Change assert implementation to not depend on a top-level function called 'assert'.

tests/language/assert_lexical_scope_test.dart

+// Copyright (c) 2012, 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.
+
+// A function that accepts 0..2 arguments.
+void poly([a, b]) {
+  polyCount++;
+  polyArg = a;
+}
+
+// First argument of most recent call to poly.
+var polyArg = 0;
+
+// Number of calls to poly.
+var polyCount = 0;
+
+// (Super)classes that declare an "assert" member.
+class SuperGet {
+  get assert => poly;
+
+  void lexicalAssert(x) {
+    assert(x);
+  }
+}
+
+class SuperMethod {
+  assert([a, b]) => poly(a, b);
+
+  void lexicalAssert(x) {
+    assert(x);
+  }
+}
+
+class SuperField {
+  var assert;
+  SuperField() : assert = poly;
+
+  void lexicalAssert(x) {
+    assert(x);
+  }
+}
+
+// Superclass that don't declare "assert", but will handle assert calls.
+class SuperNon {
+  noSuchMethod(x, y) {
+    switch (y.length) {
+      case 0: return poly();
+      case 1: return poly(y[0]);
+      case 2: return poly(y[0], y[1]);
+    }
+  }
+
+  void lexicalAssert(x) {
+    // Hack, since there is no lexically enclosing 'assert' declaration here,
+    // so just act as if there was to avoid special casing it in the test.
+    poly(x);
+  }
+}
+
+// Sub-classes that read/call "assert".
+// In every case except "assert(exp);" this should access the superclass
+// member.
+
+class SubGet extends SuperGet {
+  void getAssert(x) {
+    assert;
+  }
+  void assert0(x) {
+    assert();
+  }
+  void assert1(x) {
+    assert(x);
+  }
+  void assertExp(x) {
+    var z = assert(x);
+  }
+  void assert2(x) {
+    assert(x, x);
+  }
+}
+
+class SubMethod extends SuperMethod {
+  void getAssert(x) {
+    assert;
+  }
+  void assert0(x) {
+    assert();
+  }
+  void assert1(x) {
+    assert(x);
+  }
+  void assertExp(x) {
+    var z = assert(x);
+  }
+  void assert2(x) {
+    assert(x, x);
+  }
+}
+
+class SubField extends SuperField {
+  void getAssert(x) {
+    assert;
+  }
+  void assert0(x) {
+    assert();
+  }
+  void assert1(x) {
+    assert(x);
+  }
+  void assertExp(x) {
+    var z = assert(x);
+  }
+  void assert2(x) {
+    assert(x, x);
+  }
+}
+
+class SubNon extends SuperNon {
+  void getAssert(x) {
+    assert;
+  }
+  assert0(x) {
+    assert();
+  }
+  void assert1(x) {
+    assert(x);
+  }
+  void assertExp(x) {
+    var z = assert(x);
+  }
+  void assert2(x) {
+    assert(x, x);
+  }
+}
+
+
+class SetAssert {
+  set assert(x) {}
+  void lexicalAssert(x) {
+    assert(x);
+  }
+}
+
+
+testAssertDeclared() {
+  var get = new SubGet();
+  var method = new SubMethod();
+  var field = new SubField();
+  var non = new SubNon();
+
+  void expectCallsPoly(code, [bool noArgument = false]) {
+    int oldPolyCount = polyCount;
+    int newPolyArg = polyArg + 1;
+    int expectedPolyArg = noArgument ? null : newPolyArg;
+    code(newPolyArg);
+    Expect.equals(oldPolyCount + 1, polyCount);
+    Expect.equals(expectedPolyArg, polyArg);
+    if (noArgument) polyArg = newPolyArg;
+  }
+
+  void expectAssert(code) {
+    int oldPolyCount = polyCount;
+    // Detect whether asserts are enabled.
+    bool assertsEnabled = false;
+    assert(assertsEnabled = true);
+    try {
+      code(polyArg + 1);
+      // If asserts are enabled, we should not get here.
+      // If they are not, the call does nothing.
+      if (assertsEnabled) {
+        Expect.fail("Didn't call assert with asserts enabled.");
+      }
+    } on AssertionError catch (e) {
+      if (!assertsEnabled) Expect.fail("Called assert with asserts disabled?");
+    }
+    Expect.equals(oldPolyCount, polyCount);
+  }
+
+  // Sanity check.
+  expectCallsPoly(poly);
+
+  // Doesn't fail to read "assert".
+  get.getAssert(0);
+  method.getAssert(0);
+  field.getAssert(0);
+  expectCallsPoly(non.getAssert, true);  // Hits 'noSuchMethod'.
+
+  // Check when 'assert' is a superclass member declaration (or, simulated with
+  // noSuchMethod).
+  void testSuperAssert(object) {
+    expectCallsPoly(object.assert0, true);
+    expectAssert(object.assert1);
+    expectCallsPoly(object.assertExp);
+    expectCallsPoly(object.assert2);
+    expectCallsPoly(object.lexicalAssert);
+  }
+
+  testSuperAssert(get);
+  testSuperAssert(method);
+  testSuperAssert(field);
+  testSuperAssert(non);
+
+  // Local declarations
+  expectCallsPoly((x) {
+    var assert = poly;
+    assert(x);
+  });
+
+  expectCallsPoly((x) {
+    void assert(x) => poly(x);
+    assert(x);
+  });
+
+  // Setters don't inhibit assert.
+  expectAssert(new SetAssert().lexicalAssert);
+}
+
+main() {
+  testAssertDeclared();
+}