ONNX039: ref-attr-outside-function

Code: ONNX039

Name: ref-attr-outside-function

Severity: error

Category: spec

Target: graph

Fixable: No

Message

Reference attribute can only appear in function nodes, not in the main graph or its subgraphs.

Suggestion

Use a regular attribute instead, or move this node into a function.

Details

Reference attributes (attr_ref in ONNX protobuf, is_ref() in onnx_ir) are placeholders that refer to function parameters. They are only valid inside function bodies where they bind to attributes passed when the function is called. Using a reference attribute in the main graph or a subgraph is invalid because there is no enclosing function to provide the referenced value.