Auto merge of #55710 - kennytm:rollup, r=kennytm

Rollup of 11 pull requests

Successful merges:

 - #55490 (resolve: Fix ICE in macro import error recovery)
 - #55597 (std: Enable usage of `thread_local!` through imports)
 - #55601 (Fix tracking issue numbers for some unstable features)
 - #55621 (Add precision for create_dir function)
 - #55644 (ci: Add Dockerfile for dist-powerpcspe-linux)
 - #55664 (Make "all possible cases" help message uniform with existing help messages)
 - #55689 (miri: binary_op_val -> binary_op_imm)
 - #55694 (Fixes #31076)
 - #55696 (NLL Diagnostic Review 3: Missing errors for borrows of union fields)
 - #55700 (Update ui tests with respect to NLL)
 - #55703 (Update `configure --help` (via configure.py) to reflect decoupling of debug+optimize)

Author: bors

src/bootstrap/configure.py

@@ -40,7 +40,7 @@ def v(*args):
     options.append(Option(*args, value=True))
 
 
-o("debug", "rust.debug", "debug mode; disables optimization unless `--enable-optimize` given")
+o("debug", "rust.debug", "enables debugging environment; does not affect optimization of bootstrapped code (use `--disable-optimize` for that)")
 o("docs", "build.docs", "build standard library documentation")
 o("compiler-docs", "build.compiler-docs", "build compiler documentation")
 o("optimize-tests", "rust.optimize-tests", "build tests with optimizations")

src/ci/docker/disabled/dist-powerpcspe-linux/Dockerfile

@@ -0,0 +1,26 @@
+FROM ubuntu:16.04
+
+RUN apt-get update && apt-get install -y --no-install-recommends \
+  g++ \
+  make \
+  file \
+  curl \
+  ca-certificates \
+  python2.7 \
+  git \
+  cmake \
+  sudo \
+  gdb \
+  xz-utils \
+  g++-powerpc-linux-gnuspe \
+  libssl-dev \
+  pkg-config
+
+
+COPY scripts/sccache.sh /scripts/
+RUN sh /scripts/sccache.sh
+
+ENV HOSTS=powerpc-unknown-linux-gnuspe
+
+ENV RUST_CONFIGURE_ARGS --enable-extended --disable-docs
+ENV SCRIPT python2.7 ../x.py dist --host $HOSTS --target $HOSTS

src/librustc/middle/dead.rs

@@ -291,10 +291,8 @@ fn has_allow_dead_code_or_lang_attr(tcx: TyCtxt<'_, '_, '_>,
         return true;
     }
 
-    // (To be) stable attribute for #[lang = "panic_impl"]
-    if attr::contains_name(attrs, "panic_implementation") ||
-        attr::contains_name(attrs, "panic_handler")
-    {
+    // Stable attribute for #[lang = "panic_impl"]
+    if attr::contains_name(attrs, "panic_handler") {
         return true;
     }
 

src/librustc/middle/lang_items.rs

@@ -204,9 +204,7 @@ pub fn extract(attrs: &[ast::Attribute]) -> Option<(Symbol, Span)> {
             if let Some(value) = attribute.value_str() {
                 return Some((value, attribute.span));
             }
-        } else if attribute.check_name("panic_implementation") ||
-            attribute.check_name("panic_handler")
-        {
+        } else if attribute.check_name("panic_handler") {
             return Some((Symbol::intern("panic_impl"), attribute.span))
         } else if attribute.check_name("alloc_error_handler") {
             return Some((Symbol::intern("oom"), attribute.span))

src/librustc/mir/mod.rs

@@ -506,25 +506,25 @@ pub enum BorrowKind {
     /// implicit closure bindings. It is needed when the closure is
     /// borrowing or mutating a mutable referent, e.g.:
     ///
-    ///    let x: &mut isize = ...;
-    ///    let y = || *x += 5;
+    ///     let x: &mut isize = ...;
+    ///     let y = || *x += 5;
     ///
     /// If we were to try to translate this closure into a more explicit
     /// form, we'd encounter an error with the code as written:
     ///
-    ///    struct Env { x: & &mut isize }
-    ///    let x: &mut isize = ...;
-    ///    let y = (&mut Env { &x }, fn_ptr);  // Closure is pair of env and fn
-    ///    fn fn_ptr(env: &mut Env) { **env.x += 5; }
+    ///     struct Env { x: & &mut isize }
+    ///     let x: &mut isize = ...;
+    ///     let y = (&mut Env { &x }, fn_ptr);  // Closure is pair of env and fn
+    ///     fn fn_ptr(env: &mut Env) { **env.x += 5; }
     ///
     /// This is then illegal because you cannot mutate an `&mut` found
     /// in an aliasable location. To solve, you'd have to translate with
     /// an `&mut` borrow:
     ///
-    ///    struct Env { x: & &mut isize }
-    ///    let x: &mut isize = ...;
-    ///    let y = (&mut Env { &mut x }, fn_ptr); // changed from &x to &mut x
-    ///    fn fn_ptr(env: &mut Env) { **env.x += 5; }
+    ///     struct Env { x: & &mut isize }
+    ///     let x: &mut isize = ...;
+    ///     let y = (&mut Env { &mut x }, fn_ptr); // changed from &x to &mut x
+    ///     fn fn_ptr(env: &mut Env) { **env.x += 5; }
     ///
     /// Now the assignment to `**env.x` is legal, but creating a
     /// mutable pointer to `x` is not because `x` is not mutable. We

src/librustc_mir/hair/pattern/check_match.rs

@@ -238,8 +238,8 @@ impl<'a, 'tcx> MatchVisitor<'a, 'tcx> {
                                                         is non-empty",
                                                        pat_ty));
                     span_help!(&mut err, scrut.span,
-                               "Please ensure that all possible cases are being handled; \
-                                possibly adding wildcards or more match arms.");
+                               "ensure that all possible cases are being handled, \
+                                possibly by adding wildcards or more match arms");
                     err.emit();
                 }
                 // If the type *is* uninhabited, it's vacuously exhaustive

src/librustc_mir/interpret/intrinsics.rs

@@ -140,7 +140,7 @@ impl<'a, 'mir, 'tcx, M: Machine<'a, 'mir, 'tcx>> EvalContext<'a, 'mir, 'tcx, M>
                     "unchecked_shr" => BinOp::Shr,
                     _ => bug!("Already checked for int ops")
                 };
-                let (val, overflowed) = self.binary_op_val(bin_op, l, r)?;
+                let (val, overflowed) = self.binary_op_imm(bin_op, l, r)?;
                 if overflowed {
                     let layout = self.layout_of(substs.type_at(0))?;
                     let r_val =  r.to_scalar()?.to_bits(layout.size)?;

src/librustc_mir/interpret/operator.rs

@@ -28,7 +28,7 @@ impl<'a, 'mir, 'tcx, M: Machine<'a, 'mir, 'tcx>> EvalContext<'a, 'mir, 'tcx, M>
         right: ImmTy<'tcx, M::PointerTag>,
         dest: PlaceTy<'tcx, M::PointerTag>,
     ) -> EvalResult<'tcx> {
-        let (val, overflowed) = self.binary_op_val(op, left, right)?;
+        let (val, overflowed) = self.binary_op_imm(op, left, right)?;
         let val = Immediate::ScalarPair(val.into(), Scalar::from_bool(overflowed).into());
         self.write_immediate(val, dest)
     }
@@ -42,7 +42,7 @@ impl<'a, 'mir, 'tcx, M: Machine<'a, 'mir, 'tcx>> EvalContext<'a, 'mir, 'tcx, M>
         right: ImmTy<'tcx, M::PointerTag>,
         dest: PlaceTy<'tcx, M::PointerTag>,
     ) -> EvalResult<'tcx> {
-        let (val, _overflowed) = self.binary_op_val(op, left, right)?;
+        let (val, _overflowed) = self.binary_op_imm(op, left, right)?;
         self.write_scalar(val, dest)
     }
 }
@@ -283,9 +283,9 @@ impl<'a, 'mir, 'tcx, M: Machine<'a, 'mir, 'tcx>> EvalContext<'a, 'mir, 'tcx, M>
     }
 
     /// Convenience wrapper that's useful when keeping the layout together with the
-    /// value.
+    /// immediate value.
     #[inline]
-    pub fn binary_op_val(
+    pub fn binary_op_imm(
         &self,
         bin_op: mir::BinOp,
         left: ImmTy<'tcx, M::PointerTag>,

src/librustc_mir/monomorphize/partitioning.rs

@@ -511,7 +511,7 @@ fn mono_item_visibility(
         //
         // * First is weak lang items. These are basically mechanisms for
         //   libcore to forward-reference symbols defined later in crates like
-        //   the standard library or `#[panic_implementation]` definitions. The
+        //   the standard library or `#[panic_handler]` definitions. The
         //   definition of these weak lang items needs to be referenceable by
         //   libcore, so we're no longer a candidate for internalization.
         //   Removal of these functions can't be done by LLVM but rather must be

src/librustc_mir/transform/const_prop.rs

@@ -455,7 +455,7 @@ impl<'a, 'mir, 'tcx> ConstPropagator<'a, 'mir, 'tcx> {
                 })?;
                 trace!("const evaluating {:?} for {:?} and {:?}", op, left, right);
                 let (val, overflow) = self.use_ecx(source_info, |this| {
-                    this.ecx.binary_op_val(op, l, r)
+                    this.ecx.binary_op_imm(op, l, r)
                 })?;
                 let val = if let Rvalue::CheckedBinaryOp(..) = *rvalue {
                     Immediate::ScalarPair(