# ONNX102: duplicate-graph-output

**Code:** `ONNX102`

**Name:** `duplicate-graph-output`

**Severity:** error

**Category:** ir

**Target:** graph

**Fixable:** 🔧 Yes

## Message

Duplicate Value object in graph outputs.

## Suggestion

Remove the duplicate Value references from graph outputs, or apply `--fix` to insert Identity nodes with `OutputFixPass`.

## Details

Each Value object in a graph's outputs must appear only once.
In onnx_ir, this checks object identity (not just name equality).

## Example
```python
# Remove duplicate outputs by identity
seen = set()
unique_outputs = []
for output in graph.outputs:
    if id(output) not in seen:
        seen.add(id(output))
        unique_outputs.append(output)
graph.outputs[:] = unique_outputs
```