lib: add Math.sumPrecise type definition (ES2026 / esnext)

Math.sumPrecise is part of the TC39 proposal-math-sum which reached
Stage 4 on 2025-07-28, making it part of ES2026.

Already implemented in Firefox 137+, Safari 18.4, and Bun,
but not yet in V8/Node.js.

Adds src/lib/esnext.math.d.ts with the Math interface extension,
and wires it into esnext.d.ts and libs.json.

Fixes #63427

Author: 827652549

src/compiler/commandLineParser.ts

@@ -249,7 +249,8 @@ const libEntries: [string, string][] = [
     ["esnext.iterator", "lib.es2025.iterator.d.ts"],
     ["esnext.promise", "lib.es2025.promise.d.ts"],
     // ESNext By-feature options
-    ["esnext.array", "lib.esnext.array.d.ts"],
+    ["esnext.array", "lib.esnext.array.d.ts"],
+    ["esnext.math", "lib.esnext.math.d.ts"],
     ["esnext.collection", "lib.esnext.collection.d.ts"],
     ["esnext.date", "lib.esnext.date.d.ts"],
     ["esnext.decorators", "lib.esnext.decorators.d.ts"],

src/compiler/utilities.ts

@@ -1573,6 +1573,9 @@ export const getScriptTargetFeatures: () => ScriptTargetFeatures = /* @__PURE__
             es2025: [
                 "f16round",
             ],
+            esnext: [
+                "sumPrecise",
+            ],
         })),
         Map: new Map(Object.entries({
             es2015: [

src/lib/esnext.d.ts

@@ -9,3 +9,4 @@
 /// <reference lib="esnext.typedarrays" />
 /// <reference lib="esnext.temporal" />
 /// <reference lib="esnext.date" />
+/// <reference lib="esnext.math" />

src/lib/esnext.math.d.ts

@@ -0,0 +1,14 @@
+/// <reference lib="es2015.iterable" />
+
+interface Math {
+    /**
+     * Returns the sum of the values in the iterable using a more precise
+     * summation algorithm than naive floating-point addition.
+     * Returns `-0` if the iterable is empty.
+     * @param numbers An iterable (such as an Array) of numbers.
+     * @throws {TypeError} If `numbers` is not iterable, or if any value in the iterable is not of type `number`.
+     * @throws {RangeError} If the iterable yields 2^53 or more values.
+     * @see https://tc39.es/proposal-math-sum/
+     */
+    sumPrecise(numbers: Iterable<number>): number;
+}

src/lib/libs.json

@@ -87,6 +87,7 @@
         "es2025.promise",
         "es2025.regexp",
         "esnext.array",
+        "esnext.math",
         "esnext.collection",
         "esnext.date",
         "esnext.decorators",

tests/baselines/reference/config/commandLineParsing/parseCommandLine/Parse --lib option with extra comma.js

@@ -30,5 +30,5 @@ CompilerOptions::
   "configFilePath": "/apath/tsconfig.json"
 }
 Errors::
-error TS6046: Argument for '--lib' option must be: 'es5', 'es6', 'es2015', 'es7', 'es2016', 'es2017', 'es2018', 'es2019', 'es2020', 'es2021', 'es2022', 'es2023', 'es2024', 'es2025', 'esnext', 'dom', 'dom.iterable', 'dom.asynciterable', 'webworker', 'webworker.importscripts', 'webworker.iterable', 'webworker.asynciterable', 'scripthost', 'es2015.core', 'es2015.collection', 'es2015.generator', 'es2015.iterable', 'es2015.promise', 'es2015.proxy', 'es2015.reflect', 'es2015.symbol', 'es2015.symbol.wellknown', 'es2016.array.include', 'es2016.intl', 'es2017.arraybuffer', 'es2017.date', 'es2017.object', 'es2017.sharedmemory', 'es2017.string', 'es2017.intl', 'es2017.typedarrays', 'es2018.asyncgenerator', 'es2018.asynciterable', 'es2018.intl', 'es2018.promise', 'es2018.regexp', 'es2019.array', 'es2019.object', 'es2019.string', 'es2019.symbol', 'es2019.intl', 'es2020.bigint', 'es2020.date', 'es2020.promise', 'es2020.sharedmemory', 'es2020.string', 'es2020.symbol.wellknown', 'es2020.intl', 'es2020.number', 'es2021.promise', 'es2021.string', 'es2021.weakref', 'es2021.intl', 'es2022.array', 'es2022.error', 'es2022.intl', 'es2022.object', 'es2022.string', 'es2022.regexp', 'es2023.array', 'es2023.collection', 'es2023.intl', 'es2024.arraybuffer', 'es2024.collection', 'es2024.object', 'es2024.promise', 'es2024.regexp', 'es2024.sharedmemory', 'es2024.string', 'es2025.collection', 'es2025.float16', 'es2025.intl', 'es2025.iterator', 'es2025.promise', 'es2025.regexp', 'esnext.asynciterable', 'esnext.symbol', 'esnext.bigint', 'esnext.weakref', 'esnext.object', 'esnext.regexp', 'esnext.string', 'esnext.float16', 'esnext.iterator', 'esnext.promise', 'esnext.array', 'esnext.collection', 'esnext.date', 'esnext.decorators', 'esnext.disposable', 'esnext.error', 'esnext.intl', 'esnext.sharedmemory', 'esnext.temporal', 'esnext.typedarrays', 'decorators', 'decorators.legacy'.
+error TS6046: Argument for '--lib' option must be: 'es5', 'es6', 'es2015', 'es7', 'es2016', 'es2017', 'es2018', 'es2019', 'es2020', 'es2021', 'es2022', 'es2023', 'es2024', 'es2025', 'esnext', 'dom', 'dom.iterable', 'dom.asynciterable', 'webworker', 'webworker.importscripts', 'webworker.iterable', 'webworker.asynciterable', 'scripthost', 'es2015.core', 'es2015.collection', 'es2015.generator', 'es2015.iterable', 'es2015.promise', 'es2015.proxy', 'es2015.reflect', 'es2015.symbol', 'es2015.symbol.wellknown', 'es2016.array.include', 'es2016.intl', 'es2017.arraybuffer', 'es2017.date', 'es2017.object', 'es2017.sharedmemory', 'es2017.string', 'es2017.intl', 'es2017.typedarrays', 'es2018.asyncgenerator', 'es2018.asynciterable', 'es2018.intl', 'es2018.promise', 'es2018.regexp', 'es2019.array', 'es2019.object', 'es2019.string', 'es2019.symbol', 'es2019.intl', 'es2020.bigint', 'es2020.date', 'es2020.promise', 'es2020.sharedmemory', 'es2020.string', 'es2020.symbol.wellknown', 'es2020.intl', 'es2020.number', 'es2021.promise', 'es2021.string', 'es2021.weakref', 'es2021.intl', 'es2022.array', 'es2022.error', 'es2022.intl', 'es2022.object', 'es2022.string', 'es2022.regexp', 'es2023.array', 'es2023.collection', 'es2023.intl', 'es2024.arraybuffer', 'es2024.collection', 'es2024.object', 'es2024.promise', 'es2024.regexp', 'es2024.sharedmemory', 'es2024.string', 'es2025.collection', 'es2025.float16', 'es2025.intl', 'es2025.iterator', 'es2025.promise', 'es2025.regexp', 'esnext.asynciterable', 'esnext.symbol', 'esnext.bigint', 'esnext.weakref', 'esnext.object', 'esnext.regexp', 'esnext.string', 'esnext.float16', 'esnext.iterator', 'esnext.promise', 'esnext.array', 'esnext.math', 'esnext.collection', 'esnext.date', 'esnext.decorators', 'esnext.disposable', 'esnext.error', 'esnext.intl', 'esnext.sharedmemory', 'esnext.temporal', 'esnext.typedarrays', 'decorators', 'decorators.legacy'.