Strict mode early error (strict option warning) on assignment to declared const (383902, r=jwalden).

js/src/jsemit.cpp

@@ -2182,8 +2182,16 @@ BindNameToSlot(JSContext *cx, JSCodeGenerator *cg, JSParseNode *pn)
         }
         break;
       default:
-        if (pn->isConst())
+        if (pn->isConst()) {
+            if (cg->needStrictChecks()) {
+                JSAutoByteString name;
+                if (!js_AtomToPrintableString(cx, atom, &name) ||
+                    !ReportStrictModeError(cx, CG_TS(cg), cg, pn, JSMSG_READ_ONLY, name.ptr())) {
+                    return JS_FALSE;
+                }
+            }
             pn->pn_op = op = JSOP_NAME;
+        }
     }
 
     if (dn->isGlobal()) {

js/src/tests/js1_8_5/regress/jstests.list

@@ -1,4 +1,5 @@
 url-prefix ../../jsreftest.html?test=js1_8_5/regress/
+script regress-383902.js
 script regress-500528.js
 script regress-533876.js
 script regress-541255-0.js

js/src/tests/js1_8_5/regress/regress-383902.js

@@ -0,0 +1,43 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/*
+ * Any copyright is dedicated to the Public Domain.
+ * http://creativecommons.org/licenses/publicdomain/
+ */
+
+var c = 0;
+
+function f(a) {
+  const b = a;
+  try {
+    eval('"use strict"; b = 1 + a; c = 1');
+    assertEq(0, 1);
+  } catch (e) {
+    assertEq(e.name, 'TypeError');
+    assertEq(0, c);
+    assertEq(a, b);
+  }
+}
+
+var w = 42;
+f(w);
+
+c = 2;
+try {
+  eval('"use strict"; function g(x) { const y = x; y = 1 + x; } c = 3');
+  assertEq(0, 1);
+} catch (e) {
+  assertEq(e.name, 'TypeError');
+  assertEq(2, c);
+}
+
+c = 4;
+try {
+  eval('"use strict"; const z = w; z = 1 + w; c = 5');
+  assertEq(0, 1);
+} catch (e) {
+  assertEq(e.name, 'TypeError');
+  assertEq(4, c);
+  assertEq('z' in this, false);
+}
+
+reportCompare(0, 0, "ok");