Auto merge of #35769 - eddyb:rollup, r=eddyb

Rollup of 12 pull requests

- Successful merges: #35346, #35734, #35739, #35740, #35742, #35744, #35749, #35750, #35751, #35756, #35766, #35768
- Failed merges:

README.md

@@ -19,7 +19,7 @@ Read ["Installing Rust"] from [The Book].
    * `g++` 4.7 or later or `clang++` 3.x
    * `python` 2.7 (but not 3.x)
    * GNU `make` 3.81 or later
-   * `cmake` 2.8.8 or later
+   * `cmake` 3.4.3 or later
    * `curl`
    * `git`
 

mk/cfg/mips-unknown-linux-uclibc.mk

@@ -0,0 +1 @@
+# rustbuild-only target

mk/cfg/mipsel-unknown-linux-uclibc.mk

@@ -0,0 +1 @@
+# rustbuild-only target

src/bootstrap/mk/Makefile.in

@@ -22,6 +22,10 @@ BOOTSTRAP := $(CFG_PYTHON) $(CFG_SRC_DIR)src/bootstrap/bootstrap.py $(BOOTSTRAP_
 all:
 	$(Q)$(BOOTSTRAP)
 
+# Don’t use $(Q) here, always show how to invoke the bootstrap script directly
+help:
+	$(BOOTSTRAP) --help
+
 clean:
 	$(Q)$(BOOTSTRAP) --clean
 

src/librustc/hir/map/mod.rs

@@ -569,6 +569,13 @@ impl<'ast> Map<'ast> {
         }
     }
 
+    pub fn expect_impl_item(&self, id: NodeId) -> &'ast ImplItem {
+        match self.find(id) {
+            Some(NodeImplItem(item)) => item,
+            _ => bug!("expected impl item, found {}", self.node_to_string(id))
+        }
+    }
+
     pub fn expect_trait_item(&self, id: NodeId) -> &'ast TraitItem {
         match self.find(id) {
             Some(NodeTraitItem(item)) => item,

src/librustc/infer/error_reporting.rs

@@ -523,6 +523,7 @@ impl<'a, 'gcx, 'tcx> InferCtxt<'a, 'gcx, 'tcx> {
     pub fn note_type_err(&self,
                          diag: &mut DiagnosticBuilder<'tcx>,
                          origin: TypeOrigin,
+                         secondary_span: Option<(Span, String)>,
                          values: Option<ValuePairs<'tcx>>,
                          terr: &TypeError<'tcx>)
     {
@@ -553,6 +554,9 @@ impl<'a, 'gcx, 'tcx> InferCtxt<'a, 'gcx, 'tcx> {
         }
 
         diag.span_label(span, &terr);
+        if let Some((sp, msg)) = secondary_span {
+            diag.span_label(sp, &msg);
+        }
 
         self.note_error_origin(diag, &origin);
         self.check_and_note_conflicting_crates(diag, terr, span);
@@ -569,7 +573,7 @@ impl<'a, 'gcx, 'tcx> InferCtxt<'a, 'gcx, 'tcx> {
             self.tcx.sess, trace.origin.span(), E0308,
             "{}", trace.origin.as_failure_str()
         );
-        self.note_type_err(&mut diag, trace.origin, Some(trace.values), terr);
+        self.note_type_err(&mut diag, trace.origin, None, Some(trace.values), terr);
         diag
     }
 

src/librustc/traits/error_reporting.rs

@@ -161,7 +161,7 @@ impl<'a, 'gcx, 'tcx> InferCtxt<'a, 'gcx, 'tcx> {
                 self.tcx.sess, origin.span(), E0271,
                 "type mismatch resolving `{}`", predicate
             );
-            self.note_type_err(&mut diag, origin, values, err);
+            self.note_type_err(&mut diag, origin, None, values, err);
             self.note_obligation_cause(&mut diag, obligation);
             diag.emit();
         });

src/librustc_back/target/mips_unknown_linux_uclibc.rs

@@ -0,0 +1,30 @@
+// Copyright 2016 The Rust Project Developers. See the COPYRIGHT
+// file at the top-level directory of this distribution and at
+// http://rust-lang.org/COPYRIGHT.
+//
+// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
+// option. This file may not be copied, modified, or distributed
+// except according to those terms.
+
+use target::{Target, TargetOptions, TargetResult};
+
+pub fn target() -> TargetResult {
+    Ok(Target {
+        llvm_target: "mips-unknown-linux-uclibc".to_string(),
+        target_endian: "big".to_string(),
+        target_pointer_width: "32".to_string(),
+        data_layout: "E-m:m-p:32:32-i8:8:32-i16:16:32-i64:64-n32-S64".to_string(),
+        arch: "mips".to_string(),
+        target_os: "linux".to_string(),
+        target_env: "uclibc".to_string(),
+        target_vendor: "unknown".to_string(),
+        options: TargetOptions {
+            cpu: "mips32r2".to_string(),
+            features: "+mips32r2,+soft-float".to_string(),
+            max_atomic_width: 32,
+            ..super::linux_base::opts()
+        },
+    })
+}

src/librustc_back/target/mipsel_unknown_linux_uclibc.rs

@@ -0,0 +1,31 @@
+// Copyright 2016 The Rust Project Developers. See the COPYRIGHT
+// file at the top-level directory of this distribution and at
+// http://rust-lang.org/COPYRIGHT.
+//
+// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
+// option. This file may not be copied, modified, or distributed
+// except according to those terms.
+
+use target::{Target, TargetOptions, TargetResult};
+
+pub fn target() -> TargetResult {
+    Ok(Target {
+        llvm_target: "mipsel-unknown-linux-uclibc".to_string(),
+        target_endian: "little".to_string(),
+        target_pointer_width: "32".to_string(),
+        data_layout: "e-m:m-p:32:32-i8:8:32-i16:16:32-i64:64-n32-S64".to_string(),
+        arch: "mips".to_string(),
+        target_os: "linux".to_string(),
+        target_env: "uclibc".to_string(),
+        target_vendor: "unknown".to_string(),
+
+        options: TargetOptions {
+            cpu: "mips32".to_string(),
+            features: "+mips32,+soft-float".to_string(),
+            max_atomic_width: 32,
+            ..super::linux_base::opts()
+        },
+    })
+}

src/librustc_back/target/mod.rs

@@ -143,6 +143,8 @@ supported_targets! {
     ("i686-unknown-linux-musl", i686_unknown_linux_musl),
     ("mips-unknown-linux-musl", mips_unknown_linux_musl),
     ("mipsel-unknown-linux-musl", mipsel_unknown_linux_musl),
+    ("mips-unknown-linux-uclibc", mips_unknown_linux_uclibc),
+    ("mipsel-unknown-linux-uclibc", mipsel_unknown_linux_uclibc),
 
     ("i686-linux-android", i686_linux_android),
     ("arm-linux-androideabi", arm_linux_androideabi),

src/librustc_const_eval/check_match.rs

@@ -1121,10 +1121,11 @@ fn check_legality_of_move_bindings(cx: &MatchCheckCtxt,
                 .span_label(p.span, &format!("moves value into pattern guard"))
                 .emit();
         } else if by_ref_span.is_some() {
-            let mut err = struct_span_err!(cx.tcx.sess, p.span, E0009,
-                                           "cannot bind by-move and by-ref in the same pattern");
-            span_note!(&mut err, by_ref_span.unwrap(), "by-ref binding occurs here");
-            err.emit();
+            struct_span_err!(cx.tcx.sess, p.span, E0009,
+                            "cannot bind by-move and by-ref in the same pattern")
+                    .span_label(p.span, &format!("by-move pattern here"))
+                    .span_label(by_ref_span.unwrap(), &format!("both by-ref and by-move used"))
+                    .emit();
         }
     };
 

src/librustc_mir/build/scope.rs

@@ -198,8 +198,11 @@ impl<'tcx> Scope<'tcx> {
     ///
     /// Should always be run for all inner scopes when a drop is pushed into some scope enclosing a
     /// larger extent of code.
-    fn invalidate_cache(&mut self) {
-        self.cached_exits = FnvHashMap();
+    ///
+    /// `unwind` controls whether caches for the unwind branch are also invalidated.
+    fn invalidate_cache(&mut self, unwind: bool) {
+        self.cached_exits.clear();
+        if !unwind { return; }
         for dropdata in &mut self.drops {
             if let DropKind::Value { ref mut cached_block } = dropdata.kind {
                 *cached_block = None;
@@ -455,25 +458,65 @@ impl<'a, 'gcx, 'tcx> Builder<'a, 'gcx, 'tcx> {
         };
 
         for scope in self.scopes.iter_mut().rev() {
-            if scope.extent == extent {
+            let this_scope = scope.extent == extent;
+            // When building drops, we try to cache chains of drops in such a way so these drops
+            // could be reused by the drops which would branch into the cached (already built)
+            // blocks.  This, however, means that whenever we add a drop into a scope which already
+            // had some blocks built (and thus, cached) for it, we must invalidate all caches which
+            // might branch into the scope which had a drop just added to it. This is necessary,
+            // because otherwise some other code might use the cache to branch into already built
+            // chain of drops, essentially ignoring the newly added drop.
+            //
+            // For example consider there’s two scopes with a drop in each. These are built and
+            // thus the caches are filled:
+            //
+            // +--------------------------------------------------------+
+            // | +---------------------------------+                    |
+            // | | +--------+     +-------------+  |  +---------------+ |
+            // | | | return | <-+ | drop(outer) | <-+ |  drop(middle) | |
+            // | | +--------+     +-------------+  |  +---------------+ |
+            // | +------------|outer_scope cache|--+                    |
+            // +------------------------------|middle_scope cache|------+
+            //
+            // Now, a new, inner-most scope is added along with a new drop into both inner-most and
+            // outer-most scopes:
+            //
+            // +------------------------------------------------------------+
+            // | +----------------------------------+                       |
+            // | | +--------+      +-------------+  |   +---------------+   | +-------------+
+            // | | | return | <+   | drop(new)   | <-+  |  drop(middle) | <--+| drop(inner) |
+            // | | +--------+  |   | drop(outer) |  |   +---------------+   | +-------------+
+            // | |             +-+ +-------------+  |                       |
+            // | +---|invalid outer_scope cache|----+                       |
+            // +----=----------------|invalid middle_scope cache|-----------+
+            //
+            // If, when adding `drop(new)` we do not invalidate the cached blocks for both
+            // outer_scope and middle_scope, then, when building drops for the inner (right-most)
+            // scope, the old, cached blocks, without `drop(new)` will get used, producing the
+            // wrong results.
+            //
+            // The cache and its invalidation for unwind branch is somewhat special. The cache is
+            // per-drop, rather than per scope, which has a several different implications. Adding
+            // a new drop into a scope will not invalidate cached blocks of the prior drops in the
+            // scope. That is true, because none of the already existing drops will have an edge
+            // into a block with the newly added drop.
+            //
+            // Note that this code iterates scopes from the inner-most to the outer-most,
+            // invalidating caches of each scope visited. This way bare minimum of the
+            // caches gets invalidated. i.e. if a new drop is added into the middle scope, the
+            // cache of outer scpoe stays intact.
+            let invalidate_unwind = needs_drop && !this_scope;
+            scope.invalidate_cache(invalidate_unwind);
+            if this_scope {
                 if let DropKind::Value { .. } = drop_kind {
                     scope.needs_cleanup = true;
                 }
-
-                // No need to invalidate any caches here. The just-scheduled drop will branch into
-                // the drop that comes before it in the vector.
                 scope.drops.push(DropData {
                     span: span,
                     location: lvalue.clone(),
                     kind: drop_kind
                 });
                 return;
-            } else {
-                // We must invalidate all the cached_blocks leading up to the scope we’re
-                // looking for, because all of the blocks in the chain will become incorrect.
-                if let DropKind::Value { .. } = drop_kind {
-                    scope.invalidate_cache()
-                }
             }
         }
         span_bug!(span, "extent {:?} not in scope to drop {:?}", extent, lvalue);
@@ -490,11 +533,12 @@ impl<'a, 'gcx, 'tcx> Builder<'a, 'gcx, 'tcx> {
                              value: &Lvalue<'tcx>,
                              item_ty: Ty<'tcx>) {
         for scope in self.scopes.iter_mut().rev() {
+            // See the comment in schedule_drop above. The primary difference is that we invalidate
+            // the unwind blocks unconditionally. That’s because the box free may be considered
+            // outer-most cleanup within the scope.
+            scope.invalidate_cache(true);
             if scope.extent == extent {
                 assert!(scope.free.is_none(), "scope already has a scheduled free!");
-                // We also must invalidate the caches in the scope for which the free is scheduled
-                // because the drops must branch into the free we schedule here.
-                scope.invalidate_cache();
                 scope.needs_cleanup = true;
                 scope.free = Some(FreeData {
                     span: span,
@@ -503,11 +547,6 @@ impl<'a, 'gcx, 'tcx> Builder<'a, 'gcx, 'tcx> {
                     cached_block: None
                 });
                 return;
-            } else {
-                // We must invalidate all the cached_blocks leading up to the scope we’re looking
-                // for, because otherwise some/most of the blocks in the chain will become
-                // incorrect.
-                scope.invalidate_cache();
             }
         }
         span_bug!(span, "extent {:?} not in scope to free {:?}", extent, value);

src/librustc_resolve/diagnostics.rs

@@ -891,7 +891,7 @@ A `struct` variant name was used like a function name.
 Erroneous code example:
 
 ```compile_fail,E0423
-struct Foo { a: bool};
+struct Foo { a: bool };
 
 let f = Foo();
 // error: `Foo` is a struct variant name, but this expression uses

src/librustc_resolve/lib.rs

@@ -102,7 +102,7 @@ enum ResolutionError<'a> {
     /// error E0402: cannot use an outer type parameter in this context
     OuterTypeParameterContext,
     /// error E0403: the name is already used for a type parameter in this type parameter list
-    NameAlreadyUsedInTypeParameterList(Name),
+    NameAlreadyUsedInTypeParameterList(Name, &'a Span),
     /// error E0404: is not a trait
     IsNotATrait(&'a str),
     /// error E0405: use of undeclared trait name
@@ -209,13 +209,17 @@ fn resolve_struct_error<'b, 'a: 'b, 'c>(resolver: &'b Resolver<'a>,
                              E0402,
                              "cannot use an outer type parameter in this context")
         }
-        ResolutionError::NameAlreadyUsedInTypeParameterList(name) => {
-            struct_span_err!(resolver.session,
-                             span,
-                             E0403,
-                             "the name `{}` is already used for a type parameter in this type \
-                              parameter list",
-                             name)
+        ResolutionError::NameAlreadyUsedInTypeParameterList(name, first_use_span) => {
+             let mut err = struct_span_err!(resolver.session,
+                                            span,
+                                            E0403,
+                                            "the name `{}` is already used for a type parameter \
+                                            in this type parameter list",
+                                            name);
+             err.span_label(span, &format!("already used"));
+             err.span_label(first_use_span.clone(), &format!("first use of `{}`", name));
+             err
+
         }
         ResolutionError::IsNotATrait(name) => {
             let mut err = struct_span_err!(resolver.session,
@@ -237,12 +241,14 @@ fn resolve_struct_error<'b, 'a: 'b, 'c>(resolver: &'b Resolver<'a>,
             err
         }
         ResolutionError::MethodNotMemberOfTrait(method, trait_) => {
-            struct_span_err!(resolver.session,
-                             span,
-                             E0407,
-                             "method `{}` is not a member of trait `{}`",
-                             method,
-                             trait_)
+            let mut err = struct_span_err!(resolver.session,
+                                           span,
+                                           E0407,
+                                           "method `{}` is not a member of trait `{}`",
+                                           method,
+                                           trait_);
+            err.span_label(span, &format!("not a member of `{}`", trait_));
+            err
         }
         ResolutionError::TypeNotMemberOfTrait(type_, trait_) => {
             struct_span_err!(resolver.session,
@@ -1726,17 +1732,19 @@ impl<'a> Resolver<'a> {
         match type_parameters {
             HasTypeParameters(generics, rib_kind) => {
                 let mut function_type_rib = Rib::new(rib_kind);
-                let mut seen_bindings = HashSet::new();
+                let mut seen_bindings = HashMap::new();
                 for type_parameter in &generics.ty_params {
                     let name = type_parameter.ident.name;
                     debug!("with_type_parameter_rib: {}", type_parameter.id);
 
-                    if seen_bindings.contains(&name) {
+                    if seen_bindings.contains_key(&name) {
+                        let span = seen_bindings.get(&name).unwrap();
                         resolve_error(self,
                                       type_parameter.span,
-                                      ResolutionError::NameAlreadyUsedInTypeParameterList(name));
+                                      ResolutionError::NameAlreadyUsedInTypeParameterList(name,
+                                                                                          span));
                     }
-                    seen_bindings.insert(name);
+                    seen_bindings.entry(name).or_insert(type_parameter.span);
 
                     // plain insert (no renaming)
                     let def_id = self.definitions.local_def_id(type_parameter.id);