[JanFSchulte]

Description

The inner loops over layer functions in the Catapult, Coyote, Libero and Vivado writers reused the name of the outer template line variable. Rename it to func_line, and likewise rename the shadowing loop variable in model_to_dot.

Fixes the newly appearing flake8 errors B045.

Type of change

• Bug fix (non-breaking)
• New feature (non-breaking)
• Breaking change (existing configs, APIs or generated code behave differently)
• New frontend / backend
• New layer / operator support
• New configuration option — a new io_type, Strategy, or config attribute
• Research paper implementation
• Documentation
• Build, CI or tooling
• Refactor / cleanup (no functional change)

Affected areas

Backends:

• Catapult, Coyote, Libero and Vivado are technically affected, but no real change expected
• Backend-independent (core IR, optimizer, hls4ml.model)

Frontends:

• [ ]
• Not related to a frontend

Components:

• IR (layers + model graph) / optimizer passes
• C++ templates / HLS sources under hls4ml/templates/
• Profiling, reporting or the CLI
• Packaging, build or CI

Configurations affected and exercised

Backend	io_type	Strategy	Verified

New configuration axis introduced by this PR (if any):

Impact on generated HLS

• This PR does not change the generated HLS for existing models.
• This PR changes the generated HLS. Numbers below.

Numerical behaviour:

Model / test	Backend & version	Part	Latency (cycles)	II	LUT	FF	DSP	BRAM
before
after

Tests

pre-commit passes now.

Breaking changes and migration

AI assistance disclosure

• None — no AI tool was used.
• Assisted — completion, refactoring, docstrings, tests; design and code are mine.
• Substantial — significant AI-generated portions, reviewed and edited by me.
• Agentic — produced largely end-to-end by an AI agent from my prompts.

Tool(s) and model(s): Claude Opus 5.5

Where it was used: Verified that the pre-commit findings weren't spurious and then fixed them

If anything other than None is ticked, confirm all of the following:

• I am the author of this contribution and take full responsibility for
  it. I have read and understood every line and can explain and defend it
  in review.
• I verified the generated code against real hls4ml and HLS semantics —
  no invented APIs, config keys, pragmas or citations.
• All numbers, logs and test results quoted in this PR come from runs I
  actually performed, not from agent output.
• I have the right to submit this work under the project's licence, and to
  my knowledge it does not reproduce third-party code that would conflict
  with it.
• No AI tool is credited as an author in any commit in this branch.

Checklist

Required:

• I have read the contributing guidelines.
• I installed and ran pre-commit on the files I edited.
• I added tests under test/pytest covering this change (a bug fix should
  add a test that fails on main and passes here).
• I self-reviewed the full diff and it contains no leftover debug code,
  commented-out blocks or unrelated changes.
• The AI assistance disclosure above is complete and accurate.

If applicable:

• Documentation under docs/ updated.
• No new build or synthesis warnings.
• Public API / config schema changes are documented.

Release note

[JanFSchulte]

Ah, this is included in #1599 already.