Move eating const back into parse_const_block

Author: GrigorenkoPV

compiler/rustc_parse/src/parser/expr.rs

@@ -1472,8 +1472,8 @@ impl<'a> Parser<'a> {
                         err
                     },
                 )
-            } else if this.eat_keyword(kw::Const) {
-                this.parse_const_block(lo.to(this.prev_token.span), false)
+            } else if this.check_keyword(kw::Const) {
+                this.parse_const_block(lo.to(this.token.span), false)
             } else if this.may_recover() && this.is_do_catch_block() {
                 this.recover_do_catch()
             } else if this.is_try_block() {

compiler/rustc_parse/src/parser/mod.rs

@@ -1299,11 +1299,12 @@ impl<'a> Parser<'a> {
         }
     }
 
-    /// Parses inline const expressions. The `const` keyword was already eaten.
+    /// Parses inline const expressions.
     fn parse_const_block(&mut self, span: Span, pat: bool) -> PResult<'a, P<Expr>> {
         if pat {
             self.psess.gated_spans.gate(sym::inline_const_pat, span);
         }
+        self.expect_keyword(kw::Const)?;
         let (attrs, blk) = self.parse_inner_attrs_and_block()?;
         let anon_const = AnonConst {
             id: DUMMY_NODE_ID,

compiler/rustc_parse/src/parser/pat.rs

@@ -730,9 +730,9 @@ impl<'a> Parser<'a> {
             self.parse_pat_ident(BindingMode(ByRef::Yes(mutbl), Mutability::Not), syntax_loc)?
         } else if self.eat_keyword(kw::Box) {
             self.parse_pat_box()?
-        } else if self.eat_keyword(kw::Const) {
+        } else if self.check_keyword(kw::Const) {
             // Parse `const { pat }`
-            let const_expr = self.parse_const_block(lo.to(self.prev_token.span), true)?;
+            let const_expr = self.parse_const_block(lo.to(self.token.span), true)?;
 
             if let Some(re) = self.parse_range_end() {
                 self.parse_pat_range_begin_with(const_expr, re)?
@@ -1220,9 +1220,7 @@ impl<'a> Parser<'a> {
         .then_some(self.prev_token.span);
 
         let bound = if self.check_inline_const(0) {
-            let _eaten = self.eat_keyword(kw::Const);
-            debug_assert!(_eaten);
-            self.parse_const_block(self.prev_token.span, true)
+            self.parse_const_block(self.token.span, true)
         } else if self.check_path() {
             let lo = self.token.span;
             let (qself, path) = if self.eat_lt() {