debuginfo: Add support for argument shadowing.

src/test/debug-info/shadowed-argument.rs

@@ -0,0 +1,59 @@
+// 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.
+
+// xfail-win32 Broken because of LLVM bug: http://llvm.org/bugs/show_bug.cgi?id=16249
+
+// compile-flags:-Z extra-debug-info
+// debugger:break zzz
+// debugger:run
+
+// debugger:finish
+// debugger:print x
+// check:$1 = false
+// debugger:print y
+// check:$2 = true
+// debugger:continue
+
+// debugger:finish
+// debugger:print x
+// check:$3 = 10
+// debugger:print y
+// check:$4 = true
+// debugger:continue
+
+// debugger:finish
+// debugger:print x
+// check:$5 = 10.5
+// debugger:print y
+// check:$6 = 20
+// debugger:continue
+
+fn a_function(x: bool, y: bool) {
+    zzz();
+    sentinel();
+
+    let x = 10;
+
+    zzz();
+    sentinel();
+
+    let x = 10.5;
+    let y = 20;
+
+    zzz();
+    sentinel();
+}
+
+fn main() {
+    a_function(false, true);
+}
+
+fn zzz() {()}
+fn sentinel() {()}