parser: Remove Parser::prev_token_kind

src/librustc_parse/parser/expr.rs

@@ -1,6 +1,6 @@
 use super::pat::{GateOr, PARAM_EXPECTED};
 use super::ty::{AllowPlus, RecoverQPath};
-use super::{BlockMode, Parser, PathStyle, PrevTokenKind, Restrictions, TokenType};
+use super::{BlockMode, Parser, PathStyle, Restrictions, TokenType};
 use super::{SemiColonMode, SeqSep, TokenExpectType};
 use crate::maybe_recover_from_interpolated_ty_qpath;
 
@@ -166,17 +166,10 @@ impl<'a> Parser<'a> {
 
         self.expected_tokens.push(TokenType::Operator);
         while let Some(op) = self.check_assoc_op() {
-            // Adjust the span for interpolated LHS to point to the `$lhs` token and not to what
-            // it refers to. Interpolated identifiers are unwrapped early and never show up here
-            // as `PrevTokenKind::Interpolated` so if LHS is a single identifier we always process
-            // it as "interpolated", it doesn't change the answer for non-interpolated idents.
-            let lhs_span = match (self.prev_token_kind, &lhs.kind) {
-                (PrevTokenKind::Interpolated, _) => self.prev_span,
-                (PrevTokenKind::Ident, &ExprKind::Path(None, ref path))
-                    if path.segments.len() == 1 =>
-                {
-                    self.prev_span
-                }
+            // Adjust the span for interpolated LHS to point to the `$lhs` token
+            // and not to what it refers to.
+            let lhs_span = match self.unnormalized_prev_token().kind {
+                TokenKind::Interpolated(..) => self.prev_span,
                 _ => lhs.span,
             };
 
@@ -535,11 +528,13 @@ impl<'a> Parser<'a> {
         expr: PResult<'a, P<Expr>>,
     ) -> PResult<'a, (Span, P<Expr>)> {
         expr.map(|e| {
-            if self.prev_token_kind == PrevTokenKind::Interpolated {
-                (self.prev_span, e)
-            } else {
-                (e.span, e)
-            }
+            (
+                match self.unnormalized_prev_token().kind {
+                    TokenKind::Interpolated(..) => self.prev_span,
+                    _ => e.span,
+                },
+                e,
+            )
         })
     }
 

src/librustc_parse/parser/mod.rs

@@ -83,18 +83,6 @@ macro_rules! maybe_recover_from_interpolated_ty_qpath {
     };
 }
 
-#[derive(Debug, Clone, Copy, PartialEq)]
-enum PrevTokenKind {
-    DocComment,
-    Comma,
-    Plus,
-    Interpolated,
-    Eof,
-    Ident,
-    BitOr,
-    Other,
-}
-
 #[derive(Clone)]
 pub struct Parser<'a> {
     pub sess: &'a ParseSess,
@@ -115,9 +103,6 @@ pub struct Parser<'a> {
     /// Preferable use is through the `unnormalized_prev_token()` getter.
     /// Use span from this token if you need to concatenate it with some neighbouring spans.
     unnormalized_prev_token: Option<Token>,
-    /// Equivalent to `prev_token.kind` in simplified form.
-    /// FIXME: Remove in favor of `(unnormalized_)prev_token().kind`.
-    prev_token_kind: PrevTokenKind,
     /// Equivalent to `unnormalized_prev_token().span`.
     /// FIXME: Remove in favor of `(unnormalized_)prev_token().span`.
     pub prev_span: Span,
@@ -396,7 +381,6 @@ impl<'a> Parser<'a> {
             unnormalized_token: None,
             prev_token: Token::dummy(),
             unnormalized_prev_token: None,
-            prev_token_kind: PrevTokenKind::Other,
             prev_span: DUMMY_SP,
             restrictions: Restrictions::empty(),
             recurse_into_file_modules,
@@ -523,10 +507,11 @@ impl<'a> Parser<'a> {
                 self.bump();
                 Ok(Ident::new(name, span))
             }
-            _ => Err(if self.prev_token_kind == PrevTokenKind::DocComment {
-                self.span_fatal_err(self.prev_span, Error::UselessDocComment)
-            } else {
-                self.expected_ident_found()
+            _ => Err(match self.prev_token.kind {
+                TokenKind::DocComment(..) => {
+                    self.span_fatal_err(self.prev_span, Error::UselessDocComment)
+                }
+                _ => self.expected_ident_found(),
             }),
         }
     }
@@ -908,7 +893,7 @@ impl<'a> Parser<'a> {
 
     /// Advance the parser by one token.
     pub fn bump(&mut self) {
-        if self.prev_token_kind == PrevTokenKind::Eof {
+        if self.prev_token.kind == TokenKind::Eof {
             // Bumping after EOF is a bad sign, usually an infinite loop.
             let msg = "attempted to bump the parser past EOF (may be stuck in a loop)";
             self.span_bug(self.token.span, msg);
@@ -920,16 +905,6 @@ impl<'a> Parser<'a> {
         self.unnormalized_prev_token = self.unnormalized_token.take();
 
         // Update fields derived from the previous token.
-        self.prev_token_kind = match self.prev_token.kind {
-            token::DocComment(..) => PrevTokenKind::DocComment,
-            token::Comma => PrevTokenKind::Comma,
-            token::BinOp(token::Plus) => PrevTokenKind::Plus,
-            token::BinOp(token::Or) => PrevTokenKind::BitOr,
-            token::Interpolated(..) => PrevTokenKind::Interpolated,
-            token::Eof => PrevTokenKind::Eof,
-            token::Ident(..) => PrevTokenKind::Ident,
-            _ => PrevTokenKind::Other,
-        };
         self.prev_span = self.unnormalized_prev_token().span;
 
         self.expected_tokens.clear();
@@ -949,7 +924,6 @@ impl<'a> Parser<'a> {
         self.unnormalized_prev_token = self.unnormalized_token.take();
 
         // Update fields derived from the previous token.
-        self.prev_token_kind = PrevTokenKind::Other;
         self.prev_span = self.unnormalized_prev_token().span.with_hi(span.lo());
 
         self.expected_tokens.clear();

src/librustc_parse/parser/stmt.rs

@@ -2,7 +2,7 @@ use super::diagnostics::Error;
 use super::expr::LhsExpr;
 use super::pat::GateOr;
 use super::path::PathStyle;
-use super::{BlockMode, Parser, PrevTokenKind, Restrictions, SemiColonMode};
+use super::{BlockMode, Parser, Restrictions, SemiColonMode};
 use crate::maybe_whole;
 use crate::DirectoryOwnership;
 
@@ -190,7 +190,7 @@ impl<'a> Parser<'a> {
     /// Also error if the previous token was a doc comment.
     fn error_outer_attrs(&self, attrs: &[Attribute]) {
         if !attrs.is_empty() {
-            if self.prev_token_kind == PrevTokenKind::DocComment {
+            if matches!(self.prev_token.kind, TokenKind::DocComment(..)) {
                 self.span_fatal_err(self.prev_span, Error::UselessDocComment).emit();
             } else if attrs.iter().any(|a| a.style == AttrStyle::Outer) {
                 self.struct_span_err(self.token.span, "expected statement after outer attribute")

src/librustc_parse/parser/ty.rs

@@ -1,5 +1,5 @@
 use super::item::ParamCfg;
-use super::{Parser, PathStyle, PrevTokenKind, TokenType};
+use super::{Parser, PathStyle, TokenType};
 
 use crate::{maybe_recover_from_interpolated_ty_qpath, maybe_whole};
 
@@ -14,7 +14,7 @@ use syntax::ast::{
 };
 use syntax::ast::{Mac, Mutability};
 use syntax::ptr::P;
-use syntax::token::{self, Token};
+use syntax::token::{self, Token, TokenKind};
 
 /// Any `?` or `?const` modifiers that appear at the start of a bound.
 struct BoundModifiers {
@@ -196,7 +196,7 @@ impl<'a> Parser<'a> {
         let mut trailing_plus = false;
         let (ts, trailing) = self.parse_paren_comma_seq(|p| {
             let ty = p.parse_ty()?;
-            trailing_plus = p.prev_token_kind == PrevTokenKind::Plus;
+            trailing_plus = p.prev_token.kind == TokenKind::BinOp(token::Plus);
             Ok(ty)
         })?;
 
@@ -317,7 +317,7 @@ impl<'a> Parser<'a> {
     fn parse_impl_ty(&mut self, impl_dyn_multi: &mut bool) -> PResult<'a, TyKind> {
         // Always parse bounds greedily for better error recovery.
         let bounds = self.parse_generic_bounds(None)?;
-        *impl_dyn_multi = bounds.len() > 1 || self.prev_token_kind == PrevTokenKind::Plus;
+        *impl_dyn_multi = bounds.len() > 1 || self.prev_token.kind == TokenKind::BinOp(token::Plus);
         Ok(TyKind::ImplTrait(ast::DUMMY_NODE_ID, bounds))
     }
 
@@ -337,7 +337,7 @@ impl<'a> Parser<'a> {
         self.bump(); // `dyn`
         // Always parse bounds greedily for better error recovery.
         let bounds = self.parse_generic_bounds(None)?;
-        *impl_dyn_multi = bounds.len() > 1 || self.prev_token_kind == PrevTokenKind::Plus;
+        *impl_dyn_multi = bounds.len() > 1 || self.prev_token.kind == TokenKind::BinOp(token::Plus);
         Ok(TyKind::TraitObject(bounds, TraitObjectSyntax::Dyn))
     }