handle only postfix decrement

Author: nx2k3

compiler/rustc_parse/src/parser/diagnostics.rs

@@ -1354,16 +1354,6 @@ impl<'a> Parser<'a> {
         };
         self.recover_from_inc_dec(operand_expr, kind, op_span)
     }
-    pub(super) fn recover_from_prefix_decrement(
-        &mut self,
-        operand_expr: P<Expr>,
-        op_span: Span,
-        start_stmt: bool,
-    ) -> PResult<'a, P<Expr>> {
-        let standalone = if start_stmt { IsStandalone::Standalone } else { IsStandalone::Subexpr };
-        let kind = IncDecRecovery { standalone, op: IncOrDec::Dec, fixity: UnaryFixity::Pre };
-        self.recover_from_inc_dec(operand_expr, kind, op_span)
-    }
 
     pub(super) fn recover_from_postfix_decrement(
         &mut self,

compiler/rustc_parse/src/parser/expr.rs

@@ -561,10 +561,10 @@ impl<'a> Parser<'a> {
             token::Not => make_it!(this, attrs, |this, _| this.parse_unary_expr(lo, UnOp::Not)),
             // `~expr`
             token::Tilde => make_it!(this, attrs, |this, _| this.recover_tilde_expr(lo)),
-            // // `-expr`
-            // token::BinOp(token::Minus) => {
-            //     make_it!(this, attrs, |this, _| this.parse_unary_expr(lo, UnOp::Neg))
-            // }
+            // `-expr`
+            token::BinOp(token::Minus) => {
+                make_it!(this, attrs, |this, _| this.parse_unary_expr(lo, UnOp::Neg))
+            }
             // `*expr`
             token::BinOp(token::Star) => {
                 make_it!(this, attrs, |this, _| this.parse_unary_expr(lo, UnOp::Deref))
@@ -606,27 +606,7 @@ impl<'a> Parser<'a> {
                 let operand_expr = this.parse_dot_or_call_expr(Default::default())?;
                 this.recover_from_prefix_increment(operand_expr, pre_span, starts_stmt)
             }
-            // Recover from `--x`:
-            token::BinOp(token::Minus)
-                if this.look_ahead(1, |t| *t == token::BinOp(token::Minus))
-                    && !this.token.can_begin_expr() =>
-            {
-                let starts_stmt = this.prev_token == token::Semi
-                    || this.prev_token == token::CloseDelim(Delimiter::Brace);
-                let pre_span = this.token.span.to(this.look_ahead(1, |t| t.span));
-                // if !this.token.can_begin_expr() {
-                // Eat both `-`s.
-                this.bump();
-                this.bump();
-                let operand_expr = this.parse_dot_or_call_expr(Default::default())?;
-                this.recover_from_prefix_decrement(operand_expr, pre_span, starts_stmt)
 
-                // }
-            }
-            // `-expr`
-            token::BinOp(token::Minus) => {
-                make_it!(this, attrs, |this, _| this.parse_unary_expr(lo, UnOp::Neg))
-            }
             token::Ident(..) if this.token.is_keyword(kw::Box) => {
                 make_it!(this, attrs, |this, _| this.parse_box_expr(lo))
             }