Dependency overrides override SDK constraints.

test/dependency_override_test.dart

 // Copyright (c) 2013, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 import 'package:path/path.dart' as path;
 
 import 'descriptor.dart' as d;
 import 'test_pub.dart';
 
 main() {
@@ skipping 68 matching lines @@
       ]).create();
 
       pubCommand(command);
 
       d.packagesDir({
         "foo": "2.0.0",
         "bar": "1.0.0"
       }).validate();
     });
 
+    integration("ignores SDK constraints", () {
+      servePackages((builder) {
+        builder.serve("foo", "1.0.0", pubspec: {
+          "environment": {
+            "sdk": "5.6.7-fblthp"
+          }
+        });
+      });
+
+      d.dir(appPath, [
+        d.pubspec({
+          "name": "myapp",
+          "dependency_overrides": {
+            "foo": "any"
+          }
+        })
+      ]).create();
+
+      pubCommand(command);
+
+      d.packagesDir({
+        "foo": "1.0.0"
+      }).validate();
+    });
+
     integration("warns about overridden dependencies", () {
       servePackages((builder) {
         builder.serve("foo", "1.0.0");
         builder.serve("bar", "1.0.0");
       });
 
       d.dir("baz", [
         d.libDir("baz"),
         d.libPubspec("baz", "0.0.1")
       ]).create();
@@ skipping 14 matching lines @@
       schedulePub(args: [command.name], output: command.success, error:
           """
           Warning: You are using these overridden dependencies:
           ! bar 1.0.0
           ! baz 0.0.1 from path $bazPath
           ! foo 1.0.0
           """);
     });
   });
 }