Warn about unreachable code.

1 files changed, 20 insertions, 0 deletions

diff --git a/liblangutil/SourceLocation.h b/liblangutil/SourceLocation.h
index 840891c2..c461909f 100644
--- a/liblangutil/SourceLocation.h
+++ b/liblangutil/SourceLocation.h
@@ -49,6 +49,26 @@ struct SourceLocation
 
 	bool isEmpty() const { return start == -1 && end == -1; }
 
+	/// @returns the smallest SourceLocation that contains both @param _a and @param _b.
+	/// Assumes that @param _a and @param _b refer to the same source (exception: if the source of either one
+	/// is unset, the source of the other will be used for the result, even if that is unset as well).
+	/// Invalid start and end positions (with value of -1) are ignored (if start or end are -1 for both @param _a and
+	/// @param _b, then start resp. end of the result will be -1 as well).
+	static SourceLocation smallestCovering(SourceLocation _a, SourceLocation const& _b)
+	{
+		if (!_a.source)
+			_a.source = _b.source;
+
+		if (_a.start < 0)
+			_a.start = _b.start;
+		else if (_b.start >= 0 && _b.start < _a.start)
+			_a.start = _b.start;
+		if (_b.end > _a.end)
+			_a.end = _b.end;
+
+		return _a;
+	}
+
 	int start = -1;
 	int end = -1;
 	std::shared_ptr<CharStream> source;