Added validation for regex literals via RegExp constructor

src/compiler/diagnosticMessages.json

@@ -859,6 +859,10 @@
         "category": "Error",
         "code": 1261
     },
+    "Invalid regular expression literal: '{0}'.": {
+        "category": "Error",
+        "code": 1262
+    },
     "'with' statements are not allowed in an async function block.": {
         "category": "Error",
         "code": 1300

src/compiler/parser.ts

@@ -2370,6 +2370,12 @@ namespace ts {
                     const tokenText = scanner.getTokenText();
                     (<TemplateLiteralLikeNode>node).rawText = tokenText.substring(1, tokenText.length - (scanner.isUnterminated() ? 0 : isLast ? 1 : 2));
                     break;
+
+                case SyntaxKind.RegularExpressionLiteral:
+                    if (!isValidRegularExpressionLiteral(node.text)) {
+                        parseErrorAtCurrentToken(Diagnostics.Invalid_regular_expression_literal_Colon_0, node.text);
+                    }
+                    break;
             }
 
             if (scanner.hasExtendedUnicodeEscape()) {
@@ -2396,6 +2402,16 @@ namespace ts {
             return node;
         }
 
+        function isValidRegularExpressionLiteral(text: string) {
+            try {
+                new RegExp(text);
+                return true;
+            }
+            catch {
+                return false;
+            }
+        }
+
         // TYPES
 
         function parseTypeReference(): TypeReferenceNode {

tests/baselines/reference/parser579071.errors.txt

@@ -0,0 +1,7 @@
+tests/cases/conformance/parser/ecmascript5/RegressionTests/parser579071.ts(1,9): error TS1262: Invalid regular expression literal: '/fo(o/'.
+
+
+==== tests/cases/conformance/parser/ecmascript5/RegressionTests/parser579071.ts (1 errors) ====
+    var x = /fo(o/;
+            ~~~~~~
+!!! error TS1262: Invalid regular expression literal: '/fo(o/'.

tests/baselines/reference/parserRegularExpressionDivideAmbiguity4.errors.txt

@@ -1,12 +1,15 @@
 tests/cases/conformance/parser/ecmascript5/RegularExpressions/parserRegularExpressionDivideAmbiguity4.ts(1,1): error TS2304: Cannot find name 'foo'.
+tests/cases/conformance/parser/ecmascript5/RegularExpressions/parserRegularExpressionDivideAmbiguity4.ts(1,5): error TS1262: Invalid regular expression literal: '/notregexp);'.
 tests/cases/conformance/parser/ecmascript5/RegularExpressions/parserRegularExpressionDivideAmbiguity4.ts(1,6): error TS1161: Unterminated regular expression literal.
 tests/cases/conformance/parser/ecmascript5/RegularExpressions/parserRegularExpressionDivideAmbiguity4.ts(1,17): error TS1005: ')' expected.
 
 
-==== tests/cases/conformance/parser/ecmascript5/RegularExpressions/parserRegularExpressionDivideAmbiguity4.ts (3 errors) ====
+==== tests/cases/conformance/parser/ecmascript5/RegularExpressions/parserRegularExpressionDivideAmbiguity4.ts (4 errors) ====
     foo(/notregexp);
     ~~~
 !!! error TS2304: Cannot find name 'foo'.
+        ~~~~~~~~~~~~
+!!! error TS1262: Invalid regular expression literal: '/notregexp);'.
 
 !!! error TS1161: Unterminated regular expression literal.