Assert that string is being inserted inside the document range.

This would be caught in SplitVector::InsertFromArray but this simplifies the
failure and avoids potential for modifications.

1 files changed, 1 insertions, 0 deletions

diff --git a/src/Document.cxx b/src/Document.cxx
index 8e9c7d8c4..f3dac9aaa 100644
--- a/src/Document.cxx
+++ b/src/Document.cxx
@@ -1485,6 +1485,7 @@ Sci::Position Document::InsertString(Sci::Position position, const char *s, Sci:
 	if (insertLength <= 0) {
 		return 0;
 	}
+	PLATFORM_ASSERT((position >= 0) && (position <= Length()));
 	CheckReadOnly();	// Application may change read only state here
 	if (cb.IsReadOnly()) {
 		return 0;