fix CI warnings

CHANGELOG.md

@@ -26,6 +26,7 @@ and this project adheres to [Semantic Versioning](http://semver.org/).
 - `invalid_reference_casting` Compilation error in spi.rs for Rust version 1.73+ (
   See [PR#112431](https://github.com/rust-lang/rust/pull/112431) for more info)
 - `unused_doc_comments` Warning in rcc.rs
+- Fixed some warnings #177
 
 ## [v0.18.0] - 2021-11-14
 

examples/dac.rs

@@ -2,7 +2,6 @@
 #![no_main]
 #![no_std]
 
-use cortex_m;
 use cortex_m_rt as rt;
 use panic_halt as _;
 

examples/pwm_complementary.rs

@@ -5,7 +5,6 @@
 // Halt on panic
 use panic_halt as _;
 
-use cortex_m;
 use cortex_m_rt::entry;
 
 use stm32f0xx_hal as hal;

examples/usb_serial.rs

@@ -36,7 +36,7 @@ fn main() -> ! {
     // Configure the on-board LED (LD3, green)
     let gpiob = dp.GPIOB.split(&mut rcc);
     let mut led = cortex_m::interrupt::free(|cs| gpiob.pb3.into_push_pull_output(cs));
-    led.set_low(); // Turn off
+    led.set_low().ok(); // Turn off
 
     let gpioa = dp.GPIOA.split(&mut rcc);
 
@@ -66,7 +66,7 @@ fn main() -> ! {
 
         match serial.read(&mut buf) {
             Ok(count) if count > 0 => {
-                led.set_high(); // Turn on
+                led.set_high().ok(); // Turn on
 
                 // Echo back in upper case
                 for c in buf[0..count].iter_mut() {
@@ -88,6 +88,6 @@ fn main() -> ! {
             _ => {}
         }
 
-        led.set_low(); // Turn off
+        led.set_low().ok(); // Turn off
     }
 }

src/gpio.rs

@@ -758,4 +758,4 @@ gpio!([
         PF9: (pf9, 9, Input<Floating>),
         PF10: (pf10, 10, Input<Floating>),
     ]
-    ]);
+]);

src/signature.rs

@@ -2,8 +2,6 @@
 //!
 //! (stored in flash memory)
 
-use core::str::from_utf8_unchecked;
-
 /// This is the test voltage in millivolts of the calibration done at the factory
 pub const VDDA_CALIB: u32 = 3300;
 
@@ -54,7 +52,7 @@ impl Uid {
 
     /// Lot number
     pub fn lot_num(&self) -> &str {
-        unsafe { from_utf8_unchecked(&self.waf_lot[1..]) }
+        unsafe { core::str::from_utf8_unchecked(&self.waf_lot[1..]) }
     }
 }