# E4120

Compiler diagnostic name: `unhandled_error`.

An infix operator application may raise an error, but the error is not handled.

Most error-producing function calls are checked directly at the call site. This
diagnostic is used for operator applications after the operator has been
resolved to a function whose effect may raise. The operation must either handle
the error locally or appear in a context that can propagate it.

This diagnostic is currently tied to an operator-resolution path and is not
monitored by a source-level error-code example.

## Suggestion

Handle the error with `try`/`catch`, or use the operator only inside a function
whose signature permits the raised error.