Improve node provenance in error reporting
Description
Many parts of the codebase create synthetic mapping nodes and then compose onto them in a stack. This MR improves error reporting by clobbering target mapping node provenance when composing, so that the top-most mapping from a non-synthetic source is the one reported.
Changes proposed in this merge request:
- Clobber provenance in mapping node composition
- Test that
This merge request, when approved, will close: #1059 (closed)