Confusing error message when redefining input on operation used by other operations

[cgranade]

Describe the bug If an operation DoA is called from another operation DoB, then redefining the signature of DoA in a subsequent cell can result in confusing error messages that appear to refer to lines in the current cell, but that actually refer to lines in the DoB cell.

To Reproduce Steps to reproduce the behavior:

1. Define two operations, DoA and DoB in distinct cells, making sure that DoB calls DoA at least once.
2. In a new cell, redefine DoA and modify its signature.
3. See error

Expected behavior An error message indicating clearly that the compilation error is with respect to DoB, and not the cell currently being executed.

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System information

[guenp]

+1 to fixing this, I ran into this today and it was very confusing.