parser: don't hardcode ABIs into grammar

src/librustc/error_codes.rs

@@ -2336,6 +2336,7 @@ the future, [RFC 2091] prohibits their implementation without a follow-up RFC.
     E0657, // `impl Trait` can only capture lifetimes bound at the fn level
     E0687, // in-band lifetimes cannot be used in `fn`/`Fn` syntax
     E0688, // in-band lifetimes cannot be mixed with explicit lifetime binders
+    E0703, // invalid ABI
 //  E0707, // multiple elided lifetimes used in arguments of `async fn`
     E0708, // `async` non-`move` closures with parameters are not currently
            // supported

src/librustc/hir/lowering.rs

@@ -1216,7 +1216,7 @@ impl<'a> LoweringContext<'a> {
                                     ImplTraitContext::disallowed(),
                                 ),
                                 unsafety: this.lower_unsafety(f.unsafety),
-                                abi: f.abi,
+                                abi: this.lower_abi(f.abi),
                                 decl: this.lower_fn_decl(&f.decl, None, false, None),
                                 param_names: this.lower_fn_params_to_names(&f.decl),
                             }))

src/librustc/hir/lowering/item.rs

@@ -12,6 +12,7 @@ use crate::hir::def::{Res, DefKind};
 use crate::util::nodemap::NodeMap;
 
 use rustc_data_structures::thin_vec::ThinVec;
+use rustc_target::spec::abi;
 
 use std::collections::BTreeSet;
 use smallvec::SmallVec;
@@ -735,7 +736,7 @@ impl LoweringContext<'_> {
 
     fn lower_foreign_mod(&mut self, fm: &ForeignMod) -> hir::ForeignMod {
         hir::ForeignMod {
-            abi: fm.abi,
+            abi: self.lower_abi(fm.abi),
             items: fm.items
                 .iter()
                 .map(|x| self.lower_foreign_item(x))
@@ -1291,10 +1292,30 @@ impl LoweringContext<'_> {
             unsafety: self.lower_unsafety(h.unsafety),
             asyncness: self.lower_asyncness(h.asyncness.node),
             constness: self.lower_constness(h.constness),
-            abi: h.abi,
+            abi: self.lower_abi(h.abi),
         }
     }
 
+    pub(super) fn lower_abi(&mut self, abi: Abi) -> abi::Abi {
+        abi::lookup(&abi.symbol.as_str()).unwrap_or_else(|| {
+            self.error_on_invalid_abi(abi);
+            abi::Abi::Rust
+        })
+    }
+
+    fn error_on_invalid_abi(&self, abi: Abi) {
+        struct_span_err!(
+            self.sess,
+            abi.span,
+            E0703,
+            "invalid ABI: found `{}`",
+            abi.symbol
+        )
+        .span_label(abi.span, "invalid ABI")
+        .help(&format!("valid ABIs: {}", abi::all_names().join(", ")))
+        .emit();
+    }
+
     pub(super) fn lower_unsafety(&mut self, u: Unsafety) -> hir::Unsafety {
         match u {
             Unsafety::Unsafe => hir::Unsafety::Unsafe,

src/librustc_save_analysis/sig.rs

@@ -32,7 +32,7 @@ use rls_data::{SigElement, Signature};
 use rustc::hir::def::{Res, DefKind};
 use syntax::ast::{self, NodeId};
 use syntax::print::pprust;
-
+use syntax_pos::sym;
 
 pub fn item_signature(item: &ast::Item, scx: &SaveContext<'_, '_>) -> Option<Signature> {
     if !scx.config.signatures {
@@ -157,6 +157,12 @@ fn text_sig(text: String) -> Signature {
     }
 }
 
+fn push_abi(text: &mut String, abi: ast::Abi) {
+    if abi.symbol != sym::Rust {
+        text.push_str(&format!("extern \"{}\" ", abi.symbol));
+    }
+}
+
 impl Sig for ast::Ty {
     fn make(&self, offset: usize, _parent_id: Option<NodeId>, scx: &SaveContext<'_, '_>) -> Result {
         let id = Some(self.id);
@@ -231,11 +237,7 @@ impl Sig for ast::Ty {
                 if f.unsafety == ast::Unsafety::Unsafe {
                     text.push_str("unsafe ");
                 }
-                if f.abi != rustc_target::spec::abi::Abi::Rust {
+                push_abi(&mut text, f.abi);
-                    text.push_str("extern");
-                    text.push_str(&f.abi.to_string());
-                    text.push(' ');
-                }
                 text.push_str("fn(");
 
                 let mut defs = vec![];
@@ -385,11 +387,7 @@ impl Sig for ast::Item {
                 if header.unsafety == ast::Unsafety::Unsafe {
                     text.push_str("unsafe ");
                 }
-                if header.abi != rustc_target::spec::abi::Abi::Rust {
+                push_abi(&mut text, header.abi);
-                    text.push_str("extern");
-                    text.push_str(&header.abi.to_string());
-                    text.push(' ');
-                }
                 text.push_str("fn ");
 
                 let mut sig = name_and_generics(text, offset, generics, self.id, self.ident, scx)?;
@@ -948,11 +946,7 @@ fn make_method_signature(
     if m.header.unsafety == ast::Unsafety::Unsafe {
         text.push_str("unsafe ");
     }
-    if m.header.abi != rustc_target::spec::abi::Abi::Rust {
+    push_abi(&mut text, m.header.abi);
-        text.push_str("extern");
-        text.push_str(&m.header.abi.to_string());
-        text.push(' ');
-    }
     text.push_str("fn ");
 
     let mut sig = name_and_generics(text, 0, generics, id, ident, scx)?;

src/libsyntax/ast.rs

@@ -38,7 +38,6 @@ use rustc_data_structures::sync::Lrc;
 use rustc_data_structures::thin_vec::ThinVec;
 use rustc_index::vec::Idx;
 use rustc_serialize::{self, Decoder, Encoder};
-use rustc_target::spec::abi::Abi;
 
 #[cfg(target_arch = "x86_64")]
 use rustc_data_structures::static_assert_size;
@@ -2358,6 +2357,27 @@ impl Item {
     }
 }
 
+/// A reference to an ABI.
+///
+/// In AST our notion of an ABI is still syntactic unlike in `rustc_target::spec::abi::Abi`.
+#[derive(Clone, Copy, RustcEncodable, RustcDecodable, Debug, PartialEq)]
+pub struct Abi {
+    pub symbol: Symbol,
+    pub span: Span,
+}
+
+impl Abi {
+    pub fn new(symbol: Symbol, span: Span) -> Self {
+        Self { symbol, span }
+    }
+}
+
+impl Default for Abi {
+    fn default() -> Self {
+        Self::new(sym::Rust, DUMMY_SP)
+    }
+}
+
 /// A function header.
 ///
 /// All the information between the visibility and the name of the function is
@@ -2376,7 +2396,7 @@ impl Default for FnHeader {
             unsafety: Unsafety::Normal,
             asyncness: dummy_spanned(IsAsync::NotAsync),
             constness: dummy_spanned(Constness::NotConst),
-            abi: Abi::Rust,
+            abi: Abi::default(),
         }
     }
 }

src/libsyntax/error_codes.rs

@@ -540,6 +540,5 @@ equivalent in Rust would be to use macros directly.
     E0630,
     E0693, // incorrect `repr(align)` attribute format
 //  E0694, // an unknown tool name found in scoped attributes
-    E0703, // invalid ABI
     E0717, // rustc_promotable without stability attribute
 }

src/libsyntax/feature_gate/check.rs

@@ -18,7 +18,6 @@ use crate::tokenstream::TokenTree;
 
 use errors::{Applicability, DiagnosticBuilder, Handler};
 use rustc_data_structures::fx::FxHashMap;
-use rustc_target::spec::abi::Abi;
 use syntax_pos::{Span, DUMMY_SP, MultiSpan};
 use log::debug;
 
@@ -192,62 +191,70 @@ macro_rules! gate_feature_post {
 }
 
 impl<'a> PostExpansionVisitor<'a> {
-    fn check_abi(&self, abi: Abi, span: Span) {
+    fn check_abi(&self, abi: ast::Abi) {
-        match abi {
+        let ast::Abi { symbol, span } = abi;
-            Abi::RustIntrinsic => {
+
+        match &*symbol.as_str() {
+            // Stable
+            "Rust" |
+            "C" |
+            "cdecl" |
+            "stdcall" |
+            "fastcall" |
+            "aapcs" |
+            "win64" |
+            "sysv64" |
+            "system" => {}
+            "rust-intrinsic" => {
                 gate_feature_post!(&self, intrinsics, span,
                                    "intrinsics are subject to change");
             },
-            Abi::PlatformIntrinsic => {
+            "platform-intrinsic" => {
                 gate_feature_post!(&self, platform_intrinsics, span,
                                    "platform intrinsics are experimental and possibly buggy");
             },
-            Abi::Vectorcall => {
+            "vectorcall" => {
                 gate_feature_post!(&self, abi_vectorcall, span,
                                    "vectorcall is experimental and subject to change");
             },
-            Abi::Thiscall => {
+            "thiscall" => {
                 gate_feature_post!(&self, abi_thiscall, span,
                                    "thiscall is experimental and subject to change");
             },
-            Abi::RustCall => {
+            "rust-call" => {
                 gate_feature_post!(&self, unboxed_closures, span,
                                    "rust-call ABI is subject to change");
             },
-            Abi::PtxKernel => {
+            "ptx-kernel" => {
                 gate_feature_post!(&self, abi_ptx, span,
                                    "PTX ABIs are experimental and subject to change");
             },
-            Abi::Unadjusted => {
+            "unadjusted" => {
                 gate_feature_post!(&self, abi_unadjusted, span,
                                    "unadjusted ABI is an implementation detail and perma-unstable");
             },
-            Abi::Msp430Interrupt => {
+            "msp430-interrupt" => {
                 gate_feature_post!(&self, abi_msp430_interrupt, span,
                                    "msp430-interrupt ABI is experimental and subject to change");
             },
-            Abi::X86Interrupt => {
+            "x86-interrupt" => {
                 gate_feature_post!(&self, abi_x86_interrupt, span,
                                    "x86-interrupt ABI is experimental and subject to change");
             },
-            Abi::AmdGpuKernel => {
+            "amdgpu-kernel" => {
                 gate_feature_post!(&self, abi_amdgpu_kernel, span,
                                    "amdgpu-kernel ABI is experimental and subject to change");
             },
-            Abi::EfiApi => {
+            "efiapi" => {
                 gate_feature_post!(&self, abi_efiapi, span,
                                    "efiapi ABI is experimental and subject to change");
             },
-            // Stable
+            abi => {
-            Abi::Cdecl |
+                self.parse_sess.span_diagnostic.delay_span_bug(
-            Abi::Stdcall |
+                    span,
-            Abi::Fastcall |
+                    &format!("unrecognized ABI not caught in lowering: {}", abi),
-            Abi::Aapcs |
+                )
-            Abi::Win64 |
+            }
-            Abi::SysV64 |
-            Abi::Rust |
-            Abi::C |
-            Abi::System => {}
         }
     }
 
@@ -373,7 +380,7 @@ impl<'a> Visitor<'a> for PostExpansionVisitor<'a> {
     fn visit_item(&mut self, i: &'a ast::Item) {
         match i.kind {
             ast::ItemKind::ForeignMod(ref foreign_module) => {
-                self.check_abi(foreign_module.abi, i.span);
+                self.check_abi(foreign_module.abi);
             }
 
             ast::ItemKind::Fn(..) => {
@@ -503,7 +510,7 @@ impl<'a> Visitor<'a> for PostExpansionVisitor<'a> {
     fn visit_ty(&mut self, ty: &'a ast::Ty) {
         match ty.kind {
             ast::TyKind::BareFn(ref bare_fn_ty) => {
-                self.check_abi(bare_fn_ty.abi, ty.span);
+                self.check_abi(bare_fn_ty.abi);
             }
             ast::TyKind::Never => {
                 gate_feature_post!(&self, never_type, ty.span,
@@ -597,7 +604,7 @@ impl<'a> Visitor<'a> for PostExpansionVisitor<'a> {
             // Stability of const fn methods are covered in
             // `visit_trait_item` and `visit_impl_item` below; this is
             // because default methods don't pass through this point.
-            self.check_abi(header.abi, span);
+            self.check_abi(header.abi);
         }
 
         if fn_decl.c_variadic() {
@@ -631,7 +638,7 @@ impl<'a> Visitor<'a> for PostExpansionVisitor<'a> {
         match ti.kind {
             ast::TraitItemKind::Method(ref sig, ref block) => {
                 if block.is_none() {
-                    self.check_abi(sig.header.abi, ti.span);
+                    self.check_abi(sig.header.abi);
                 }
                 if sig.decl.c_variadic() {
                     gate_feature_post!(&self, c_variadic, ti.span,

src/libsyntax/parse/parser.rs

@@ -12,7 +12,7 @@ mod diagnostics;
 use diagnostics::Error;
 
 use crate::ast::{
-    self, DUMMY_NODE_ID, AttrStyle, Attribute, CrateSugar, Ident,
+    self, Abi, DUMMY_NODE_ID, AttrStyle, Attribute, CrateSugar, Ident,
     IsAsync, MacDelimiter, Mutability, StrStyle, Visibility, VisibilityKind, Unsafety,
 };
 use crate::parse::{PResult, Directory, DirectoryOwnership};
@@ -28,7 +28,6 @@ use crate::tokenstream::{self, DelimSpan, TokenTree, TokenStream, TreeAndJoint};
 use crate::ThinVec;
 
 use errors::{Applicability, DiagnosticBuilder, DiagnosticId, FatalError};
-use rustc_target::spec::abi::{self, Abi};
 use syntax_pos::{Span, BytePos, DUMMY_SP, FileName};
 use log::debug;
 
@@ -1208,48 +1207,27 @@ impl<'a> Parser<'a> {
 
     /// Parses `extern` followed by an optional ABI string, or nothing.
     fn parse_extern_abi(&mut self) -> PResult<'a, Abi> {
-        if self.eat_keyword(kw::Extern) {
+        Ok(if self.eat_keyword(kw::Extern) {
-            Ok(self.parse_opt_abi()?.unwrap_or(Abi::C))
+            let ext_sp = self.prev_span;
+            self.parse_opt_abi()?.unwrap_or_else(|| Abi::new(sym::C, ext_sp))
         } else {
-            Ok(Abi::Rust)
+            Abi::default()
-        }
+        })
     }
 
-    /// Parses a string as an ABI spec on an extern type or module. Consumes
+    /// Parses a string as an ABI spec on an extern type or module.
-    /// the `extern` keyword, if one is found.
     fn parse_opt_abi(&mut self) -> PResult<'a, Option<Abi>> {
         match self.token.kind {
             token::Literal(token::Lit { kind: token::Str, symbol, suffix }) |
             token::Literal(token::Lit { kind: token::StrRaw(..), symbol, suffix }) => {
                 self.expect_no_suffix(self.token.span, "an ABI spec", suffix);
                 self.bump();
-                match abi::lookup(&symbol.as_str()) {
+                Ok(Some(Abi::new(symbol, self.prev_span)))
-                    Some(abi) => Ok(Some(abi)),
-                    None => {
-                        self.error_on_invalid_abi(symbol);
-                        Ok(None)
-                    }
-                }
             }
             _ => Ok(None),
         }
     }
 
-    /// Emit an error where `symbol` is an invalid ABI.
-    fn error_on_invalid_abi(&self, symbol: Symbol) {
-        let prev_span = self.prev_span;
-        struct_span_err!(
-            self.sess.span_diagnostic,
-            prev_span,
-            E0703,
-            "invalid ABI: found `{}`",
-            symbol
-        )
-        .span_label(prev_span, "invalid ABI")
-        .help(&format!("valid ABIs: {}", abi::all_names().join(", ")))
-        .emit();
-    }
-
     /// We are parsing `async fn`. If we are on Rust 2015, emit an error.
     fn ban_async_in_2015(&self, async_span: Span) {
         if async_span.rust_2015() {

src/libsyntax/parse/parser/item.rs

@@ -3,7 +3,7 @@ use super::diagnostics::{Error, dummy_arg, ConsumeClosingDelim};
 
 use crate::maybe_whole;
 use crate::ptr::P;
-use crate::ast::{self, DUMMY_NODE_ID, Ident, Attribute, AttrKind, AttrStyle, AnonConst, Item};
+use crate::ast::{self, Abi, DUMMY_NODE_ID, Ident, Attribute, AttrKind, AttrStyle, AnonConst, Item};
 use crate::ast::{ItemKind, ImplItem, ImplItemKind, TraitItem, TraitItemKind, UseTree, UseTreeKind};
 use crate::ast::{PathSegment, IsAuto, Constness, IsAsync, Unsafety, Defaultness};
 use crate::ast::{Visibility, VisibilityKind, Mutability, FnHeader, ForeignItem, ForeignItemKind};
@@ -17,7 +17,6 @@ use crate::ThinVec;
 
 use log::debug;
 use std::mem;
-use rustc_target::spec::abi::Abi;
 use errors::{Applicability, DiagnosticBuilder, DiagnosticId, StashKey};
 use syntax_pos::BytePos;
 
@@ -111,7 +110,7 @@ impl<'a> Parser<'a> {
                 return Ok(Some(self.parse_item_extern_crate(lo, vis, attrs)?));
             }
 
-            let opt_abi = self.parse_opt_abi()?;
+            let abi = self.parse_opt_abi()?.unwrap_or_else(|| Abi::new(sym::C, extern_sp));
 
             if self.eat_keyword(kw::Fn) {
                 // EXTERN FUNCTION ITEM
@@ -120,12 +119,12 @@ impl<'a> Parser<'a> {
                     unsafety: Unsafety::Normal,
                     asyncness: respan(fn_span, IsAsync::NotAsync),
                     constness: respan(fn_span, Constness::NotConst),
-                    abi: opt_abi.unwrap_or(Abi::C),
+                    abi,
                 };
                 return self.parse_item_fn(lo, vis, attrs, header);
             } else if self.check(&token::OpenDelim(token::Brace)) {
                 return Ok(Some(
-                    self.parse_item_foreign_mod(lo, opt_abi, vis, attrs, extern_sp)?,
+                    self.parse_item_foreign_mod(lo, abi, vis, attrs, extern_sp)?,
                 ));
             }
 
@@ -201,7 +200,7 @@ impl<'a> Parser<'a> {
                     unsafety,
                     asyncness,
                     constness: respan(fn_span, Constness::NotConst),
-                    abi: Abi::Rust,
+                    abi: Abi::new(sym::Rust, fn_span),
                 };
                 return self.parse_item_fn(lo, vis, attrs, header);
             }
@@ -238,7 +237,7 @@ impl<'a> Parser<'a> {
                 unsafety: Unsafety::Normal,
                 asyncness: respan(fn_span, IsAsync::NotAsync),
                 constness: respan(fn_span, Constness::NotConst),
-                abi: Abi::Rust,
+                abi: Abi::new(sym::Rust, fn_span),
             };
             return self.parse_item_fn(lo, vis, attrs, header);
         }
@@ -1115,15 +1114,13 @@ impl<'a> Parser<'a> {
     fn parse_item_foreign_mod(
         &mut self,
         lo: Span,
-        opt_abi: Option<Abi>,
+        abi: Abi,
         visibility: Visibility,
         mut attrs: Vec<Attribute>,
         extern_sp: Span,
     ) -> PResult<'a, P<Item>> {
         self.expect(&token::OpenDelim(token::Brace))?;
 
-        let abi = opt_abi.unwrap_or(Abi::C);
-
         attrs.extend(self.parse_inner_attributes()?);
 
         let mut foreign_items = vec![];
@@ -1801,7 +1798,7 @@ impl<'a> Parser<'a> {
     ) -> PResult<'a, Option<P<Item>>> {
         let (ident, decl, generics) = self.parse_fn_sig(ParamCfg {
             is_self_allowed: false,
-            allow_c_variadic: header.abi == Abi::C && header.unsafety == Unsafety::Unsafe,
+            allow_c_variadic: header.abi.symbol == sym::C && header.unsafety == Unsafety::Unsafe,
             is_name_required: |_| true,
         })?;
         let (inner_attrs, body) = self.parse_inner_attrs_and_block()?;
@@ -1930,7 +1927,7 @@ impl<'a> Parser<'a> {
         let asyncness = respan(self.prev_span, asyncness);
         let unsafety = self.parse_unsafety();
         let (constness, unsafety, abi) = if is_const_fn {
-            (respan(const_span, Constness::Const), unsafety, Abi::Rust)
+            (respan(const_span, Constness::Const), unsafety, Abi::default())
         } else {
             let abi = self.parse_extern_abi()?;
             (respan(self.prev_span, Constness::NotConst), unsafety, abi)

src/libsyntax/print/pprust.rs

@@ -14,7 +14,6 @@ use crate::sess::ParseSess;
 use crate::symbol::{kw, sym};
 use crate::tokenstream::{self, TokenStream, TokenTree};
 
-use rustc_target::spec::abi::{self, Abi};
 use syntax_pos::{self, BytePos};
 use syntax_pos::{FileName, Span};
 
@@ -1230,7 +1229,7 @@ impl<'a> State<'a> {
             }
             ast::ItemKind::ForeignMod(ref nmod) => {
                 self.head("extern");
-                self.word_nbsp(nmod.abi.to_string());
+                self.print_abi(nmod.abi);
                 self.bopen();
                 self.print_foreign_mod(nmod, &item.attrs);
                 self.bclose(item.span);
@@ -2823,7 +2822,7 @@ impl<'a> State<'a> {
     }
 
     crate fn print_ty_fn(&mut self,
-                       abi: abi::Abi,
+                       abi: ast::Abi,
                        unsafety: ast::Unsafety,
                        decl: &ast::FnDecl,
                        name: Option<ast::Ident>,
@@ -2884,14 +2883,18 @@ impl<'a> State<'a> {
         self.print_asyncness(header.asyncness.node);
         self.print_unsafety(header.unsafety);
 
-        if header.abi != Abi::Rust {
+        if header.abi.symbol != sym::Rust {
             self.word_nbsp("extern");
-            self.word_nbsp(header.abi.to_string());
+            self.print_abi(header.abi);
         }
 
         self.s.word("fn")
     }
 
+    fn print_abi(&mut self, abi: ast::Abi) {
+        self.word_nbsp(format!("\"{}\"", abi.symbol));
+    }
+
     crate fn print_unsafety(&mut self, s: ast::Unsafety) {
         match s {
             ast::Unsafety::Normal => {},

src/libsyntax/print/pprust/tests.rs

@@ -34,12 +34,7 @@ fn test_fun_to_string() {
         assert_eq!(
             fun_to_string(
                 &decl,
-                ast::FnHeader {
+                ast::FnHeader::default(),
-                    unsafety: ast::Unsafety::Normal,
-                    constness: source_map::dummy_spanned(ast::Constness::NotConst),
-                    asyncness: source_map::dummy_spanned(ast::IsAsync::NotAsync),
-                    abi: Abi::Rust,
-                },
                 abba_ident,
                 &generics
             ),

src/libsyntax_ext/deriving/generic/mod.rs

@@ -182,8 +182,7 @@ use std::iter;
 use std::vec;
 
 use rustc_data_structures::thin_vec::ThinVec;
-use rustc_target::spec::abi::Abi;
+use syntax::ast::{self, Abi, BinOpKind, EnumDef, Expr, Generics, Ident, PatKind};
-use syntax::ast::{self, BinOpKind, EnumDef, Expr, Generics, Ident, PatKind};
 use syntax::ast::{VariantData, GenericParamKind, GenericArg};
 use syntax::attr;
 use syntax::source_map::respan;
@@ -738,7 +737,7 @@ impl<'a> TraitDef<'a> {
                                          self,
                                          type_ident,
                                          generics,
-                                         Abi::Rust,
+                                         sym::Rust,
                                          explicit_self,
                                          tys,
                                          body)
@@ -793,7 +792,7 @@ impl<'a> TraitDef<'a> {
                                          self,
                                          type_ident,
                                          generics,
-                                         Abi::Rust,
+                                         sym::Rust,
                                          explicit_self,
                                          tys,
                                          body)
@@ -919,7 +918,7 @@ impl<'a> MethodDef<'a> {
                      trait_: &TraitDef<'_>,
                      type_ident: Ident,
                      generics: &Generics,
-                     abi: Abi,
+                     abi: Symbol,
                      explicit_self: Option<ast::ExplicitSelf>,
                      arg_types: Vec<(Ident, P<ast::Ty>)>,
                      body: P<Expr>)
@@ -949,23 +948,27 @@ impl<'a> MethodDef<'a> {
             ast::Unsafety::Normal
         };
 
+        let trait_lo_sp = trait_.span.shrink_to_lo();
+
+        let sig = ast::MethodSig {
+            header: ast::FnHeader {
+                unsafety,
+                abi: Abi::new(abi, trait_lo_sp),
+                ..ast::FnHeader::default()
+            },
+            decl: fn_decl,
+        };
+
         // Create the method.
         ast::ImplItem {
             id: ast::DUMMY_NODE_ID,
             attrs: self.attributes.clone(),
             generics: fn_generics,
             span: trait_.span,
-            vis: respan(trait_.span.shrink_to_lo(), ast::VisibilityKind::Inherited),
+            vis: respan(trait_lo_sp, ast::VisibilityKind::Inherited),
             defaultness: ast::Defaultness::Final,
             ident: method_ident,
-            kind: ast::ImplItemKind::Method(ast::MethodSig {
+            kind: ast::ImplItemKind::Method(sig, body_block),
-                                                header: ast::FnHeader {
-                                                    unsafety, abi,
-                                                    ..ast::FnHeader::default()
-                                                },
-                                                decl: fn_decl,
-                                            },
-                                            body_block),
             tokens: None,
         }
     }

src/libsyntax_pos/symbol.rs

@@ -563,6 +563,7 @@ symbols! {
         rust_2018_preview,
         rust_begin_unwind,
         rustc,
+        Rust,
         RustcDecodable,
         RustcEncodable,
         rustc_allocator,

src/test/ui/feature-gated-feature-in-macro-arg.stderr

@@ -1,10 +1,8 @@
 error[E0658]: intrinsics are subject to change
-  --> $DIR/feature-gated-feature-in-macro-arg.rs:8:9
+  --> $DIR/feature-gated-feature-in-macro-arg.rs:8:16
    |
-LL | /         extern "rust-intrinsic" {
+LL |         extern "rust-intrinsic" {
-LL | |             fn atomic_fence();
+   |                ^^^^^^^^^^^^^^^^
-LL | |         }
-   | |_________^
    |
    = help: add `#![feature(intrinsics)]` to the crate attributes to enable
 

src/test/ui/feature-gates/feature-gate-abi-msp430-interrupt.stderr

@@ -1,8 +1,8 @@
 error[E0658]: msp430-interrupt ABI is experimental and subject to change
-  --> $DIR/feature-gate-abi-msp430-interrupt.rs:4:1
+  --> $DIR/feature-gate-abi-msp430-interrupt.rs:4:8
    |
 LL | extern "msp430-interrupt" fn foo() {}
-   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+   |        ^^^^^^^^^^^^^^^^^^
    |
    = note: for more information, see https://github.com/rust-lang/rust/issues/38487
    = help: add `#![feature(abi_msp430_interrupt)]` to the crate attributes to enable

src/test/ui/feature-gates/feature-gate-abi_unadjusted.stderr

@@ -1,10 +1,8 @@
 error[E0658]: unadjusted ABI is an implementation detail and perma-unstable
-  --> $DIR/feature-gate-abi_unadjusted.rs:1:1
+  --> $DIR/feature-gate-abi_unadjusted.rs:1:8
    |
-LL | / extern "unadjusted" fn foo() {
+LL | extern "unadjusted" fn foo() {
-LL | |
+   |        ^^^^^^^^^^^^
-LL | | }
-   | |_^
    |
    = help: add `#![feature(abi_unadjusted)]` to the crate attributes to enable
 

src/test/ui/feature-gates/feature-gate-intrinsics.stderr

@@ -1,18 +1,16 @@
 error[E0658]: intrinsics are subject to change
-  --> $DIR/feature-gate-intrinsics.rs:1:1
+  --> $DIR/feature-gate-intrinsics.rs:1:8
    |
-LL | / extern "rust-intrinsic" {
+LL | extern "rust-intrinsic" {
-LL | |     fn bar();
+   |        ^^^^^^^^^^^^^^^^
-LL | | }
-   | |_^
    |
    = help: add `#![feature(intrinsics)]` to the crate attributes to enable
 
 error[E0658]: intrinsics are subject to change
-  --> $DIR/feature-gate-intrinsics.rs:5:1
+  --> $DIR/feature-gate-intrinsics.rs:5:8
    |
 LL | extern "rust-intrinsic" fn baz() {}
-   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+   |        ^^^^^^^^^^^^^^^^
    |
    = help: add `#![feature(intrinsics)]` to the crate attributes to enable
 

src/test/ui/feature-gates/feature-gate-unboxed-closures-manual-impls.stderr

@@ -1,35 +1,35 @@
 error[E0658]: rust-call ABI is subject to change
-  --> $DIR/feature-gate-unboxed-closures-manual-impls.rs:11:5
+  --> $DIR/feature-gate-unboxed-closures-manual-impls.rs:11:12
    |
 LL |     extern "rust-call" fn call(self, args: ()) -> () {}
-   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+   |            ^^^^^^^^^^^
    |
    = note: for more information, see https://github.com/rust-lang/rust/issues/29625
    = help: add `#![feature(unboxed_closures)]` to the crate attributes to enable
 
 error[E0658]: rust-call ABI is subject to change
-  --> $DIR/feature-gate-unboxed-closures-manual-impls.rs:17:5
+  --> $DIR/feature-gate-unboxed-closures-manual-impls.rs:17:12
    |
 LL |     extern "rust-call" fn call_once(self, args: ()) -> () {}
-   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+   |            ^^^^^^^^^^^
    |
    = note: for more information, see https://github.com/rust-lang/rust/issues/29625
    = help: add `#![feature(unboxed_closures)]` to the crate attributes to enable
 
 error[E0658]: rust-call ABI is subject to change
-  --> $DIR/feature-gate-unboxed-closures-manual-impls.rs:23:5
+  --> $DIR/feature-gate-unboxed-closures-manual-impls.rs:23:12
    |
 LL |     extern "rust-call" fn call_mut(&self, args: ()) -> () {}
-   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+   |            ^^^^^^^^^^^
    |
    = note: for more information, see https://github.com/rust-lang/rust/issues/29625
    = help: add `#![feature(unboxed_closures)]` to the crate attributes to enable
 
 error[E0658]: rust-call ABI is subject to change
-  --> $DIR/feature-gate-unboxed-closures-manual-impls.rs:29:5
+  --> $DIR/feature-gate-unboxed-closures-manual-impls.rs:29:12
    |
 LL |     extern "rust-call" fn call_once(&self, args: ()) -> () {}
-   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+   |            ^^^^^^^^^^^
    |
    = note: for more information, see https://github.com/rust-lang/rust/issues/29625
    = help: add `#![feature(unboxed_closures)]` to the crate attributes to enable

src/test/ui/feature-gates/feature-gate-unboxed-closures.stderr

@@ -1,10 +1,8 @@
 error[E0658]: rust-call ABI is subject to change
-  --> $DIR/feature-gate-unboxed-closures.rs:9:5
+  --> $DIR/feature-gate-unboxed-closures.rs:9:12
    |
-LL | /     extern "rust-call" fn call_once(self, (a, b): (u32, u32)) -> u32 {
+LL |     extern "rust-call" fn call_once(self, (a, b): (u32, u32)) -> u32 {
-LL | |         a + b
+   |            ^^^^^^^^^^^
-LL | |     }
-   | |_____^
    |
    = note: for more information, see https://github.com/rust-lang/rust/issues/29625
    = help: add `#![feature(unboxed_closures)]` to the crate attributes to enable