# ONNX008: graph-ssa-violation

**Code:** `ONNX008`

**Name:** `graph-ssa-violation`

**Severity:** error

**Category:** spec

**Target:** graph

**Fixable:** No

## Message

Value name is assigned multiple times, violating SSA form.

## Suggestion

Rename values so each name is assigned exactly once.

## Details

Graphs must be in Single Static Assignment (SSA) form, meaning each
value name is assigned exactly once. Multiple assignments to the same
name violate this invariant.