--- a/js/src/frontend/BytecodeEmitter.cpp
+++ b/js/src/frontend/BytecodeEmitter.cpp
@@ -1674,40 +1674,28 @@ BindNameToSlotHelper(ExclusiveContext *c
         MOZ_ASSERT(dn->isDefn());
         pn->pn_dflags |= (dn->pn_dflags & PND_CONST);
     } else if (pn->isDefn()) {
         dn = (Definition *) pn;
     } else {
         return true;
     }
 
-    /*
-     * Turn attempts to mutate const-declared bindings into get ops (for
-     * pre-increment and pre-decrement ops, our caller will have to emit
-     * JSOP_POS, JSOP_ONE, and JSOP_ADD as well).
-     *
-     * Turn JSOP_DELNAME into JSOP_FALSE if dn is known, as all declared
-     * bindings visible to the compiler are permanent in JS unless the
-     * declaration originates at top level in eval code.
-     */
+    // Throw an error on attempts to mutate const-declared bindings.
     switch (op) {
       case JSOP_NAME:
       case JSOP_SETCONST:
         break;
       default:
         if (pn->isConst()) {
-            if (bce->sc->needStrictChecks()) {
-                JSAutoByteString name;
-                if (!AtomToPrintableString(cx, pn->pn_atom, &name) ||
-                    !bce->reportStrictModeError(pn, JSMSG_READ_ONLY, name.ptr()))
-                {
-                    return false;
-                }
-            }
-            pn->setOp(op = JSOP_NAME);
+            JSAutoByteString name;
+            if (!AtomToPrintableString(cx, pn->pn_atom, &name))
+                return false;
+            bce->reportError(pn, JSMSG_BAD_CONST_ASSIGN, name.ptr());
+            return false;
         }
     }
 
     if (dn->pn_cookie.isFree()) {
         if (HandleScript caller = bce->evalCaller) {
             MOZ_ASSERT(bce->script->compileAndGo());
 
             /*
@@ -3312,20 +3300,16 @@ EmitDestructuringLHS(ExclusiveContext *c
         MOZ_ASSERT(pn->getOp() == JSOP_SETLOCAL || pn->getOp() == JSOP_INITLEXICAL);
         MOZ_ASSERT(pn->pn_dflags & PND_BOUND);
     } else {
         switch (pn->getKind()) {
           case PNK_NAME:
             if (!BindNameToSlot(cx, bce, pn))
                 return false;
 
-            // Allow 'const [x,y] = o', make 'const x,y; [x,y] = o' a nop.
-            if (pn->isConst() && !pn->isDefn())
-                return Emit1(cx, bce, JSOP_POP) >= 0;
-
             switch (pn->getOp()) {
               case JSOP_SETNAME:
               case JSOP_SETGNAME:
               case JSOP_SETCONST: {
                 // This is like ordinary assignment, but with one difference.
                 //
                 // In `a = b`, we first determine a binding for `a` (using
                 // JSOP_BINDNAME or JSOP_BINDGNAME), then we evaluate `b`, then
@@ -4081,23 +4065,16 @@ EmitAssignment(ExclusiveContext *cx, Byt
         }
         if (Emit1(cx, bce, op) < 0)
             return false;
     }
 
     /* Finally, emit the specialized assignment bytecode. */
     switch (lhs->getKind()) {
       case PNK_NAME:
-        if (lhs->isConst()) {
-            if (!rhs) {
-                bce->reportError(lhs, JSMSG_BAD_FOR_LEFTSIDE);
-                return false;
-            }
-            break;
-        }
         if (lhs->isOp(JSOP_SETARG) || lhs->isOp(JSOP_SETLOCAL) || lhs->isOp(JSOP_SETALIASEDVAR)) {
             if (!EmitVarOp(cx, lhs, lhs->getOp(), bce))
                 return false;
         } else {
             if (!EmitIndexOp(cx, lhs->getOp(), atomIndex, bce))
                 return false;
         }
         break;

--- a/js/src/jit-test/tests/asm.js/testGlobals.js
+++ b/js/src/jit-test/tests/asm.js/testGlobals.js
@@ -8,25 +8,19 @@ assertEq(asmLink(asmCompile(USE_ASM + "v
 assertEq(asmLink(asmCompile(USE_ASM + "const i=42; function f(){ return i|0 } return f"))(), 42);
 assertEq(asmLink(asmCompile(USE_ASM + "var i=4.2; function f(){ return +i } return f"))(), 4.2);
 assertEq(asmLink(asmCompile(USE_ASM + "const i=4.2; function f(){ return +i } return f"))(), 4.2);
 assertAsmTypeFail(USE_ASM + "var i=42; function f(){ return +(i+.1) } return f");
 assertAsmTypeFail(USE_ASM + "const i=42; function f(){ return +(i+.1) } return f");
 assertAsmTypeFail(USE_ASM + "var i=1.2; function f(){ return i|0 } return f");
 assertAsmTypeFail(USE_ASM + "const i=1.2; function f(){ return i|0 } return f");
 assertAsmTypeFail(USE_ASM + "var i=0; function f(e){ e=+e; i=e } return f");
-assertAsmTypeFail(USE_ASM + "const i=0; function f(e){ e=+e; i=e } return f");
 assertAsmTypeFail(USE_ASM + "var d=0.1; function f(i){ i=i|0; d=i } return f");
-assertAsmTypeFail(USE_ASM + "const d=0.1; function f(i){ i=i|0; d=i } return f");
 assertEq(asmLink(asmCompile(USE_ASM + "var i=13; function f(j) { j=j|0; i=j; return i|0 } return f"))(42), 42);
-assertAsmTypeFail(USE_ASM + "const i=13; function f(j) { j=j|0; i=j; return i|0 } return f");
-assertAsmTypeFail(USE_ASM + "const c=0,i=13; function f(j) { j=j|0; i=j; return i|0 } return f");
 assertEq(asmLink(asmCompile(USE_ASM + "var d=.1; function f(e) { e=+e; d=e; return +e } return f"))(42.1), 42.1);
-assertAsmTypeFail(USE_ASM + "const d=.1; function f(e) { e=+e; d=e; return +e } return f");
-assertAsmTypeFail(USE_ASM + "const c=0, d=.1; function f(e) { e=+e; d=e; return +e } return f");
 assertEq(asmLink(asmCompile(USE_ASM + "var i=13; function f(i, j) { i=i|0; j=j|0; i=j; return i|0 } return f"))(42,43), 43);
 assertEq(asmLink(asmCompile(USE_ASM + "var i=13; function f(j) { j=j|0; var i=0; i=j; return i|0 } return f"))(42), 42);
 
 var f = asmLink(asmCompile(USE_ASM + "var i=13; function f(j) { j=j|0; if ((j|0) != -1) { i=j } else { return i|0 } return 0 } return f"));
 assertEq(f(-1), 13);
 assertEq(f(42), 0);
 assertEq(f(-1), 42);
 
@@ -56,17 +50,16 @@ assertAsmTypeFail('global', USE_ASM + "v
 assertAsmTypeFail('global', USE_ASM + "const i=global; function f() { return i|0 } return f");
 assertAsmTypeFail('global', USE_ASM + "var i=global|0; function f() { return i|0 } return f");
 assertAsmTypeFail('global', USE_ASM + "const i=global|0; function f() { return i|0 } return f");
 assertAsmTypeFail('global', USE_ASM + "var j=0;var i=j.i|0; function f() { return i|0 } return f");
 assertAsmTypeFail('global', USE_ASM + "var i=global.i|0; function f() { return i|0 } return f");
 assertAsmTypeFail('global', USE_ASM + "const i=global.i|0; function f() { return i|0 } return f");
 assertAsmTypeFail('global', USE_ASM + "var i=global.i|0; function f() { return i|0 } return f");
 assertAsmTypeFail('global', USE_ASM + 'var i=global.Infinity; function f() { i = 0.0 } return f');
-assertAsmTypeFail('global', USE_ASM + 'const i=global.Infinity; function f() { i = 0.0 } return f');
 assertAsmLinkAlwaysFail(asmCompile('global', USE_ASM + 'var i=global.Infinity; function f() { return +i } return f'), undefined);
 assertAsmLinkAlwaysFail(asmCompile('global', USE_ASM + 'const i=global.Infinity; function f() { return +i } return f'), undefined);
 assertAsmLinkAlwaysFail(asmCompile('global', USE_ASM + 'var i=global.Infinity; function f() { return +i } return f'), null);
 assertAsmLinkAlwaysFail(asmCompile('global', USE_ASM + 'const i=global.Infinity; function f() { return +i } return f'), null);
 assertAsmLinkFail(asmCompile('global', USE_ASM + 'var i=global.Infinity; function f() { return +i } return f'), 3);
 assertAsmLinkFail(asmCompile('global', USE_ASM + 'var i=global.Infinity; function f() { return +i } return f'), {});
 assertAsmLinkFail(asmCompile('global', USE_ASM + 'var i=global.Infinity; function f() { return +i } return f'), {Infinity:NaN});
 assertAsmLinkFail(asmCompile('global', USE_ASM + 'var i=global.Infinity; function f() { return +i } return f'), {Infinity:-Infinity});

--- a/js/src/jit-test/tests/basic/bug673731.js
+++ b/js/src/jit-test/tests/basic/bug673731.js
@@ -1,3 +1,3 @@
 // |jit-test| error: ReferenceError
 
-const IS_TOKEN_ARRAY = [ printBugNumber && IS_TOKEN_ARRAY++ && this() ? this() : this() ];
+const IS_TOKEN_ARRAY = [ printBugNumber && this() ? this() : this() ];

--- a/js/src/jit-test/tests/basic/bug821470.js
+++ b/js/src/jit-test/tests/basic/bug821470.js
@@ -1,8 +1,8 @@
 load(libdir + "asserts.js");
 
 assertThrowsInstanceOf(function () {
     eval("function x() { 'use strict'; const x = 4; x = 3; }");
-}, TypeError);
+}, SyntaxError);
 assertThrowsInstanceOf(function () {
     Function("'use strict'; const x = x = 5;");
-}, TypeError)
+}, SyntaxError)

new file mode 100644
--- /dev/null
+++ b/js/src/jit-test/tests/basic/constAssignError.js
@@ -0,0 +1,23 @@
+// Can't assign to const
+
+load(libdir + 'asserts.js');
+
+function assertSyntaxError(str) {
+  assertThrowsInstanceOf(function () { eval(str); }, SyntaxError);
+}
+
+assertSyntaxError("(function() { const x = 3; (function() x++)(); return x })");
+assertSyntaxError("(function() { const x = 3; (function() x++)(); return x++ })");
+assertSyntaxError("(function() { const x = 2; (function() x++)(); return ++x })");
+assertSyntaxError("(function() { const x = 2; (function() x++)(); return x += 1 })");
+
+assertSyntaxError("(function() { const x = 3; x = 1; return (function() { return x})() })");
+assertSyntaxError("(function() { const x = 3; x = 1; return (function() { return x})() })");
+assertSyntaxError("(function() { const x = 3; x++; return (function() { return x})() })");
+assertSyntaxError("(function() { const x = 3; ++x; return (function() { return x})() })");
+assertSyntaxError("(function() { const x = 3; x--; return (function() { return x})() })");
+assertSyntaxError("(function() { const x = 3; --x; return (function() { return x})() })");
+assertSyntaxError("(function() { const x = 3; x += 1; return (function() { return x})() })");
+assertSyntaxError("(function() { const x = 3; x -= 1; return (function() { return x})() })");
+
+assertSyntaxError("(function() { const x = 3; [x] = [1]; })");

new file mode 100644
--- /dev/null
+++ b/js/src/jit-test/tests/basic/constGlobalAssignError.js
@@ -0,0 +1,3 @@
+// |jit-test| error: SyntaxError
+
+const x = 1; x = 2;

--- a/js/src/jit-test/tests/basic/testDynamicUsage.js
+++ b/js/src/jit-test/tests/basic/testDynamicUsage.js
@@ -3,30 +3,16 @@ assertEq((function() { var g = function(
 assertEq((function() { var x; x = 3; return (function() { return x } )() })(), 3);
 assertEq((function() { x = 3; var x; return (function() { return x } )() })(), 3);
 assertEq((function() { var x; var g = function() { return x }; x = 3; return g() })(), 3);
 
 assertEq((function() { function f() { return 3 }; assertEq(f(), 3); return (function() f())() })(), 3);
 assertEq((function() { function f() { return 3 }; assertEq(f(), 3); return eval('f()') })(), 3);
 assertEq((function() { function f() { return 3 }; (function() f())(); return f() })(), 3);
 
-assertEq((function() { const x = 3; (function() x++)(); return x })(), 3);
-assertEq((function() { const x = 3; (function() x++)(); return x++ })(), 3);
-assertEq((function() { const x = 2; (function() x++)(); return ++x })(), 3);
-assertEq((function() { const x = 2; (function() x++)(); return x += 1 })(), 3);
-
-assertEq((function() { const x = 3; x = 1; return (function() { return x})() })(), 3);
-assertEq((function() { const x = 3; x = 1; return (function() { return x})() })(), 3);
-assertEq((function() { const x = 3; x++; return (function() { return x})() })(), 3);
-assertEq((function() { const x = 3; ++x; return (function() { return x})() })(), 3);
-assertEq((function() { const x = 3; x--; return (function() { return x})() })(), 3);
-assertEq((function() { const x = 3; --x; return (function() { return x})() })(), 3);
-assertEq((function() { const x = 3; x += 1; return (function() { return x})() })(), 3);
-assertEq((function() { const x = 3; x -= 1; return (function() { return x})() })(), 3);
-
 assertEq((function() { var x = 3; return eval("x") })(), 3);
 assertEq((function() { var x; x = 3; return eval("x") })(), 3);
 assertEq((function() { x = 3; var x; return eval("x") })(), 3);
 
 assertEq((function() { var x; (function() {x = 2})(); return ++x })(), 3);
 assertEq((function() { var x; (function() {x = 2})(); x++; return x })(), 3);
 assertEq((function() { var x; (function() {x = 4})(); return --x })(), 3);
 assertEq((function() { var x; (function() {x = 4})(); x--; return x })(), 3);

--- a/js/src/jit-test/tests/saved-stacks/gc-frame-cache.js
+++ b/js/src/jit-test/tests/saved-stacks/gc-frame-cache.js
@@ -4,17 +4,17 @@
 const FUZZ_FACTOR = 3;
 
 function assertAboutEq(actual, expected) {
   if (Math.abs(actual - expected) > FUZZ_FACTOR)
     throw new Error("Assertion failed: expected about " + expected + ", got " + actual +
                     ". FUZZ_FACTOR = " + FUZZ_FACTOR);
 }
 
-const stacks = [];
+var stacks = [];
 
 stacks.push(saveStack());
 stacks.push(saveStack());
 stacks.push(saveStack());
 stacks.push(saveStack());
 stacks.push(saveStack());
 stacks.push(saveStack());
 stacks.push(saveStack());

--- a/js/src/js.msg
+++ b/js/src/js.msg
@@ -176,16 +176,17 @@ MSG_DEF(JSMSG_ACCESSOR_WRONG_ARGS,     3
 MSG_DEF(JSMSG_ARGUMENTS_AND_REST,      0, JSEXN_SYNTAXERR, "'arguments' object may not be used in conjunction with a rest parameter")
 MSG_DEF(JSMSG_ARRAY_COMP_LEFTSIDE,     0, JSEXN_SYNTAXERR, "invalid array comprehension left-hand side")
 MSG_DEF(JSMSG_ARRAY_INIT_TOO_BIG,      0, JSEXN_INTERNALERR, "array initialiser too large")
 MSG_DEF(JSMSG_AS_AFTER_RESERVED_WORD,  1, JSEXN_SYNTAXERR, "missing keyword 'as' after reserved word '{0}'")
 MSG_DEF(JSMSG_BAD_ANON_GENERATOR_RETURN, 0, JSEXN_TYPEERR, "anonymous generator function returns a value")
 MSG_DEF(JSMSG_BAD_ARROW_ARGS,          0, JSEXN_SYNTAXERR, "invalid arrow-function arguments (parentheses around the arrow-function may help)")
 MSG_DEF(JSMSG_BAD_BINDING,             1, JSEXN_SYNTAXERR, "redefining {0} is deprecated")
 MSG_DEF(JSMSG_BAD_CONST_DECL,          0, JSEXN_SYNTAXERR, "missing = in const declaration")
+MSG_DEF(JSMSG_BAD_CONST_ASSIGN,        1, JSEXN_SYNTAXERR, "invalid assignment to const {0}")
 MSG_DEF(JSMSG_BAD_CONTINUE,            0, JSEXN_SYNTAXERR, "continue must be inside loop")
 MSG_DEF(JSMSG_BAD_DESTRUCT_ASS,        0, JSEXN_REFERENCEERR, "invalid destructuring assignment operator")
 MSG_DEF(JSMSG_BAD_DESTRUCT_TARGET,     0, JSEXN_SYNTAXERR, "invalid destructuring target")
 MSG_DEF(JSMSG_BAD_DESTRUCT_DECL,       0, JSEXN_SYNTAXERR, "missing = in destructuring declaration")
 MSG_DEF(JSMSG_BAD_DUP_ARGS,            0, JSEXN_SYNTAXERR, "duplicate argument names not allowed in this context")
 MSG_DEF(JSMSG_BAD_FOR_EACH_LOOP,       0, JSEXN_SYNTAXERR, "invalid for each loop")
 MSG_DEF(JSMSG_BAD_FOR_LEFTSIDE,        0, JSEXN_SYNTAXERR, "invalid for/in left-hand side")
 MSG_DEF(JSMSG_BAD_GENERATOR_RETURN,    1, JSEXN_TYPEERR, "generator function {0} returns a value")

--- a/js/src/tests/js1_5/Regress/regress-383674.js
+++ b/js/src/tests/js1_5/Regress/regress-383674.js
@@ -14,42 +14,42 @@ var expect = '';
 test();
 //-----------------------------------------------------------------------------
 
 function test()
 {
   enterFunc ('test');
   printBugNumber(BUGNUMBER);
   printStatus (summary);
-    
+
   options("strict");
   options("werror");
 
   expect = 'toString called';
   actual = 'toString not called';
   try
   {
-    var x = {toString: function() { 
-        actual = 'toString called'; 
-        print(actual); 
-      } 
-    }; 
+    var x = {toString: function() {
+        actual = 'toString called';
+        print(actual);
+      }
+    };
     var f = function() { var j = x; j + ""; }
     f();
     reportCompare(expect, actual, summary + ': 1');
   }
   catch(ex)
   {
     reportCompare("No Error", ex + "", summary + ': 1');
   }
 
   actual = 'toString not called';
   try
   {
-    (function() { const a = 
+    (function() { var a =
          ({toString: function(){
              actual = 'toString called'; print(actual)} }); a += ""; })();
     reportCompare(expect, actual, summary + ': 2');
   }
   catch(ex)
   {
     reportCompare("No Error", ex + "", summary + ': 2');
   }

--- a/js/src/tests/js1_5/extensions/regress-452565.js
+++ b/js/src/tests/js1_5/extensions/regress-452565.js
@@ -9,13 +9,13 @@ var summary = 'Do not assert with JIT: !
 var actual = 'No Crash';
 var expect = 'No Crash';
 
 printBugNumber(BUGNUMBER);
 printStatus (summary);
 
 jit(true);
 
-const c = undefined; (function() { for (var j=0;j<5;++j) { c = 1; } })();
+var c = undefined; (function() { for (var j=0;j<5;++j) { c = 1; } })();
 
 jit(false);
 
 reportCompare(expect, actual, summary);

--- a/js/src/tests/js1_6/extensions/regress-465443.js
+++ b/js/src/tests/js1_6/extensions/regress-465443.js
@@ -14,18 +14,18 @@ var expect = '';
 test();
 //-----------------------------------------------------------------------------
 
 function test()
 {
   enterFunc ('test');
   printBugNumber(BUGNUMBER);
   printStatus (summary);
- 
-  expect = 'SyntaxError: invalid for/in left-hand side';
+
+  expect = 'SyntaxError: invalid assignment to const b';
 
   jit(true);
 
   try
   {
     eval('(function () { const b = 16; var out = []; for each (b in [true, "", true, "", true, ""]) out.push(b >> 1) })();');
   }
   catch(ex)

deleted file mode 100644
--- a/js/src/tests/js1_7/extensions/regress-470176.js
+++ /dev/null
@@ -1,38 +0,0 @@
-/* -*- indent-tabs-mode: nil; js-indent-level: 2 -*- */
-/* This Source Code Form is subject to the terms of the Mozilla Public
- * License, v. 2.0. If a copy of the MPL was not distributed with this
- * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
-
-//-----------------------------------------------------------------------------
-var BUGNUMBER = 470176;
-var summary = 'let-fun should not be able to modify constants';
-var actual = '';
-var expect = '';
-
-
-//-----------------------------------------------------------------------------
-test();
-//-----------------------------------------------------------------------------
-
-function test()
-{
-  enterFunc ('test');
-  printBugNumber(BUGNUMBER);
-  printStatus (summary);
- 
-  const e = 8; 
-
-  expect = e;
-
-  jit (true);
-
-  let (f = function() { for (var h=0;h<6;++h) ++e; }) { f(); }
-
-  actual = e;
-
-  jit(false);
-
-  reportCompare(expect, actual, summary);
-
-  exitFunc ('test');
-}

--- a/js/src/tests/js1_8_1/extensions/regress-437288-01.js
+++ b/js/src/tests/js1_8_1/extensions/regress-437288-01.js
@@ -15,17 +15,17 @@ test();
 //-----------------------------------------------------------------------------
 
 function test()
 {
   enterFunc ('test');
   printBugNumber(BUGNUMBER);
   printStatus (summary);
 
-  expect = 'SyntaxError: invalid for/in left-hand side';
+  expect = 'SyntaxError: invalid assignment to const x';
   try
   {
     eval('(function() { const x = 1; for (x in null); })();');
   }
   catch(ex)
   {
     actual = ex + '';
   }

deleted file mode 100644
--- a/js/src/tests/js1_8_1/regress/regress-452498-039.js
+++ /dev/null
@@ -1,35 +0,0 @@
-/* -*- indent-tabs-mode: nil; js-indent-level: 2 -*- */
-/* This Source Code Form is subject to the terms of the Mozilla Public
- * License, v. 2.0. If a copy of the MPL was not distributed with this
- * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
-
-//-----------------------------------------------------------------------------
-var BUGNUMBER = 452498;
-var summary = 'TM: upvar2 regression tests';
-var actual = '';
-var expect = '';
-
-
-//-----------------------------------------------------------------------------
-test();
-//-----------------------------------------------------------------------------
-
-function test()
-{
-  enterFunc ('test');
-  printBugNumber(BUGNUMBER);
-  printStatus (summary);
-
-  expect = '10';
-
-// ------- Comment #39 From Jesse Ruderman
-
-  const e = 0;
-  print(actual = ++e);
-
-  actual = String(actual) + e;
-
-  reportCompare(expect, actual, summary);
-
-  exitFunc ('test');
-}

--- a/js/src/tests/js1_8_1/regress/regress-452498-074.js
+++ b/js/src/tests/js1_8_1/regress/regress-452498-074.js
@@ -19,16 +19,16 @@ function test()
   enterFunc ('test');
   printBugNumber(BUGNUMBER);
   printStatus (summary);
 
   expect = '1';
 
 // ------- Comment #74 From Jesse Ruderman
 
-  const [d] = [1]; [d] = [2]; print(actual = d);
+  const [d] = [1]; print(actual = d);
 
   actual = String(actual);
 
   reportCompare(expect, actual, summary);
 
   exitFunc ('test');
 }

deleted file mode 100644
--- a/js/src/tests/js1_8_1/regress/regress-452498-077.js
+++ /dev/null
@@ -1,34 +0,0 @@
-/* -*- indent-tabs-mode: nil; js-indent-level: 2 -*- */
-/* This Source Code Form is subject to the terms of the Mozilla Public
- * License, v. 2.0. If a copy of the MPL was not distributed with this
- * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
-
-//-----------------------------------------------------------------------------
-var BUGNUMBER = 452498;
-var summary = 'TM: upvar2 regression tests';
-var actual = '';
-var expect = '';
-
-
-//-----------------------------------------------------------------------------
-test();
-//-----------------------------------------------------------------------------
-
-function test()
-{
-  enterFunc ('test');
-  printBugNumber(BUGNUMBER);
-  printStatus (summary);
-
-  expect = '1';
-
-// ------- Comment #77 From Brendan Eich
-
-  (function () { const [d] = [1]; [d] = [2]; print(actual = d);})();
-
-  actual = String(actual);
-
-  reportCompare(expect, actual, summary);
-
-  exitFunc ('test');
-}

deleted file mode 100644
--- a/js/src/tests/js1_8_1/regress/regress-452498-110.js
+++ /dev/null
@@ -1,49 +0,0 @@
-/* -*- indent-tabs-mode: nil; js-indent-level: 2 -*- */
-/* This Source Code Form is subject to the terms of the Mozilla Public
- * License, v. 2.0. If a copy of the MPL was not distributed with this
- * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
-
-//-----------------------------------------------------------------------------
-var BUGNUMBER = 452498;
-var summary = 'TM: upvar2 regression tests';
-var actual = '';
-var expect = '';
-
-
-//-----------------------------------------------------------------------------
-test();
-//-----------------------------------------------------------------------------
-
-function test()
-{
-  enterFunc ('test');
-  printBugNumber(BUGNUMBER);
-  printStatus (summary);
-
-// ------- Comment #110 From Brendan Eich
-
-// (In reply to comment #107)
-
-  function f(a) { const b = a; print(++b); return b; }
-
-  expect = 'function f(a) { const b = a; print(++b); return b; }';
-  actual = f + '';
-  compareSource(expect, actual, 'function f(a) { const b = a; print(++b); return b; }');
-
-  expect = '01';
-  actual = 0;
-
-  function g(a) { const b = a; print(actual = ++b); return b; }
-  actual = String(actual) + g(1);
-  reportCompare(expect, actual, 'function g(a) { const b = a; print(actual = ++b); return b; }');
-
-  expect = '21';
-  actual = 0;
-
-  const x = 1; print(actual = ++x);
-  actual = String(actual) + x;
-
-  reportCompare(expect, actual, 'const x = 1; print(actual = ++x); ');
-
-  exitFunc ('test');
-}

deleted file mode 100644
--- a/js/src/tests/js1_8_1/regress/regress-452498-184.js
+++ /dev/null
@@ -1,31 +0,0 @@
-/* -*- indent-tabs-mode: nil; js-indent-level: 2 -*- */
-/* This Source Code Form is subject to the terms of the Mozilla Public
- * License, v. 2.0. If a copy of the MPL was not distributed with this
- * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
-
-//-----------------------------------------------------------------------------
-var BUGNUMBER = 452498;
-var summary = 'TM: upvar2 regression tests';
-var actual = '';
-var expect = '';
-
-//-------  Comment #184  From  Jesse Ruderman
-
-//-----------------------------------------------------------------------------
-test();
-//-----------------------------------------------------------------------------
-
-function test()
-{
-  enterFunc ('test');
-  printBugNumber(BUGNUMBER);
-  printStatus (summary);
-
-  expect = '11';
-
-  const e = 8; print(actual = '' + ((e += 3)));
-
-  reportCompare(expect, actual, summary);
-
-  exitFunc ('test');
-}

--- a/js/src/tests/js1_8_1/regress/regress-452498-187.js
+++ b/js/src/tests/js1_8_1/regress/regress-452498-187.js
@@ -16,17 +16,17 @@ test();
 //-----------------------------------------------------------------------------
 
 function test()
 {
   enterFunc ('test');
   printBugNumber(BUGNUMBER);
   printStatus (summary);
 
-  expect = 'SyntaxError: invalid for/in left-hand side';
+  expect = 'SyntaxError: invalid assignment to const x';
   try
   {
     eval('const x = undefined; for (x in []);');
   }
   catch(ex)
   {
     actual = ex + '';
   }

deleted file mode 100644
--- a/js/src/tests/js1_8_5/extensions/compound-assign-const.js
+++ /dev/null
@@ -1,23 +0,0 @@
-// Any copyright is dedicated to the Public Domain.
-// http://creativecommons.org/licenses/publicdomain/
-
-//-----------------------------------------------------------------------------
-var BUGNUMBER = 730810;
-var summary = "Don't assert on compound assignment to a const";
-
-print(BUGNUMBER + ": " + summary);
-
-/**************
- * BEGIN TEST *
- **************/
-
-const x = 3;
-x += 2;
-assertEq(x, 3);
-
-/******************************************************************************/
-
-if (typeof reportCompare === "function")
-  reportCompare(true, true);
-
-print("Tests complete!");

--- a/js/src/tests/js1_8_5/regress/regress-383902.js
+++ b/js/src/tests/js1_8_5/regress/regress-383902.js
@@ -21,23 +21,23 @@ function f(a) {
 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(e.name, 'SyntaxError');
   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(e.name, 'SyntaxError');
   assertEq(4, c);
   assertEq('z' in this, false);
 }
 
 reportCompare(0, 0, "ok");