Changeset 217200 in webkit

Timestamp:

May 21, 2017 10:47:33 PM (7 years ago)

Author:

sbarati@apple.com

Message:

We incorrectly throw a syntax error when declaring a top level for-loop iteration variable the same as a parameter
​https://bugs.webkit.org/show_bug.cgi?id=171041
<rdar://problem/32082516>

Reviewed by Yusuke Suzuki.

JSTests:

• stress/lexical-scoping-for-loop.js: Added.

(assert):
(test1):
(test2):
(test3):
(test4):
(test5):
(test6):
(let.test7):
(let.test8):
(let.test9):
(let.test10):
(let.test11):
(let.test12):

Source/JavaScriptCore:

We were treating a for-loop variable declaration potentially as a top
level statement, e.g, in a program like this:
`
function foo() {

for (let variable of expr) { }

}
`
But we should not be. This had the consequence of making this type of program
throw a syntax error:
`
function foo(arg) {

for (let arg of expr) { }

}
`
even though it should not. The fix is simple, we just need to increment the
statement depth before parsing anything inside the for loop.

• parser/Parser.cpp:

(JSC::Parser<LexerType>::parseForStatement):

LayoutTests:

• js/parser-syntax-check-expected.txt:
• js/script-tests/parser-syntax-check.js:

Location:

trunk

Files:

• JSTests/ChangeLog (modified) (1 diff)
• JSTests/stress/lexical-scoping-for-loop.js (added)
• LayoutTests/ChangeLog (modified) (1 diff)
• LayoutTests/js/parser-syntax-check-expected.txt (modified) (1 diff)
• LayoutTests/js/script-tests/parser-syntax-check.js (modified) (1 diff)
• Source/JavaScriptCore/ChangeLog (modified) (1 diff)
• Source/JavaScriptCore/parser/Parser.cpp (modified) (1 diff)

trunk/JSTests/ChangeLog

@@ +1 @@
+2017-05-21  Saam Barati  <sbarati@apple.com>
+
+        We incorrectly throw a syntax error when declaring a top level for-loop iteration variable the same as a parameter
+        https://bugs.webkit.org/show_bug.cgi?id=171041
+        <rdar://problem/32082516>
+
+        Reviewed by Yusuke Suzuki.
+
+        * stress/lexical-scoping-for-loop.js: Added.
+        (assert):
+        (test1):
+        (test2):
+        (test3):
+        (test4):
+        (test5):
+        (test6):
+        (let.test7):
+        (let.test8):
+        (let.test9):
+        (let.test10):
+        (let.test11):
+        (let.test12):
+
 2017-05-19  Yusuke Suzuki  <utatane.tea@gmail.com>
 

trunk/LayoutTests/ChangeLog

@@ +1 @@
+2017-05-21  Saam Barati  <sbarati@apple.com>
+
+        We incorrectly throw a syntax error when declaring a top level for-loop iteration variable the same as a parameter
+        https://bugs.webkit.org/show_bug.cgi?id=171041
+        <rdar://problem/32082516>
+
+        Reviewed by Yusuke Suzuki.
+
+        * js/parser-syntax-check-expected.txt:
+        * js/script-tests/parser-syntax-check.js:
+
 2017-05-21  Antti Koivisto  <antti@apple.com>
 

trunk/LayoutTests/js/parser-syntax-check-expected.txt

@@ -557 +557 @@
 PASS Invalid: "for (let {i} = 20 in b) { }". Produced the following syntax error: "SyntaxError: Cannot assign to the loop variable inside a for-in loop header."
 PASS Invalid: "function f() { for (let {i} = 20 in b) { } }". Produced the following syntax error: "SyntaxError: Cannot assign to the loop variable inside a for-in loop header."
+PASS Valid:   "function x(i) { for (let i in {}) { } }"
+PASS Valid:   "function f() { function x(i) { for (let i in {}) { } } }"
+PASS Valid:   "function x(i) { for (let i of []) { } }"
+PASS Valid:   "function f() { function x(i) { for (let i of []) { } } }"
+PASS Valid:   "function x(i) { for (let i of []) { } }"
+PASS Valid:   "function f() { function x(i) { for (let i of []) { } } }"
+PASS Valid:   "function x(i) { for (let i; false; ) { } }"
+PASS Valid:   "function f() { function x(i) { for (let i; false; ) { } } }"
+PASS Valid:   "let f = (i) => { for (let i in {}) { } }"
+PASS Valid:   "function f() { let f = (i) => { for (let i in {}) { } } }"
+PASS Valid:   "let f = (i) => { for (let i of []) { } }"
+PASS Valid:   "function f() { let f = (i) => { for (let i of []) { } } }"
+PASS Valid:   "let f = (i) => { for (let i of []) { } }"
+PASS Valid:   "function f() { let f = (i) => { for (let i of []) { } } }"
+PASS Valid:   "let f = (i) => { for (let i; false; ) { } }"
+PASS Valid:   "function f() { let f = (i) => { for (let i; false; ) { } } }"
+PASS Valid:   "function* x(i) { for (let i in {}) { } }"
+PASS Valid:   "function f() { function* x(i) { for (let i in {}) { } } }"
+PASS Valid:   "function* x(i) { for (let i of []) { } }"
+PASS Valid:   "function f() { function* x(i) { for (let i of []) { } } }"
+PASS Valid:   "function* x(i) { for (let i of []) { } }"
+PASS Valid:   "function f() { function* x(i) { for (let i of []) { } } }"
+PASS Valid:   "function* x(i) { for (let i; false; ) { } }"
+PASS Valid:   "function f() { function* x(i) { for (let i; false; ) { } } }"
+PASS Valid:   "function x(i) { for (const i in {}) { } }"
+PASS Valid:   "function f() { function x(i) { for (const i in {}) { } } }"
+PASS Valid:   "function x(i) { for (const i of []) { } }"
+PASS Valid:   "function f() { function x(i) { for (const i of []) { } } }"
+PASS Valid:   "function x(i) { for (const i of []) { } }"
+PASS Valid:   "function f() { function x(i) { for (const i of []) { } } }"
+PASS Valid:   "function x(i) { for (const i = 20; false; ) { } }"
+PASS Valid:   "function f() { function x(i) { for (const i = 20; false; ) { } } }"
+PASS Valid:   "let f = (i) => { for (const i in {}) { } }"
+PASS Valid:   "function f() { let f = (i) => { for (const i in {}) { } } }"
+PASS Valid:   "let f = (i) => { for (const i of []) { } }"
+PASS Valid:   "function f() { let f = (i) => { for (const i of []) { } } }"
+PASS Valid:   "let f = (i) => { for (const i of []) { } }"
+PASS Valid:   "function f() { let f = (i) => { for (const i of []) { } } }"
+PASS Valid:   "let f = (i) => { for (const i = 20; false; ) { } }"
+PASS Valid:   "function f() { let f = (i) => { for (const i = 20; false; ) { } } }"
+PASS Valid:   "function* x(i) { for (const i in {}) { } }"
+PASS Valid:   "function f() { function* x(i) { for (const i in {}) { } } }"
+PASS Valid:   "function* x(i) { for (const i of []) { } }"
+PASS Valid:   "function f() { function* x(i) { for (const i of []) { } } }"
+PASS Valid:   "function* x(i) { for (const i of []) { } }"
+PASS Valid:   "function f() { function* x(i) { for (const i of []) { } } }"
+PASS Valid:   "function* x(i) { for (const i = 20; false; ) { } }"
+PASS Valid:   "function f() { function* x(i) { for (const i = 20; false; ) { } } }"
 try statement
 PASS Invalid: "try { break } catch(e) {}". Produced the following syntax error: "SyntaxError: 'break' is only valid inside a switch or loop statement."

trunk/LayoutTests/js/script-tests/parser-syntax-check.js

@@ -372 +372 @@
 invalid("for (const {i} = 20 in b) { }");
 invalid("for (let {i} = 20 in b) { }");
+valid("function x(i) { for (let i in {}) { } }");
+valid("function x(i) { for (let i of []) { } }");
+valid("function x(i) { for (let i of []) { } }");
+valid("function x(i) { for (let i; false; ) { } }");
+valid("let f = (i) => { for (let i in {}) { } }");
+valid("let f = (i) => { for (let i of []) { } }");
+valid("let f = (i) => { for (let i of []) { } }");
+valid("let f = (i) => { for (let i; false; ) { } }");
+valid("function* x(i) { for (let i in {}) { } }");
+valid("function* x(i) { for (let i of []) { } }");
+valid("function* x(i) { for (let i of []) { } }");
+valid("function* x(i) { for (let i; false; ) { } }");
+valid("function x(i) { for (const i in {}) { } }");
+valid("function x(i) { for (const i of []) { } }");
+valid("function x(i) { for (const i of []) { } }");
+valid("function x(i) { for (const i = 20; false; ) { } }");
+valid("let f = (i) => { for (const i in {}) { } }");
+valid("let f = (i) => { for (const i of []) { } }");
+valid("let f = (i) => { for (const i of []) { } }");
+valid("let f = (i) => { for (const i = 20; false; ) { } }");
+valid("function* x(i) { for (const i in {}) { } }");
+valid("function* x(i) { for (const i of []) { } }");
+valid("function* x(i) { for (const i of []) { } }");
+valid("function* x(i) { for (const i = 20; false; ) { } }");
 
 debug  ("try statement");

trunk/Source/JavaScriptCore/ChangeLog

@@ +1 @@
+2017-05-21  Saam Barati  <sbarati@apple.com>
+
+        We incorrectly throw a syntax error when declaring a top level for-loop iteration variable the same as a parameter
+        https://bugs.webkit.org/show_bug.cgi?id=171041
+        <rdar://problem/32082516>
+
+        Reviewed by Yusuke Suzuki.
+
+        We were treating a for-loop variable declaration potentially as a top
+        level statement, e.g, in a program like this:
+        ```
+        function foo() {
+            for (let variable of expr) { }
+        }
+        ```
+        But we should not be. This had the consequence of making this type of program
+        throw a syntax error:
+        ```
+        function foo(arg) {
+            for (let arg of expr) { }
+        }
+        ```
+        even though it should not. The fix is simple, we just need to increment the
+        statement depth before parsing anything inside the for loop.
+
+        * parser/Parser.cpp:
+        (JSC::Parser<LexerType>::parseForStatement):
+
 2017-05-19  Yusuke Suzuki  <utatane.tea@gmail.com>
 

trunk/Source/JavaScriptCore/parser/Parser.cpp

@@ -1134 +1134 @@
     int startLine = tokenLine();
     next();
+
+    DepthManager statementDepth(&m_statementDepth);
+    m_statementDepth++;
+
     handleProductionOrFail(OPENPAREN, "(", "start", "for-loop header");
     int nonLHSCount = m_parserState.nonLHSCount;