Rollup merge of rust-lang#63535 - petrochenkov:expndata, r=matthewjasper

Continue refactoring resolve and hygiene

The general goal is addressing FIXMEs from the previous PRs.

Merging similar data structures (+ prerequisites for such merging), accounting for the fact that all `ExpnId`s have associated data in `HygieneData` now (less `Option`s).

Also, some renaming.
This should be the last renaming session in this area, I think.

r? @matthewjasper

src/librustc/hir/lowering.rs

@@ -67,7 +67,7 @@ use syntax::errors;
 use syntax::ext::base::SpecialDerives;
 use syntax::ext::hygiene::ExpnId;
 use syntax::print::pprust;
-use syntax::source_map::{respan, ExpnInfo, ExpnKind, DesugaringKind, Spanned};
+use syntax::source_map::{respan, ExpnData, ExpnKind, DesugaringKind, Spanned};
 use syntax::symbol::{kw, sym, Symbol};
 use syntax::tokenstream::{TokenStream, TokenTree};
 use syntax::parse::token::{self, Token};
@@ -704,10 +704,9 @@ impl<'a> LoweringContext<'a> {
         span: Span,
         allow_internal_unstable: Option<Lrc<[Symbol]>>,
     ) -> Span {
-        span.fresh_expansion(ExpnId::root(), ExpnInfo {
-            def_site: span,
+        span.fresh_expansion(ExpnData {
             allow_internal_unstable,
-            ..ExpnInfo::default(ExpnKind::Desugaring(reason), span, self.sess.edition())
+            ..ExpnData::default(ExpnKind::Desugaring(reason), span, self.sess.edition())
         })
     }
 
@@ -1224,7 +1223,7 @@ impl<'a> LoweringContext<'a> {
                     P(hir::Path {
                         res,
                         segments: hir_vec![hir::PathSegment::from_ident(
-                            Ident::with_empty_ctxt(kw::SelfUpper)
+                            Ident::with_dummy_span(kw::SelfUpper)
                         )],
                         span: t.span,
                     }),
@@ -1558,7 +1557,7 @@ impl<'a> LoweringContext<'a> {
 
                     let (name, kind) = match name {
                         hir::LifetimeName::Underscore => (
-                            hir::ParamName::Plain(Ident::with_empty_ctxt(kw::UnderscoreLifetime)),
+                            hir::ParamName::Plain(Ident::with_dummy_span(kw::UnderscoreLifetime)),
                             hir::LifetimeParamKind::Elided,
                         ),
                         hir::LifetimeName::Param(param_name) => (
@@ -2002,7 +2001,7 @@ impl<'a> LoweringContext<'a> {
                         bindings: hir_vec![
                             hir::TypeBinding {
                                 hir_id: this.next_id(),
-                                ident: Ident::with_empty_ctxt(FN_OUTPUT_NAME),
+                                ident: Ident::with_dummy_span(FN_OUTPUT_NAME),
                                 kind: hir::TypeBindingKind::Equality {
                                     ty: output
                                         .as_ref()
@@ -2394,7 +2393,7 @@ impl<'a> LoweringContext<'a> {
         let future_params = P(hir::GenericArgs {
             args: hir_vec![],
             bindings: hir_vec![hir::TypeBinding {
-                ident: Ident::with_empty_ctxt(FN_OUTPUT_NAME),
+                ident: Ident::with_dummy_span(FN_OUTPUT_NAME),
                 kind: hir::TypeBindingKind::Equality {
                     ty: output_ty,
                 },

src/librustc/hir/lowering/expr.rs

@@ -552,7 +552,7 @@ impl LoweringContext<'_> {
 
         // let mut pinned = <expr>;
         let expr = P(self.lower_expr(expr));
-        let pinned_ident = Ident::with_empty_ctxt(sym::pinned);
+        let pinned_ident = Ident::with_dummy_span(sym::pinned);
         let (pinned_pat, pinned_pat_hid) = self.pat_ident_binding_mode(
             span,
             pinned_ident,
@@ -593,7 +593,7 @@ impl LoweringContext<'_> {
         let loop_node_id = self.sess.next_node_id();
         let loop_hir_id = self.lower_node_id(loop_node_id);
         let ready_arm = {
-            let x_ident = Ident::with_empty_ctxt(sym::result);
+            let x_ident = Ident::with_dummy_span(sym::result);
             let (x_pat, x_pat_hid) = self.pat_ident(span, x_ident);
             let x_expr = P(self.expr_ident(span, x_ident, x_pat_hid));
             let ready_pat = self.pat_std_enum(
@@ -1070,9 +1070,9 @@ impl LoweringContext<'_> {
         );
         head.span = desugared_span;
 
-        let iter = Ident::with_empty_ctxt(sym::iter);
+        let iter = Ident::with_dummy_span(sym::iter);
 
-        let next_ident = Ident::with_empty_ctxt(sym::__next);
+        let next_ident = Ident::with_dummy_span(sym::__next);
         let (next_pat, next_pat_hid) = self.pat_ident_binding_mode(
             desugared_span,
             next_ident,
@@ -1081,7 +1081,7 @@ impl LoweringContext<'_> {
 
         // `::std::option::Option::Some(val) => __next = val`
         let pat_arm = {
-            let val_ident = Ident::with_empty_ctxt(sym::val);
+            let val_ident = Ident::with_dummy_span(sym::val);
             let (val_pat, val_pat_hid) = self.pat_ident(pat.span, val_ident);
             let val_expr = P(self.expr_ident(pat.span, val_ident, val_pat_hid));
             let next_expr = P(self.expr_ident(pat.span, next_ident, next_pat_hid));
@@ -1247,7 +1247,7 @@ impl LoweringContext<'_> {
 
         // `Ok(val) => #[allow(unreachable_code)] val,`
         let ok_arm = {
-            let val_ident = Ident::with_empty_ctxt(sym::val);
+            let val_ident = Ident::with_dummy_span(sym::val);
             let (val_pat, val_pat_nid) = self.pat_ident(span, val_ident);
             let val_expr = P(self.expr_ident_with_attrs(
                 span,
@@ -1263,7 +1263,7 @@ impl LoweringContext<'_> {
         // `Err(err) => #[allow(unreachable_code)]
         //              return Try::from_error(From::from(err)),`
         let err_arm = {
-            let err_ident = Ident::with_empty_ctxt(sym::err);
+            let err_ident = Ident::with_dummy_span(sym::err);
             let (err_local, err_local_nid) = self.pat_ident(try_span, err_ident);
             let from_expr = {
                 let from_path = &[sym::convert, sym::From, sym::from];

src/librustc/hir/mod.rs

@@ -202,7 +202,7 @@ impl ParamName {
         match *self {
             ParamName::Plain(ident) => ident,
             ParamName::Fresh(_) |
-            ParamName::Error => Ident::with_empty_ctxt(kw::UnderscoreLifetime),
+            ParamName::Error => Ident::with_dummy_span(kw::UnderscoreLifetime),
         }
     }
 
@@ -237,8 +237,8 @@ impl LifetimeName {
     pub fn ident(&self) -> Ident {
         match *self {
             LifetimeName::Implicit | LifetimeName::Error => Ident::invalid(),
-            LifetimeName::Underscore => Ident::with_empty_ctxt(kw::UnderscoreLifetime),
-            LifetimeName::Static => Ident::with_empty_ctxt(kw::StaticLifetime),
+            LifetimeName::Underscore => Ident::with_dummy_span(kw::UnderscoreLifetime),
+            LifetimeName::Static => Ident::with_dummy_span(kw::StaticLifetime),
             LifetimeName::Param(param_name) => param_name.ident(),
         }
     }

src/librustc/hir/print.rs

@@ -1457,7 +1457,7 @@ impl<'a> State<'a> {
     }
 
     pub fn print_name(&mut self, name: ast::Name) {
-        self.print_ident(ast::Ident::with_empty_ctxt(name))
+        self.print_ident(ast::Ident::with_dummy_span(name))
     }
 
     pub fn print_for_decl(&mut self, loc: &hir::Local, coll: &hir::Expr) {

src/librustc/ich/hcx.rs

@@ -350,7 +350,7 @@ impl<'a> HashStable<StableHashingContext<'a>> for Span {
         let line_col_len = col | line | len;
         std_hash::Hash::hash(&line_col_len, hasher);
 
-        if span.ctxt == SyntaxContext::empty() {
+        if span.ctxt == SyntaxContext::root() {
             TAG_NO_EXPANSION.hash_stable(hcx, hasher);
         } else {
             TAG_EXPANSION.hash_stable(hcx, hasher);
@@ -370,7 +370,7 @@ impl<'a> HashStable<StableHashingContext<'a>> for Span {
                 }
 
                 let mut hasher = StableHasher::new();
-                expn_id.expn_info().hash_stable(hcx, &mut hasher);
+                expn_id.expn_data().hash_stable(hcx, &mut hasher);
                 let sub_hash: Fingerprint = hasher.finish();
                 let sub_hash = sub_hash.to_smaller_hash();
                 cache.borrow_mut().insert(expn_id, sub_hash);

src/librustc/ich/impls_syntax.rs

@@ -397,9 +397,10 @@ impl_stable_hash_for!(enum ::syntax_pos::hygiene::Transparency {
     Opaque,
 });
 
-impl_stable_hash_for!(struct ::syntax_pos::hygiene::ExpnInfo {
-    call_site,
+impl_stable_hash_for!(struct ::syntax_pos::hygiene::ExpnData {
     kind,
+    parent -> _,
+    call_site,
     def_site,
     default_transparency,
     allow_internal_unstable,

src/librustc/lint/internal.rs

@@ -9,7 +9,6 @@ use errors::Applicability;
 use rustc_data_structures::fx::FxHashMap;
 use syntax::ast::{Ident, Item, ItemKind};
 use syntax::symbol::{sym, Symbol};
-use syntax_pos::ExpnInfo;
 
 declare_tool_lint! {
     pub rustc::DEFAULT_HASH_TYPES,
@@ -108,7 +107,7 @@ impl<'a, 'tcx> LateLintPass<'a, 'tcx> for TyTyKind {
                             .help("try using `Ty` instead")
                             .emit();
                         } else {
-                            if ty.span.ctxt().outer_expn_info().is_some() {
+                            if ty.span.from_expansion() {
                                 return;
                             }
                             if let Some(t) = is_ty_or_ty_ctxt(cx, ty) {
@@ -228,30 +227,20 @@ impl EarlyLintPass for LintPassImpl {
         if let ItemKind::Impl(_, _, _, _, Some(lint_pass), _, _) = &item.node {
             if let Some(last) = lint_pass.path.segments.last() {
                 if last.ident.name == sym::LintPass {
-                    match &lint_pass.path.span.ctxt().outer_expn_info() {
-                        Some(info) if is_lint_pass_expansion(info) => {}
-                        _ => {
-                            cx.struct_span_lint(
-                                LINT_PASS_IMPL_WITHOUT_MACRO,
-                                lint_pass.path.span,
-                                "implementing `LintPass` by hand",
-                            )
-                            .help("try using `declare_lint_pass!` or `impl_lint_pass!` instead")
-                            .emit();
-                        }
+                    let expn_data = lint_pass.path.span.ctxt().outer_expn_data();
+                    let call_site = expn_data.call_site;
+                    if expn_data.kind.descr() != sym::impl_lint_pass &&
+                       call_site.ctxt().outer_expn_data().kind.descr() != sym::declare_lint_pass {
+                        cx.struct_span_lint(
+                            LINT_PASS_IMPL_WITHOUT_MACRO,
+                            lint_pass.path.span,
+                            "implementing `LintPass` by hand",
+                        )
+                        .help("try using `declare_lint_pass!` or `impl_lint_pass!` instead")
+                        .emit();
                     }
                 }
             }
         }
     }
 }
-
-fn is_lint_pass_expansion(expn_info: &ExpnInfo) -> bool {
-    if expn_info.kind.descr() == sym::impl_lint_pass {
-        true
-    } else if let Some(info) = expn_info.call_site.ctxt().outer_expn_info() {
-        info.kind.descr() == sym::declare_lint_pass
-    } else {
-        false
-    }
-}

src/librustc/lint/mod.rs

@@ -885,21 +885,16 @@ pub fn provide(providers: &mut Providers<'_>) {
 /// This is used to test whether a lint should not even begin to figure out whether it should
 /// be reported on the current node.
 pub fn in_external_macro(sess: &Session, span: Span) -> bool {
-    let info = match span.ctxt().outer_expn_info() {
-        Some(info) => info,
-        // no ExpnInfo means this span doesn't come from a macro
-        None => return false,
-    };
-
-    match info.kind {
+    let expn_data = span.ctxt().outer_expn_data();
+    match expn_data.kind {
         ExpnKind::Root | ExpnKind::Desugaring(DesugaringKind::ForLoop) => false,
         ExpnKind::Desugaring(_) => true, // well, it's "external"
         ExpnKind::Macro(MacroKind::Bang, _) => {
-            if info.def_site.is_dummy() {
+            if expn_data.def_site.is_dummy() {
                 // dummy span for the def_site means it's an external macro
                 return true;
             }
-            match sess.source_map().span_to_snippet(info.def_site) {
+            match sess.source_map().span_to_snippet(expn_data.def_site) {
                 Ok(code) => !code.starts_with("macro_rules"),
                 // no snippet = external macro or compiler-builtin expansion
                 Err(_) => true,
@@ -911,10 +906,8 @@ pub fn in_external_macro(sess: &Session, span: Span) -> bool {
 
 /// Returns whether `span` originates in a derive macro's expansion
 pub fn in_derive_expansion(span: Span) -> bool {
-    if let Some(info) = span.ctxt().outer_expn_info() {
-        if let ExpnKind::Macro(MacroKind::Derive, _) = info.kind {
-            return true;
-        }
+    if let ExpnKind::Macro(MacroKind::Derive, _) = span.ctxt().outer_expn_data().kind {
+        return true;
     }
     false
 }

src/librustc/traits/error_reporting.rs

@@ -36,7 +36,7 @@ use errors::{Applicability, DiagnosticBuilder};
 use std::fmt;
 use syntax::ast;
 use syntax::symbol::sym;
-use syntax_pos::{DUMMY_SP, Span, ExpnInfo, ExpnKind};
+use syntax_pos::{DUMMY_SP, Span, ExpnKind};
 
 impl<'a, 'tcx> InferCtxt<'a, 'tcx> {
     pub fn report_fulfillment_errors(&self,
@@ -61,9 +61,9 @@ impl<'a, 'tcx> InferCtxt<'a, 'tcx> {
             // We want to ignore desugarings here: spans are equivalent even
             // if one is the result of a desugaring and the other is not.
             let mut span = error.obligation.cause.span;
-            if let Some(ExpnInfo { kind: ExpnKind::Desugaring(_), def_site, .. })
-                    = span.ctxt().outer_expn_info() {
-                span = def_site;
+            let expn_data = span.ctxt().outer_expn_data();
+            if let ExpnKind::Desugaring(_) = expn_data.kind {
+                span = expn_data.call_site;
             }
 
             error_map.entry(span).or_default().push(

src/librustc/traits/project.rs

@@ -1417,7 +1417,7 @@ fn confirm_callable_candidate<'cx, 'tcx>(
                 projection_ty: ty::ProjectionTy::from_ref_and_name(
                     tcx,
                     trait_ref,
-                    Ident::with_empty_ctxt(FN_OUTPUT_NAME),
+                    Ident::with_dummy_span(FN_OUTPUT_NAME),
                 ),
                 ty: ret_type
             }