No Import Access Checks

Xtend does not check visibility for imports. It thus generates not-compilable Java out of compilable Xtend. Consider the following examples:

package packageA

final package class Foo {
	
	def static bar(Object o) {
		
	}
	
	def instanceBar() {
		
	}
}

package packageB;

import static packageA.Foo.*

public class ImportTest {

	def badUsage() {
		bar("")
	}
}

This does not create any errors in Xtend, even though Foo is not visible from ImportTest. When building these classes, the corresponding Java code is erroneous:

Java problem: The type packageA.Foo is not visible

and

Java problem: Foo cannot be resolved

Similar errors occur for

package packageB;

import packageA.Foo;

public class ImportTest {

	def badUsage() {
		new Foo().instanceBar()
	}
}

and

package packageB;

import static extension packageA.Foo.*;

public class ImportTest {

	def badUsage() {
		"".bar
	}
}

Neither of these examples produce Xtend errors.

I’m using Xtend IDE version 2.12.0.v20170519-1412

Reproduce the three import examples in the Xtend IDE or build and compare the results with the Java compiler errors described in the issue. Trace the import resolution and visibility-checking entry points, then add validation so inaccessible imports and their usages produce Xtend errors before Java generation.