💅 noUnsafePlusOperands is 3.94x slower in 2.5.12 on Zod-inferred form values #11616

Environment information

CLI:
  Version: 2.5.12

Platform:
  CPU Architecture: aarch64
  OS: macos 27.0
  CPU: Apple M1 Max

Environment:
  BIOME_DISTRIBUTION: npm
  JS_RUNTIME_VERSION: v24.12.0
  JS_RUNTIME_NAME: node

Biome Configuration:
  Status: Loaded successfully
  Path: biome.json
  VCS enabled: false
  Enabled rule: nursery/noUnsafePlusOperands

Rule name

nursery/noUnsafePlusOperands

Playground link

https://github.com/jakeleventhal/biome-no-unsafe-plus-operands-perf-repro

The repository pins Biome 2.5.10 and 2.5.12 side by side. Run:

bun install --frozen-lockfile
bun run bench
bun run profile:2.5.10
bun run profile:2.5.12

The analyzed file contains one binary + expression. Its operands come from React Hook Form values whose type is inferred from a minimal Zod schema:

import type { UseFormReturn } from "react-hook-form";
import { z } from "zod";

const formSchema = z.object({
	ounces: z.number().nonnegative(),
	pounds: z.number().nonnegative(),
});

declare const form: UseFormReturn<z.infer<typeof formSchema>>;

export function getWeightInOunces() {
	const ounces = form.watch("ounces");
	const pounds = form.watch("pounds");
	return 16 * pounds + ounces;
}

Five-run averages on the machine above:

That is a 3.75x end-to-end slowdown and a 3.94x increase inside the rule. Removing the binary + removes the expensive rule invocation and reduces the 2.5.12 check to about 52 milliseconds.

Expected result

Biome 2.5.12 should process this expression in roughly the same time as 2.5.10. noUnsafePlusOperands should not spend more than five seconds resolving two numeric React Hook Form values.

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