@Override
	protected void validate(FunctionLocation location) {
		if (location == null) {
			throw new NullPointerException(
				"Cannot create a LocationDescriptor from a null ProgramLocation");
		}

		if (!(programLocation instanceof VariableNameFieldLocation)) {
			throw new AssertException("Unexpected ProgramLocation type - Cannot create a " +
				"LocationDescriptor for type: " + programLocation);
		}
	}
Note: this is the same as {@link #VariableNameLocationDescriptor(ProgramLocation, Program)}
except that it allows you to specify an alternate home location.  This is useful for
finding references to function variable names from operand fields.
Ghidra/Features/Base/src/main/java/ghidra/app/plugin/core/navigation/locationreferences/VariableNameLocationDescriptor.java