Implement simple codegen for unsized rvalues.

src/test/run-pass-valgrind/unsized-locals/long-live-the-unsized-temporary.rs

@@ -0,0 +1,65 @@
+// Copyright 2018 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.
+
+#![feature(unsized_locals)]
+
+use std::fmt;
+
+fn gen_foo() -> Box<fmt::Display> {
+    Box::new(Box::new("foo"))
+}
+
+fn foo(x: fmt::Display) {
+    assert_eq!(x.to_string(), "foo");
+}
+
+fn foo_indirect(x: fmt::Display) {
+    foo(x);
+}
+
+fn main() {
+    foo(*gen_foo());
+    foo_indirect(*gen_foo());
+
+    {
+        let x: fmt::Display = *gen_foo();
+        foo(x);
+    }
+
+    {
+        let x: fmt::Display = *gen_foo();
+        let y: fmt::Display = *gen_foo();
+        foo(x);
+        foo(y);
+    }
+
+    {
+        let mut cnt: usize = 3;
+        let x = loop {
+            let x: fmt::Display = *gen_foo();
+            if cnt == 0 {
+                break x;
+            } else {
+                cnt -= 1;
+            }
+        };
+        foo(x);
+    }
+
+    {
+        let x: fmt::Display = *gen_foo();
+        let x = if true {
+            x
+        } else {
+            *gen_foo()
+        };
+        foo(x);
+    }
+}

src/test/run-pass/unsized-locals/reference-unsized-locals.rs

@@ -0,0 +1,17 @@
+// Copyright 2018 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.
+
+#![feature(unsized_locals)]
+
+fn main() {
+    let foo: Box<[u8]> = Box::new(*b"foo");
+    let foo: [u8] = *foo;
+    assert_eq!(&foo, b"foo" as &[u8]);
+}

src/test/run-pass/unsized-locals/simple-unsized-locals.rs

@@ -0,0 +1,16 @@
+// Copyright 2018 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.
+
+#![feature(unsized_locals)]
+
+fn main() {
+    let foo: Box<[u8]> = Box::new(*b"foo");
+    let _foo: [u8] = *foo;
+}

src/test/run-pass/unsized-locals/unsized-exprs.rs

@@ -0,0 +1,45 @@
+// Copyright 2018 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.
+
+#![feature(unsized_tuple_coercion, unsized_locals)]
+
+struct A<X: ?Sized>(X);
+
+fn udrop<T: ?Sized>(_x: T) {}
+fn foo() -> Box<[u8]> {
+    Box::new(*b"foo")
+}
+fn tfoo() -> Box<(i32, [u8])> {
+    Box::new((42, *b"foo"))
+}
+fn afoo() -> Box<A<[u8]>> {
+    Box::new(A(*b"foo"))
+}
+
+impl std::ops::Add<i32> for A<[u8]> {
+    type Output = ();
+    fn add(self, _rhs: i32) -> Self::Output {}
+}
+
+fn main() {
+    udrop::<[u8]>(loop {
+        break *foo();
+    });
+    udrop::<[u8]>(if true {
+        *foo()
+    } else {
+        *foo()
+    });
+    udrop::<[u8]>({*foo()});
+    #[allow(unused_parens)]
+    udrop::<[u8]>((*foo()));
+    udrop::<[u8]>((*tfoo()).1);
+    *afoo() + 42;
+}

src/test/run-pass/unsized-locals/unsized-parameters.rs

@@ -0,0 +1,20 @@
+// Copyright 2018 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.
+
+#![feature(unsized_locals)]
+
+pub fn f0(_f: dyn FnOnce()) {}
+pub fn f1(_s: str) {}
+pub fn f2((_x, _y): (i32, [i32])) {}
+
+fn main() {
+    let foo = "foo".to_string().into_boxed_str();
+    f1(*foo);
+}