Use Token::uninterpolate in couple more places matching on (Nt)Ident

src/librustc_ast/attr/mod.rs

@@ -441,7 +441,7 @@ impl MetaItem {
         I: Iterator<Item = TokenTree>,
     {
         // FIXME: Share code with `parse_path`.
-        let path = match tokens.next() {
+        let path = match tokens.next().map(TokenTree::uninterpolate) {
             Some(TokenTree::Token(Token { kind: kind @ token::Ident(..), span }))
             | Some(TokenTree::Token(Token { kind: kind @ token::ModSep, span })) => 'arm: {
                 let mut segments = if let token::Ident(name, _) = kind {
@@ -457,7 +457,7 @@ impl MetaItem {
                 };
                 loop {
                     if let Some(TokenTree::Token(Token { kind: token::Ident(name, _), span })) =
-                        tokens.next()
+                        tokens.next().map(TokenTree::uninterpolate)
                     {
                         segments.push(PathSegment::from_ident(Ident::new(name, span)));
                     } else {
@@ -474,7 +474,6 @@ impl MetaItem {
                 Path { span, segments }
             }
             Some(TokenTree::Token(Token { kind: token::Interpolated(nt), .. })) => match *nt {
-                token::Nonterminal::NtIdent(ident, _) => Path::from_ident(ident),
                 token::Nonterminal::NtMeta(ref item) => return item.meta(item.path.span),
                 token::Nonterminal::NtPath(ref path) => path.clone(),
                 _ => return None,

src/librustc_ast/token.rs

@@ -357,7 +357,7 @@ impl Token {
 
     /// Returns `true` if the token can appear at the start of an expression.
     pub fn can_begin_expr(&self) -> bool {
-        match self.kind {
+        match self.uninterpolate().kind {
             Ident(name, is_raw)              =>
                 ident_can_begin_expr(name, self.span, is_raw), // value name or keyword
             OpenDelim(..)                     | // tuple, array or block
@@ -375,12 +375,10 @@ impl Token {
             Lifetime(..)                      | // labeled loop
             Pound                             => true, // expression attributes
             Interpolated(ref nt) => match **nt {
-                NtIdent(ident, is_raw) => ident_can_begin_expr(ident.name, ident.span, is_raw),
                 NtLiteral(..) |
                 NtExpr(..)    |
                 NtBlock(..)   |
-                NtPath(..)    |
-                NtLifetime(..) => true,
+                NtPath(..) => true,
                 _ => false,
             },
             _ => false,
@@ -389,7 +387,7 @@ impl Token {
 
     /// Returns `true` if the token can appear at the start of a type.
     pub fn can_begin_type(&self) -> bool {
-        match self.kind {
+        match self.uninterpolate().kind {
             Ident(name, is_raw)        =>
                 ident_can_begin_type(name, self.span, is_raw), // type name or keyword
             OpenDelim(Paren)            | // tuple
@@ -403,8 +401,7 @@ impl Token {
             Lt | BinOp(Shl)             | // associated path
             ModSep                      => true, // global path
             Interpolated(ref nt) => match **nt {
-                NtIdent(ident, is_raw) => ident_can_begin_type(ident.name, ident.span, is_raw),
-                NtTy(..) | NtPath(..) | NtLifetime(..) => true,
+                NtTy(..) | NtPath(..) => true,
                 _ => false,
             },
             _ => false,
@@ -445,11 +442,10 @@ impl Token {
     ///
     /// Keep this in sync with `Lit::from_token`.
     pub fn can_begin_literal_or_bool(&self) -> bool {
-        match self.kind {
+        match self.uninterpolate().kind {
             Literal(..) | BinOp(Minus) => true,
             Ident(name, false) if name.is_bool_lit() => true,
             Interpolated(ref nt) => match &**nt {
-                NtIdent(ident, false) if ident.name.is_bool_lit() => true,
                 NtExpr(e) | NtLiteral(e) => matches!(e.kind, ast::ExprKind::Lit(_)),
                 _ => false,
             },
@@ -475,24 +471,18 @@ impl Token {
 
     /// Returns an identifier if this token is an identifier.
     pub fn ident(&self) -> Option<(ast::Ident, /* is_raw */ bool)> {
-        match self.kind {
-            Ident(name, is_raw) => Some((ast::Ident::new(name, self.span), is_raw)),
-            Interpolated(ref nt) => match **nt {
-                NtIdent(ident, is_raw) => Some((ident, is_raw)),
-                _ => None,
-            },
+        let token = self.uninterpolate();
+        match token.kind {
+            Ident(name, is_raw) => Some((ast::Ident::new(name, token.span), is_raw)),
             _ => None,
         }
     }
 
     /// Returns a lifetime identifier if this token is a lifetime.
     pub fn lifetime(&self) -> Option<ast::Ident> {
-        match self.kind {
-            Lifetime(name) => Some(ast::Ident::new(name, self.span)),
-            Interpolated(ref nt) => match **nt {
-                NtLifetime(ident) => Some(ident),
-                _ => None,
-            },
+        let token = self.uninterpolate();
+        match token.kind {
+            Lifetime(name) => Some(ast::Ident::new(name, token.span)),
             _ => None,
         }
     }

src/librustc_ast/tokenstream.rs

@@ -116,6 +116,13 @@ impl TokenTree {
     pub fn close_tt(span: DelimSpan, delim: DelimToken) -> TokenTree {
         TokenTree::token(token::CloseDelim(delim), span.close)
     }
+
+    pub fn uninterpolate(self) -> TokenTree {
+        match self {
+            TokenTree::Token(token) => TokenTree::Token(token.uninterpolate().into_owned()),
+            tt => tt,
+        }
+    }
 }
 
 impl<CTX> HashStable<CTX> for TokenStream

src/librustc_ast/util/literal.rs

@@ -191,23 +191,16 @@ impl Lit {
     ///
     /// Keep this in sync with `Token::can_begin_literal_or_bool`.
     pub fn from_token(token: &Token) -> Result<Lit, LitError> {
-        let lit = match token.kind {
+        let lit = match token.uninterpolate().kind {
             token::Ident(name, false) if name.is_bool_lit() => {
                 token::Lit::new(token::Bool, name, None)
             }
             token::Literal(lit) => lit,
             token::Interpolated(ref nt) => {
-                match &**nt {
-                    token::NtIdent(ident, false) if ident.name.is_bool_lit() => {
-                        let lit = token::Lit::new(token::Bool, ident.name, None);
-                        return Lit::from_lit_token(lit, ident.span);
+                if let token::NtExpr(expr) | token::NtLiteral(expr) = &**nt {
+                    if let ast::ExprKind::Lit(lit) = &expr.kind {
+                        return Ok(lit.clone());
                     }
-                    token::NtExpr(expr) | token::NtLiteral(expr) => {
-                        if let ast::ExprKind::Lit(lit) = &expr.kind {
-                            return Ok(lit.clone());
-                        }
-                    }
-                    _ => {}
                 }
                 return Err(LitError::NotLiteral);
             }

src/librustc_parse/parser/expr.rs

@@ -50,7 +50,6 @@ macro_rules! maybe_whole_expr {
                         AttrVec::new(),
                     ));
                 }
-                // N.B., `NtIdent(ident)` is normalized to `Ident` in `fn bump`.
                 _ => {}
             };
         }
@@ -482,7 +481,7 @@ impl<'a> Parser<'a> {
     }
 
     fn is_mistaken_not_ident_negation(&self) -> bool {
-        let token_cannot_continue_expr = |t: &Token| match t.kind {
+        let token_cannot_continue_expr = |t: &Token| match t.uninterpolate().kind {
             // These tokens can start an expression after `!`, but
             // can't continue an expression after an ident
             token::Ident(name, is_raw) => token::ident_can_begin_expr(name, t.span, is_raw),

src/librustc_parse/parser/item.rs

@@ -1544,6 +1544,8 @@ impl<'a> Parser<'a> {
 
         let is_name_required = match self.token.kind {
             token::DotDotDot => false,
+            // FIXME: Consider using interpolated token for this edition check,
+            // it should match the intent of edition hygiene better.
             _ => req_name(self.token.uninterpolate().span.edition()),
         };
         let (pat, ty) = if is_name_required || self.is_named_param() {

src/librustc_parse/parser/pat.rs

@@ -151,7 +151,7 @@ impl<'a> Parser<'a> {
     /// Note that there are more tokens such as `@` for which we know that the `|`
     /// is an illegal parse. However, the user's intent is less clear in that case.
     fn recover_trailing_vert(&mut self, lo: Option<Span>) -> bool {
-        let is_end_ahead = self.look_ahead(1, |token| match &token.kind {
+        let is_end_ahead = self.look_ahead(1, |token| match &token.uninterpolate().kind {
             token::FatArrow // e.g. `a | => 0,`.
             | token::Ident(kw::If, false) // e.g. `a | if expr`.
             | token::Eq // e.g. `let a | = 0`.