diff --git a/modules/juce_core/files/juce_FileOutputStream.cpp b/modules/juce_core/files/juce_FileOutputStream.cpp
index 32fa52fdfc..95d7355d5f 100644
--- a/modules/juce_core/files/juce_FileOutputStream.cpp
+++ b/modules/juce_core/files/juce_FileOutputStream.cpp
@@ -119,6 +119,8 @@ bool FileOutputStream::write (const void* const src, const int numBytes)
 
 void FileOutputStream::writeRepeatedByte (uint8 byte, int numBytes)
 {
+    jassert (numBytes >= 0);
+
     if (bytesInBuffer + numBytes < bufferSize)
     {
         memset (buffer + bytesInBuffer, byte, (size_t) numBytes);
diff --git a/modules/juce_core/xml/juce_XmlElement.cpp b/modules/juce_core/xml/juce_XmlElement.cpp
index 9db7d0e51c..d3f6b1d6aa 100644
--- a/modules/juce_core/xml/juce_XmlElement.cpp
+++ b/modules/juce_core/xml/juce_XmlElement.cpp
@@ -219,7 +219,9 @@ void XmlElement::writeElementAsText (OutputStream& outputStream,
                                      const int lineWrapLength) const
 {
     using namespace XmlOutputFunctions;
-    writeSpaces (outputStream, indentationLevel);
+
+    if (indentationLevel >= 0)
+        writeSpaces (outputStream, indentationLevel);
 
     if (! isTextElement())
     {