rustc: Improve span for error about using a method as a field.

libsyntax: ExprField now contains a SpannedIdent rather than Ident.

[breaking-change]

src/librustc/back/svh.rs

@@ -270,7 +270,7 @@ mod svh_visitor {
             ExprBlock(..)            => SawExprBlock,
             ExprAssign(..)           => SawExprAssign,
             ExprAssignOp(op, _, _)   => SawExprAssignOp(op),
-            ExprField(_, id, _)      => SawExprField(content(id)),
+            ExprField(_, id, _)      => SawExprField(content(id.node)),
             ExprIndex(..)            => SawExprIndex,
             ExprPath(..)             => SawExprPath,
             ExprAddrOf(m, _)         => SawExprAddrOf(m),

src/librustc/middle/dead.rs

@@ -235,7 +235,7 @@ impl<'a> Visitor<MarkSymbolVisitorContext> for MarkSymbolVisitor<'a> {
                 self.lookup_and_handle_method(expr.id, expr.span);
             }
             ast::ExprField(ref lhs, ref ident, _) => {
-                self.handle_field_access(&**lhs, ident);
+                self.handle_field_access(&**lhs, &ident.node);
             }
             _ => ()
         }

src/librustc/middle/mem_categorization.rs

@@ -447,7 +447,7 @@ impl<'t,TYPER:Typer> MemCategorizationContext<'t,TYPER> {
 
           ast::ExprField(ref base, f_name, _) => {
             let base_cmt = if_ok!(self.cat_expr(&**base));
-            Ok(self.cat_field(expr, base_cmt, f_name, expr_ty))
+            Ok(self.cat_field(expr, base_cmt, f_name.node, expr_ty))
           }
 
           ast::ExprIndex(ref base, _) => {

src/librustc/middle/privacy.rs

@@ -801,7 +801,7 @@ impl<'a> Visitor<()> for PrivacyVisitor<'a> {
             ast::ExprField(ref base, ident, _) => {
                 match ty::get(ty::expr_ty_adjusted(self.tcx, &**base)).sty {
                     ty::ty_struct(id, _) => {
-                        self.check_field(expr.span, id, NamedField(ident));
+                        self.check_field(expr.span, id, NamedField(ident.node));
                     }
                     _ => {}
                 }

src/librustc/middle/resolve.rs

@@ -5241,7 +5241,7 @@ impl<'a> Resolver<'a> {
                 // field, we need to add any trait methods we find that match
                 // the field name so that we can do some nice error reporting
                 // later on in typeck.
-                let traits = self.search_for_traits_containing_method(ident.name);
+                let traits = self.search_for_traits_containing_method(ident.node.name);
                 self.trait_map.insert(expr.id, traits);
             }
             ExprMethodCall(ident, _, _) => {

src/librustc/middle/save/mod.rs

@@ -1210,7 +1210,7 @@ impl<'l> Visitor<DxrVisitorEnv> for DxrVisitor<'l> {
                     ty::ty_struct(def_id, _) => {
                         let fields = ty::lookup_struct_fields(&self.analysis.ty_cx, def_id);
                         for f in fields.iter() {
-                            if f.name == ident.name {
+                            if f.name == ident.node.name {
                                 let sub_span = self.span.span_for_last_ident(ex.span);
                                 self.fmt.ref_str(recorder::VarRef,
                                                  ex.span,

src/librustc/middle/trans/consts.rs

@@ -419,7 +419,7 @@ fn const_expr_unadjusted(cx: &CrateContext, e: &ast::Expr,
               let brepr = adt::represent_type(cx, bt);
               let (bv, inlineable) = const_expr(cx, &**base, is_local);
               expr::with_field_tys(cx.tcx(), bt, None, |discr, field_tys| {
-                  let ix = ty::field_idx_strict(cx.tcx(), field.name, field_tys);
+                  let ix = ty::field_idx_strict(cx.tcx(), field.node.name, field_tys);
                   (adt::const_get_field(cx, &*brepr, bv, discr, ix), inlineable)
               })
           }

src/librustc/middle/trans/expr.rs

@@ -389,7 +389,7 @@ fn trans_datum_unadjusted<'a>(bcx: &'a Block<'a>,
             trans_def(bcx, expr, bcx.def(expr.id))
         }
         ast::ExprField(ref base, ident, _) => {
-            trans_rec_field(bcx, &**base, ident)
+            trans_rec_field(bcx, &**base, ident.node)
         }
         ast::ExprIndex(ref base, ref idx) => {
             trans_index(bcx, expr, &**base, &**idx)

src/librustc/middle/typeck/check/mod.rs

@@ -2352,7 +2352,7 @@ fn check_expr_with_unifier(fcx: &FnCtxt,
                    expr: &ast::Expr,
                    lvalue_pref: LvaluePreference,
                    base: &ast::Expr,
-                   field: ast::Name,
+                   field: &ast::SpannedIdent,
                    tys: &[ast::P<ast::Ty>]) {
         let tcx = fcx.ccx.tcx;
         check_expr_with_lvalue_pref(fcx, base, lvalue_pref);
@@ -2365,7 +2365,7 @@ fn check_expr_with_unifier(fcx: &FnCtxt,
                     ty::ty_struct(base_id, ref substs) => {
                         debug!("struct named {}", ppaux::ty_to_str(tcx, base_t));
                         let fields = ty::lookup_struct_fields(tcx, base_id);
-                        lookup_field_ty(tcx, base_id, fields.as_slice(), field, &(*substs))
+                        lookup_field_ty(tcx, base_id, fields.as_slice(), field.node.name, &(*substs))
                     }
                     _ => None
                 }
@@ -2383,7 +2383,7 @@ fn check_expr_with_unifier(fcx: &FnCtxt,
         match method::lookup(fcx,
                              expr,
                              base,
-                             field,
+                             field.node.name,
                              expr_t,
                              tps.as_slice(),
                              DontDerefArgs,
@@ -2392,14 +2392,14 @@ fn check_expr_with_unifier(fcx: &FnCtxt,
                              IgnoreStaticMethods) {
             Some(_) => {
                 fcx.type_error_message(
-                    expr.span,
+                    field.span,
                     |actual| {
                         format!("attempted to take value of method `{}` on type \
-                                 `{}`", token::get_name(field), actual)
+                                 `{}`", token::get_ident(field.node), actual)
                     },
                     expr_t, None);
 
-                tcx.sess.span_note(expr.span,
+                tcx.sess.span_note(field.span,
                     "maybe a missing `()` to call it? If not, try an anonymous function.");
             }
 
@@ -2410,7 +2410,7 @@ fn check_expr_with_unifier(fcx: &FnCtxt,
                         format!("attempted access of field `{}` on \
                                         type `{}`, but no field with that \
                                         name was found",
-                                       token::get_name(field),
+                                       token::get_ident(field.node),
                                        actual)
                     },
                     expr_t, None);
@@ -3214,7 +3214,7 @@ fn check_expr_with_unifier(fcx: &FnCtxt,
         }
       }
       ast::ExprField(ref base, ref field, ref tys) => {
-        check_field(fcx, expr, lvalue_pref, &**base, field.name, tys.as_slice());
+        check_field(fcx, expr, lvalue_pref, &**base, field, tys.as_slice());
       }
       ast::ExprIndex(ref base, ref idx) => {
           check_expr_with_lvalue_pref(fcx, &**base, lvalue_pref);

src/libsyntax/ast.rs

@@ -464,7 +464,7 @@ pub enum Expr_ {
 
     ExprAssign(Gc<Expr>, Gc<Expr>),
     ExprAssignOp(BinOp, Gc<Expr>, Gc<Expr>),
-    ExprField(Gc<Expr>, Ident, Vec<P<Ty>>),
+    ExprField(Gc<Expr>, SpannedIdent, Vec<P<Ty>>),
     ExprIndex(Gc<Expr>, Gc<Expr>),
 
     /// Expression that looks like a "name". For example,

src/libsyntax/ext/build.rs

@@ -13,7 +13,7 @@ use ast::{P, Ident, Generics, NodeId, Expr};
 use ast;
 use ast_util;
 use attr;
-use codemap::{Span, respan, Spanned, DUMMY_SP};
+use codemap::{Span, respan, Spanned, DUMMY_SP, Pos};
 use ext::base::ExtCtxt;
 use fold::Folder;
 use owned_slice::OwnedSlice;
@@ -560,7 +560,15 @@ impl<'a> AstBuilder for ExtCtxt<'a> {
     }
 
     fn expr_field_access(&self, sp: Span, expr: Gc<ast::Expr>, ident: ast::Ident) -> Gc<ast::Expr> {
-        self.expr(sp, ast::ExprField(expr, ident, Vec::new()))
+        let field_name = token::get_ident(ident);
+        let field_span = Span {
+            lo: sp.lo - Pos::from_uint(field_name.get().len()),
+            hi: sp.hi,
+            expn_info: sp.expn_info,
+        };
+
+        let id = Spanned { node: ident, span: field_span };
+        self.expr(sp, ast::ExprField(expr, id, Vec::new()))
     }
     fn expr_addr_of(&self, sp: Span, e: Gc<ast::Expr>) -> Gc<ast::Expr> {
         self.expr(sp, ast::ExprAddrOf(ast::MutImmutable, e))

src/libsyntax/fold.rs

@@ -876,7 +876,7 @@ pub fn noop_fold_expr<T: Folder>(e: Gc<Expr>, folder: &mut T) -> Gc<Expr> {
         }
         ExprField(el, id, ref tys) => {
             ExprField(folder.fold_expr(el),
-                      folder.fold_ident(id),
+                      respan(id.span, folder.fold_ident(id.node)),
                       tys.iter().map(|&x| folder.fold_ty(x)).collect())
         }
         ExprIndex(el, er) => {

src/libsyntax/parse/parser.rs

@@ -1796,7 +1796,7 @@ impl<'a> Parser<'a> {
         ExprIndex(expr, idx)
     }
 
-    pub fn mk_field(&mut self, expr: Gc<Expr>, ident: Ident,
+    pub fn mk_field(&mut self, expr: Gc<Expr>, ident: ast::SpannedIdent,
                     tys: Vec<P<Ty>>) -> ast::Expr_ {
         ExprField(expr, ident, tys)
     }
@@ -2090,7 +2090,8 @@ impl<'a> Parser<'a> {
                             e = self.mk_expr(lo, hi, nd);
                         }
                         _ => {
-                            let field = self.mk_field(e, i, tys);
+                            let id = spanned(dot, hi, i);
+                            let field = self.mk_field(e, id, tys);
                             e = self.mk_expr(lo, hi, field)
                         }
                     }

src/libsyntax/print/pprust.rs

@@ -1487,7 +1487,7 @@ impl<'a> State<'a> {
             ast::ExprField(ref expr, id, ref tys) => {
                 try!(self.print_expr(&**expr));
                 try!(word(&mut self.s, "."));
-                try!(self.print_ident(id));
+                try!(self.print_ident(id.node));
                 if tys.len() > 0u {
                     try!(word(&mut self.s, "::<"));
                     try!(self.commasep(

src/test/compile-fail/method-missing-call.rs

@@ -28,7 +28,16 @@ impl Point {
 
 fn main() {
     let point: Point = Point::new();
-    let px: int =  point.get_x;//~ ERROR attempted to take value of method `get_x` on type `Point`
+    let px: int =  point
+                        .get_x;//~ ERROR attempted to take value of method `get_x` on type `Point`
+                        //~^ NOTE maybe a missing `()` to call it? If not, try an anonymous
+
+    // Ensure the span is useful
+    let ys = &[1,2,3,4,5,6,7];
+    let a = ys.iter()
+              .map(|x| x)
+              .filter(|&&x| x == 1)
+              .filter_map; //~ ERROR attempted to take value of method `filter_map` on type
               //~^ NOTE maybe a missing `()` to call it? If not, try an anonymous function.
 }