Fix clippy warnings (#2108)

* Fix clippy warnings

* review feedback.

src/platform_impl/linux/x11/ime/callbacks.rs

@@ -62,7 +62,7 @@ pub unsafe fn set_destroy_callback(
     inner: &ImeInner,
 ) -> Result<(), XError> {
     xim_set_callback(
-        &xconn,
+        xconn,
         im,
         ffi::XNDestroyCallback_0.as_ptr() as *const _,
         &inner.destroy_callback as *const _ as *mut _,
@@ -70,6 +70,7 @@ pub unsafe fn set_destroy_callback(
 }
 
 #[derive(Debug)]
+#[allow(clippy::enum_variant_names)]
 enum ReplaceImError {
     MethodOpenFailed(PotentialInputMethods),
     ContextCreationFailed(ImeContextCreationError),
@@ -136,13 +137,17 @@ pub unsafe extern "C" fn xim_instantiate_callback(
     let inner: *mut ImeInner = client_data as _;
     if !inner.is_null() {
         let xconn = &(*inner).xconn;
-        let result = replace_im(inner);
-        if result.is_ok() {
-            let _ = unset_instantiate_callback(xconn, client_data);
-            (*inner).is_fallback = false;
-        } else if result.is_err() && (*inner).is_destroyed {
-            // We have no usable input methods!
-            result.expect("Failed to reopen input method");
+        match replace_im(inner) {
+            Ok(()) => {
+                let _ = unset_instantiate_callback(xconn, client_data);
+                (*inner).is_fallback = false;
+            }
+            Err(err) => {
+                if (*inner).is_destroyed {
+                    // We have no usable input methods!
+                    panic!("Failed to reopen input method: {:?}", err);
+                }
+            }
         }
     }
 }
@@ -163,12 +168,12 @@ pub unsafe extern "C" fn xim_destroy_callback(
         if !(*inner).is_fallback {
             let _ = set_instantiate_callback(xconn, client_data);
             // Attempt to open fallback input method.
-            let result = replace_im(inner);
-            if result.is_ok() {
-                (*inner).is_fallback = true;
-            } else {
-                // We have no usable input methods!
-                result.expect("Failed to open fallback input method");
+            match replace_im(inner) {
+                Ok(()) => (*inner).is_fallback = true,
+                Err(err) => {
+                    // We have no usable input methods!
+                    panic!("Failed to open fallback input method: {:?}", err);
+                }
             }
         }
     }

src/platform_impl/linux/x11/ime/context.rs

@@ -58,7 +58,7 @@ impl ImeContext {
 
         Ok(ImeContext {
             ic,
-            ic_spot: ic_spot.unwrap_or_else(|| ffi::XPoint { x: 0, y: 0 }),
+            ic_spot: ic_spot.unwrap_or(ffi::XPoint { x: 0, y: 0 }),
         })
     }
 

src/platform_impl/linux/x11/ime/inner.rs

@@ -58,10 +58,8 @@ impl ImeInner {
     }
 
     pub unsafe fn destroy_all_contexts_if_necessary(&self) -> Result<bool, XError> {
-        for context in self.contexts.values() {
-            if let &Some(ref context) = context {
-                self.destroy_ic_if_necessary(context.ic)?;
-            }
+        for context in self.contexts.values().flatten() {
+            self.destroy_ic_if_necessary(context.ic)?;
         }
         Ok(!self.is_destroyed)
     }

src/platform_impl/linux/x11/ime/input_method.rs

@@ -63,11 +63,7 @@ pub enum InputMethodResult {
 
 impl InputMethodResult {
     pub fn is_fallback(&self) -> bool {
-        if let &InputMethodResult::Fallback(_) = self {
-            true
-        } else {
-            false
-        }
+        matches!(self, InputMethodResult::Fallback(_))
     }
 
     pub fn ok(self) -> Option<InputMethod> {
@@ -249,7 +245,7 @@ impl PotentialInputMethods {
     pub fn open_im(
         &mut self,
         xconn: &Arc<XConnection>,
-        callback: Option<&dyn Fn() -> ()>,
+        callback: Option<&dyn Fn()>,
     ) -> InputMethodResult {
         use self::InputMethodResult::*;
 
@@ -259,10 +255,8 @@ impl PotentialInputMethods {
             let im = input_method.open_im(xconn);
             if let Some(im) = im {
                 return XModifiers(im);
-            } else {
-                if let Some(ref callback) = callback {
-                    callback();
-                }
+            } else if let Some(ref callback) = callback {
+                callback();
             }
         }