Rollup merge of #23201 - pnkfelix:fsk-struct-ooe-23112, r=nikomatsakis

For FRU, eval field exprs (into scratch temps) before base expr

Fix #23112.

src/test/run-pass/struct-order-of-eval-1.rs

@@ -12,11 +12,12 @@ struct S { f0: String, f1: int }
 
 pub fn main() {
     let s = "Hello, world!".to_string();
-    let _s = S {
+    let s = S {
         f0: s.to_string(),
         ..S {
             f0: s,
             f1: 23
         }
     };
+    assert_eq!(s.f0, "Hello, world!");
 }

src/test/run-pass/struct-order-of-eval-2.rs

@@ -15,8 +15,9 @@ struct S {
 
 pub fn main() {
     let s = "Hello, world!".to_string();
-    let _s = S {
+    let s = S {
         f1: s.to_string(),
         f0: s
     };
+    assert_eq!(s.f0, "Hello, world!");
 }

src/test/run-pass/struct-order-of-eval-3.rs

@@ -0,0 +1,46 @@
+// 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.
+
+// Checks that functional-record-update order-of-eval is as expected
+// even when no Drop-implementations are involved.
+
+use std::sync::atomic::{Ordering, AtomicUsize, ATOMIC_USIZE_INIT};
+
+struct W { wrapped: u32 }
+struct S { f0: W, _f1: i32 }
+
+pub fn main() {
+    const VAL: u32 = 0x89AB_CDEF;
+    let w = W { wrapped: VAL };
+    let s = S {
+        f0: { event(0x01); W { wrapped: w.wrapped + 1 } },
+        ..S {
+            f0: { event(0x02); w},
+            _f1: 23
+        }
+    };
+    assert_eq!(s.f0.wrapped, VAL + 1);
+    let actual = event_log();
+    let expect = 0x01_02;
+    assert!(expect == actual,
+            "expect: 0x{:x} actual: 0x{:x}", expect, actual);
+}
+
+static LOG: AtomicUsize = ATOMIC_USIZE_INIT;
+
+fn event_log() -> usize {
+    LOG.load(Ordering::SeqCst)
+}
+
+fn event(tag: u8) {
+    let old_log = LOG.load(Ordering::SeqCst);
+    let new_log = (old_log << 8) + tag as usize;
+    LOG.store(new_log, Ordering::SeqCst);
+}

src/test/run-pass/struct-order-of-eval-4.rs

@@ -0,0 +1,43 @@
+// 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.
+
+// Checks that struct-literal expression order-of-eval is as expected
+// even when no Drop-implementations are involved.
+
+use std::sync::atomic::{Ordering, AtomicUsize, ATOMIC_USIZE_INIT};
+
+struct W { wrapped: u32 }
+struct S { f0: W, _f1: i32 }
+
+pub fn main() {
+    const VAL: u32 = 0x89AB_CDEF;
+    let w = W { wrapped: VAL };
+    let s = S {
+        _f1: { event(0x01); 23 },
+        f0: { event(0x02); w },
+    };
+    assert_eq!(s.f0.wrapped, VAL);
+    let actual = event_log();
+    let expect = 0x01_02;
+    assert!(expect == actual,
+            "expect: 0x{:x} actual: 0x{:x}", expect, actual);
+}
+
+static LOG: AtomicUsize = ATOMIC_USIZE_INIT;
+
+fn event_log() -> usize {
+    LOG.load(Ordering::SeqCst)
+}
+
+fn event(tag: u8) {
+    let old_log = LOG.load(Ordering::SeqCst);
+    let new_log = (old_log << 8) + tag as usize;
+    LOG.store(new_log, Ordering::SeqCst);
+}