[BUG] Erroneous error raised by empty array constructor

[joewiz]

Describe the bug

The expression array {} raises the following error:

Index 0 out of bounds for length 0

Expected behavior

The expression is valid and should not raise an error.

(Note that the error also lacks location information.)

To Reproduce

Evaluate a query containing the expression array {}. Given the following query:

xquery version "3.1";

array {}

eXist returns the following error:

Index 0 out of bounds for length 0

BaseX and Saxon return the expected result:

[]

Context (please always complete the following information):

• OS: macOS 10.13.6
• eXist-db version: 5.3.0-SNAPSHOT
• Java Version: JDK 11.0.7+10 (Liberica 2020-04-14 LTS)

Additional context

• How is eXist-db installed? 5.3.0-SNAPSHOT built from source
• Any custom changes in e.g. conf.xml? None.

[joewiz]

The current develop branch (eXist 5.3.0-SNAPSHOT e92ea8f 20200915110349) is still affected.