Enable regexp unicode sets parsing by default

packages/babel-core/src/parser/util/missing-plugin-helper.ts

@@ -106,16 +106,6 @@ const pluginNameMap: Record<
       url: "https://github.com/babel/babel/tree/main/packages/babel-plugin-syntax-record-and-tuple",
     },
   },
-  regexpUnicodeSets: {
-    syntax: {
-      name: "@babel/plugin-syntax-unicode-sets-regex",
-      url: "https://github.com/babel/babel/blob/main/packages/babel-plugin-syntax-unicode-sets-regex/README.md",
-    },
-    transform: {
-      name: "@babel/plugin-proposal-unicode-sets-regex",
-      url: "https://github.com/babel/babel/blob/main/packages/babel-plugin-proposalunicode-sets-regex/README.md",
-    },
-  },
   throwExpressions: {
     syntax: {
       name: "@babel/plugin-syntax-throw-expressions",
@@ -289,6 +279,16 @@ if (!process.env.BABEL_8_BREAKING) {
         url: "https://github.com/babel/babel/tree/main/packages/babel-plugin-proposal-private-property-in-object",
       },
     },
+    regexpUnicodeSets: {
+      syntax: {
+        name: "@babel/plugin-syntax-unicode-sets-regex",
+        url: "https://github.com/babel/babel/blob/main/packages/babel-plugin-syntax-unicode-sets-regex/README.md",
+      },
+      transform: {
+        name: "@babel/plugin-proposal-unicode-sets-regex",
+        url: "https://github.com/babel/babel/blob/main/packages/babel-plugin-proposalunicode-sets-regex/README.md",
+      },
+    },
   });
 }
 

packages/babel-helper-create-regexp-features-plugin/src/features.ts

@@ -3,6 +3,7 @@ export const FEATURES = Object.freeze({
   dotAllFlag: 1 << 1,
   unicodePropertyEscape: 1 << 2,
   namedCaptureGroups: 1 << 3,
+  // Not used, for backward compatibility with syntax-unicode-sets-regex
   unicodeSetsFlag_syntax: 1 << 4,
   unicodeSetsFlag: 1 << 5,
   duplicateNamedCaptureGroups: 1 << 6,

packages/babel-helper-create-regexp-features-plugin/src/util.ts

@@ -33,9 +33,7 @@ export function generateRegexpuOptions(
 
   return {
     unicodeFlag: feat("unicodeFlag"),
-    unicodeSetsFlag:
-      feat<Experimental>("unicodeSetsFlag") ||
-      feat<Experimental>("unicodeSetsFlag_syntax", "parse"),
+    unicodeSetsFlag: feat<Experimental>("unicodeSetsFlag") || "parse",
     dotAllFlag: feat("dotAllFlag"),
     unicodePropertyEscapes: feat("unicodePropertyEscape"),
     namedGroups: feat("namedCaptureGroups") || featDuplicateNamedGroups(),

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

@@ -57,7 +57,6 @@ const VALID_REGEX_FLAGS = new Set([
   charCodes.lowercaseY,
   charCodes.lowercaseU,
   charCodes.lowercaseD,
-  // This is only valid when using the regexpUnicodeSets plugin
   charCodes.lowercaseV,
 ]);
 
@@ -1100,8 +1099,6 @@ export default abstract class Tokenizer extends CommentsParser {
       // @ts-expect-error VALID_REGEX_FLAGS.has should accept expanded type: number
       if (VALID_REGEX_FLAGS.has(cp)) {
         if (cp === charCodes.lowercaseV) {
-          this.expectPlugin("regexpUnicodeSets", nextPos());
-
           if (mods.includes("u")) {
             this.raise(Errors.IncompatibleRegExpUVFlags, { at: nextPos() });
           }

packages/babel-parser/src/typings.d.ts

@@ -34,7 +34,7 @@ export type Plugin =
   | "partialApplication"
   | "placeholders"
   | "privateIn" // Enabled by default
-  | "regexpUnicodeSets"
+  | "regexpUnicodeSets" // Enabled by default
   | "throwExpressions"
   | "topLevelAwait"
   | "v8intrinsic"

packages/babel-parser/typings/babel-parser.d.ts

@@ -38,7 +38,7 @@ type Plugin =
   | "partialApplication"
   | "placeholders"
   | "privateIn" // Enabled by default
-  | "regexpUnicodeSets"
+  | "regexpUnicodeSets" // Enabled by default
   | "throwExpressions"
   | "topLevelAwait"
   | "v8intrinsic"