[MERGE #5818 @wyrichte] Throw a syntax error when the statement of a with statement is a labeled function.

Merge pull request #5818 from wyrichte:build/wyrichte/with_label

Repro:
cmd: ch bug.js

`with ({}) L: function f(){}`

Should output a syntax error as the[ statement of a WithStatement is not allowed to be a LabelledFunction](https://tc39.github.io/ecma262/#sec-with-statement-static-semantics-early-errors), but instead Chakra does not output a syntax error.

Author: wyrichte

lib/Parser/Parse.cpp

@@ -10037,14 +10037,38 @@ ParseNodePtr Parser::ParseStatement()
         }
 
         Assert(pnode != nullptr);
-        ParseNodeFnc* pNodeFnc = (ParseNodeFnc*)pnode;
+
         if (labelledStatement)
         {
             if (IsStrictMode())
             {
                 Error(ERRFunctionAfterLabelInStrict);
             }
-            else if (pNodeFnc->IsAsync())
+            // #sec-with-statement-static-semantics-early-errors states that the Statement of
+            // a WithStatement throws a Syntax Error if the Statement is a LabelledFunction.
+            else if (m_pstmtCur && m_pstmtCur->pnodeStmt && m_pstmtCur->pnodeStmt->nop == knopWith)
+            {
+                Error(ERRStmtOfWithIsLabelledFunc);
+            }
+
+            ParseNodeFnc* pNodeFnc = nullptr;
+
+            // pnode can be a knopBlock due to ParseFncDeclCheckScope, which
+            // can return a ParseNodeBlock that contains a ParseNodeFnc.
+            if (pnode->nop == knopBlock)
+            {
+                ParseNodeBlock* pNodeBlock = pnode->AsParseNodeBlock();
+                if (pNodeBlock->pnodeStmt && pNodeBlock->pnodeStmt->nop == knopFncDecl)
+                {
+                    pNodeFnc = pNodeBlock->pnodeStmt->AsParseNodeFnc();
+                }
+            }
+            if (pNodeFnc == nullptr)
+            {
+                pNodeFnc = pnode->AsParseNodeFnc();
+            }
+
+            if (pNodeFnc->IsAsync())
             {
                 Error(ERRLabelBeforeAsyncFncDeclaration);
             }

lib/Parser/perrors.h

@@ -111,7 +111,8 @@ LSC_ERROR_MSG(1095, ERRFunctionAfterLabelInStrict, "Function declarations not al
 LSC_ERROR_MSG(1096, ERRAwaitAsLabelInAsync, "Use of 'await' as label in async function is not allowed.")
 LSC_ERROR_MSG(1097, ERRExperimental, "Use of disabled experimental feature")
 LSC_ERROR_MSG(1098, ERRDuplicateExport, "Duplicate export of name '%s'")
-//1098-1199 available for future use
+LSC_ERROR_MSG(1099, ERRStmtOfWithIsLabelledFunc, "The statement of a 'with' statement cannot be a labelled function.")
+//1100-1199 available for future use
 
 // Generic errors intended to be re-usable
 LSC_ERROR_MSG(1200, ERRKeywordAfter, "Unexpected keyword '%s' after '%s'")

test/Function/LabelFuncAsWithStmt.baseline

@@ -0,0 +1,2 @@
+SyntaxError: The statement of a 'with' statement cannot be a labelled function.
+	at code (LabelFuncAsWithStmt.js:7:1)

test/Function/LabelFuncAsWithStmt.js

@@ -0,0 +1,6 @@
+//-------------------------------------------------------------------------------------------------------
+// Copyright (C) Microsoft. All rights reserved.
+// Licensed under the MIT license. See LICENSE.txt file in the project root for full license information.
+//-------------------------------------------------------------------------------------------------------
+
+with ({}) L: function f() { }