src/vs/workbench/contrib/mergeEditor/browser/model/mergeEditorModel.ts/MergeEditorModel/getInputResultMapping
class MergeEditorModel:	private getInputResultMapping(inputLinesDiffs: DetailedLineRangeMapping[], resultDiffs: DetailedLineRangeMapping[], inputLineCount: number) {
		const map = DocumentLineRangeMap.betweenOutputs(inputLinesDiffs, resultDiffs, inputLineCount);
		return new DocumentLineRangeMap(
			map.lineRangeMappings.map((m) =>
				m.inputRange.isEmpty || m.outputRange.isEmpty
					? new LineRangeMapping(
						// We can do this because two adjacent diffs have one line in between.
						m.inputRange.deltaStart(-1),
						m.outputRange.deltaStart(-1)
					)
					: m
			),
			map.inputLineCount
		);
	}