Add es-x/no-regexp-duplicate-named-capturing-groups rule

Author: ota-meshi

docs/rules/no-regexp-duplicate-named-capturing-groups.md

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+---
+title: "es-x/no-regexp-duplicate-named-capturing-groups"
+description: "disallow RegExp duplicate named capturing groups"
+---
+
+# es-x/no-regexp-duplicate-named-capturing-groups
+> disallow RegExp duplicate named capturing groups
+
+- ❗ <badge text="This rule has not been released yet." vertical="middle" type="error"> ***This rule has not been released yet.*** </badge>
+
+This rule reports ES2025 [RegExp duplicate named capture groups](https://github.com/tc39/proposal-duplicate-named-capturing-groups) as errors.
+
+## 💡 Examples
+
+⛔ Examples of **incorrect** code for this rule:
+
+<eslint-playground type="bad">
+
+```js
+/*eslint es-x/no-regexp-duplicate-named-capturing-groups: error */
+const r1 = /(?<year>\d{4})-\d{2}|\d{2}-(?<year>\d{4})/
+const r2 = /(?<x>a)|(?<x>b)/
+```
+
+</eslint-playground>
+
+## 📚 References
+
+- [Rule source](https://github.com/eslint-community/eslint-plugin-es-x/blob/master/lib/rules/no-regexp-duplicate-named-capturing-groups.js)
+- [Test source](https://github.com/eslint-community/eslint-plugin-es-x/blob/master/tests/lib/rules/no-regexp-duplicate-named-capturing-groups.js)

lib/rules/no-regexp-duplicate-named-capturing-groups.js

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+"use strict"
+
+const { getSourceCode } = require("eslint-compat-utils")
+const { defineRegExpHandler } = require("../util/define-regexp-handler")
+
+module.exports = {
+    meta: {
+        docs: {
+            description: "disallow RegExp duplicate named capturing groups.",
+            category: "ES2025",
+            recommended: false,
+            url: "http://eslint-community.github.io/eslint-plugin-es-x/rules/no-regexp-duplicate-named-capturing-groups.html",
+        },
+        fixable: null,
+        messages: {
+            forbidden:
+                "ES2025 RegExp duplicate named capturing groups are forbidden.",
+        },
+        schema: [],
+        type: "problem",
+    },
+    create(context) {
+        return defineRegExpHandler(context, (node) => {
+            const found = new Map()
+            return {
+                onPatternEnter() {
+                    found.clear()
+                },
+                onCapturingGroupLeave(start, end, name) {
+                    if (!name) {
+                        return
+                    }
+                    const list = found.get(name)
+                    if (list) {
+                        list.push({ start, end })
+                    } else {
+                        found.set(name, [{ start, end }])
+                    }
+                },
+                onExit() {
+                    for (const [, dupe] of found.values()) {
+                        if (!dupe) {
+                            continue
+                        }
+                        const { start, end } = dupe
+                        const sourceCode = getSourceCode(context)
+                        context.report({
+                            node,
+                            loc:
+                                node.type === "Literal"
+                                    ? {
+                                          start: sourceCode.getLocFromIndex(
+                                              node.range[0] +
+                                                  1 /* slash */ +
+                                                  start,
+                                          ),
+                                          end: sourceCode.getLocFromIndex(
+                                              node.range[0] +
+                                                  1 /* slash */ +
+                                                  end,
+                                          ),
+                                      }
+                                    : null,
+                            messageId: "forbidden",
+                        })
+                    }
+                },
+            }
+        })
+    },
+}

tests/lib/rules/no-regexp-duplicate-named-capturing-groups.js

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+"use strict"
+
+const RuleTester = require("../../tester")
+const rule = require("../../../lib/rules/no-regexp-duplicate-named-capturing-groups.js")
+
+if (!RuleTester.isSupported(2025)) {
+    //eslint-disable-next-line no-console
+    console.log("Skip the tests of no-regexp-duplicate-named-capturing-groups.")
+    return
+}
+
+new RuleTester().run("no-regexp-duplicate-named-capturing-groups", rule, {
+    valid: [
+        String.raw`/(?<x>a)/`,
+        String.raw`/(a)/`,
+        String.raw`/(?<x>a)(?<y>b)/`,
+        String.raw`/(?<x>a)(b)/`,
+        String.raw`/(?<x>a)|(?<y>b)/`,
+        String.raw`new RegExp("(?<x>a)")`,
+        String.raw`new RegExp("(a)")`,
+        String.raw`new RegExp("(?<x>a)(?<y>b)")`,
+        String.raw`new RegExp("(?<x>a)(b)")`,
+        String.raw`new RegExp("(?<x>a)|(?<y>b)")`,
+    ],
+    invalid: [
+        {
+            code: String.raw`/(?<x>a)|(?<x>b)/`,
+            errors: [
+                {
+                    message:
+                        "ES2025 RegExp duplicate named capturing groups are forbidden.",
+                    column: 10,
+                },
+            ],
+        },
+        {
+            code: String.raw`/(?<x>a)|(?<x>b)|(?<x>c)/`,
+            errors: [
+                {
+                    message:
+                        "ES2025 RegExp duplicate named capturing groups are forbidden.",
+                    column: 10,
+                },
+            ],
+        },
+        {
+            code: String.raw`new RegExp("(?<x>a)|(?<x>b)")`,
+            errors: [
+                {
+                    message:
+                        "ES2025 RegExp duplicate named capturing groups are forbidden.",
+                    column: 1,
+                },
+            ],
+        },
+        {
+            code: String.raw`new RegExp("(?<x>a)|(?<x>b)|(?<x>c)")`,
+            errors: [
+                {
+                    message:
+                        "ES2025 RegExp duplicate named capturing groups are forbidden.",
+                    column: 1,
+                },
+            ],
+        },
+        {
+            code: String.raw`/(?<x>a)|(?<y>b)|(?<x>c)/`,
+            errors: [
+                {
+                    message:
+                        "ES2025 RegExp duplicate named capturing groups are forbidden.",
+                    column: 18,
+                },
+            ],
+        },
+    ],
+})