Auto merge of #67903 - Dylan-DPC:rollup-k9djyrf, r=Dylan-DPC

Rollup of 5 pull requests

Successful merges:

 - #67818 (rustdoc: Avoid panic when parsing codeblocks for playground links)
 - #67845 (Also remove const-hack for abs)
 - #67879 (Remove negative number check from float sqrt)
 - #67881 (Add backticks to various diagnostics)
 - #67882 (remove bespoke flock bindings)

Failed merges:

r? @ghost

src/libcore/num/mod.rs

@@ -2001,6 +2001,9 @@ $EndFeature, "
             #[inline]
             #[rustc_inherit_overflow_checks]
             pub const fn abs(self) -> Self {
+                // Note that the #[inline] above means that the overflow
+                // semantics of the subtraction depend on the crate we're being
+                // inlined into.
                 if self.is_negative() {
                     -self
                 } else {

src/librustc/infer/error_reporting/mod.rs

@@ -661,7 +661,7 @@ impl<'a, 'tcx> InferCtxt<'a, 'tcx> {
             },
             ObligationCauseCode::IfExpression(box IfExpressionCause { then, outer, semicolon }) => {
                 err.span_label(then, "expected because of this");
-                outer.map(|sp| err.span_label(sp, "if and else have incompatible types"));
+                outer.map(|sp| err.span_label(sp, "`if` and `else` have incompatible types"));
                 if let Some(sp) = semicolon {
                     err.span_suggestion_short(
                         sp,
@@ -1883,13 +1883,13 @@ impl<'tcx> ObligationCause<'tcx> {
                     hir::MatchSource::TryDesugar => {
                         "try expression alternatives have incompatible types"
                     }
-                    _ => "match arms have incompatible types",
+                    _ => "`match` arms have incompatible types",
                 })
             }
-            IfExpression { .. } => Error0308("if and else have incompatible types"),
-            IfExpressionWithNoElse => Error0317("if may be missing an else clause"),
-            MainFunctionType => Error0580("main function has wrong type"),
-            StartFunctionType => Error0308("start function has wrong type"),
+            IfExpression { .. } => Error0308("`if` and `else` have incompatible types"),
+            IfExpressionWithNoElse => Error0317("`if` may be missing an `else` clause"),
+            MainFunctionType => Error0580("`main` function has wrong type"),
+            StartFunctionType => Error0308("`#[start]` function has wrong type"),
             IntrinsicType => Error0308("intrinsic has wrong type"),
             MethodReceiver => Error0308("mismatched `self` parameter type"),
 
@@ -1917,12 +1917,12 @@ impl<'tcx> ObligationCause<'tcx> {
             ExprAssignable => "expression is assignable",
             MatchExpressionArm(box MatchExpressionArmCause { source, .. }) => match source {
                 hir::MatchSource::IfLetDesugar { .. } => "`if let` arms have compatible types",
-                _ => "match arms have compatible types",
+                _ => "`match` arms have compatible types",
             },
-            IfExpression { .. } => "if and else have incompatible types",
-            IfExpressionWithNoElse => "if missing an else returns ()",
+            IfExpression { .. } => "`if` and `else` have incompatible types",
+            IfExpressionWithNoElse => "`if` missing an `else` returns `()`",
             MainFunctionType => "`main` function has the correct type",
-            StartFunctionType => "`start` function has the correct type",
+            StartFunctionType => "`#[start]` function has the correct type",
             IntrinsicType => "intrinsic has the correct type",
             MethodReceiver => "method receiver has the correct type",
             _ => "types are compatible",

src/librustc_data_structures/flock.rs

@@ -13,96 +13,9 @@ use std::path::Path;
 cfg_if! {
     if #[cfg(unix)] {
         use std::ffi::{CString, OsStr};
+        use std::mem;
         use std::os::unix::prelude::*;
 
-        #[cfg(any(target_os = "linux", target_os = "android"))]
-        mod os {
-            #[repr(C)]
-            pub struct flock {
-                pub l_type: libc::c_short,
-                pub l_whence: libc::c_short,
-                pub l_start: libc::off_t,
-                pub l_len: libc::off_t,
-                pub l_pid: libc::pid_t,
-
-                // not actually here, but brings in line with freebsd
-                pub l_sysid: libc::c_int,
-            }
-        }
-
-        #[cfg(target_os = "freebsd")]
-        mod os {
-            #[repr(C)]
-            pub struct flock {
-                pub l_start: libc::off_t,
-                pub l_len: libc::off_t,
-                pub l_pid: libc::pid_t,
-                pub l_type: libc::c_short,
-                pub l_whence: libc::c_short,
-                pub l_sysid: libc::c_int,
-            }
-        }
-
-        #[cfg(any(target_os = "dragonfly",
-                  target_os = "netbsd",
-                  target_os = "openbsd"))]
-        mod os {
-            #[repr(C)]
-            pub struct flock {
-                pub l_start: libc::off_t,
-                pub l_len: libc::off_t,
-                pub l_pid: libc::pid_t,
-                pub l_type: libc::c_short,
-                pub l_whence: libc::c_short,
-
-                // not actually here, but brings in line with freebsd
-                pub l_sysid: libc::c_int,
-            }
-        }
-
-        #[cfg(target_os = "haiku")]
-        mod os {
-            #[repr(C)]
-            pub struct flock {
-                pub l_type: libc::c_short,
-                pub l_whence: libc::c_short,
-                pub l_start: libc::off_t,
-                pub l_len: libc::off_t,
-                pub l_pid: libc::pid_t,
-
-                // not actually here, but brings in line with freebsd
-                pub l_sysid: libc::c_int,
-            }
-        }
-
-        #[cfg(any(target_os = "macos", target_os = "ios"))]
-        mod os {
-            #[repr(C)]
-            pub struct flock {
-                pub l_start: libc::off_t,
-                pub l_len: libc::off_t,
-                pub l_pid: libc::pid_t,
-                pub l_type: libc::c_short,
-                pub l_whence: libc::c_short,
-
-                // not actually here, but brings in line with freebsd
-                pub l_sysid: libc::c_int,
-            }
-        }
-
-        #[cfg(target_os = "solaris")]
-        mod os {
-            #[repr(C)]
-            pub struct flock {
-                pub l_type: libc::c_short,
-                pub l_whence: libc::c_short,
-                pub l_start: libc::off_t,
-                pub l_len: libc::off_t,
-                pub l_sysid: libc::c_int,
-                pub l_pid: libc::pid_t,
-            }
-        }
-
         #[derive(Debug)]
         pub struct Lock {
             fd: libc::c_int,
@@ -132,19 +45,17 @@ cfg_if! {
                 }
 
                 let lock_type = if exclusive {
-                    libc::F_WRLCK as libc::c_short
+                    libc::F_WRLCK
                 } else {
-                    libc::F_RDLCK as libc::c_short
+                    libc::F_RDLCK
                 };
 
-                let flock = os::flock {
-                    l_start: 0,
-                    l_len: 0,
-                    l_pid: 0,
-                    l_whence: libc::SEEK_SET as libc::c_short,
-                    l_type: lock_type,
-                    l_sysid: 0,
-                };
+                let mut flock: libc::flock = unsafe { mem::zeroed() };
+                flock.l_type = lock_type as libc::c_short;
+                flock.l_whence = libc::SEEK_SET as libc::c_short;
+                flock.l_start = 0;
+                flock.l_len = 0;
+
                 let cmd = if wait { libc::F_SETLKW } else { libc::F_SETLK };
                 let ret = unsafe {
                     libc::fcntl(fd, cmd, &flock)
@@ -161,14 +72,12 @@ cfg_if! {
 
         impl Drop for Lock {
             fn drop(&mut self) {
-                let flock = os::flock {
-                    l_start: 0,
-                    l_len: 0,
-                    l_pid: 0,
-                    l_whence: libc::SEEK_SET as libc::c_short,
-                    l_type: libc::F_UNLCK as libc::c_short,
-                    l_sysid: 0,
-                };
+                let mut flock: libc::flock = unsafe { mem::zeroed() };
+                flock.l_type = libc::F_UNLCK as libc::c_short;
+                flock.l_whence = libc::SEEK_SET as libc::c_short;
+                flock.l_start = 0;
+                flock.l_len = 0;
+
                 unsafe {
                     libc::fcntl(self.fd, libc::F_SETLK, &flock);
                     libc::close(self.fd);

src/librustc_passes/entry.rs

@@ -134,7 +134,7 @@ fn find_item(item: &Item<'_>, ctxt: &mut EntryContext<'_, '_>, at_root: bool) {
                 ctxt.start_fn = Some((item.hir_id, item.span));
             } else {
                 struct_span_err!(ctxt.session, item.span, E0138, "multiple `start` functions")
-                    .span_label(ctxt.start_fn.unwrap().1, "previous `start` function here")
+                    .span_label(ctxt.start_fn.unwrap().1, "previous `#[start]` function here")
                     .span_label(item.span, "multiple `start` functions")
                     .emit();
             }

src/librustc_target/spec/wasm32_base.rs

@@ -81,7 +81,7 @@ pub fn options() -> TargetOptions {
         dynamic_linking: true,
         only_cdylib: true,
 
-        // This means we'll just embed a `start` function in the wasm module
+        // This means we'll just embed a `#[start]` function in the wasm module
         executables: true,
 
         // relatively self-explanatory!

src/librustc_typeck/check/_match.rs

@@ -298,7 +298,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
             // LL ||         10u32
             //    ||         ^^^^^ expected `i32`, found `u32`
             // LL ||     };
-            //    ||_____- if and else have incompatible types
+            //    ||_____- `if` and `else` have incompatible types
             // ```
             Some(span)
         } else {
@@ -340,7 +340,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
                 // by not pointing at the entire expression:
                 // ```
                 // 2 |       let x = if true {
-                //   |               ------- if and else have incompatible types
+                //   |               ------- `if` and `else` have incompatible types
                 // 3 |           3
                 //   |           - expected because of this
                 // 4 |       } else {