Unreviewed, reverting 265614@main.

https://bugs.webkit.org/show_bug.cgi?id=259073

Leads to a crash if there is are multiple hoisted functions by the same name <rdar://112017932>

Reverted changeset:

"[JSC] Align duplicate declaration checks in EvalDeclarationInstantiation with the spec"
https://bugs.webkit.org/show_bug.cgi?id=167837
https://commits.webkit.org/265614@main

Canonical link: https://commits.webkit.org/265915@main

JSTests/ChakraCore/test/Closures/bug_OS_2299723.baseline-jsc

@@ -1,5 +1,4 @@
-eval('var x = 5') threw 'Can't create duplicate variable in eval: 'x''
 x: 5
-eval('var y = 5') threw 'Can't create duplicate variable in eval: 'y''
+eval('var y = 5') threw 'Attempted to assign to readonly property.'
 eval('y = 5') threw 'Attempted to assign to readonly property.'
 y: 1

JSTests/stress/const-not-strict-mode.js

@@ -62,13 +62,13 @@ function foo() {
         try {
             eval("var x = 20;");
         } catch(e) {
-            threw = true;
-            assert(e.toString() === "SyntaxError: Can't create duplicate variable in eval: 'x'");
+            if (e.name.indexOf("TypeError") !== -1 && e.message.indexOf("readonly") !== -1)
+                threw = true;
         }
         assert(threw);
         assert(x === 40);
     }
-    assert(typeof x === "undefined");
+    assert(x === undefined);
 }
 
 function bar() {
@@ -87,13 +87,13 @@ function bar() {
         try {
             eval("var x = 20;");
         } catch(e) {
-            threw = true;
-            assert(e.toString() === "SyntaxError: Can't create duplicate variable in eval: 'x'");
+            if (e.name.indexOf("TypeError") !== -1 && e.message.indexOf("readonly") !== -1)
+                threw = true;
         }
         assert(threw);
         assert(x === 40);
     }
-    assert(typeof x === "undefined");
+    assert(x === undefined);
 }
 
 function baz() {

JSTests/stress/eval-func-decl-in-eval-within-catch-scope.js

@@ -1,5 +1,4 @@
 var err = new Error();
-err.e = "foo";
 
 function assert(x) {
     if (!x)
@@ -26,31 +25,7 @@ function shouldThrow(func, errorMessage) {
         throw err;
     } catch (e) {
         eval(`function e() { return 1; }`); // no error
-        assert(e === err);
     }
-    assert(e() === 1);
-})();
-
-(function() {
-    var e = 1;
-    try {
-        throw err;
-    } catch (e) {
-        eval(`if (true) { function e() { return 1; } }`); // no error
-        assert(e === err);
-    }
-    assert(e() === 1);
-})();
-
-(function() {
-    var e = 1;
-    try {
-        throw err;
-    } catch ({e}) {
-        eval(`if (true) { function e() { return 1; } }`); // no error
-        assert(e === "foo");
-    }
-    assert(e === 1);
 })();
 
 shouldThrow(function() {
@@ -61,20 +36,3 @@ shouldThrow(function() {
         eval(`function e() { return 1; }`); // syntax error
     }
 }, "SyntaxError: Can't create duplicate variable in eval: 'e'");
-
-shouldThrow(function() {
-    var e = 2;
-    try {
-        throw err;
-    } catch ({e}) {
-        eval(`var e = 1;`); // syntax error
-    }
-}, "SyntaxError: Can't create duplicate variable in eval: 'e'");
-
-shouldThrow(function() {
-    try {
-        throw err;
-    } catch ({...e}) {
-        eval(`var e;`); // syntax error
-    }
-}, "SyntaxError: Can't create duplicate variable in eval: 'e'");

JSTests/stress/eval-func-decl-in-global-of-eval.js

@@ -64,46 +64,3 @@ function foobar() {
 foobar();
 assertThrow(() => g, "ReferenceError: Can't find variable: g");
 
-(function() {
-    try {
-        let b;
-        let c;
-        eval('var a; var b; var c;');
-    } catch (e) {
-        var error = e;
-    }
-
-    assert(error.toString(), "SyntaxError: Can't create duplicate variable in eval: 'c'");
-    assertThrow(() => a, "ReferenceError: Can't find variable: a");
-    assertThrow(() => b, "ReferenceError: Can't find variable: b");
-    assertThrow(() => c, "ReferenceError: Can't find variable: c");
-})();
-
-(function() {
-    try {
-        let x1;
-        eval('function x1() {} function x2() {} function x3() {}');
-    } catch (e) {
-        var error = e;
-    }
-
-    assert(error.toString(), "SyntaxError: Can't create duplicate variable in eval: 'x1'");
-    assertThrow(() => x1, "ReferenceError: Can't find variable: x1");
-    assertThrow(() => x2, "ReferenceError: Can't find variable: x2");
-    assertThrow(() => x3, "ReferenceError: Can't find variable: x3");
-})();
-
-(function() {
-    var x3;
-    try {
-        let x2;
-        eval('function x1() {} function x2() {} function x3() {}');
-    } catch (e) {
-        var error = e;
-    }
-
-    assert(error.toString(), "SyntaxError: Can't create duplicate variable in eval: 'x2'");
-    assertThrow(() => x1, "ReferenceError: Can't find variable: x1");
-    assertThrow(() => x2, "ReferenceError: Can't find variable: x2");
-    assert(x3, undefined);
-})();

JSTests/stress/eval-func-decl-within-eval-with-reassign-to-var.js

@@ -57,8 +57,10 @@ for (var i = 0; i < 10000; i++){
     assertThrow(() => _bar, "ReferenceError: Can't find variable: _bar");
 }
 
+// Fixme:  https://bugs.webkit.org/show_bug.cgi?id=167837
 // Current test does not work because it should raise exception
 // that f could not be redeclared
+/*
 function goo() {
     {   
         var error = false;
@@ -77,14 +79,13 @@ for (var i = 0; i < 10000; i++) {
     goo();
     assert(typeof f, "undefined", "#7");
 }
+*/
 
 function hoo() {
     {
         let h = 20;
-        try { eval('var h = 15;'); } catch (e) { var evalError = e; }
-        assert(evalError.toString(), "SyntaxError: Can't create duplicate variable in eval: 'h'");
-        eval('eval("if (false) { function h() {} } ");');
-        assert(h, 20);
+        eval('var h = 15; eval(" if (false){ function h() { }; } ");');
+        assert(h, 15);
     }
     assert(typeof h, "undefined");
 }
@@ -124,8 +125,6 @@ for (var i = 0; i < 10000; i++){
 
 function loo() { 
     let h = 20; 
-    // FIXME: This should throw SyntaxError.
-    // https://bugs.webkit.org/show_bug.cgi?id=258507
     eval("var h; if (false) { function h() { } }"); 
     return h; 
 }