Rollup merge of rust-lang#62422 - lzutao:remove-some-mem-uinit, r=alexcrichton

Remove some uses of mem::uninitialized

cc rust-lang#62397
r? @RalfJung

Author: Centril

src/librustc_codegen_llvm/common.rs

@@ -170,8 +170,7 @@ impl CodegenCx<'ll, 'tcx> {
     pub fn const_get_real(&self, v: &'ll Value) -> Option<(f64, bool)> {
         unsafe {
             if self.is_const_real(v) {
-                #[allow(deprecated)]
-                let mut loses_info: llvm::Bool = ::std::mem::uninitialized();
+                let mut loses_info: llvm::Bool = 0;
                 let r = llvm::LLVMConstRealGetDouble(v, &mut loses_info);
                 let loses_info = if loses_info == 1 { true } else { false };
                 Some((r, loses_info))

src/libterm/win.rs

@@ -2,8 +2,6 @@
 
 // FIXME (#13400): this is only a tiny fraction of the Windows console api
 
-extern crate libc;
-
 use std::io;
 use std::io::prelude::*;
 
@@ -20,19 +18,36 @@ pub struct WinConsole<T> {
     background: color::Color,
 }
 
+type SHORT = i16;
 type WORD = u16;
 type DWORD = u32;
 type BOOL = i32;
 type HANDLE = *mut u8;
 
+#[allow(non_snake_case)]
+#[repr(C)]
+struct SMALL_RECT {
+    Left: SHORT,
+    Top: SHORT,
+    Right: SHORT,
+    Bottom: SHORT,
+}
+
+#[allow(non_snake_case)]
+#[repr(C)]
+struct COORD {
+    X: SHORT,
+    Y: SHORT,
+}
+
 #[allow(non_snake_case)]
 #[repr(C)]
 struct CONSOLE_SCREEN_BUFFER_INFO {
-    dwSize: [libc::c_short; 2],
-    dwCursorPosition: [libc::c_short; 2],
+    dwSize: COORD,
+    dwCursorPosition: COORD,
     wAttributes: WORD,
-    srWindow: [libc::c_short; 4],
-    dwMaximumWindowSize: [libc::c_short; 2],
+    srWindow: SMALL_RECT,
+    dwMaximumWindowSize: COORD,
 }
 
 #[allow(non_snake_case)]
@@ -105,12 +120,17 @@ impl<T: Write + Send + 'static> WinConsole<T> {
 
     /// Returns `None` whenever the terminal cannot be created for some reason.
     pub fn new(out: T) -> io::Result<WinConsole<T>> {
+        use std::mem::MaybeUninit;
+
         let fg;
         let bg;
         unsafe {
-            #[allow(deprecated)]
-            let mut buffer_info = ::std::mem::uninitialized();
-            if GetConsoleScreenBufferInfo(GetStdHandle(-11i32 as DWORD), &mut buffer_info) != 0 {
+            let mut buffer_info = MaybeUninit::<CONSOLE_SCREEN_BUFFER_INFO>::uninit();
+            if GetConsoleScreenBufferInfo(
+                GetStdHandle(-11i32 as DWORD),
+                buffer_info.as_mut_ptr()
+            ) != 0 {
+                let buffer_info = buffer_info.assume_init() ;
                 fg = bits_to_color(buffer_info.wAttributes);
                 bg = bits_to_color(buffer_info.wAttributes >> 4);
             } else {