Auto merge of #37837 - GuillaumeGomez:rollup, r=GuillaumeGomez

Rollup of 8 pull requests

- Successful merges: #37752, #37757, #37759, #37766, #37772, #37799, #37806, #37821
- Failed merges: #37442

Author: bors

src/doc/book/testing.md

@@ -586,3 +586,45 @@ you add more examples.
 
 We haven’t covered all of the details with writing documentation tests. For more,
 please see the [Documentation chapter](documentation.html).
+
+# Testing and concurrency
+
+One thing that is important to note when writing tests are run concurrently
+using threads. For this reason you should take care that your tests are written
+in such a way as to not depend on each-other, or on any shared state. "Shared
+state" can also include the environment, such as the current working directory,
+or environment variables.
+
+If this is an issue it is possible to control this concurrency, either by
+setting the environment variable `RUST_TEST_THREADS`, or by passing the argument
+`--test-threads` to the tests:
+
+```bash
+$ RUST_TEST_THREADS=1 cargo test   # Run tests with no concurrency
+...
+$ cargo test -- --test-threads=1   # Same as above
+...
+```
+
+# Test output
+
+By default Rust's test library captures and discards output to standard
+out/error, e.g. output from `println!()`. This too can be controlled using the
+environment or a switch:
+
+
+```bash
+$ RUST_TEST_NOCAPTURE=1 cargo test   # Preserve stdout/stderr
+...
+$ cargo test -- --nocapture          # Same as above
+...
+```
+
+However a better method avoiding capture is to use logging rather than raw
+output. Rust has a [standard logging API][log], which provides a frontend to
+multiple logging implementations. This can be used in conjunction with the
+default [env_logger] to output any debugging information in a manner that can be
+controlled at runtime.
+
+[log]: https://crates.io/crates/log
+[env_logger]: https://crates.io/crates/env_logger

src/librustc_const_eval/diagnostics.rs

@@ -40,7 +40,9 @@ Ensure the ordering of the match arm is correct and remove any superfluous
 arms.
 "##,
 
-/*E0002: r##"
+E0002: r##"
+## Note: this error code is no longer emitted by the compiler.
+
 This error indicates that an empty match expression is invalid because the type
 it is matching on is non-empty (there exist values of this type). In safe code
 it is impossible to create an instance of an empty type, so empty match
@@ -68,10 +70,11 @@ fn foo(x: Option<String>) {
     }
 }
 ```
-"##,*/
+"##,
 
+E0003: r##"
+## Note: this error code is no longer emitted by the compiler.
 
-/*E0003: r##"
 Not-a-Number (NaN) values cannot be compared for equality and hence can never
 match the input to a match expression. So, the following will not compile:
 
@@ -98,7 +101,6 @@ match number {
 }
 ```
 "##,
-*/
 
 E0004: r##"
 This error indicates that the compiler cannot guarantee a matching pattern for

src/librustc_typeck/check/method/suggest.rs

@@ -308,7 +308,7 @@ impl<'a, 'gcx, 'tcx> FnCtxt<'a, 'gcx, 'tcx> {
 
             let limit = if candidates.len() == 5 { 5 } else { 4 };
             for (i, trait_did) in candidates.iter().take(limit).enumerate() {
-                err.help(&format!("candidate #{}: `use {}`",
+                err.help(&format!("candidate #{}: `use {};`",
                                   i + 1,
                                   self.tcx.item_path_str(*trait_did)));
             }

src/librustc_typeck/coherence/overlap.rs

@@ -14,7 +14,7 @@
 
 use hir::def_id::DefId;
 use rustc::traits::{self, Reveal};
-use rustc::ty::{self, TyCtxt};
+use rustc::ty::{self, TyCtxt, TypeFoldable};
 use syntax::ast;
 use rustc::dep_graph::DepNode;
 use rustc::hir;
@@ -134,6 +134,12 @@ impl<'cx, 'tcx, 'v> intravisit::Visitor<'v> for OverlapChecker<'cx, 'tcx> {
                 let trait_ref = self.tcx.impl_trait_ref(impl_def_id).unwrap();
                 let trait_def_id = trait_ref.def_id;
 
+                if trait_ref.references_error() {
+                    debug!("coherence: skipping impl {:?} with error {:?}",
+                           impl_def_id, trait_ref);
+                    return
+                }
+
                 let _task =
                     self.tcx.dep_graph.in_task(DepNode::CoherenceOverlapCheck(trait_def_id));
 

src/librustdoc/html/render.rs

@@ -874,12 +874,12 @@ fn extern_location(e: &clean::ExternalCrate, dst: &Path) -> ExternalLocation {
 impl<'a> DocFolder for SourceCollector<'a> {
     fn fold_item(&mut self, item: clean::Item) -> Option<clean::Item> {
         // If we're including source files, and we haven't seen this file yet,
-        // then we need to render it out to the filesystem
+        // then we need to render it out to the filesystem.
         if self.scx.include_sources
             // skip all invalid spans
             && item.source.filename != ""
-            // macros from other libraries get special filenames which we can
-            // safely ignore
+            // Macros from other libraries get special filenames which we can
+            // safely ignore.
             && !(item.source.filename.starts_with("<")
                 && item.source.filename.ends_with("macros>")) {
 
@@ -974,13 +974,13 @@ impl DocFolder for Cache {
         };
 
         // Register any generics to their corresponding string. This is used
-        // when pretty-printing types
+        // when pretty-printing types.
         if let Some(generics) = item.inner.generics() {
             self.generics(generics);
         }
 
-        // Propagate a trait methods' documentation to all implementors of the
-        // trait
+        // Propagate a trait method's documentation to all implementors of the
+        // trait.
         if let clean::TraitItem(ref t) = item.inner {
             self.traits.entry(item.def_id).or_insert_with(|| t.clone());
         }
@@ -996,7 +996,7 @@ impl DocFolder for Cache {
             }
         }
 
-        // Index this method for searching later on
+        // Index this method for searching later on.
         if let Some(ref s) = item.name {
             let (parent, is_inherent_impl_item) = match item.inner {
                 clean::StrippedItem(..) => ((None, None), false),
@@ -1097,8 +1097,8 @@ impl DocFolder for Cache {
                                       (self.stack.clone(), item.type_()));
                 }
             }
-            // link variants to their parent enum because pages aren't emitted
-            // for each variant
+            // Link variants to their parent enum because pages aren't emitted
+            // for each variant.
             clean::VariantItem(..) if !self.stripped_mod => {
                 let mut stack = self.stack.clone();
                 stack.pop();
@@ -1144,8 +1144,8 @@ impl DocFolder for Cache {
             _ => false
         };
 
-        // Once we've recursively found all the generics, then hoard off all the
-        // implementations elsewhere
+        // Once we've recursively found all the generics, hoard off all the
+        // implementations elsewhere.
         let ret = self.fold_item_recur(item).and_then(|item| {
             if let clean::Item { inner: clean::ImplItem(_), .. } = item {
                 // Figure out the id of this impl. This may map to a
@@ -1206,7 +1206,7 @@ impl Context {
     }
 
     /// Recurse in the directory structure and change the "root path" to make
-    /// sure it always points to the top (relatively)
+    /// sure it always points to the top (relatively).
     fn recurse<T, F>(&mut self, s: String, f: F) -> T where
         F: FnOnce(&mut Context) -> T,
     {
@@ -1237,11 +1237,11 @@ impl Context {
     fn krate(self, mut krate: clean::Crate) -> Result<(), Error> {
         let mut item = match krate.module.take() {
             Some(i) => i,
-            None => return Ok(())
+            None => return Ok(()),
         };
         item.name = Some(krate.name);
 
-        // render the crate documentation
+        // Render the crate documentation
         let mut work = vec![(self, item)];
 
         while let Some((mut cx, item)) = work.pop() {
@@ -2987,7 +2987,7 @@ impl<'a> fmt::Display for Sidebar<'a> {
         let it = self.item;
         let parentlen = cx.current.len() - if it.is_mod() {1} else {0};
 
-        // the sidebar is designed to display sibling functions, modules and
+        // The sidebar is designed to display sibling functions, modules and
         // other miscellaneous information. since there are lots of sibling
         // items (and that causes quadratic growth in large modules),
         // we refactor common parts into a shared JavaScript file per module.
@@ -3006,7 +3006,7 @@ impl<'a> fmt::Display for Sidebar<'a> {
         }
         write!(fmt, "</p>")?;
 
-        // sidebar refers to the enclosing module, not this module
+        // Sidebar refers to the enclosing module, not this module.
         let relpath = if it.is_mod() { "../" } else { "" };
         write!(fmt,
                "<script>window.sidebarCurrent = {{\
@@ -3018,7 +3018,7 @@ impl<'a> fmt::Display for Sidebar<'a> {
                ty = it.type_().css_class(),
                path = relpath)?;
         if parentlen == 0 {
-            // there is no sidebar-items.js beyond the crate root path
+            // There is no sidebar-items.js beyond the crate root path
             // FIXME maybe dynamic crate loading can be merged here
         } else {
             write!(fmt, "<script defer src=\"{path}sidebar-items.js\"></script>",