Auto merge of #30375 - aaronkeen:issue_28777, r=eddyb

RESTRICTION_STMT_EXPR restriction to allow subsequent expressions to
contain braces.

https://github.com/rust-lang/rust/issues/28777

src/libsyntax/parse/parser.rs

@@ -2809,16 +2809,25 @@ impl<'a> Parser<'a> {
             }
 
             let rhs = try!(match op.fixity() {
-                Fixity::Right => self.with_res(restrictions, |this|{
+                Fixity::Right => self.with_res(
-                    this.parse_assoc_expr_with(op.precedence(), LhsExpr::NotYetParsed)
+                    restrictions - Restrictions::RESTRICTION_STMT_EXPR,
+                    |this| {
+                        this.parse_assoc_expr_with(op.precedence(),
+                            LhsExpr::NotYetParsed)
                 }),
-                Fixity::Left => self.with_res(restrictions, |this|{
+                Fixity::Left => self.with_res(
-                    this.parse_assoc_expr_with(op.precedence() + 1, LhsExpr::NotYetParsed)
+                    restrictions - Restrictions::RESTRICTION_STMT_EXPR,
+                    |this| {
+                        this.parse_assoc_expr_with(op.precedence() + 1,
+                            LhsExpr::NotYetParsed)
                 }),
                 // We currently have no non-associative operators that are not handled above by
                 // the special cases. The code is here only for future convenience.
-                Fixity::None => self.with_res(restrictions, |this|{
+                Fixity::None => self.with_res(
-                    this.parse_assoc_expr_with(op.precedence() + 1, LhsExpr::NotYetParsed)
+                    restrictions - Restrictions::RESTRICTION_STMT_EXPR,
+                    |this| {
+                        this.parse_assoc_expr_with(op.precedence() + 1,
+                            LhsExpr::NotYetParsed)
                 }),
             });
 

src/test/run-pass/assoc-oddities-3.rs

@@ -8,9 +8,14 @@
 // option. This file may not be copied, modified, or distributed
 // except according to those terms.
 
-// compile-flags: -Z parse-only
+fn that_odd_parse(c: bool, n: usize) -> u32 {
-
+    let x = 2;
-fn that_odd_parse() {
+    let a = [1, 2, 3, 4];
-    // see assoc-oddities-1 for explanation
+    let b = [5, 6, 7, 7];
-    x + if c { a } else { b }[n]; //~ ERROR expected one of
+    x + if c { a } else { b }[n]
+}
+
+fn main() {
+    assert_eq!(4, that_odd_parse(true, 1));
+    assert_eq!(8, that_odd_parse(false, 1));
 }

src/test/run-pass/issue-28777.rs

@@ -0,0 +1,30 @@
+// Copyright 2015 The Rust Project Developers. See the COPYRIGHT
+// file at the top-level directory of this distribution and at
+// http://rust-lang.org/COPYRIGHT.
+//
+// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
+// option. This file may not be copied, modified, or distributed
+// except according to those terms.
+
+fn main() {
+    let v1 = { 1 + {2} * {3} };
+    let v2 =   1 + {2} * {3}  ;
+
+    assert_eq!(7, v1);
+    assert_eq!(7, v2);
+
+    let v3;
+    v3 = { 1 + {2} * {3} };
+    let v4;
+    v4 = 1 + {2} * {3};
+    assert_eq!(7, v3);
+    assert_eq!(7, v4);
+
+    let v5 = { 1 + {2} * 3 };
+    assert_eq!(7, v5);
+
+    let v9 = { 1 + if 1 > 2 {1} else {2} * {3} };
+    assert_eq!(7, v9);
+}