Statically check for assignments to const in harmony mode.

test/mjsunit/harmony/block-const-assign.js

+// Copyright 2011 the V8 project authors. All rights reserved.
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+// modification, are permitted provided that the following conditions are
+// met:
+//
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+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+// Flags: --harmony-scoping
+
+// Test that we throw early syntax errors in harmony mode
+// when using an immutable binding in an assigment or with
+// prefix/postfix decrement/increment operators.
+// TODO(ES6): properly activate extended mode
+"use strict";
+
+
+// Function local const.
+function constDecl0(use) {
+  return "(function() { const constvar = 1; " + use + "; });";
+}
+
+
+function constDecl1(use) {
+  return "(function() { " + use + "; const constvar = 1; });";
+}
+
+
+// Function local const, assign from eval.
+function constDecl2(use) {
+  use = "eval('(function() { " + use + " })')";
+  return "(function() { const constvar = 1; " + use + "; })();";
+}
+
+
+function constDecl3(use) {
+  use = "eval('(function() { " + use + " })')";
+  return "(function() { " + use + "; const constvar = 1; })();";
+}
+
+
+// Block local const.
+function constDecl4(use) {
+  return "(function() { { const constvar = 1; " + use + "; } });";
+}
+
+
+function constDecl5(use) {
+  return "(function() { { " + use + "; const constvar = 1; } });";
+}
+
+
+// Block local const, assign from eval.
+function constDecl6(use) {
+  use = "eval('(function() {" + use + "})')";
+  return "(function() { { const constvar = 1; " + use + "; } })();";
+}
+
+
+function constDecl7(use) {
+  use = "eval('(function() {" + use + "})')";
+  return "(function() { { " + use + "; const constvar = 1; } })();";
+}
+
+
+// Function expression name.
+function constDecl8(use) {
+  return "(function constvar() { " + use + "; });";
+}
+
+
+// Function expression name, assign from eval.
+function constDecl9(use) {
+  use = "eval('(function(){" + use + "})')";
+  return "(function constvar() { " + use + "; })();";
+}
+
+let decls = [ constDecl0,
+              constDecl1,
+              constDecl2,
+              constDecl3,
+              constDecl4,
+              constDecl5,
+              constDecl6,
+              constDecl7,
+              constDecl8,
+              constDecl9
+              ];
+let uses = [ 'constvar = 1;',
+             'constvar += 1;',
+             '++constvar;',
+             'constvar++;'
+             ];
+
+function Test(d,u) {
+  'use strict';
+  try {
+    print(d(u));
+    eval(d(u));
+  } catch (e) {
+    assertInstanceof(e, SyntaxError);
+    assertTrue(e.toString().indexOf("Assignment to constant variable") >= 0);
+    return;
+  }
+  assertUnreachable();
+}
+
+for (var d = 0; d < decls.length; ++d) {
+  for (var u = 0; u < uses.length; ++u) {
+    Test(decls[d], uses[u]);
+  }
+}