Auto merge of rust-lang#124256 - nnethercote:rm-NtIdent-NtLifetime, r…

…=petrochenkov

Remove `NtIdent` and `NtLifetime`

This is one part of the bigger "remove `Nonterminal` and `TokenKind::Interpolated`" change drafted in rust-lang#114647. More details in the individual commit messages.

r? `@petrochenkov`

compiler/rustc_ast/src/ast_traits.rs

@@ -240,7 +240,6 @@ impl HasTokens for Nonterminal {
             Nonterminal::NtPath(path) => path.tokens(),
             Nonterminal::NtVis(vis) => vis.tokens(),
             Nonterminal::NtBlock(block) => block.tokens(),
-            Nonterminal::NtIdent(..) | Nonterminal::NtLifetime(..) => None,
         }
     }
     fn tokens_mut(&mut self) -> Option<&mut Option<LazyAttrTokenStream>> {
@@ -254,7 +253,6 @@ impl HasTokens for Nonterminal {
             Nonterminal::NtPath(path) => path.tokens_mut(),
             Nonterminal::NtVis(vis) => vis.tokens_mut(),
             Nonterminal::NtBlock(block) => block.tokens_mut(),
-            Nonterminal::NtIdent(..) | Nonterminal::NtLifetime(..) => None,
         }
     }
 }

compiler/rustc_ast/src/attr/mod.rs

@@ -345,7 +345,7 @@ impl MetaItem {
                 let span = span.with_hi(segments.last().unwrap().ident.span.hi());
                 Path { span, segments, tokens: None }
             }
-            Some(TokenTree::Token(Token { kind: token::Interpolated(nt), .. }, _)) => match &nt.0 {
+            Some(TokenTree::Token(Token { kind: token::Interpolated(nt), .. }, _)) => match &**nt {
                 token::Nonterminal::NtMeta(item) => return item.meta(item.path.span),
                 token::Nonterminal::NtPath(path) => (**path).clone(),
                 _ => return None,

compiler/rustc_ast/src/mut_visit.rs

@@ -781,10 +781,14 @@ pub fn visit_token<T: MutVisitor>(t: &mut Token, vis: &mut T) {
             *span = ident.span;
             return; // Avoid visiting the span for the second time.
         }
+        token::NtIdent(ident, _is_raw) => {
+            vis.visit_ident(ident);
+        }
+        token::NtLifetime(ident) => {
+            vis.visit_ident(ident);
+        }
         token::Interpolated(nt) => {
             let nt = Lrc::make_mut(nt);
-            let (nt, sp) = (&mut nt.0, &mut nt.1);
-            vis.visit_span(sp);
             visit_nonterminal(nt, vis);
         }
         _ => {}
@@ -834,8 +838,6 @@ fn visit_nonterminal<T: MutVisitor>(nt: &mut token::Nonterminal, vis: &mut T) {
         token::NtPat(pat) => vis.visit_pat(pat),
         token::NtExpr(expr) => vis.visit_expr(expr),
         token::NtTy(ty) => vis.visit_ty(ty),
-        token::NtIdent(ident, _is_raw) => vis.visit_ident(ident),
-        token::NtLifetime(ident) => vis.visit_ident(ident),
         token::NtLiteral(expr) => vis.visit_expr(expr),
         token::NtMeta(item) => {
             let AttrItem { path, args, tokens } = item.deref_mut();

compiler/rustc_ast/src/token.rs

@@ -111,7 +111,7 @@ impl Lit {
             Ident(name, IdentIsRaw::No) if name.is_bool_lit() => Some(Lit::new(Bool, name, None)),
             Literal(token_lit) => Some(token_lit),
             Interpolated(ref nt)
-                if let NtExpr(expr) | NtLiteral(expr) = &nt.0
+                if let NtExpr(expr) | NtLiteral(expr) = &**nt
                     && let ast::ExprKind::Lit(token_lit) = expr.kind =>
             {
                 Some(token_lit)
@@ -318,11 +318,20 @@ pub enum TokenKind {
     /// It's recommended to use `Token::(ident,uninterpolate,uninterpolated_span)` to
     /// treat regular and interpolated identifiers in the same way.
     Ident(Symbol, IdentIsRaw),
+    /// This identifier (and its span) is the identifier passed to the
+    /// declarative macro. The span in the surrounding `Token` is the span of
+    /// the `ident` metavariable in the macro's RHS.
+    NtIdent(Ident, IdentIsRaw),
+
     /// Lifetime identifier token.
     /// Do not forget about `NtLifetime` when you want to match on lifetime identifiers.
     /// It's recommended to use `Token::(lifetime,uninterpolate,uninterpolated_span)` to
     /// treat regular and interpolated lifetime identifiers in the same way.
     Lifetime(Symbol),
+    /// This identifier (and its span) is the lifetime passed to the
+    /// declarative macro. The span in the surrounding `Token` is the span of
+    /// the `lifetime` metavariable in the macro's RHS.
+    NtLifetime(Ident),
 
     /// An embedded AST node, as produced by a macro. This only exists for
     /// historical reasons. We'd like to get rid of it, for multiple reasons.
@@ -333,7 +342,11 @@ pub enum TokenKind {
     /// - It prevents `Token` from implementing `Copy`.
     /// It adds complexity and likely slows things down. Please don't add new
     /// occurrences of this token kind!
-    Interpolated(Lrc<(Nonterminal, Span)>),
+    ///
+    /// The span in the surrounding `Token` is that of the metavariable in the
+    /// macro's RHS. The span within the Nonterminal is that of the fragment
+    /// passed to the macro at the call site.
+    Interpolated(Lrc<Nonterminal>),
 
     /// A doc comment token.
     /// `Symbol` is the doc comment's data excluding its "quotes" (`///`, `/**`, etc)
@@ -440,8 +453,9 @@ impl Token {
     /// Note that keywords are also identifiers, so they should use this
     /// if they keep spans or perform edition checks.
     pub fn uninterpolated_span(&self) -> Span {
-        match &self.kind {
-            Interpolated(nt) => nt.0.use_span(),
+        match self.kind {
+            NtIdent(ident, _) | NtLifetime(ident) => ident.span,
+            Interpolated(ref nt) => nt.use_span(),
             _ => self.span,
         }
     }
@@ -459,7 +473,7 @@ impl Token {
             }
 
             OpenDelim(..) | CloseDelim(..) | Literal(..) | DocComment(..) | Ident(..)
-            | Lifetime(..) | Interpolated(..) | Eof => false,
+            | NtIdent(..) | Lifetime(..) | NtLifetime(..) | Interpolated(..) | Eof => false,
         }
     }
 
@@ -486,7 +500,7 @@ impl Token {
             PathSep                            | // global path
             Lifetime(..)                      | // labeled loop
             Pound                             => true, // expression attributes
-            Interpolated(ref nt) => matches!(&nt.0, NtLiteral(..) |
+            Interpolated(ref nt) => matches!(&**nt, NtLiteral(..) |
                 NtExpr(..)    |
                 NtBlock(..)   |
                 NtPath(..)),
@@ -510,7 +524,7 @@ impl Token {
             | DotDot | DotDotDot | DotDotEq      // ranges
             | Lt | BinOp(Shl)                    // associated path
             | PathSep                    => true, // global path
-            Interpolated(ref nt) => matches!(&nt.0, NtLiteral(..) |
+            Interpolated(ref nt) => matches!(&**nt, NtLiteral(..) |
                 NtPat(..)     |
                 NtBlock(..)   |
                 NtPath(..)),
@@ -533,7 +547,7 @@ impl Token {
             Lifetime(..)                | // lifetime bound in trait object
             Lt | BinOp(Shl)             | // associated path
             PathSep                      => true, // global path
-            Interpolated(ref nt) => matches!(&nt.0, NtTy(..) | NtPath(..)),
+            Interpolated(ref nt) => matches!(&**nt, NtTy(..) | NtPath(..)),
             // For anonymous structs or unions, which only appear in specific positions
             // (type of struct fields or union fields), we don't consider them as regular types
             _ => false,
@@ -544,7 +558,7 @@ impl Token {
     pub fn can_begin_const_arg(&self) -> bool {
         match self.kind {
             OpenDelim(Delimiter::Brace) => true,
-            Interpolated(ref nt) => matches!(&nt.0, NtExpr(..) | NtBlock(..) | NtLiteral(..)),
+            Interpolated(ref nt) => matches!(&**nt, NtExpr(..) | NtBlock(..) | NtLiteral(..)),
             _ => self.can_begin_literal_maybe_minus(),
         }
     }
@@ -589,7 +603,7 @@ impl Token {
         match self.uninterpolate().kind {
             Literal(..) | BinOp(Minus) => true,
             Ident(name, IdentIsRaw::No) if name.is_bool_lit() => true,
-            Interpolated(ref nt) => match &nt.0 {
+            Interpolated(ref nt) => match &**nt {
                 NtLiteral(_) => true,
                 NtExpr(e) => match &e.kind {
                     ast::ExprKind::Lit(_) => true,
@@ -609,14 +623,9 @@ impl Token {
     /// into the regular identifier or lifetime token it refers to,
     /// otherwise returns the original token.
     pub fn uninterpolate(&self) -> Cow<'_, Token> {
-        match &self.kind {
-            Interpolated(nt) => match &nt.0 {
-                NtIdent(ident, is_raw) => {
-                    Cow::Owned(Token::new(Ident(ident.name, *is_raw), ident.span))
-                }
-                NtLifetime(ident) => Cow::Owned(Token::new(Lifetime(ident.name), ident.span)),
-                _ => Cow::Borrowed(self),
-            },
+        match self.kind {
+            NtIdent(ident, is_raw) => Cow::Owned(Token::new(Ident(ident.name, is_raw), ident.span)),
+            NtLifetime(ident) => Cow::Owned(Token::new(Lifetime(ident.name), ident.span)),
             _ => Cow::Borrowed(self),
         }
     }
@@ -625,12 +634,9 @@ impl Token {
     #[inline]
     pub fn ident(&self) -> Option<(Ident, IdentIsRaw)> {
         // We avoid using `Token::uninterpolate` here because it's slow.
-        match &self.kind {
-            &Ident(name, is_raw) => Some((Ident::new(name, self.span), is_raw)),
-            Interpolated(nt) => match &nt.0 {
-                NtIdent(ident, is_raw) => Some((*ident, *is_raw)),
-                _ => None,
-            },
+        match self.kind {
+            Ident(name, is_raw) => Some((Ident::new(name, self.span), is_raw)),
+            NtIdent(ident, is_raw) => Some((ident, is_raw)),
             _ => None,
         }
     }
@@ -639,12 +645,9 @@ impl Token {
     #[inline]
     pub fn lifetime(&self) -> Option<Ident> {
         // We avoid using `Token::uninterpolate` here because it's slow.
-        match &self.kind {
-            &Lifetime(name) => Some(Ident::new(name, self.span)),
-            Interpolated(nt) => match &nt.0 {
-                NtLifetime(ident) => Some(*ident),
-                _ => None,
-            },
+        match self.kind {
+            Lifetime(name) => Some(Ident::new(name, self.span)),
+            NtLifetime(ident) => Some(ident),
             _ => None,
         }
     }
@@ -668,7 +671,7 @@ impl Token {
     /// Returns `true` if the token is an interpolated path.
     fn is_whole_path(&self) -> bool {
         if let Interpolated(nt) = &self.kind
-            && let NtPath(..) = &nt.0
+            && let NtPath(..) = &**nt
         {
             return true;
         }
@@ -681,7 +684,7 @@ impl Token {
     /// (which happens while parsing the result of macro expansion)?
     pub fn is_whole_expr(&self) -> bool {
         if let Interpolated(nt) = &self.kind
-            && let NtExpr(_) | NtLiteral(_) | NtPath(_) | NtBlock(_) = &nt.0
+            && let NtExpr(_) | NtLiteral(_) | NtPath(_) | NtBlock(_) = &**nt
         {
             return true;
         }
@@ -692,7 +695,7 @@ impl Token {
     /// Is the token an interpolated block (`$b:block`)?
     pub fn is_whole_block(&self) -> bool {
         if let Interpolated(nt) = &self.kind
-            && let NtBlock(..) = &nt.0
+            && let NtBlock(..) = &**nt
         {
             return true;
         }
@@ -833,8 +836,10 @@ impl Token {
 
             Le | EqEq | Ne | Ge | AndAnd | OrOr | Tilde | BinOpEq(..) | At | DotDotDot
             | DotDotEq | Comma | Semi | PathSep | RArrow | LArrow | FatArrow | Pound | Dollar
-            | Question | OpenDelim(..) | CloseDelim(..) | Literal(..) | Ident(..)
-            | Lifetime(..) | Interpolated(..) | DocComment(..) | Eof => return None,
+            | Question | OpenDelim(..) | CloseDelim(..) | Literal(..) | Ident(..) | NtIdent(..)
+            | Lifetime(..) | NtLifetime(..) | Interpolated(..) | DocComment(..) | Eof => {
+                return None;
+            }
         };
 
         Some(Token::new(kind, self.span.to(joint.span)))
@@ -857,8 +862,6 @@ pub enum Nonterminal {
     NtPat(P<ast::Pat>),
     NtExpr(P<ast::Expr>),
     NtTy(P<ast::Ty>),
-    NtIdent(Ident, IdentIsRaw),
-    NtLifetime(Ident),
     NtLiteral(P<ast::Expr>),
     /// Stuff inside brackets for attributes
     NtMeta(P<ast::AttrItem>),
@@ -953,7 +956,6 @@ impl Nonterminal {
             NtPat(pat) => pat.span,
             NtExpr(expr) | NtLiteral(expr) => expr.span,
             NtTy(ty) => ty.span,
-            NtIdent(ident, _) | NtLifetime(ident) => ident.span,
             NtMeta(attr_item) => attr_item.span(),
             NtPath(path) => path.span,
             NtVis(vis) => vis.span,
@@ -969,8 +971,6 @@ impl Nonterminal {
             NtExpr(..) => "expression",
             NtLiteral(..) => "literal",
             NtTy(..) => "type",
-            NtIdent(..) => "identifier",
-            NtLifetime(..) => "lifetime",
             NtMeta(..) => "attribute",
             NtPath(..) => "path",
             NtVis(..) => "visibility",
@@ -979,18 +979,12 @@ impl Nonterminal {
 }
 
 impl PartialEq for Nonterminal {
-    fn eq(&self, rhs: &Self) -> bool {
-        match (self, rhs) {
-            (NtIdent(ident_lhs, is_raw_lhs), NtIdent(ident_rhs, is_raw_rhs)) => {
-                ident_lhs == ident_rhs && is_raw_lhs == is_raw_rhs
-            }
-            (NtLifetime(ident_lhs), NtLifetime(ident_rhs)) => ident_lhs == ident_rhs,
-            // FIXME: Assume that all "complex" nonterminal are not equal, we can't compare them
-            // correctly based on data from AST. This will prevent them from matching each other
-            // in macros. The comparison will become possible only when each nonterminal has an
-            // attached token stream from which it was parsed.
-            _ => false,
-        }
+    fn eq(&self, _rhs: &Self) -> bool {
+        // FIXME: Assume that all nonterminals are not equal, we can't compare them
+        // correctly based on data from AST. This will prevent them from matching each other
+        // in macros. The comparison will become possible only when each nonterminal has an
+        // attached token stream from which it was parsed.
+        false
     }
 }
 
@@ -1003,12 +997,10 @@ impl fmt::Debug for Nonterminal {
             NtPat(..) => f.pad("NtPat(..)"),
             NtExpr(..) => f.pad("NtExpr(..)"),
             NtTy(..) => f.pad("NtTy(..)"),
-            NtIdent(..) => f.pad("NtIdent(..)"),
             NtLiteral(..) => f.pad("NtLiteral(..)"),
             NtMeta(..) => f.pad("NtMeta(..)"),
             NtPath(..) => f.pad("NtPath(..)"),
             NtVis(..) => f.pad("NtVis(..)"),
-            NtLifetime(..) => f.pad("NtLifetime(..)"),
         }
     }
 }

compiler/rustc_ast/src/tokenstream.rs

@@ -466,12 +466,6 @@ impl TokenStream {
 
     pub fn from_nonterminal_ast(nt: &Nonterminal) -> TokenStream {
         match nt {
-            Nonterminal::NtIdent(ident, is_raw) => {
-                TokenStream::token_alone(token::Ident(ident.name, *is_raw), ident.span)
-            }
-            Nonterminal::NtLifetime(ident) => {
-                TokenStream::token_alone(token::Lifetime(ident.name), ident.span)
-            }
             Nonterminal::NtItem(item) => TokenStream::from_ast(item),
             Nonterminal::NtBlock(block) => TokenStream::from_ast(block),
             Nonterminal::NtStmt(stmt) if let StmtKind::Empty = stmt.kind => {
@@ -489,15 +483,21 @@ impl TokenStream {
     }
 
     fn flatten_token(token: &Token, spacing: Spacing) -> TokenTree {
-        match &token.kind {
-            token::Interpolated(nt) if let token::NtIdent(ident, is_raw) = nt.0 => {
+        match token.kind {
+            token::NtIdent(ident, is_raw) => {
                 TokenTree::Token(Token::new(token::Ident(ident.name, is_raw), ident.span), spacing)
             }
-            token::Interpolated(nt) => TokenTree::Delimited(
+            token::NtLifetime(ident) => TokenTree::Delimited(
+                DelimSpan::from_single(token.span),
+                DelimSpacing::new(Spacing::JointHidden, spacing),
+                Delimiter::Invisible,
+                TokenStream::token_alone(token::Lifetime(ident.name), ident.span),
+            ),
+            token::Interpolated(ref nt) => TokenTree::Delimited(
                 DelimSpan::from_single(token.span),
                 DelimSpacing::new(Spacing::JointHidden, spacing),
                 Delimiter::Invisible,
-                TokenStream::from_nonterminal_ast(&nt.0).flattened(),
+                TokenStream::from_nonterminal_ast(&nt).flattened(),
             ),
             _ => TokenTree::Token(token.clone(), spacing),
         }
@@ -516,7 +516,10 @@ impl TokenStream {
     pub fn flattened(&self) -> TokenStream {
         fn can_skip(stream: &TokenStream) -> bool {
             stream.trees().all(|tree| match tree {
-                TokenTree::Token(token, _) => !matches!(token.kind, token::Interpolated(_)),
+                TokenTree::Token(token, _) => !matches!(
+                    token.kind,
+                    token::NtIdent(..) | token::NtLifetime(..) | token::Interpolated(..)
+                ),
                 TokenTree::Delimited(.., inner) => can_skip(inner),
             })
         }