[parser] Disallow numeric separator in unicode scape sequences (#10468)

* [parser] Disallow numeric separator in unicode scape sequences (#10460)

* raise error only when numeric separator plugin is set

* Adds argument for checking numeric separator

* Fix condition for readability

* Add test for hex escape sequence and rephrase error message

* Remove exposure for allowNumSeparator in readHexChar method

packages/babel-parser/src/tokenizer/index.js

@@ -880,7 +880,11 @@ export default class Tokenizer extends LocationParser {
   // were read, the integer value otherwise. When `len` is given, this
   // will return `null` unless the integer has exactly `len` digits.
 
-  readInt(radix: number, len?: number): number | null {
+  readInt(
+    radix: number,
+    len?: number,
+    allowNumSeparator: boolean = true,
+  ): number | null {
     const start = this.state.pos;
     const forbiddenSiblings =
       radix === 16
@@ -917,6 +921,13 @@ export default class Tokenizer extends LocationParser {
             this.raise(this.state.pos, "Invalid or unexpected token");
           }
 
+          if (!allowNumSeparator) {
+            this.raise(
+              this.state.pos,
+              "Numeric separators are not allowed inside unicode escape sequences or hex escape sequences",
+            );
+          }
+
           // Ignore this _ character
           ++this.state.pos;
           continue;
@@ -1252,7 +1263,7 @@ export default class Tokenizer extends LocationParser {
 
   readHexChar(len: number, throwOnInvalid: boolean): number | null {
     const codePos = this.state.pos;
-    const n = this.readInt(16, len);
+    const n = this.readInt(16, len, false);
     if (n === null) {
       if (throwOnInvalid) {
         this.raise(codePos, "Bad character escape sequence");

packages/babel-parser/test/fixtures/experimental/numeric-separator/invalid-hex/input.js

@@ -0,0 +1 @@
+"\x1_0";

packages/babel-parser/test/fixtures/experimental/numeric-separator/invalid-hex/options.json

@@ -0,0 +1 @@
+{ "throws": "Numeric separators are not allowed inside unicode escape sequences or hex escape sequences (1:4)" }

packages/babel-parser/test/fixtures/experimental/numeric-separator/invalid-unicode-2/input.js

@@ -0,0 +1 @@
+"\u12_34"

packages/babel-parser/test/fixtures/experimental/numeric-separator/invalid-unicode-2/options.json

@@ -0,0 +1 @@
+{ "throws": "Numeric separators are not allowed inside unicode escape sequences or hex escape sequences (1:5)" }

packages/babel-parser/test/fixtures/experimental/numeric-separator/invalid-unicode/input.js

@@ -0,0 +1 @@
+"\u{1F_639}"

packages/babel-parser/test/fixtures/experimental/numeric-separator/invalid-unicode/options.json

@@ -0,0 +1 @@
+{ "throws": "Numeric separators are not allowed inside unicode escape sequences or hex escape sequences (1:6)" }

scripts/tests/test262/test262_whitelist.txt

@@ -104,10 +104,6 @@ language/expressions/object/method-definition/private-name-early-error-gen-insid
 language/expressions/object/method-definition/private-name-early-error-gen-inside-class.js(strict mode)
 language/expressions/object/method-definition/private-name-early-error-method-inside-class.js(default)
 language/expressions/object/method-definition/private-name-early-error-method-inside-class.js(strict mode)
-language/expressions/template-literal/unicode-escape-nls-err.js(default)
-language/expressions/template-literal/unicode-escape-nls-err.js(strict mode)
-language/identifiers/unicode-escape-nls-err.js(default)
-language/identifiers/unicode-escape-nls-err.js(strict mode)
 language/literals/bigint/non-octal-like-invalid-0008n.js(default)
 language/literals/bigint/non-octal-like-invalid-012348n.js(default)
 language/literals/bigint/non-octal-like-invalid-08n.js(default)
@@ -128,10 +124,6 @@ language/literals/numeric/numeric-separators/numeric-separator-literal-nonoctal-
 language/literals/numeric/numeric-separators/numeric-separator-literal-nonoctal-0_8-err.js(default)
 language/literals/numeric/numeric-separators/numeric-separator-literal-nonoctal-0_9-err.js(default)
 language/literals/numeric/numeric-separators/numeric-separator-literal-nzd-nsl-dds-leading-zero-err.js(default)
-language/literals/string/unicode-escape-nls-err-double.js(default)
-language/literals/string/unicode-escape-nls-err-double.js(strict mode)
-language/literals/string/unicode-escape-nls-err-single.js(default)
-language/literals/string/unicode-escape-nls-err-single.js(strict mode)
 language/module-code/privatename-not-valid-earlyerr-module-1.js(default)
 language/module-code/privatename-not-valid-earlyerr-module-1.js(strict mode)
 language/module-code/privatename-not-valid-earlyerr-module-2.js(default)