DebugFileInfo.cs

public class DebugFileInfo {
	Dictionary<StackFrame, string> FrameToLine;
	Dictionary<string, string[]> PathToLines;

	public DebugFileInfo() {
		FrameToLine = new Dictionary<StackFrame, string>();
		PathToLines = new Dictionary<string, string[]>();
	}

	[Conditional("DEBUG")]
	public void SetDebugName(ref string target, int skipFrames) {
		var withoutFileInfo = new StackTrace(1 + skipFrames, fNeedFileInfo: false).GetFrame(0);
		if (TryGetLine(withoutFileInfo, out var line)) {
			target = line;
			return;
		}

		var fullFrame = new StackTrace(1 + skipFrames, fNeedFileInfo: true).GetFrame(0);
		GetLine(withoutFileInfo, fullFrame, out line);
		target = line;
	}

	bool TryGetLine(StackFrame withoutFileInfo, out string line) {
		return FrameToLine.TryGetValue(withoutFileInfo, out line);
	}

	void GetLine(StackFrame withoutFileInfo, StackFrame withFileInfo, out string line) {
		var path = withFileInfo.GetFileName();
		if (!PathToLines.TryGetValue(path, out var lines)) {
			if (!File.Exists(path)) {
				line = default;
				return;
			}

			lines = File.ReadAllLines(path);
			PathToLines.Add(path, lines);
		}

		var fileLineNumber = withFileInfo.GetFileLineNumber();
		var s = lines[fileLineNumber - 1];
		// line = $"{s.Trim()} | {Path.GetFileName(path)}:{fileLineNumber}";
		var col = withFileInfo.GetFileColumnNumber();
		line = $"{s.Substring(col - 1).Trim()} [{fileLineNumber}]";
		FrameToLine.Add(withoutFileInfo, line);
	}
}