Fix CI warnings (#1356)

* Modernize the error types

* Address compilation warnings on Windows

* Fix unused variable warning for iOS

* Stop using `Error::description` on X11

* Remove unused `#[macro_use]` import of `log`

* Fully qualify use of `log::warn`

This is apparently the only place in Glutin where the `log` crate is
used.

* Factor out redundant inherent `to_string` method

glutin/src/api/egl/mod.rs

@@ -108,9 +108,11 @@ mod make_current_guard;
 
 pub use self::egl::Egl;
 use self::make_current_guard::MakeCurrentGuard;
+#[cfg(not(target_os = "windows"))]
+use crate::Rect;
 use crate::{
     Api, ContextError, CreationError, GlAttributes, GlRequest, PixelFormat,
-    PixelFormatRequirements, Rect, ReleaseBehavior, Robustness,
+    PixelFormatRequirements, ReleaseBehavior, Robustness,
 };
 
 use glutin_egl_sys as ffi;
@@ -612,6 +614,7 @@ impl Context {
     }
 
     #[inline]
+    #[cfg(not(target_os = "windows"))]
     pub fn swap_buffers_with_damage(&self, rects: &[Rect]) -> Result<(), ContextError> {
         let egl = EGL.as_ref().unwrap();
 
@@ -655,6 +658,7 @@ impl Context {
     }
 
     #[inline]
+    #[cfg(not(target_os = "windows"))]
     pub fn swap_buffers_with_damage_supported(&self) -> bool {
         let egl = EGL.as_ref().unwrap();
         egl.SwapBuffersWithDamageKHR.is_loaded()
@@ -1217,7 +1221,7 @@ where
             }
             value
         }};
-    };
+    }
 
     let desc = PixelFormat {
         hardware_accelerated: attrib!(egl, display, config_id, ffi::egl::CONFIG_CAVEAT)

glutin/src/api/ios/mod.rs

@@ -306,7 +306,7 @@ impl Context {
     }
 
     #[inline]
-    pub fn swap_buffers_with_damage(&self, rects: &[Rect]) -> Result<(), ContextError> {
+    pub fn swap_buffers_with_damage(&self, _rects: &[Rect]) -> Result<(), ContextError> {
         Err(ContextError::OsError("buffer damage not suported".to_string()))
     }
 

glutin/src/lib.rs

@@ -84,15 +84,6 @@ extern crate lazy_static;
 #[cfg(any(target_os = "macos", target_os = "ios"))]
 #[macro_use]
 extern crate objc;
-#[cfg(any(
-    target_os = "linux",
-    target_os = "dragonfly",
-    target_os = "freebsd",
-    target_os = "netbsd",
-    target_os = "openbsd",
-))]
-#[macro_use]
-extern crate log;
 
 pub mod platform;
 
@@ -323,29 +314,29 @@ impl CreationError {
         }
     }
 
-    fn to_string(&self) -> &str {
-        match *self {
-            CreationError::OsError(ref text) | CreationError::NotSupported(ref text) => &text,
-            CreationError::NoBackendAvailable(_) => "No backend is available",
+    fn to_string(&self) -> String {
+        match self {
+            CreationError::OsError(text) | CreationError::NotSupported(text) => text.clone(),
+            CreationError::NoBackendAvailable(_) => "No backend is available".to_string(),
             CreationError::RobustnessNotSupported => {
-                "You requested robustness, but it is not supported."
+                "You requested robustness, but it is not supported.".to_string()
             }
             CreationError::OpenGlVersionNotSupported => {
-                "The requested OpenGL version is not supported."
+                "The requested OpenGL version is not supported.".to_string()
             }
             CreationError::NoAvailablePixelFormat => {
-                "Couldn't find any pixel format that matches the criteria."
+                "Couldn't find any pixel format that matches the criteria.".to_string()
             }
-            CreationError::PlatformSpecific(ref text) => &text,
-            CreationError::Window(ref err) => std::error::Error::description(err),
-            CreationError::CreationErrors(_) => "Received multiple errors.",
+            CreationError::PlatformSpecific(text) => text.clone(),
+            CreationError::Window(err) => err.to_string(),
+            CreationError::CreationErrors(_) => "Received multiple errors.".to_string(),
         }
     }
 }
 
 impl std::fmt::Display for CreationError {
     fn fmt(&self, formatter: &mut std::fmt::Formatter) -> Result<(), std::fmt::Error> {
-        formatter.write_str(self.to_string())?;
+        formatter.write_str(&self.to_string())?;
 
         if let CreationError::CreationErrors(ref es) = *self {
             use std::fmt::Debug;
@@ -362,10 +353,6 @@ impl std::fmt::Display for CreationError {
 }
 
 impl std::error::Error for CreationError {
-    fn description(&self) -> &str {
-        self.to_string()
-    }
-
     fn cause(&self) -> Option<&dyn std::error::Error> {
         match *self {
             CreationError::NoBackendAvailable(ref err) => Some(&**err),
@@ -393,29 +380,18 @@ pub enum ContextError {
     FunctionUnavailable,
 }
 
-impl ContextError {
-    fn to_string(&self) -> &str {
-        use std::error::Error;
-        match *self {
-            ContextError::OsError(ref string) => string,
-            ContextError::IoError(ref err) => err.description(),
-            ContextError::ContextLost => "Context lost",
-            ContextError::FunctionUnavailable => "Function unavailable",
-        }
-    }
-}
-
 impl std::fmt::Display for ContextError {
     fn fmt(&self, formatter: &mut std::fmt::Formatter) -> Result<(), std::fmt::Error> {
-        formatter.write_str(self.to_string())
+        match self {
+            ContextError::OsError(string) => write!(formatter, "{}", string),
+            ContextError::IoError(err) => write!(formatter, "{}", err),
+            ContextError::ContextLost => write!(formatter, "Context lost"),
+            ContextError::FunctionUnavailable => write!(formatter, "Function unavailable"),
+        }
     }
 }
 
-impl std::error::Error for ContextError {
-    fn description(&self) -> &str {
-        self.to_string()
-    }
-}
+impl std::error::Error for ContextError {}
 
 /// All APIs related to OpenGL that you can possibly get while using glutin.
 #[derive(Debug, Clone, Copy, PartialEq, Eq)]

glutin/src/platform_impl/unix/x11.rs

@@ -27,15 +27,11 @@ pub mod utils;
 #[derive(Debug)]
 struct NoX11Connection;
 
-impl std::error::Error for NoX11Connection {
-    fn description(&self) -> &str {
-        "failed to get x11 connection"
-    }
-}
+impl std::error::Error for NoX11Connection {}
 
 impl std::fmt::Display for NoX11Connection {
     fn fmt(&self, f: &mut std::fmt::Formatter) -> std::fmt::Result {
-        f.write_str(std::error::Error::description(self))
+        f.write_str("failed to get x11 connection")
     }
 }
 
@@ -151,7 +147,7 @@ where
 
     match lacks_what {
         Some(Ok(())) => (),
-        Some(Err(Lacks::Transparency)) => warn!(
+        Some(Err(Lacks::Transparency)) => log::warn!(
             "Glutin could not a find fb config with an alpha mask. Transparency may be broken."
         ),
         Some(Err(Lacks::XID)) => panic!(),

glutin/src/platform_impl/windows/mod.rs

@@ -233,7 +233,7 @@ impl Context {
     }
 
     #[inline]
-    pub fn swap_buffers_with_damage(&self, rects: &[Rect]) -> Result<(), ContextError> {
+    pub fn swap_buffers_with_damage(&self, _rects: &[Rect]) -> Result<(), ContextError> {
         Err(ContextError::OsError("buffer damage not suported".to_string()))
     }