[MERGE #5605 @yullin-ms] Checking label lists for labels

Merge pull request #5605 from pr/yullin/continue_break_after_label

Fixes OS: 18576812
In defer parsing, when continue or break to label is in the same statement as label; check current label lists for labels.

Author: dilijev

lib/Parser/Parse.cpp

@@ -10509,25 +10509,32 @@ ParseNodePtr Parser::ParseStatement()
             else
             {
                 this->GetScanner()->Scan();
-                for (pstmt = m_pstmtCur; pstmt; pstmt = pstmt->pstmtOuter)
+                // Check if label is found within the current label id list.
+                auto checkLabelList = [&](LabelId* list, StmtNest* checkStmtOp)
                 {
-                    LabelId* pLabelId;
-                    for (pLabelId = pstmt->pLabelId; pLabelId; pLabelId = pLabelId->next)
+                    for (LabelId* pLabelId = list; pLabelId; pLabelId = pLabelId->next)
                     {
-
                         if (pid == pLabelId->pid)
                         {
                             // Found the label. Make sure we can use it. We can
                             // break out of any statement, but we can only
                             // continue loops.
                             if (fnop == fnopContinue &&
-                                !(ParseNode::Grfnop(pstmt->op) & fnop))
+                                !(ParseNode::Grfnop(checkStmtOp->op) & fnop))
                             {
                                 Error(ERRbadContinue);
                             }
-                            goto LNeedTerminator;
+                            return true;
                         }
                     }
+                    return false;
+                };
+
+                if (checkLabelList(pLabelIdList, m_pstmtCur)) goto LNeedTerminator;
+
+                for (pstmt = m_pstmtCur; pstmt; pstmt = pstmt->pstmtOuter)
+                {
+                    if (checkLabelList(pstmt->pLabelId, pstmt)) goto LNeedTerminator;
                 }
             }
             Error(ERRnoLabel);

test/Basics/Labels.js

@@ -338,6 +338,19 @@ testNoSyntaxErrorWithDanglingStaticAfterLabel=
 testRuntimeErrorWithDanglingStaticAfterLabel=
     `L: static
     x = 0`
+
+testSyntaxErrorWithContinueAfterLabel=
+    `function fn() {
+        L:
+            continue L;
+    }`
+
+testNoLabelNotFoundWithBreakAfterLabel=
+    `function fn() {
+        L:
+            break L;
+    }`
+
 
 function testModuleScript(source, message, shouldFail = false) {
     let testfunc = () => testRunner.LoadModule(source, 'samethread', shouldFail);
@@ -467,6 +480,8 @@ var tests = [
             assert.throws(() => eval(testRuntimeErrorWithDanglingAwaitAfterLabel), ReferenceError, "Expected reference error from stranded await being used after label", "'await' is not defined")
             assert.throws(() => eval(testRuntimeErrorWithDanglingStaticAfterLabel), ReferenceError, "Expected reference error from stranded static being used after label", "'static' is not defined")
             assert.doesNotThrow(() => eval(testNoSyntaxErrorWithDanglingStaticAfterLabel), "Expected no issue parsing since static is viewed as an identifier")
+            assert.throws(() => eval(testSyntaxErrorWithContinueAfterLabel), SyntaxError, "Expected syntax error from having continue outside of loop", "Can't have 'continue' outside of loop")
+            assert.doesNotThrow(() => eval(testNoLabelNotFoundWithBreakAfterLabel), "Expected no issue from finding label")
         }
     }
 ];