Auto merge of #47572 - GuillaumeGomez:rollup, r=GuillaumeGomez

Rollup of 8 pull requests

- Successful merges: #46938, #47334, #47420, #47508, #47510, #47512, #47535, #47559
- Failed merges:

Author: bors

CONTRIBUTING.md

@@ -301,12 +301,12 @@ It's absolutely fine to have multiple build directories with different
 [pull-requests]: #pull-requests
 
 Pull requests are the primary mechanism we use to change Rust. GitHub itself
-has some [great documentation][pull-requests] on using the Pull Request feature.
+has some [great documentation][about-pull-requests] on using the Pull Request feature.
 We use the "fork and pull" model [described here][development-models], where
 contributors push changes to their personal fork and create pull requests to
 bring those changes into the source repository.
 
-[pull-requests]: https://help.github.com/articles/about-pull-requests/
+[about-pull-requests]: https://help.github.com/articles/about-pull-requests/
 [development-models]: https://help.github.com/articles/about-collaborative-development-models/
 
 Please make pull requests against the `master` branch.

src/doc/index.md

@@ -28,6 +28,7 @@ Rust provides a number of book-length sets of documentation, collectively
 nicknamed 'The Rust Bookshelf.'
 
 * [The Rust Programming Language][book] teaches you how to program in Rust.
+* [Rust By Example][rbe] teaches you how to program in Rust using editable examples.
 * [The Cargo Book][cargo-book] is a guide to Cargo, Rust's build tool and dependency manager.
 * [The Unstable Book][unstable-book] has documentation for unstable features.
 * [The Rustonomicon][nomicon] is your guidebook to the dark arts of unsafe Rust.
@@ -51,6 +52,7 @@ before this policy was put into place. That work is being tracked
 [refchecklist]: https://github.com/rust-lang-nursery/reference/issues/9
 [err]: error-index.html
 [book]: book/index.html
+[rbe]: rust-by-example/index.html
 [nomicon]: nomicon/index.html
 [unstable-book]: unstable-book/index.html
 [rustdoc-book]: rustdoc/index.html

src/librustc/infer/error_reporting/mod.rs

@@ -958,7 +958,8 @@ impl<'a, 'gcx, 'tcx> InferCtxt<'a, 'gcx, 'tcx> {
                             // `sp` only covers `T`, change it so that it covers
                             // `T:` when appropriate
                             let sp = if has_lifetimes {
-                                sp.to(sp.next_point().next_point())
+                                sp.to(self.tcx.sess.codemap().next_point(
+                                        self.tcx.sess.codemap().next_point(sp)))
                             } else {
                                 sp
                             };

src/librustc_borrowck/borrowck/check_loans.rs

@@ -484,8 +484,8 @@ impl<'a, 'tcx> CheckLoanCtxt<'a, 'tcx> {
             // 3. Where does old loan expire.
 
             let previous_end_span =
-                Some(old_loan.kill_scope.span(self.tcx(), &self.bccx.region_scope_tree)
-                     .end_point());
+                Some(self.tcx().sess.codemap().end_point(
+                        old_loan.kill_scope.span(self.tcx(), &self.bccx.region_scope_tree)));
 
             let mut err = match (new_loan.kind, old_loan.kind) {
                 (ty::MutBorrow, ty::MutBorrow) =>

src/librustc_borrowck/borrowck/mod.rs

@@ -1343,7 +1343,8 @@ impl<'a, 'tcx> BorrowckCtxt<'a, 'tcx> {
     fn region_end_span(&self, region: ty::Region<'tcx>) -> Option<Span> {
         match *region {
             ty::ReScope(scope) => {
-                Some(scope.span(self.tcx, &self.region_scope_tree).end_point())
+                Some(self.tcx.sess.codemap().end_point(
+                        scope.span(self.tcx, &self.region_scope_tree)))
             }
             _ => None
         }

src/librustc_mir/borrow_check/mod.rs

@@ -1090,10 +1090,11 @@ impl<'cx, 'gcx, 'tcx> MirBorrowckCtxt<'cx, 'gcx, 'tcx> {
             debug!("check_for_invalidation_at_exit({:?}): INVALID", place);
             // FIXME: should be talking about the region lifetime instead
             // of just a span here.
+            let span = self.tcx.sess.codemap().end_point(span);
             self.report_borrowed_value_does_not_live_long_enough(
                 context,
                 borrow,
-                span.end_point(),
+                span,
                 flow_state.borrows.operator(),
             )
         }

src/librustc_mir/build/scope.rs

@@ -695,10 +695,12 @@ impl<'a, 'gcx, 'tcx> Builder<'a, 'gcx, 'tcx> {
                 if let DropKind::Value { .. } = drop_kind {
                     scope.needs_cleanup = true;
                 }
+
                 let region_scope_span = region_scope.span(self.hir.tcx(),
                                                           &self.hir.region_scope_tree);
-                // Attribute scope exit drops to scope's closing brace
-                let scope_end = region_scope_span.with_lo(region_scope_span.hi());
+                // Attribute scope exit drops to scope's closing brace.
+                let scope_end = self.hir.tcx().sess.codemap().end_point(region_scope_span);
+
                 scope.drops.push(DropData {
                     span: scope_end,
                     location: place.clone(),

src/librustc_mir/dataflow/impls/borrows.rs

@@ -537,8 +537,8 @@ impl<'a, 'gcx, 'tcx> ActiveBorrows<'a, 'gcx, 'tcx> {
             Some(_) => None,
             None => {
                 match self.0.region_span_map.get(region) {
-                    Some(span) => Some(span.end_point()),
-                    None => Some(self.0.mir.span.end_point())
+                    Some(span) => Some(self.0.tcx.sess.codemap().end_point(*span)),
+                    None => Some(self.0.tcx.sess.codemap().end_point(self.0.mir.span))
                 }
             }
         }

src/librustc_resolve/diagnostics.rs

@@ -1621,6 +1621,59 @@ println!("const value: {}", SomeModule::PRIVATE); // ok!
 ```
 "##,
 
+E0659: r##"
+An item usage is ambiguous.
+
+Erroneous code example:
+
+```compile_fail,E0659
+pub mod moon {
+    pub fn foo() {}
+}
+
+pub mod earth {
+    pub fn foo() {}
+}
+
+mod collider {
+    pub use moon::*;
+    pub use earth::*;
+}
+
+fn main() {
+    collider::foo(); // ERROR: `foo` is ambiguous
+}
+```
+
+This error generally appears when two items with the same name are imported into
+a module. Here, the `foo` functions are imported and reexported from the
+`collider` module and therefore, when we're using `collider::foo()`, both
+functions collide.
+
+To solve this error, the best solution is generally to keep the path before the
+item when using it. Example:
+
+```
+pub mod moon {
+    pub fn foo() {}
+}
+
+pub mod earth {
+    pub fn foo() {}
+}
+
+mod collider {
+    pub use moon;
+    pub use earth;
+}
+
+fn main() {
+    collider::moon::foo(); // ok!
+    collider::earth::foo(); // ok!
+}
+```
+"##,
+
 }
 
 register_diagnostics! {

src/librustc_resolve/lib.rs

@@ -2791,8 +2791,8 @@ impl<'a> Resolver<'a> {
         if let Some(sp) = self.current_type_ascription.last() {
             let mut sp = *sp;
             loop {  // try to find the `:`, bail on first non-':'/non-whitespace
-                sp = sp.next_point();
-                if let Ok(snippet) = cm.span_to_snippet(sp.to(sp.next_point())) {
+                sp = cm.next_point(sp);
+                if let Ok(snippet) = cm.span_to_snippet(sp.to(cm.next_point(sp))) {
                     debug!("snippet {:?}", snippet);
                     let line_sp = cm.lookup_char_pos(sp.hi()).line;
                     let line_base_sp = cm.lookup_char_pos(base_span.lo()).line;
@@ -3783,7 +3783,7 @@ impl<'a> Resolver<'a> {
                 self.session.buffer_lint(lint::builtin::LEGACY_IMPORTS, id, span, &msg);
             } else {
                 let mut err =
-                    self.session.struct_span_err(span, &format!("`{}` is ambiguous", name));
+                    struct_span_err!(self.session, span, E0659, "`{}` is ambiguous", name);
                 err.span_note(b1.span, &msg1);
                 match b2.def() {
                     Def::Macro(..) if b2.span == DUMMY_SP =>