rollup merge of #18728: thestinger/int

This fixes the gap in the language definition causing #18726 by defining
a clear bound on the maximum size for libraries to enforce.

Closes #18069

src/test/compile-fail/huge-enum.rs

@@ -12,6 +12,12 @@
 
 // FIXME: work properly with higher limits
 
+#[cfg(target_word_size = "32")]
 fn main() {
     let big: Option<[u32, ..(1<<29)-1]> = None;
 }
+
+#[cfg(target_word_size = "64")]
+fn main() {
+    let big: Option<[u32, ..(1<<45)-1]> = None;
+}

src/test/run-pass/huge-largest-array.rs

@@ -0,0 +1,21 @@
+// Copyright 2014 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.
+
+use std::mem::size_of;
+
+#[cfg(target_word_size = "32")]
+pub fn main() {
+    assert_eq!(size_of::<[u8, ..(1 << 31) - 1]>(), (1 << 31) - 1);
+}
+
+#[cfg(target_word_size = "64")]
+pub fn main() {
+    assert_eq!(size_of::<[u8, ..(1 << 47) - 1]>(), (1 << 47) - 1);
+}