@ -868,7 +868,7 @@ unsafe fn set_draft_raw(context: &Context, chat_id: u32, mut msg: Option<&mut Me
         } else if msgtype_has_file(msg.type_0) {
             if let Some(path_filename) = msg.param.get(Param::File) {
                 let mut path_filename = path_filename.to_string();
-                if 0 != dc_msg_is_increation(msg) && !dc_is_blobdir_path(context, &path_filename) {
+                if dc_msg_is_increation(msg) && !dc_is_blobdir_path(context, &path_filename) {
                     OK_TO_CONTINUE = false;
                 } else if !dc_make_rel_and_copy(context, &mut path_filename) {
                     OK_TO_CONTINUE = false;
diff --git a/src/dc_imex.rs b/src/dc_imex.rs
index 54d6161ab..06f6c6e87 100644
--- a/src/dc_imex.rs
+++ b/src/dc_imex.rs
@@ -168,7 +168,7 @@ pub unsafe fn dc_initiate_key_transfer(context: &Context) -> *mut libc::c_char {
                                     }
                                     std::thread::sleep(std::time::Duration::from_secs(1));
                                     if let Ok(msg) = dc_get_msg(context, msg_id) {
-                                        if 0 != dc_msg_is_sent(&msg) {
+                                        if dc_msg_is_sent(&msg) {
                                             info!(context, "... setup message sent.",);
                                             break;
                                         }
diff --git a/src/dc_mimefactory.rs b/src/dc_mimefactory.rs
index 371c55b33..090cc4a00 100644
--- a/src/dc_mimefactory.rs
+++ b/src/dc_mimefactory.rs
@@ -39,7 +39,7 @@ pub struct dc_mimefactory_t<'a> {
     pub loaded: dc_mimefactory_loaded_t,
     pub msg: Message,
     pub chat: Option<Chat>,
-    pub increation: libc::c_int,
+    pub increation: bool,
     pub in_reply_to: *mut libc::c_char,
     pub references: *mut libc::c_char,
     pub req_mdn: libc::c_int,
@@ -102,7 +102,7 @@ pub unsafe fn dc_mimefactory_load_msg(
         loaded: DC_MF_NOTHING_LOADED,
         msg,
         chat: Some(chat),
-        increation: 0,
+        increation: false,
         in_reply_to: ptr::null_mut(),
         references: ptr::null_mut(),
         req_mdn: 0,
@@ -290,7 +290,7 @@ pub unsafe fn dc_mimefactory_load_mdn<'a>(
         loaded: DC_MF_NOTHING_LOADED,
         msg,
         chat: None,
-        increation: 0,
+        increation: false,
         in_reply_to: ptr::null_mut(),
         references: ptr::null_mut(),
         req_mdn: 0,
diff --git a/src/message.rs b/src/message.rs
index 7b50fb9b5..368a2f83f 100644
--- a/src/message.rs
+++ b/src/message.rs
@@ -87,7 +87,7 @@ impl Lot {
             self.text1 = Some(context.stock_str(StockMessage::Draft).to_owned().into());
             self.text1_meaning = Meaning::Text1Draft;
         } else if msg.from_id == DC_CONTACT_ID_SELF {
-            if 0 != dc_msg_is_info(msg) || chat.is_self_talk() {
+            if dc_msg_is_info(msg) || chat.is_self_talk() {
                 self.text1 = None;
                 self.text1_meaning = Meaning::None;
             } else {
@@ -95,7 +95,7 @@ impl Lot {
                 self.text1_meaning = Meaning::Text1Self;
             }
         } else if chat.typ == Chattype::Group || chat.typ == Chattype::VerifiedGroup {
-            if 0 != dc_msg_is_info(msg) || contact.is_none() {
+            if dc_msg_is_info(msg) || contact.is_none() {
                 self.text1 = None;
                 self.text1_meaning = Meaning::None;
             } else {
@@ -820,48 +820,27 @@ pub unsafe fn dc_msg_has_deviating_timestamp(msg: &Message) -> libc::c_int {
     (sort_timestamp / 86400 != send_timestamp / 86400) as libc::c_int
 }
 
-// TODO should return bool /rtn
-pub fn dc_msg_is_sent(msg: &Message) -> libc::c_int {
-    if msg.state as i32 >= MessageState::OutDelivered as i32 {
-        1
-    } else {
-        0
-    }
+pub fn dc_msg_is_sent(msg: &Message) -> bool {
+    msg.state as i32 >= MessageState::OutDelivered as i32
 }
 
 pub fn dc_msg_is_starred(msg: &Message) -> bool {
     msg.starred
 }
 
-// TODO should return bool /rtn
-pub fn dc_msg_is_forwarded(msg: &Message) -> libc::c_int {
-    if 0 != msg.param.get_int(Param::Forwarded).unwrap_or_default() {
-        1
-    } else {
-        0
-    }
+pub fn dc_msg_is_forwarded(msg: &Message) -> bool {
+    0 != msg.param.get_int(Param::Forwarded).unwrap_or_default()
 }
 
-// TODO should return bool /rtn
-pub fn dc_msg_is_info(msg: &Message) -> libc::c_int {
+pub fn dc_msg_is_info(msg: &Message) -> bool {
     let cmd = msg.param.get_int(Param::Cmd).unwrap_or_default();
-    if msg.from_id == 2i32 as libc::c_uint
+    msg.from_id == 2i32 as libc::c_uint
         || msg.to_id == 2i32 as libc::c_uint
         || 0 != cmd && cmd != 6i32
-    {
-        return 1;
-    }
-
-    0
 }
 
-// TODO should return bool /rtn
-pub fn dc_msg_is_increation(msg: &Message) -> libc::c_int {
-    if chat::msgtype_has_file(msg.type_0) && msg.state == MessageState::OutPreparing {
-        1
-    } else {
-        0
-    }
+pub fn dc_msg_is_increation(msg: &Message) -> bool {
+    chat::msgtype_has_file(msg.type_0) && msg.state == MessageState::OutPreparing
 }
 
 pub fn dc_msg_is_setupmessage(msg: &Message) -> bool {