Saxon

Not confirmed, but from looking at the code, when we compile an instruction, e.g. XSLElement.compile(), we set location information on the compiled instruction by calling StyleElement.allocateLocation(), and this uses the StyleElement itself as the Location object. This means that the source XSLT tree is referenced from the compiled expression tree, and cannot be garbage collected.

When fixing this, we need to check that there aren't any other links holding the source stylesheet tree in memory. At one time the code was carefully designed to avoid this but there may have been other lapses, since it's difficult to test.

It may be appropriate for the Location object to be the source element in cases where tracing is enabled, to make life easier for debuggers.