libsyntax: fail lexing with an error message on an int literal larger than 2^64.

Stops an ICE.

Closes #5544.

src/libsyntax/parse/lexer.rs

@@ -442,7 +442,11 @@ fn scan_number(c: char, rdr: @mut StringReader) -> token::Token {
         if str::len(num_str) == 0u {
             rdr.fatal(~"no valid digits found for number");
         }
-        let parsed = u64::from_str_radix(num_str, base as uint).get();
+        let parsed = match u64::from_str_radix(num_str, base as uint) {
+            Some(p) => p,
+            None => rdr.fatal(~"int literal is too large")
+        };
+
         match tp {
           either::Left(t) => return token::LIT_INT(parsed as i64, t),
           either::Right(t) => return token::LIT_UINT(parsed, t)
@@ -503,7 +507,10 @@ fn scan_number(c: char, rdr: @mut StringReader) -> token::Token {
         if str::len(num_str) == 0u {
             rdr.fatal(~"no valid digits found for number");
         }
-        let parsed = u64::from_str_radix(num_str, base as uint).get();
+        let parsed = match u64::from_str_radix(num_str, base as uint) {
+            Some(p) => p,
+            None => rdr.fatal(~"int literal is too large")
+        };
 
         debug!("lexing %s as an unsuffixed integer literal",
                num_str);

src/test/compile-fail/issue-5544-a.rs

@@ -0,0 +1,14 @@
+// Copyright 2013 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 _i = 18446744073709551616; // 2^64
+    //~^ ERROR int literal is too large
+}

src/test/compile-fail/issue-5544-b.rs

@@ -0,0 +1,14 @@
+// Copyright 2013 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 _i = 0xff_ffff_ffff_ffff_ffff;
+    //~^ ERROR int literal is too large
+}