Hi Andy,
interesting issue. I just tried some other XQuery processors in order to find out how they resolve the name of a local file:
• File: [].xml • Query: base-uri(doc('[].xml'))
• Saxon: FODC0002: Exception thrown by URIResolver: Invalid relative URI {[].xml}: Illegal character in path at index 0: [].xml • Zorba: [err:FODC0005]: "[].xml": invalid URI literal: "91": invalid character c • BaseX: [FODC0005] Invalid document URI: '[].xml'.
I have added an issue in the W3 bug tracker [1]; let's wait for the response.
Christian