Rollup merge of #40369 - petrochenkov:segspan, r=eddyb

Give spans to individual path segments in AST

And use these spans in path resolution diagnostics.

The spans are spans of identifiers in segments, not whole segments. I'm not sure what spans are more useful in general, but identifier spans are a better fit for resolve errors.

HIR still doesn't have spans.

Fixes https://github.com/rust-lang/rust/pull/38927#discussion_r95336667 https://github.com/rust-lang/rust/pull/38890#issuecomment-271731008

r? @nrc @eddyb

14 files changed, 124 insertions, 88 deletions

diff --git a/src/librustc_resolve/lib.rs b/src/librustc_resolve/lib.rs
index 0958748ed09..104cc78597a 100644
--- a/src/librustc_resolve/lib.rs
+++ b/src/librustc_resolve/lib.rs
@@ -407,7 +407,7 @@ enum PathSource<'a> {
     // Trait paths in bounds or impls.
     Trait,
     // Expression paths `path`, with optional parent context.
-    Expr(Option<&'a ExprKind>),
+    Expr(Option<&'a Expr>),
     // Paths in path patterns `Path`.
     Pat,
     // Paths in struct expressions and patterns `Path { .. }`.
@@ -464,7 +464,7 @@ impl<'a> PathSource<'a> {
                 ValueNS => "method or associated constant",
                 MacroNS => bug!("associated macro"),
             },
-            PathSource::Expr(parent) => match parent {
+            PathSource::Expr(parent) => match parent.map(|p| &p.node) {
                 // "function" here means "anything callable" rather than `Def::Fn`,
                 // this is not precise but usually more helpful than just "value".
                 Some(&ExprKind::Call(..)) => "function",
@@ -2200,7 +2200,8 @@ impl<'a> Resolver<'a> {
                           source: PathSource)
                           -> PathResolution {
         let segments = &path.segments.iter().map(|seg| seg.identifier).collect::<Vec<_>>();
-        self.smart_resolve_path_fragment(id, qself, segments, path.span, source)
+        let ident_span = path.segments.last().map_or(path.span, |seg| seg.span);
+        self.smart_resolve_path_fragment(id, qself, segments, path.span, ident_span, source)
     }
 
     fn smart_resolve_path_fragment(&mut self,
@@ -2208,6 +2209,7 @@ impl<'a> Resolver<'a> {
                                    qself: Option<&QSelf>,
                                    path: &[Ident],
                                    span: Span,
+                                   ident_span: Span,
                                    source: PathSource)
                                    -> PathResolution {
         let ns = source.namespace();
@@ -2219,9 +2221,9 @@ impl<'a> Resolver<'a> {
             let expected = source.descr_expected();
             let path_str = names_to_string(path);
             let code = source.error_code(def.is_some());
-            let (base_msg, fallback_label) = if let Some(def) = def {
+            let (base_msg, fallback_label, base_span) = if let Some(def) = def {
                 (format!("expected {}, found {} `{}`", expected, def.kind_name(), path_str),
-                 format!("not a {}", expected))
+                 format!("not a {}", expected), span)
             } else {
                 let item_str = path[path.len() - 1];
                 let (mod_prefix, mod_str) = if path.len() == 1 {
@@ -2237,9 +2239,9 @@ impl<'a> Resolver<'a> {
                     (mod_prefix, format!("`{}`", names_to_string(mod_path)))
                 };
                 (format!("cannot find {} `{}` in {}{}", expected, item_str, mod_prefix, mod_str),
-                 format!("not found in {}", mod_str))
+                 format!("not found in {}", mod_str), ident_span)
             };
-            let mut err = this.session.struct_span_err_with_code(span, &base_msg, code);
+            let mut err = this.session.struct_span_err_with_code(base_span, &base_msg, code);
 
             // Emit special messages for unresolved `Self` and `self`.
             if is_self_type(path, ns) {
@@ -2297,15 +2299,15 @@ impl<'a> Resolver<'a> {
                         err.span_label(span, &format!("type aliases cannot be used for traits"));
                         return err;
                     }
-                    (Def::Mod(..), PathSource::Expr(Some(parent))) => match *parent {
+                    (Def::Mod(..), PathSource::Expr(Some(parent))) => match parent.node {
                         ExprKind::Field(_, ident) => {
-                            err.span_label(span, &format!("did you mean `{}::{}`?",
-                                                           path_str, ident.node));
+                            err.span_label(parent.span, &format!("did you mean `{}::{}`?",
+                                                                 path_str, ident.node));
                             return err;
                         }
                         ExprKind::MethodCall(ident, ..) => {
-                            err.span_label(span, &format!("did you mean `{}::{}(...)`?",
-                                                           path_str, ident.node));
+                            err.span_label(parent.span, &format!("did you mean `{}::{}(...)`?",
+                                                                 path_str, ident.node));
                             return err;
                         }
                         _ => {}
@@ -2330,12 +2332,12 @@ impl<'a> Resolver<'a> {
 
             // Try Levenshtein if nothing else worked.
             if let Some(candidate) = this.lookup_typo_candidate(path, ns, is_expected) {
-                err.span_label(span, &format!("did you mean `{}`?", candidate));
+                err.span_label(ident_span, &format!("did you mean `{}`?", candidate));
                 return err;
             }
 
             // Fallback label.
-            err.span_label(span, &fallback_label);
+            err.span_label(base_span, &fallback_label);
             err
         };
         let report_errors = |this: &mut Self, def: Option<Def>| {
@@ -2455,7 +2457,7 @@ impl<'a> Resolver<'a> {
             // Make sure `A::B` in `<T as A>::B::C` is a trait item.
             let ns = if qself.position + 1 == path.len() { ns } else { TypeNS };
             let res = self.smart_resolve_path_fragment(id, None, &path[..qself.position + 1],
-                                                       span, PathSource::TraitItem(ns));
+                                                       span, span, PathSource::TraitItem(ns));
             return Some(PathResolution::with_unresolved_segments(
                 res.base_def(), res.unresolved_segments() + path.len() - qself.position - 1
             ));
@@ -2813,7 +2815,7 @@ impl<'a> Resolver<'a> {
                                        path: &[Ident],
                                        ns: Namespace,
                                        filter_fn: FilterFn)
-                                       -> Option<String>
+                                       -> Option<Symbol>
         where FilterFn: Fn(Def) -> bool
     {
         let add_module_candidates = |module: Module, names: &mut Vec<Name>| {
@@ -2827,7 +2829,7 @@ impl<'a> Resolver<'a> {
         };
 
         let mut names = Vec::new();
-        let prefix_str = if path.len() == 1 {
+        if path.len() == 1 {
             // Search in lexical scope.
             // Walk backwards up the ribs in scope and collect candidates.
             for rib in self.ribs[ns].iter().rev() {
@@ -2861,21 +2863,19 @@ impl<'a> Resolver<'a> {
                     names.push(*name);
                 }
             }
-            String::new()
         } else {
             // Search in module.
             let mod_path = &path[..path.len() - 1];
             if let PathResult::Module(module) = self.resolve_path(mod_path, Some(TypeNS), None) {
                 add_module_candidates(module, &mut names);
             }
-            names_to_string(mod_path) + "::"
-        };
+        }
 
         let name = path[path.len() - 1].name;
         // Make sure error reporting is deterministic.
         names.sort_by_key(|name| name.as_str());
         match find_best_match_for_name(names.iter(), &name.as_str(), None) {
-            Some(found) if found != name => Some(format!("{}{}", prefix_str, found)),
+            Some(found) if found != name => Some(found),
             _ => None,
         }
     }
@@ -2898,7 +2898,7 @@ impl<'a> Resolver<'a> {
         self.with_resolved_label(label, id, |this| this.visit_block(block));
     }
 
-    fn resolve_expr(&mut self, expr: &Expr, parent: Option<&ExprKind>) {
+    fn resolve_expr(&mut self, expr: &Expr, parent: Option<&Expr>) {
         // First, record candidate traits for this expression if it could
         // result in the invocation of a method call.
 
@@ -2979,11 +2979,11 @@ impl<'a> Resolver<'a> {
 
             // Equivalent to `visit::walk_expr` + passing some context to children.
             ExprKind::Field(ref subexpression, _) => {
-                self.resolve_expr(subexpression, Some(&expr.node));
+                self.resolve_expr(subexpression, Some(expr));
             }
             ExprKind::MethodCall(_, ref types, ref arguments) => {
                 let mut arguments = arguments.iter();
-                self.resolve_expr(arguments.next().unwrap(), Some(&expr.node));
+                self.resolve_expr(arguments.next().unwrap(), Some(expr));
                 for argument in arguments {
                     self.resolve_expr(argument, None);
                 }
@@ -2999,7 +2999,7 @@ impl<'a> Resolver<'a> {
                 });
             }
             ExprKind::Call(ref callee, ref arguments) => {
-                self.resolve_expr(callee, Some(&expr.node));
+                self.resolve_expr(callee, Some(expr));
                 for argument in arguments {
                     self.resolve_expr(argument, None);
                 }
@@ -3130,11 +3130,10 @@ impl<'a> Resolver<'a> {
                 if ident.name == lookup_name && ns == namespace {
                     if filter_fn(name_binding.def()) {
                         // create the path
-                        let span = name_binding.span;
                         let mut segms = path_segments.clone();
-                        segms.push(ident.into());
+                        segms.push(ast::PathSegment::from_ident(ident, name_binding.span));
                         let path = Path {
-                            span: span,
+                            span: name_binding.span,
                             segments: segms,
                         };
                         // the entity is accessible in the following cases:
@@ -3154,7 +3153,7 @@ impl<'a> Resolver<'a> {
                 if let Some(module) = name_binding.module() {
                     // form the path
                     let mut path_segments = path_segments.clone();
-                    path_segments.push(ident.into());
+                    path_segments.push(ast::PathSegment::from_ident(ident, name_binding.span));
 
                     if !in_module_is_extern || name_binding.vis == ty::Visibility::Public {
                         // add the module to the lookup
diff --git a/src/librustc_resolve/macros.rs b/src/librustc_resolve/macros.rs
index 7ad122d1c31..dbdf3a0b21e 100644
--- a/src/librustc_resolve/macros.rs
+++ b/src/librustc_resolve/macros.rs
@@ -111,8 +111,11 @@ impl<'a> base::Resolver for Resolver<'a> {
                     path.segments[0].identifier.name = keywords::CrateRoot.name();
                     let module = self.0.resolve_crate_var(ident.ctxt);
                     if !module.is_local() {
+                        let span = path.segments[0].span;
                         path.segments.insert(1, match module.kind {
-                            ModuleKind::Def(_, name) => ast::Ident::with_empty_ctxt(name).into(),
+                            ModuleKind::Def(_, name) => ast::PathSegment::from_ident(
+                                ast::Ident::with_empty_ctxt(name), span
+                            ),
                             _ => unreachable!(),
                         })
                     }
@@ -569,7 +572,6 @@ impl<'a> Resolver<'a> {
             };
             let ident = Ident::from_str(name);
             self.lookup_typo_candidate(&vec![ident], MacroNS, is_macro)
-                .as_ref().map(|s| Symbol::intern(s))
         });
 
         if let Some(suggestion) = suggestion {
diff --git a/src/libsyntax/ast.rs b/src/libsyntax/ast.rs
index 981667337d5..fa320d2ca8b 100644
--- a/src/libsyntax/ast.rs
+++ b/src/libsyntax/ast.rs
@@ -134,7 +134,7 @@ impl Path {
     pub fn from_ident(s: Span, identifier: Ident) -> Path {
         Path {
             span: s,
-            segments: vec![identifier.into()],
+            segments: vec![PathSegment::from_ident(identifier, s)],
         }
     }
 
@@ -159,6 +159,8 @@ impl Path {
 pub struct PathSegment {
     /// The identifier portion of this path segment.
     pub identifier: Ident,
+    /// Span of the segment identifier.
+    pub span: Span,
 
     /// Type/lifetime parameters attached to this path. They come in
     /// two flavors: `Path<A,B,C>` and `Path(A,B) -> C`. Note that
@@ -170,16 +172,14 @@ pub struct PathSegment {
     pub parameters: Option<P<PathParameters>>,
 }
 
-impl From<Ident> for PathSegment {
-    fn from(id: Ident) -> Self {
-        PathSegment { identifier: id, parameters: None }
-    }
-}
-
 impl PathSegment {
+    pub fn from_ident(ident: Ident, span: Span) -> Self {
+        PathSegment { identifier: ident, span: span, parameters: None }
+    }
     pub fn crate_root() -> Self {
         PathSegment {
             identifier: keywords::CrateRoot.ident(),
+            span: DUMMY_SP,
             parameters: None,
         }
     }
diff --git a/src/libsyntax/ext/build.rs b/src/libsyntax/ext/build.rs
index f8d4eff80b2..e0fb46ff5eb 100644
--- a/src/libsyntax/ext/build.rs
+++ b/src/libsyntax/ext/build.rs
@@ -38,11 +38,11 @@ pub trait AstBuilder {
 
     fn qpath(&self, self_type: P<ast::Ty>,
              trait_path: ast::Path,
-             ident: ast::Ident)
+             ident: ast::SpannedIdent)
              -> (ast::QSelf, ast::Path);
     fn qpath_all(&self, self_type: P<ast::Ty>,
                 trait_path: ast::Path,
-                ident: ast::Ident,
+                ident: ast::SpannedIdent,
                 lifetimes: Vec<ast::Lifetime>,
                 types: Vec<P<ast::Ty>>,
                 bindings: Vec<ast::TypeBinding>)
@@ -323,7 +323,7 @@ impl<'a> AstBuilder for ExtCtxt<'a> {
             segments.push(ast::PathSegment::crate_root());
         }
 
-        segments.extend(idents.into_iter().map(Into::into));
+        segments.extend(idents.into_iter().map(|i| ast::PathSegment::from_ident(i, sp)));
         let parameters = if lifetimes.is_empty() && types.is_empty() && bindings.is_empty() {
             None
         } else {
@@ -333,7 +333,11 @@ impl<'a> AstBuilder for ExtCtxt<'a> {
                 bindings: bindings,
             })))
         };
-        segments.push(ast::PathSegment { identifier: last_identifier, parameters: parameters });
+        segments.push(ast::PathSegment {
+            identifier: last_identifier,
+            span: sp,
+            parameters: parameters
+        });
         ast::Path {
             span: sp,
             segments: segments,
@@ -346,7 +350,7 @@ impl<'a> AstBuilder for ExtCtxt<'a> {
     fn qpath(&self,
              self_type: P<ast::Ty>,
              trait_path: ast::Path,
-             ident: ast::Ident)
+             ident: ast::SpannedIdent)
              -> (ast::QSelf, ast::Path) {
         self.qpath_all(self_type, trait_path, ident, vec![], vec![], vec![])
     }
@@ -357,7 +361,7 @@ impl<'a> AstBuilder for ExtCtxt<'a> {
     fn qpath_all(&self,
                  self_type: P<ast::Ty>,
                  trait_path: ast::Path,
-                 ident: ast::Ident,
+                 ident: ast::SpannedIdent,
                  lifetimes: Vec<ast::Lifetime>,
                  types: Vec<P<ast::Ty>>,
                  bindings: Vec<ast::TypeBinding>)
@@ -369,7 +373,8 @@ impl<'a> AstBuilder for ExtCtxt<'a> {
             bindings: bindings,
         };
         path.segments.push(ast::PathSegment {
-            identifier: ident,
+            identifier: ident.node,
+            span: ident.span,
             parameters: Some(P(ast::PathParameters::AngleBracketed(parameters))),
         });
 
diff --git a/src/libsyntax/fold.rs b/src/libsyntax/fold.rs
index fb4eb19be2b..aa968f03d68 100644
--- a/src/libsyntax/fold.rs
+++ b/src/libsyntax/fold.rs
@@ -434,8 +434,9 @@ pub fn noop_fold_usize<T: Folder>(i: usize, _: &mut T) -> usize {
 
 pub fn noop_fold_path<T: Folder>(Path { segments, span }: Path, fld: &mut T) -> Path {
     Path {
-        segments: segments.move_map(|PathSegment {identifier, parameters}| PathSegment {
+        segments: segments.move_map(|PathSegment {identifier, span, parameters}| PathSegment {
             identifier: fld.fold_ident(identifier),
+            span: fld.new_span(span),
             parameters: parameters.map(|ps| ps.map(|ps| fld.fold_path_parameters(ps))),
         }),
         span: fld.new_span(span)
diff --git a/src/libsyntax/parse/mod.rs b/src/libsyntax/parse/mod.rs
index c00d2952b3b..88535f91379 100644
--- a/src/libsyntax/parse/mod.rs
+++ b/src/libsyntax/parse/mod.rs
@@ -617,13 +617,17 @@ mod tests {
         Span {lo: BytePos(a), hi: BytePos(b), expn_id: NO_EXPANSION}
     }
 
+    fn str2seg(s: &str, lo: u32, hi: u32) -> ast::PathSegment {
+        ast::PathSegment::from_ident(Ident::from_str(s), sp(lo, hi))
+    }
+
     #[test] fn path_exprs_1() {
         assert!(string_to_expr("a".to_string()) ==
                    P(ast::Expr{
                     id: ast::DUMMY_NODE_ID,
                     node: ast::ExprKind::Path(None, ast::Path {
                         span: sp(0, 1),
-                        segments: vec![Ident::from_str("a").into()],
+                        segments: vec![str2seg("a", 0, 1)],
                     }),
                     span: sp(0, 1),
                     attrs: ThinVec::new(),
@@ -637,8 +641,8 @@ mod tests {
                     node: ast::ExprKind::Path(None, ast::Path {
                         span: sp(0, 6),
                         segments: vec![ast::PathSegment::crate_root(),
-                                       Ident::from_str("a").into(),
-                                       Ident::from_str("b").into()]
+                                       str2seg("a", 2, 3),
+                                       str2seg("b", 5, 6)]
                     }),
                     span: sp(0, 6),
                     attrs: ThinVec::new(),
@@ -744,7 +748,7 @@ mod tests {
                         id: ast::DUMMY_NODE_ID,
                         node:ast::ExprKind::Path(None, ast::Path{
                             span: sp(7, 8),
-                            segments: vec![Ident::from_str("d").into()],
+                            segments: vec![str2seg("d", 7, 8)],
                         }),
                         span:sp(7,8),
                         attrs: ThinVec::new(),
@@ -761,7 +765,7 @@ mod tests {
                            id: ast::DUMMY_NODE_ID,
                            node: ast::ExprKind::Path(None, ast::Path {
                                span:sp(0,1),
-                               segments: vec![Ident::from_str("b").into()],
+                               segments: vec![str2seg("b", 0, 1)],
                             }),
                            span: sp(0,1),
                            attrs: ThinVec::new()})),
@@ -802,7 +806,7 @@ mod tests {
                                     ty: P(ast::Ty{id: ast::DUMMY_NODE_ID,
                                                   node: ast::TyKind::Path(None, ast::Path{
                                         span:sp(10,13),
-                                        segments: vec![Ident::from_str("i32").into()],
+                                        segments: vec![str2seg("i32", 10, 13)],
                                         }),
                                         span:sp(10,13)
                                     }),
@@ -844,7 +848,7 @@ mod tests {
                                                 node: ast::ExprKind::Path(None,
                                                       ast::Path{
                                                         span:sp(17,18),
-                                                        segments: vec![Ident::from_str("b").into()],
+                                                        segments: vec![str2seg("b", 17, 18)],
                                                       }),
                                                 span: sp(17,18),
                                                 attrs: ThinVec::new()})),
diff --git a/src/libsyntax/parse/parser.rs b/src/libsyntax/parse/parser.rs
index 4164932e90e..ff7918cc278 100644
--- a/src/libsyntax/parse/parser.rs
+++ b/src/libsyntax/parse/parser.rs
@@ -27,7 +27,7 @@ use ast::Local;
 use ast::MacStmtStyle;
 use ast::Mac_;
 use ast::{MutTy, Mutability};
-use ast::{Pat, PatKind};
+use ast::{Pat, PatKind, PathSegment};
 use ast::{PolyTraitRef, QSelf};
 use ast::{Stmt, StmtKind};
 use ast::{VariantData, StructField};
@@ -1811,7 +1811,7 @@ impl<'a> Parser<'a> {
         };
 
         if is_global {
-            segments.insert(0, ast::PathSegment::crate_root());
+            segments.insert(0, PathSegment::crate_root());
         }
 
         // Assemble the span.
@@ -1829,11 +1829,12 @@ impl<'a> Parser<'a> {
     /// - `a::b<T,U>::c<V,W>`
     /// - `a::b<T,U>::c(V) -> W`
     /// - `a::b<T,U>::c(V)`
-    pub fn parse_path_segments_without_colons(&mut self) -> PResult<'a, Vec<ast::PathSegment>> {
+    pub fn parse_path_segments_without_colons(&mut self) -> PResult<'a, Vec<PathSegment>> {
         let mut segments = Vec::new();
         loop {
             // First, parse an identifier.
             let identifier = self.parse_path_segment_ident()?;
+            let ident_span = self.prev_span;
 
             if self.check(&token::ModSep) && self.look_ahead(1, |t| *t == token::Lt) {
                 self.bump();
@@ -1881,7 +1882,11 @@ impl<'a> Parser<'a> {
             };
 
             // Assemble and push the result.
-            segments.push(ast::PathSegment { identifier: identifier, parameters: parameters });
+            segments.push(PathSegment {
+                identifier: identifier,
+                span: ident_span,
+                parameters: parameters
+            });
 
             // Continue only if we see a `::`
             if !self.eat(&token::ModSep) {
@@ -1892,15 +1897,16 @@ impl<'a> Parser<'a> {
 
     /// Examples:
     /// - `a::b::<T,U>::c`
-    pub fn parse_path_segments_with_colons(&mut self) -> PResult<'a, Vec<ast::PathSegment>> {
+    pub fn parse_path_segments_with_colons(&mut self) -> PResult<'a, Vec<PathSegment>> {
         let mut segments = Vec::new();
         loop {
             // First, parse an identifier.
             let identifier = self.parse_path_segment_ident()?;
+            let ident_span = self.prev_span;
 
             // If we do not see a `::`, stop.
             if !self.eat(&token::ModSep) {
-                segments.push(identifier.into());
+                segments.push(PathSegment::from_ident(identifier, ident_span));
                 return Ok(segments);
             }
 
@@ -1909,8 +1915,9 @@ impl<'a> Parser<'a> {
                 // Consumed `a::b::<`, go look for types
                 let (lifetimes, types, bindings) = self.parse_generic_args()?;
                 self.expect_gt()?;
-                segments.push(ast::PathSegment {
+                segments.push(PathSegment {
                     identifier: identifier,
+                    span: ident_span,
                     parameters: ast::AngleBracketedParameterData {
                         lifetimes: lifetimes,
                         types: types,
@@ -1924,7 +1931,7 @@ impl<'a> Parser<'a> {
                 }
             } else {
                 // Consumed `a::`, go look for `b`
-                segments.push(identifier.into());
+                segments.push(PathSegment::from_ident(identifier, ident_span));
             }
         }
     }
@@ -1932,14 +1939,14 @@ impl<'a> Parser<'a> {
     /// Examples:
     /// - `a::b::c`
     pub fn parse_path_segments_without_types(&mut self)
-                                             -> PResult<'a, Vec<ast::PathSegment>> {
+                                             -> PResult<'a, Vec<PathSegment>> {
         let mut segments = Vec::new();
         loop {
             // First, parse an identifier.
             let identifier = self.parse_path_segment_ident()?;
 
             // Assemble and push the result.
-            segments.push(identifier.into());
+            segments.push(PathSegment::from_ident(identifier, self.prev_span));
 
             // If we do not see a `::` or see `::{`/`::*`, stop.
             if !self.check(&token::ModSep) || self.is_import_coupler() {
@@ -5950,7 +5957,7 @@ impl<'a> Parser<'a> {
             // `{foo, bar}`, `::{foo, bar}`, `*`, or `::*`.
             self.eat(&token::ModSep);
             let prefix = ast::Path {
-                segments: vec![ast::PathSegment::crate_root()],
+                segments: vec![PathSegment::crate_root()],
                 span: mk_sp(lo, self.span.hi),
             };
             let view_path_kind = if self.eat(&token::BinOp(token::Star)) {
diff --git a/src/libsyntax/std_inject.rs b/src/libsyntax/std_inject.rs
index 4a2dfaf6124..2192d203cdc 100644
--- a/src/libsyntax/std_inject.rs
+++ b/src/libsyntax/std_inject.rs
@@ -82,7 +82,7 @@ pub fn maybe_inject_crates_ref(sess: &ParseSess,
         vis: ast::Visibility::Inherited,
         node: ast::ItemKind::Use(P(codemap::dummy_spanned(ast::ViewPathGlob(ast::Path {
             segments: ["{{root}}", name, "prelude", "v1"].into_iter().map(|name| {
-                ast::Ident::from_str(name).into()
+                ast::PathSegment::from_ident(ast::Ident::from_str(name), DUMMY_SP)
             }).collect(),
             span: span,
         })))),
diff --git a/src/libsyntax/test.rs b/src/libsyntax/test.rs
index dd2756cd2b2..e052d2cda3a 100644
--- a/src/libsyntax/test.rs
+++ b/src/libsyntax/test.rs
@@ -580,7 +580,7 @@ fn nospan<T>(t: T) -> codemap::Spanned<T> {
 fn path_node(ids: Vec<Ident>) -> ast::Path {
     ast::Path {
         span: DUMMY_SP,
-        segments: ids.into_iter().map(Into::into).collect(),
+        segments: ids.into_iter().map(|id| ast::PathSegment::from_ident(id, DUMMY_SP)).collect(),
     }
 }
 
diff --git a/src/libsyntax_ext/concat_idents.rs b/src/libsyntax_ext/concat_idents.rs
index 1fc1bdff593..dc4b8eb24cd 100644
--- a/src/libsyntax_ext/concat_idents.rs
+++ b/src/libsyntax_ext/concat_idents.rs
@@ -61,7 +61,7 @@ pub fn expand_syntax_ext<'cx>(cx: &'cx mut ExtCtxt,
         fn path(&self) -> ast::Path {
             ast::Path {
                 span: self.span,
-                segments: vec![self.ident.into()],
+                segments: vec![ast::PathSegment::from_ident(self.ident, self.span)],
             }
         }
     }
diff --git a/src/test/ui/resolve/enums-are-namespaced-xc.stderr b/src/test/ui/resolve/enums-are-namespaced-xc.stderr
index d541aa599a4..dd04c5ce356 100644
--- a/src/test/ui/resolve/enums-are-namespaced-xc.stderr
+++ b/src/test/ui/resolve/enums-are-namespaced-xc.stderr
@@ -1,26 +1,26 @@
 error[E0425]: cannot find value `A` in module `namespaced_enums`
-  --> $DIR/enums-are-namespaced-xc.rs:15:13
+  --> $DIR/enums-are-namespaced-xc.rs:15:31
    |
 15 |     let _ = namespaced_enums::A;
-   |             ^^^^^^^^^^^^^^^^^^^ not found in `namespaced_enums`
+   |                               ^ not found in `namespaced_enums`
    |
    = help: possible candidate is found in another module, you can import it into scope:
              `use namespaced_enums::Foo::A;`
 
 error[E0425]: cannot find function `B` in module `namespaced_enums`
-  --> $DIR/enums-are-namespaced-xc.rs:18:13
+  --> $DIR/enums-are-namespaced-xc.rs:18:31
    |
 18 |     let _ = namespaced_enums::B(10);
-   |             ^^^^^^^^^^^^^^^^^^^ not found in `namespaced_enums`
+   |                               ^ not found in `namespaced_enums`
    |
    = help: possible candidate is found in another module, you can import it into scope:
              `use namespaced_enums::Foo::B;`
 
 error[E0422]: cannot find struct, variant or union type `C` in module `namespaced_enums`
-  --> $DIR/enums-are-namespaced-xc.rs:21:13
+  --> $DIR/enums-are-namespaced-xc.rs:21:31
    |
 21 |     let _ = namespaced_enums::C { a: 10 };
-   |             ^^^^^^^^^^^^^^^^^^^ not found in `namespaced_enums`
+   |                               ^ not found in `namespaced_enums`
    |
    = help: possible candidate is found in another module, you can import it into scope:
              `use namespaced_enums::Foo::C;`
diff --git a/src/test/ui/resolve/levenshtein.stderr b/src/test/ui/resolve/levenshtein.stderr
index c7c42bcf239..4dff2620319 100644
--- a/src/test/ui/resolve/levenshtein.stderr
+++ b/src/test/ui/resolve/levenshtein.stderr
@@ -14,7 +14,7 @@ error[E0412]: cannot find type `Opiton` in this scope
   --> $DIR/levenshtein.rs:20:10
    |
 20 | type B = Opiton<u8>; // Misspelled type name from the prelude.
-   |          ^^^^^^^^^^ did you mean `Option`?
+   |          ^^^^^^ did you mean `Option`?
 
 error[E0412]: cannot find type `Baz` in this scope
   --> $DIR/levenshtein.rs:23:14
@@ -35,16 +35,16 @@ error[E0425]: cannot find function `foobar` in this scope
    |     ^^^^^^ did you mean `foo_bar`?
 
 error[E0412]: cannot find type `first` in module `m`
-  --> $DIR/levenshtein.rs:32:12
+  --> $DIR/levenshtein.rs:32:15
    |
 32 |     let b: m::first = m::second; // Misspelled item in module.
-   |            ^^^^^^^^ did you mean `m::First`?
+   |               ^^^^^ did you mean `First`?
 
 error[E0425]: cannot find value `second` in module `m`
-  --> $DIR/levenshtein.rs:32:23
+  --> $DIR/levenshtein.rs:32:26
    |
 32 |     let b: m::first = m::second; // Misspelled item in module.
-   |                       ^^^^^^^^^ did you mean `m::Second`?
+   |                          ^^^^^^ did you mean `Second`?
 
 error: aborting due to 8 previous errors
 
diff --git a/src/test/ui/resolve/suggest-path-instead-of-mod-dot-item.stderr b/src/test/ui/resolve/suggest-path-instead-of-mod-dot-item.stderr
index 57c0ecc8135..85fb1777dea 100644
--- a/src/test/ui/resolve/suggest-path-instead-of-mod-dot-item.stderr
+++ b/src/test/ui/resolve/suggest-path-instead-of-mod-dot-item.stderr
@@ -2,55 +2,73 @@ error[E0423]: expected value, found module `a`
   --> $DIR/suggest-path-instead-of-mod-dot-item.rs:27:5
    |
 27 |     a.I
-   |     ^ did you mean `a::I`?
+   |     ^--
+   |     |
+   |     did you mean `a::I`?
 
 error[E0423]: expected value, found module `a`
   --> $DIR/suggest-path-instead-of-mod-dot-item.rs:33:5
    |
 33 |     a.g()
-   |     ^ did you mean `a::g(...)`?
+   |     ^----
+   |     |
+   |     did you mean `a::g(...)`?
 
 error[E0423]: expected value, found module `a`
   --> $DIR/suggest-path-instead-of-mod-dot-item.rs:39:5
    |
 39 |     a.b.J
-   |     ^ did you mean `a::b`?
+   |     ^--
+   |     |
+   |     did you mean `a::b`?
 
 error[E0423]: expected value, found module `a::b`
   --> $DIR/suggest-path-instead-of-mod-dot-item.rs:45:5
    |
 45 |     a::b.J
-   |     ^^^^ did you mean `a::b::J`?
+   |     ^^^^--
+   |     |
+   |     did you mean `a::b::J`?
 
 error[E0423]: expected value, found module `a`
   --> $DIR/suggest-path-instead-of-mod-dot-item.rs:51:5
    |
 51 |     a.b.f();
-   |     ^ did you mean `a::b`?
+   |     ^--
+   |     |
+   |     did you mean `a::b`?
 
 error[E0423]: expected value, found module `a::b`
   --> $DIR/suggest-path-instead-of-mod-dot-item.rs:55:12
    |
 55 |     v.push(a::b);
-   |            ^^^^ did you mean `a::I`?
+   |            ^^^-
+   |               |
+   |               did you mean `I`?
 
 error[E0423]: expected value, found module `a::b`
   --> $DIR/suggest-path-instead-of-mod-dot-item.rs:61:5
    |
 61 |     a::b.f()
-   |     ^^^^ did you mean `a::b::f(...)`?
+   |     ^^^^----
+   |     |
+   |     did you mean `a::b::f(...)`?
 
 error[E0423]: expected value, found module `a::b`
   --> $DIR/suggest-path-instead-of-mod-dot-item.rs:67:5
    |
 67 |     a::b
-   |     ^^^^ did you mean `a::I`?
+   |     ^^^-
+   |        |
+   |        did you mean `I`?
 
 error[E0423]: expected function, found module `a::b`
   --> $DIR/suggest-path-instead-of-mod-dot-item.rs:73:5
    |
 73 |     a::b()
-   |     ^^^^ did you mean `a::I`?
+   |     ^^^-
+   |        |
+   |        did you mean `I`?
 
 error: main function not found
 
diff --git a/src/test/ui/resolve/unboxed-closure-sugar-nonexistent-trait.stderr b/src/test/ui/resolve/unboxed-closure-sugar-nonexistent-trait.stderr
index f0d363f7335..015dbfc3dc7 100644
--- a/src/test/ui/resolve/unboxed-closure-sugar-nonexistent-trait.stderr
+++ b/src/test/ui/resolve/unboxed-closure-sugar-nonexistent-trait.stderr
@@ -2,7 +2,7 @@ error[E0405]: cannot find trait `Nonexist` in this scope
   --> $DIR/unboxed-closure-sugar-nonexistent-trait.rs:11:8
    |
 11 | fn f<F:Nonexist(isize) -> isize>(x: F) {}
-   |        ^^^^^^^^^^^^^^^^^^^^^^^^ not found in this scope
+   |        ^^^^^^^^ not found in this scope
 
 error[E0404]: expected trait, found type alias `Typedef`
   --> $DIR/unboxed-closure-sugar-nonexistent-trait.rs:17:8