From 83abed9df6ad0a8881270f166a02ffcaf437422f Mon Sep 17 00:00:00 2001
From: Santiago Pastorino <spastorino@gmail.com>
Date: Mon, 19 Oct 2020 18:44:37 -0300
Subject: Make inline const work for half open ranges

---
 compiler/rustc_parse/src/parser/expr.rs | 2 +-
 compiler/rustc_parse/src/parser/mod.rs  | 6 +++---
 compiler/rustc_parse/src/parser/pat.rs  | 8 ++++----
 3 files changed, 8 insertions(+), 8 deletions(-)

(limited to 'compiler/rustc_parse/src/parser')

diff --git a/compiler/rustc_parse/src/parser/expr.rs b/compiler/rustc_parse/src/parser/expr.rs
index 51ecc53ca26..78c95428c72 100644
--- a/compiler/rustc_parse/src/parser/expr.rs
+++ b/compiler/rustc_parse/src/parser/expr.rs
@@ -1062,7 +1062,7 @@ impl<'a> Parser<'a> {
             })
         } else if self.eat_keyword(kw::Unsafe) {
             self.parse_block_expr(None, lo, BlockCheckMode::Unsafe(ast::UserProvided), attrs)
-        } else if self.check_inline_const() {
+        } else if self.check_inline_const(0) {
             self.parse_const_block(lo.to(self.token.span))
         } else if self.is_do_catch_block() {
             self.recover_do_catch(attrs)
diff --git a/compiler/rustc_parse/src/parser/mod.rs b/compiler/rustc_parse/src/parser/mod.rs
index 4999498e4f7..8ff97453c14 100644
--- a/compiler/rustc_parse/src/parser/mod.rs
+++ b/compiler/rustc_parse/src/parser/mod.rs
@@ -522,9 +522,9 @@ impl<'a> Parser<'a> {
         self.check_or_expected(self.token.can_begin_const_arg(), TokenType::Const)
     }
 
-    fn check_inline_const(&mut self) -> bool {
-        self.check_keyword(kw::Const)
-            && self.look_ahead(1, |t| match t.kind {
+    fn check_inline_const(&self, dist: usize) -> bool {
+        self.is_keyword_ahead(dist, &[kw::Const])
+            && self.look_ahead(dist + 1, |t| match t.kind {
                 token::Interpolated(ref nt) => matches!(**nt, token::NtBlock(..)),
                 token::OpenDelim(DelimToken::Brace) => true,
                 _ => false,
diff --git a/compiler/rustc_parse/src/parser/pat.rs b/compiler/rustc_parse/src/parser/pat.rs
index 8da0a2f57d8..27fe75a23b6 100644
--- a/compiler/rustc_parse/src/parser/pat.rs
+++ b/compiler/rustc_parse/src/parser/pat.rs
@@ -313,7 +313,7 @@ impl<'a> Parser<'a> {
             let pat = self.parse_pat_with_range_pat(false, None)?;
             self.sess.gated_spans.gate(sym::box_patterns, lo.to(self.prev_token.span));
             PatKind::Box(pat)
-        } else if self.check_inline_const() {
+        } else if self.check_inline_const(0) {
             // Parse `const pat`
             let const_expr = self.parse_const_block(lo.to(self.token.span))?;
 
@@ -722,8 +722,8 @@ impl<'a> Parser<'a> {
     }
 
     /// Is the token `dist` away from the current suitable as the start of a range patterns end?
-    fn is_pat_range_end_start(&mut self, dist: usize) -> bool {
-        self.check_inline_const()
+    fn is_pat_range_end_start(&self, dist: usize) -> bool {
+        self.check_inline_const(dist)
             || self.look_ahead(dist, |t| {
                 t.is_path_start() // e.g. `MY_CONST`;
                 || t.kind == token::Dot // e.g. `.5` for recovery;
@@ -733,7 +733,7 @@ impl<'a> Parser<'a> {
     }
 
     fn parse_pat_range_end(&mut self) -> PResult<'a, P<Expr>> {
-        if self.check_inline_const() {
+        if self.check_inline_const(0) {
             self.parse_const_block(self.token.span)
         } else if self.check_path() {
             let lo = self.token.span;
-- 
cgit 1.4.1-3-g733a5