diff --git a/src/librustc/hir/lowering.rs b/src/librustc/hir/lowering.rs
index b50cfa00f09..58789a10609 100644
--- a/src/librustc/hir/lowering.rs
+++ b/src/librustc/hir/lowering.rs
@@ -1316,7 +1316,7 @@ impl<'a> LoweringContext<'a> {
                             ImplTraitContext::Universal(in_band_ty_params),
                         );
                         // Set the name to `impl Bound1 + Bound2`.
-                        let ident = Ident::from_str(&pprust::ty_to_string(t)).with_span_pos(span);
+                        let ident = Ident::from_str_and_span(&pprust::ty_to_string(t), span);
                         in_band_ty_params.push(hir::GenericParam {
                             hir_id: self.lower_node_id(def_node_id),
                             name: ParamName::Plain(ident),
diff --git a/src/libsyntax/ext/base.rs b/src/libsyntax/ext/base.rs
index 7759a985d61..d3f6717ee87 100644
--- a/src/libsyntax/ext/base.rs
+++ b/src/libsyntax/ext/base.rs
@@ -1081,8 +1081,8 @@ impl<'a> ExtCtxt<'a> {
     pub fn set_trace_macros(&mut self, x: bool) {
         self.ecfg.trace_mac = x
     }
-    pub fn ident_of(&self, st: &str) -> ast::Ident {
-        ast::Ident::from_str(st)
+    pub fn ident_of(&self, st: &str, sp: Span) -> ast::Ident {
+        ast::Ident::from_str_and_span(st, sp)
     }
     pub fn std_path(&self, components: &[Symbol]) -> Vec<ast::Ident> {
         let def_site = self.with_def_site_ctxt(DUMMY_SP);
diff --git a/src/libsyntax/ext/build.rs b/src/libsyntax/ext/build.rs
index eea66f9147d..f1d0e0b68f7 100644
--- a/src/libsyntax/ext/build.rs
+++ b/src/libsyntax/ext/build.rs
@@ -525,7 +525,7 @@ impl<'a> ExtCtxt<'a> {
         let err = self.std_path(&[sym::result, sym::Result, sym::Err]);
         let err_path = self.path_global(sp, err);
 
-        let binding_variable = self.ident_of("__try_var");
+        let binding_variable = self.ident_of("__try_var", sp);
         let binding_pat = self.pat_ident(sp, binding_variable);
         let binding_expr = self.expr_ident(sp, binding_variable);
 
diff --git a/src/libsyntax/parse/parser/item.rs b/src/libsyntax/parse/parser/item.rs
index baae6155f34..cf196645e4f 100644
--- a/src/libsyntax/parse/parser/item.rs
+++ b/src/libsyntax/parse/parser/item.rs
@@ -1256,7 +1256,7 @@ impl<'a> Parser<'a> {
             for part in idents {
                 fixed_name.push_str(&format!("_{}", part.name));
             }
-            ident = Ident::from_str(&fixed_name).with_span_pos(fixed_name_sp);
+            ident = Ident::from_str_and_span(&fixed_name, fixed_name_sp);
 
             self.struct_span_err(fixed_name_sp, error_msg)
                 .span_label(fixed_name_sp, "dash-separated idents are not valid")
diff --git a/src/libsyntax_ext/deriving/cmp/partial_ord.rs b/src/libsyntax_ext/deriving/cmp/partial_ord.rs
index debdc300e64..13d63aaf2a8 100644
--- a/src/libsyntax_ext/deriving/cmp/partial_ord.rs
+++ b/src/libsyntax_ext/deriving/cmp/partial_ord.rs
@@ -109,7 +109,7 @@ pub fn some_ordering_collapsed(
         GtOp => "gt",
         GeOp => "ge",
     };
-    cx.expr_method_call(span, lft, ast::Ident::from_str_and_span(op_str, span), vec![rgt])
+    cx.expr_method_call(span, lft, cx.ident_of(op_str, span), vec![rgt])
 }
 
 pub fn cs_partial_cmp(cx: &mut ExtCtxt<'_>, span: Span, substr: &Substructure<'_>) -> P<Expr> {
diff --git a/src/libsyntax_ext/deriving/debug.rs b/src/libsyntax_ext/deriving/debug.rs
index 781645a574e..088b61be8b8 100644
--- a/src/libsyntax_ext/deriving/debug.rs
+++ b/src/libsyntax_ext/deriving/debug.rs
@@ -62,7 +62,7 @@ fn show_substructure(cx: &mut ExtCtxt<'_>, span: Span, substr: &Substructure<'_>
     // We want to make sure we have the ctxt set so that we can use unstable methods
     let span = cx.with_def_site_ctxt(span);
     let name = cx.expr_lit(span, ast::LitKind::Str(ident.name, ast::StrStyle::Cooked));
-    let builder = Ident::from_str_and_span("debug_trait_builder", span);
+    let builder = cx.ident_of("debug_trait_builder", span);
     let builder_expr = cx.expr_ident(span, builder.clone());
 
     let fmt = substr.nonself_args[0].clone();
@@ -72,7 +72,7 @@ fn show_substructure(cx: &mut ExtCtxt<'_>, span: Span, substr: &Substructure<'_>
         ast::VariantData::Tuple(..) | ast::VariantData::Unit(..) => {
             // tuple struct/"normal" variant
             let expr =
-                cx.expr_method_call(span, fmt, Ident::from_str("debug_tuple"), vec![name]);
+                cx.expr_method_call(span, fmt, cx.ident_of("debug_tuple", span), vec![name]);
             stmts.push(cx.stmt_let(span, true, builder, expr));
 
             for field in fields {
@@ -93,7 +93,7 @@ fn show_substructure(cx: &mut ExtCtxt<'_>, span: Span, substr: &Substructure<'_>
         ast::VariantData::Struct(..) => {
             // normal struct/struct variant
             let expr =
-                cx.expr_method_call(span, fmt, Ident::from_str("debug_struct"), vec![name]);
+                cx.expr_method_call(span, fmt, cx.ident_of("debug_struct", span), vec![name]);
             stmts.push(cx.stmt_let(DUMMY_SP, true, builder, expr));
 
             for field in fields {
@@ -113,7 +113,7 @@ fn show_substructure(cx: &mut ExtCtxt<'_>, span: Span, substr: &Substructure<'_>
         }
     }
 
-    let expr = cx.expr_method_call(span, builder_expr, Ident::from_str("finish"), vec![]);
+    let expr = cx.expr_method_call(span, builder_expr, cx.ident_of("finish", span), vec![]);
 
     stmts.push(cx.stmt_expr(expr));
     let block = cx.block(span, stmts);
diff --git a/src/libsyntax_ext/deriving/decodable.rs b/src/libsyntax_ext/deriving/decodable.rs
index d3d604b7252..cde72abbdef 100644
--- a/src/libsyntax_ext/deriving/decodable.rs
+++ b/src/libsyntax_ext/deriving/decodable.rs
@@ -66,10 +66,14 @@ fn decodable_substructure(cx: &mut ExtCtxt<'_>,
                           krate: &str)
                           -> P<Expr> {
     let decoder = substr.nonself_args[0].clone();
-    let recurse = vec![cx.ident_of(krate), cx.ident_of("Decodable"), cx.ident_of("decode")];
+    let recurse = vec![
+        cx.ident_of(krate, trait_span),
+        cx.ident_of("Decodable", trait_span),
+        cx.ident_of("decode", trait_span),
+    ];
     let exprdecode = cx.expr_path(cx.path_global(trait_span, recurse));
     // throw an underscore in front to suppress unused variable warnings
-    let blkarg = cx.ident_of("_d");
+    let blkarg = cx.ident_of("_d", trait_span);
     let blkdecoder = cx.expr_ident(trait_span, blkarg);
 
     return match *substr.fields {
@@ -78,7 +82,7 @@ fn decodable_substructure(cx: &mut ExtCtxt<'_>,
                 Unnamed(ref fields, _) => fields.len(),
                 Named(ref fields) => fields.len(),
             };
-            let read_struct_field = cx.ident_of("read_struct_field");
+            let read_struct_field = cx.ident_of("read_struct_field", trait_span);
 
             let path = cx.path_ident(trait_span, substr.type_ident);
             let result =
@@ -94,17 +98,17 @@ fn decodable_substructure(cx: &mut ExtCtxt<'_>,
             let result = cx.expr_ok(trait_span, result);
             cx.expr_method_call(trait_span,
                                 decoder,
-                                cx.ident_of("read_struct"),
+                                cx.ident_of("read_struct", trait_span),
                                 vec![cx.expr_str(trait_span, substr.type_ident.name),
                                      cx.expr_usize(trait_span, nfields),
                                      cx.lambda1(trait_span, result, blkarg)])
         }
         StaticEnum(_, ref fields) => {
-            let variant = cx.ident_of("i");
+            let variant = cx.ident_of("i", trait_span);
 
             let mut arms = Vec::with_capacity(fields.len() + 1);
             let mut variants = Vec::with_capacity(fields.len());
-            let rvariant_arg = cx.ident_of("read_enum_variant_arg");
+            let rvariant_arg = cx.ident_of("read_enum_variant_arg", trait_span);
 
             for (i, &(ident, v_span, ref parts)) in fields.iter().enumerate() {
                 variants.push(cx.expr_str(v_span, ident.name));
@@ -132,11 +136,11 @@ fn decodable_substructure(cx: &mut ExtCtxt<'_>,
             let variant_vec = cx.expr_addr_of(trait_span, variant_vec);
             let result = cx.expr_method_call(trait_span,
                                              blkdecoder,
-                                             cx.ident_of("read_enum_variant"),
+                                             cx.ident_of("read_enum_variant", trait_span),
                                              vec![variant_vec, lambda]);
             cx.expr_method_call(trait_span,
                                 decoder,
-                                cx.ident_of("read_enum"),
+                                cx.ident_of("read_enum", trait_span),
                                 vec![cx.expr_str(trait_span, substr.type_ident.name),
                                      cx.lambda1(trait_span, result, blkarg)])
         }
diff --git a/src/libsyntax_ext/deriving/encodable.rs b/src/libsyntax_ext/deriving/encodable.rs
index 8b18fb25e90..655d3bb7c4a 100644
--- a/src/libsyntax_ext/deriving/encodable.rs
+++ b/src/libsyntax_ext/deriving/encodable.rs
@@ -153,16 +153,16 @@ fn encodable_substructure(cx: &mut ExtCtxt<'_>,
                           -> P<Expr> {
     let encoder = substr.nonself_args[0].clone();
     // throw an underscore in front to suppress unused variable warnings
-    let blkarg = cx.ident_of("_e");
+    let blkarg = cx.ident_of("_e", trait_span);
     let blkencoder = cx.expr_ident(trait_span, blkarg);
     let fn_path = cx.expr_path(cx.path_global(trait_span,
-                                              vec![cx.ident_of(krate),
-                                                   cx.ident_of("Encodable"),
-                                                   cx.ident_of("encode")]));
+                                              vec![cx.ident_of(krate, trait_span),
+                                                   cx.ident_of("Encodable", trait_span),
+                                                   cx.ident_of("encode", trait_span)]));
 
     return match *substr.fields {
         Struct(_, ref fields) => {
-            let emit_struct_field = cx.ident_of("emit_struct_field");
+            let emit_struct_field = cx.ident_of("emit_struct_field", trait_span);
             let mut stmts = Vec::new();
             for (i, &FieldInfo { name, ref self_, span, .. }) in fields.iter().enumerate() {
                 let name = match name {
@@ -201,7 +201,7 @@ fn encodable_substructure(cx: &mut ExtCtxt<'_>,
 
             cx.expr_method_call(trait_span,
                                 encoder,
-                                cx.ident_of("emit_struct"),
+                                cx.ident_of("emit_struct", trait_span),
                                 vec![cx.expr_str(trait_span, substr.type_ident.name),
                                      cx.expr_usize(trait_span, fields.len()),
                                      blk])
@@ -214,7 +214,7 @@ fn encodable_substructure(cx: &mut ExtCtxt<'_>,
             // actually exist.
             let me = cx.stmt_let(trait_span, false, blkarg, encoder);
             let encoder = cx.expr_ident(trait_span, blkarg);
-            let emit_variant_arg = cx.ident_of("emit_enum_variant_arg");
+            let emit_variant_arg = cx.ident_of("emit_enum_variant_arg", trait_span);
             let mut stmts = Vec::new();
             if !fields.is_empty() {
                 let last = fields.len() - 1;
@@ -244,7 +244,7 @@ fn encodable_substructure(cx: &mut ExtCtxt<'_>,
             let name = cx.expr_str(trait_span, variant.ident.name);
             let call = cx.expr_method_call(trait_span,
                                            blkencoder,
-                                           cx.ident_of("emit_enum_variant"),
+                                           cx.ident_of("emit_enum_variant", trait_span),
                                            vec![name,
                                                 cx.expr_usize(trait_span, idx),
                                                 cx.expr_usize(trait_span, fields.len()),
@@ -252,7 +252,7 @@ fn encodable_substructure(cx: &mut ExtCtxt<'_>,
             let blk = cx.lambda1(trait_span, call, blkarg);
             let ret = cx.expr_method_call(trait_span,
                                           encoder,
-                                          cx.ident_of("emit_enum"),
+                                          cx.ident_of("emit_enum", trait_span),
                                           vec![cx.expr_str(trait_span ,substr.type_ident.name),
                                                blk]);
             cx.expr_block(cx.block(trait_span, vec![me, cx.stmt_expr(ret)]))
diff --git a/src/libsyntax_ext/deriving/generic/mod.rs b/src/libsyntax_ext/deriving/generic/mod.rs
index da16ee7a544..aceee62e89b 100644
--- a/src/libsyntax_ext/deriving/generic/mod.rs
+++ b/src/libsyntax_ext/deriving/generic/mod.rs
@@ -843,7 +843,7 @@ impl<'a> MethodDef<'a> {
                                 -> P<Expr> {
         let substructure = Substructure {
             type_ident,
-            method_ident: cx.ident_of(self.name),
+            method_ident: cx.ident_of(self.name, trait_.span),
             self_args,
             nonself_args,
             fields,
@@ -890,7 +890,7 @@ impl<'a> MethodDef<'a> {
 
         for (ty, name) in self.args.iter() {
             let ast_ty = ty.to_ty(cx, trait_.span, type_ident, generics);
-            let ident = ast::Ident::from_str_and_span(name, trait_.span);
+            let ident = cx.ident_of(name, trait_.span);
             arg_tys.push((ident, ast_ty));
 
             let arg_expr = cx.expr_ident(trait_.span, ident);
@@ -938,7 +938,7 @@ impl<'a> MethodDef<'a> {
 
         let ret_type = self.get_ret_ty(cx, trait_, generics, type_ident);
 
-        let method_ident = cx.ident_of(self.name);
+        let method_ident = cx.ident_of(self.name, trait_.span);
         let fn_decl = cx.fn_decl(args, ast::FunctionRetTy::Ty(ret_type));
         let body_block = cx.block_expr(body);
 
@@ -1201,7 +1201,7 @@ impl<'a> MethodDef<'a> {
             ).collect::<Vec<String>>();
 
         let self_arg_idents = self_arg_names.iter()
-            .map(|name| cx.ident_of(&name[..]))
+            .map(|name| cx.ident_of(name, sp))
             .collect::<Vec<ast::Ident>>();
 
         // The `vi_idents` will be bound, solely in the catch-all, to
@@ -1210,7 +1210,7 @@ impl<'a> MethodDef<'a> {
         let vi_idents = self_arg_names.iter()
             .map(|name| {
                 let vi_suffix = format!("{}_vi", &name[..]);
-                ast::Ident::from_str_and_span(&vi_suffix[..], trait_.span)
+                cx.ident_of(&vi_suffix[..], trait_.span)
             })
             .collect::<Vec<ast::Ident>>();
 
@@ -1389,7 +1389,7 @@ impl<'a> MethodDef<'a> {
 
                 let target_ty = cx.ty_ident(
                     sp,
-                    ast::Ident::from_str_and_span(target_type_name, sp),
+                    cx.ident_of(target_type_name, sp),
                 );
                 let variant_disr = cx.expr_cast(sp, variant_value, target_ty);
                 let let_stmt = cx.stmt_let(sp, false, ident, variant_disr);
@@ -1591,7 +1591,7 @@ impl<'a> TraitDef<'a> {
         let mut ident_exprs = Vec::new();
         for (i, struct_field) in struct_def.fields().iter().enumerate() {
             let sp = struct_field.span.with_ctxt(self.span.ctxt());
-            let ident = ast::Ident::from_str_and_span(&format!("{}_{}", prefix, i), self.span);
+            let ident = cx.ident_of(&format!("{}_{}", prefix, i), self.span);
             paths.push(ident.with_span_pos(sp));
             let val = cx.expr_path(cx.path_ident(sp, ident));
             let val = if use_temporaries {
diff --git a/src/libsyntax_ext/deriving/generic/ty.rs b/src/libsyntax_ext/deriving/generic/ty.rs
index d47ef2c5d59..b341a076752 100644
--- a/src/libsyntax_ext/deriving/generic/ty.rs
+++ b/src/libsyntax_ext/deriving/generic/ty.rs
@@ -72,7 +72,7 @@ impl<'a> Path<'a> {
                    self_ty: Ident,
                    self_generics: &Generics)
                    -> ast::Path {
-        let mut idents = self.path.iter().map(|s| Ident::from_str_and_span(*s, span)).collect();
+        let mut idents = self.path.iter().map(|s| cx.ident_of(*s, span)).collect();
         let lt = mk_lifetimes(cx, span, &self.lifetime);
         let tys: Vec<P<ast::Ty>> =
             self.params.iter().map(|t| t.to_ty(cx, span, self_ty, self_generics)).collect();
@@ -207,7 +207,7 @@ fn mk_ty_param(cx: &ExtCtxt<'_>,
             cx.trait_bound(path)
         })
         .collect();
-    cx.typaram(span, ast::Ident::from_str_and_span(name, span), attrs.to_owned(), bounds, None)
+    cx.typaram(span, cx.ident_of(name, span), attrs.to_owned(), bounds, None)
 }
 
 fn mk_generics(params: Vec<ast::GenericParam>, span: Span) -> Generics {
diff --git a/src/libsyntax_ext/env.rs b/src/libsyntax_ext/env.rs
index 179b7fe00a9..3b0ddeeea2d 100644
--- a/src/libsyntax_ext/env.rs
+++ b/src/libsyntax_ext/env.rs
@@ -23,13 +23,13 @@ pub fn expand_option_env<'cx>(cx: &'cx mut ExtCtxt<'_>,
     let sp = cx.with_legacy_ctxt(sp);
     let e = match env::var(&*var.as_str()) {
         Err(..) => {
-            let lt = cx.lifetime(sp, Ident::with_dummy_span(kw::StaticLifetime));
+            let lt = cx.lifetime(sp, Ident::new(kw::StaticLifetime, sp));
             cx.expr_path(cx.path_all(sp,
                                      true,
                                      cx.std_path(&[sym::option, sym::Option, sym::None]),
                                      vec![GenericArg::Type(cx.ty_rptr(sp,
                                                      cx.ty_ident(sp,
-                                                                 Ident::with_dummy_span(sym::str)),
+                                                                 Ident::new(sym::str, sp)),
                                                      Some(lt),
                                                      ast::Mutability::Immutable))],
                                      vec![]))
diff --git a/src/libsyntax_ext/format.rs b/src/libsyntax_ext/format.rs
index 5bfbdc99917..46c7cbb83de 100644
--- a/src/libsyntax_ext/format.rs
+++ b/src/libsyntax_ext/format.rs
@@ -486,7 +486,7 @@ impl<'a, 'b> Context<'a, 'b> {
         let sp = self.macsp;
         let count = |c, arg| {
             let mut path = Context::rtpath(self.ecx, "Count");
-            path.push(self.ecx.ident_of(c));
+            path.push(self.ecx.ident_of(c, sp));
             match arg {
                 Some(arg) => self.ecx.expr_call_global(sp, path, vec![arg]),
                 None => self.ecx.expr_path(self.ecx.path_global(sp, path)),
@@ -534,7 +534,7 @@ impl<'a, 'b> Context<'a, 'b> {
                 let pos = {
                     let pos = |c, arg| {
                         let mut path = Context::rtpath(self.ecx, "Position");
-                        path.push(self.ecx.ident_of(c));
+                        path.push(self.ecx.ident_of(c, sp));
                         match arg {
                             Some(i) => {
                                 let arg = self.ecx.expr_usize(sp, i);
@@ -603,7 +603,7 @@ impl<'a, 'b> Context<'a, 'b> {
                 let fill = self.ecx.expr_lit(sp, ast::LitKind::Char(fill));
                 let align = |name| {
                     let mut p = Context::rtpath(self.ecx, "Alignment");
-                    p.push(self.ecx.ident_of(name));
+                    p.push(self.ecx.ident_of(name, sp));
                     self.ecx.path_global(sp, p)
                 };
                 let align = match arg.format.align {
@@ -621,11 +621,11 @@ impl<'a, 'b> Context<'a, 'b> {
                     sp,
                     path,
                     vec![
-                        self.ecx.field_imm(sp, self.ecx.ident_of("fill"), fill),
-                        self.ecx.field_imm(sp, self.ecx.ident_of("align"), align),
-                        self.ecx.field_imm(sp, self.ecx.ident_of("flags"), flags),
-                        self.ecx.field_imm(sp, self.ecx.ident_of("precision"), prec),
-                        self.ecx.field_imm(sp, self.ecx.ident_of("width"), width),
+                        self.ecx.field_imm(sp, self.ecx.ident_of("fill", sp), fill),
+                        self.ecx.field_imm(sp, self.ecx.ident_of("align", sp), align),
+                        self.ecx.field_imm(sp, self.ecx.ident_of("flags", sp), flags),
+                        self.ecx.field_imm(sp, self.ecx.ident_of("precision", sp), prec),
+                        self.ecx.field_imm(sp, self.ecx.ident_of("width", sp), width),
                     ],
                 );
 
@@ -634,8 +634,8 @@ impl<'a, 'b> Context<'a, 'b> {
                     sp,
                                           path,
                     vec![
-                        self.ecx.field_imm(sp, self.ecx.ident_of("position"), pos),
-                        self.ecx.field_imm(sp, self.ecx.ident_of("format"), fmt),
+                        self.ecx.field_imm(sp, self.ecx.ident_of("position", sp), pos),
+                        self.ecx.field_imm(sp, self.ecx.ident_of("format", sp), fmt),
                     ],
                 ))
             }
@@ -653,7 +653,7 @@ impl<'a, 'b> Context<'a, 'b> {
         let mut heads = Vec::with_capacity(self.args.len());
 
         let names_pos: Vec<_> = (0..self.args.len())
-            .map(|i| ast::Ident::from_str_and_span(&format!("arg{}", i), self.macsp))
+            .map(|i| self.ecx.ident_of(&format!("arg{}", i), self.macsp))
             .collect();
 
         // First, build up the static array which will become our precompiled
diff --git a/src/libsyntax_ext/global_allocator.rs b/src/libsyntax_ext/global_allocator.rs
index f4af1699cd6..c57e5eec0b6 100644
--- a/src/libsyntax_ext/global_allocator.rs
+++ b/src/libsyntax_ext/global_allocator.rs
@@ -43,7 +43,7 @@ pub fn expand(
     let const_ty = ecx.ty(span, TyKind::Tup(Vec::new()));
     let const_body = ecx.expr_block(ecx.block(span, stmts));
     let const_item =
-        ecx.item_const(span, Ident::with_dummy_span(kw::Underscore), const_ty, const_body);
+        ecx.item_const(span, Ident::new(kw::Underscore, span), const_ty, const_body);
 
     // Return the original item and the new methods.
     vec![Annotatable::Item(item), Annotatable::Item(const_item)]
@@ -61,7 +61,7 @@ impl AllocFnFactory<'_, '_> {
         let mut abi_args = Vec::new();
         let mut i = 0;
         let ref mut mk = || {
-            let name = Ident::from_str(&format!("arg{}", i));
+            let name = self.cx.ident_of(&format!("arg{}", i), self.span);
             i += 1;
             name
         };
@@ -83,7 +83,7 @@ impl AllocFnFactory<'_, '_> {
         );
         let item = self.cx.item(
             self.span,
-            Ident::from_str(&self.kind.fn_name(method.name)),
+            self.cx.ident_of(&self.kind.fn_name(method.name), self.span),
             self.attrs(),
             kind,
         );
@@ -119,7 +119,7 @@ impl AllocFnFactory<'_, '_> {
     ) -> P<Expr> {
         match *ty {
             AllocatorTy::Layout => {
-                let usize = self.cx.path_ident(self.span, Ident::with_dummy_span(sym::usize));
+                let usize = self.cx.path_ident(self.span, Ident::new(sym::usize, self.span));
                 let ty_usize = self.cx.ty_path(usize);
                 let size = ident();
                 let align = ident();
@@ -177,12 +177,12 @@ impl AllocFnFactory<'_, '_> {
     }
 
     fn usize(&self) -> P<Ty> {
-        let usize = self.cx.path_ident(self.span, Ident::with_dummy_span(sym::usize));
+        let usize = self.cx.path_ident(self.span, Ident::new(sym::usize, self.span));
         self.cx.ty_path(usize)
     }
 
     fn ptr_u8(&self) -> P<Ty> {
-        let u8 = self.cx.path_ident(self.span, Ident::with_dummy_span(sym::u8));
+        let u8 = self.cx.path_ident(self.span, Ident::new(sym::u8, self.span));
         let ty_u8 = self.cx.ty_path(u8);
         self.cx.ty_ptr(self.span, ty_u8, Mutability::Mutable)
     }
diff --git a/src/libsyntax_ext/proc_macro_harness.rs b/src/libsyntax_ext/proc_macro_harness.rs
index 31d32d23a64..a5dcfb9840a 100644
--- a/src/libsyntax_ext/proc_macro_harness.rs
+++ b/src/libsyntax_ext/proc_macro_harness.rs
@@ -340,12 +340,12 @@ fn mk_decls(
                         Vec::new(),
                         ast::ItemKind::ExternCrate(None));
 
-    let bridge = Ident::from_str_and_span("bridge", span);
-    let client = Ident::from_str_and_span("client", span);
-    let proc_macro_ty = Ident::from_str_and_span("ProcMacro", span);
-    let custom_derive = Ident::from_str_and_span("custom_derive", span);
-    let attr = Ident::from_str_and_span("attr", span);
-    let bang = Ident::from_str_and_span("bang", span);
+    let bridge = cx.ident_of("bridge", span);
+    let client = cx.ident_of("client", span);
+    let proc_macro_ty = cx.ident_of("ProcMacro", span);
+    let custom_derive = cx.ident_of("custom_derive", span);
+    let attr = cx.ident_of("attr", span);
+    let bang = cx.ident_of("bang", span);
 
     let decls = {
         let local_path = |sp: Span, name| {
@@ -378,7 +378,7 @@ fn mk_decls(
 
     let decls_static = cx.item_static(
         span,
-        Ident::from_str_and_span("_DECLS", span),
+        cx.ident_of("_DECLS", span),
         cx.ty_rptr(span,
             cx.ty(span, ast::TyKind::Slice(
                 cx.ty_path(cx.path(span,
diff --git a/src/libsyntax_ext/test.rs b/src/libsyntax_ext/test.rs
index be5aca73f5c..0910c00a8a2 100644
--- a/src/libsyntax_ext/test.rs
+++ b/src/libsyntax_ext/test.rs
@@ -98,20 +98,20 @@ pub fn expand_test_or_bench(
 
     // creates test::$name
     let test_path = |name| {
-        cx.path(sp, vec![test_id, cx.ident_of(name)])
+        cx.path(sp, vec![test_id, cx.ident_of(name, sp)])
     };
 
     // creates test::ShouldPanic::$name
     let should_panic_path = |name| {
-        cx.path(sp, vec![test_id, cx.ident_of("ShouldPanic"), cx.ident_of(name)])
+        cx.path(sp, vec![test_id, cx.ident_of("ShouldPanic", sp), cx.ident_of(name, sp)])
     };
 
     // creates $name: $expr
-    let field = |name, expr| cx.field_imm(sp, cx.ident_of(name), expr);
+    let field = |name, expr| cx.field_imm(sp, cx.ident_of(name, sp), expr);
 
     let test_fn = if is_bench {
         // A simple ident for a lambda
-        let b = ast::Ident::from_str_and_span("b", attr_sp);
+        let b = cx.ident_of("b", attr_sp);
 
         cx.expr_call(sp, cx.expr_path(test_path("StaticBenchFn")), vec![
             // |b| self::test::assert_test_result(
diff --git a/src/libsyntax_ext/test_harness.rs b/src/libsyntax_ext/test_harness.rs
index 257c967d0d0..56de0c97f81 100644
--- a/src/libsyntax_ext/test_harness.rs
+++ b/src/libsyntax_ext/test_harness.rs
@@ -250,7 +250,7 @@ fn mk_main(cx: &mut TestCtxt<'_>) -> P<ast::Item> {
 
     // test::test_main_static(...)
     let mut test_runner = cx.test_runner.clone().unwrap_or(
-        ecx.path(sp, vec![test_id, Ident::from_str_and_span("test_main_static", sp)]));
+        ecx.path(sp, vec![test_id, ecx.ident_of("test_main_static", sp)]));
 
     test_runner.span = sp;
 
diff --git a/src/libsyntax_pos/symbol.rs b/src/libsyntax_pos/symbol.rs
index ab32d4461ef..597ae83572c 100644
--- a/src/libsyntax_pos/symbol.rs
+++ b/src/libsyntax_pos/symbol.rs
@@ -765,7 +765,7 @@ impl Ident {
         Ident::with_dummy_span(string.as_symbol())
     }
 
-    /// Maps a string to an identifier with an empty span.
+    /// Maps a string to an identifier with a dummy span.
     pub fn from_str(string: &str) -> Ident {
         Ident::with_dummy_span(Symbol::intern(string))
     }